Intervertebral Disc
subject: Intervertebral
description: The bodies of adjacent vertebrae are separated and united by an intervertebral disc, which provides padding and allows for movements between adjacent vertebrae. The disc consists of a fibrous outer layer called the anulus fibrosus and a gel-like center called the nucleus pulposus. The intervertebral foramen is the opening formed between adjacent vertebrae for the exit of a spinal nerve.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Cervical Vertebrae
subject: Cervical Vertebrae
description: A typical cervical vertebra has a small body, a bifid spinous process, transverse processes that have a transverse foramen and are curved for spinal nerve passage. The atlas (C1 vertebra) does not have a body or spinous process. It consists of an anterior and a posterior arch and elongated transverse processes. The axis (C2 vertebra) has the upward projecting dens, which articulates with the anterior arch of the atlas.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Thoracic Vertebrae
subject: Thoracic Vertebrae
description: A typical thoracic vertebra is distinguished by the spinous process, which is long and projects downward to overlap the next inferior vertebra. It also has articulation sites (facets) on the vertebral body and a transverse process for rib attachment.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Lumbar Vertebrae
subject: Lumbar Vertebrae
description: Lumbar vertebrae are characterized by having a large, thick body and a short, rounded spinous process.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Sacrum and Coccyx
subject: Sacrum
subject: Coccyx
description: The sacrum is formed from the fusion of five sacral vertebrae, whose lines of fusion are indicated by the transverse ridges. The fused spinous processes form the median sacral crest, while the lateral sacral crest arises from the fused transverse processes. The coccyx is formed by the fusion of four small coccygeal vertebrae.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Herniated Intervertebral Disc
subject: Intervertebral
description: Weakening of the anulus fibrosus can result in herniation (protrusion) of the nucleus pulposus and compression of a spinal nerve, resulting in pain and/or muscle weakness in the body regions supplied by that nerve.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Ligaments of Vertebral Column
subject: Ligaments
subject: Vertebral Column
description: The anterior longitudinal ligament runs the length of the vertebral column, uniting the anterior sides of the vertebral bodies. The supraspinous ligament connects the spinous processes of the thoracic and lumbar vertebrae. In the posterior neck, the supraspinous ligament enlarges to form the nuchal ligament, which attaches to the cervical spinous processes and to the base of the skull.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Rib Articulation in Thoracic Vertebrae
subject: Rib Articulation
subject: Thoracic Vertebrae
description: Thoracic vertebrae have superior and inferior articular facets on the vertebral body for articulation with the head of a rib, and a transverse process facet for articulation with the rib tubercle.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Thoracic Cage
subject: Thoracic Cage
description: The thoracic cage is formed by the (a) sternum and (b) 12 pairs of ribs with their costal cartilages. The ribs are anchored posteriorly to the 12 thoracic vertebrae. The sternum consists of the manubrium, body, and xiphoid process. The ribs are classified as true ribs (1–7) and false ribs (8–12). The last two pairs of false ribs are also known as floating ribs (11–12).
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Newborn Skull
subject: Newborn Skull
description: The bones of the newborn skull are not fully ossified and are separated by large areas called fontanelles, which are filled with fibrous connective tissue. The fontanelles allow for continued growth of the skull after birth. At the time of birth, the facial bones are small and underdeveloped, and the mastoid process has not yet formed.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Pectoral Girdle
subject: Pectoral Girdle
description: The pectoral girdle consists of the clavicle and the scapula, which serve to attach the upper limb to the sternum of the axial skeleton.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Scapula
subject: Scapula
description: The isolated scapula is shown here from its anterior (deep) side and its posterior (superficial) side.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Humerus and Elbow Joint
subject: Humerus
subject: Elbow Joint
description: The humerus is the single bone of the upper arm region. It articulates with the radius and ulna bones of the forearm to form the elbow joint.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Ulna and Radius
subject: Ulna
subject: Radius
description: The ulna is located on the medial side of the forearm, and the radius is on the lateral side. These bones are attached to each other by an interosseous membrane.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Bones of the Wrist and Hand
subject: Bones
subject: Wrist
subject: Hand
description: The eight carpal bones form the base of the hand. These are arranged into proximal and distal rows of four bones each. The metacarpal bones form the palm of the hand. The thumb and fingers consist of the phalanx bones.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Bones of the Hand
subject: Bones
subject: Hand
description: This radiograph shows the position of the bones within the hand. Note the carpal bones that form the base of the hand
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Carpal Tunnel
subject: Carpal Tunnel
description: The carpal tunnel is the passageway by which nine muscle tendons and a major nerve enter the hand from the anterior forearm. The walls and floor of the carpal tunnel are formed by the U-shaped grouping of the carpal bones, and the roof is formed by the flexor retinaculum, a strong ligament that anteriorly unites the bones.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Hand During Gripping
subject: Hand
description: During tight gripping—compare (b) to (a)—the fourth and, particularly, the fifth metatarsal bones are pulled anteriorly. This increases the contact between the object and the medial side of the hand, thus improving the firmness of the grip.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Fractures of the Humerus and Radius
subject: Fractures
subject: Humerus
subject: Radius
description: Falls or direct blows can result in fractures of the surgical neck or shaft of the humerus. Falls onto the elbow can fracture the distal humerus. A Colles fracture of the distal radius is the most common forearm fracture.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Pelvis
subject: Pelvis
description: The pelvic girdle is formed by a single hip bone. The hip bone attaches the lower limb to the axial skeleton through its articulation with the sacrum. The right and left hip bones, plus the sacrum and the coccyx, together form the pelvis.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

The Hip Bone
subject: Bone
description: The adult hip bone consists of three regions. The ilium forms the large, fan-shaped superior portion, the ischium forms the posteroinferior portion, and the pubis forms the anteromedial portion.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Ligaments of the Pelvis
subject: Ligaments
subject: Pelvis
description: The posterior sacroiliac ligament supports the sacroiliac joint. The sacrospinous ligament spans the sacrum to the ischial spine, and the sacrotuberous ligament spans the sacrum to the ischial tuberosity. The sacrospinous and sacrotuberous ligaments contribute to the formation of the greater and lesser sciatic foramens.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Male and Female Pelvis
subject: Male
subject: Female
subject: Pelvis
description: The female pelvis is adapted for childbirth and is broader, with a larger subpubic angle, a rounder pelvic brim, and a wider and more shallow lesser pelvic cavity than the male pelvis.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Femur and Patella
subject: Femur
subject: Patella
description: The femur is the single bone of the thigh region. It articulates superiorly with the hip bone at the hip joint, and inferiorly with the tibia at the knee joint. The patella only articulates with the distal end of the femur.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

The Q-Angle
subject: Q-Angle
description: The Q-angle is a measure of the amount of lateral deviation of the femur from the vertical line of the tibia. Adult females have a larger Q-angle due to their wider pelvis than adult males.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Tibia and Fibula
subject: Tibia
subject: Fibula
description: The tibia is the larger, weight-bearing bone located on the medial side of the leg. The fibula is the slender bone of the lateral side of the leg and does not bear weight.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Bones of the Foot
subject: Bones
subject: Foot
description: The bones of the foot are divided into three groups. The posterior foot is formed by the seven tarsal bones. The mid-foot has the five metatarsal bones. The toes contain the phalanges.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Embryo at Seven Weeks
subject: Embryo
description: Limb buds are visible in an embryo at the end of the seventh week of development (embryo derived from an ectopic pregnancy)
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Clubfoot
subject: Clubfoot
description: Clubfoot This photograph shows a baby with a clubfoot.Clubfoot is a common deformity of the ankle and foot that is present at birth. Most cases are corrected without surgery, and affected individuals will grow up to lead normal, active lives. (credit: James W. Hanson)
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Suture Joints of Skull
subject: Skull
description: The suture joints of the skull are an example of a synarthrosis, an immobile or essentially immobile joint.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Multiaxial Joint
subject: Multiaxial Joint
description: A multiaxial joint, such as the hip joint, allows for three types of movement: anterior-posterior, medial-lateral, and rotational.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Fibrous Joints
subject: Joints
description: Fibrous joints form strong connections between bones. (a) Sutures join most bones of the skull. (b) An interosseous membrane forms a syndesmosis between the radius and ulna bones of the forearm. (c) A gomphosis is a specialized fibrous joint that anchors a tooth to its socket in the jaw.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

The Newborn Skull
subject: Newborn Skull
description: The fontanelles of a newborn’s skull are broad areas of fibrous connective tissue that form fibrous joints between the bones of the skull.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Cartiliginous Joints
subject: Cartiliginous Joints
description: At cartilaginous joints, bones are united by hyaline cartilage to form a synchondrosis or by fibrocartilage to form a symphysis. (a) The hyaline cartilage of the epiphyseal plate (growth plate) forms a synchondrosis that unites the shaft (diaphysis) and end (epiphysis) of a long bone and allows the bone to grow in length. (b) The pubic portions of the right and left hip bones of the pelvis are joined together by fibrocartilage, forming the pubic symphysis.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Synovial Joints
subject: Synovial Joints
description: Synovial joints allow for smooth movements between the adjacent bones. The joint is surrounded by an articular capsule that defines a joint cavity filled with synovial fluid. The articulating surfaces of the bones are covered by a thin layer of articular cartilage. Ligaments support the joint by holding the bones together and resisting excess or abnormal joint motions.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Bursae
subject: Bursae
description: Bursae are fluid-filled sacs that serve to prevent friction between skin, muscle, or tendon and an underlying bone. Three major bursae and a fat pad are part of the complex joint that unites the femur and tibia of the leg.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Types of Synovial Joints
subject: Synovial Joints
description: The six types of synovial joints allow the body to move in a variety of ways. (a) Pivot joints allow for rotation around an axis, such as between the first and second cervical vertebrae, which allows for side-to-side rotation of the head. (b) The hinge joint of the elbow works like a door hinge. (c) The articulation between the trapezium carpal bone and the first metacarpal bone at the base of the thumb is a saddle joint. (d) Plane joints, such as those between the tarsal bones of the foot, allow for limited gliding movements between bones. (e) The radiocarpal joint of the wrist is a condyloid joint. (f) The hip and shoulder joints are the only ball-and-socket joints of the body.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Osteoarthritis
subject: Osteoarthritis
description: Osteoarthritis of a synovial joint results from aging or prolonged joint wear and tear. These cause erosion and loss of the articular cartilage covering the surfaces of the bones, resulting in inflammation that causes joint stiffness and pain.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Movements of the Body, Part 1
subject: Movements
subject: Body
description: Synovial joints give the body many ways in which to move. (a)–(b) Flexion and extension motions are in the sagittal (anterior–posterior) plane of motion. These movements take place at the shoulder, hip, elbow, knee, wrist, metacarpophalangeal, metatarsophalangeal, and interphalangeal joints. (c)–(d) Anterior bending of the head or vertebral column is flexion, while any posterior-going movement is extension. (e) Abduction and adduction are motions of the limbs, hand, fingers, or toes in the coronal (medial–lateral) plane of movement. Moving the limb or hand laterally away from the body, or spreading the fingers or toes, is abduction. Adduction brings the limb or hand toward or across the midline of the body, or brings the fingers or toes together. Circumduction is the movement of the limb, hand, or fingers in a circular pattern, using the sequential combination of flexion, adduction, extension, and abduction motions. Adduction/abduction and circumduction take place at the shoulder, hip, wrist, metacarpophalangeal, and metatarsophalangeal joints. (f) Turning of the head side to side or twisting of the body is rotation. Medial and lateral rotation of the upper limb at the shoulder or lower limb at the hip involves turning the anterior surface of the limb toward the midline of the body (medial or internal rotation) or away from the midline (lateral or external rotation).
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Movements of the Body, Part 2
subject: Movements
subject: Body
description: (g) Supination of the forearm turns the hand to the palm forward position in which the radius and ulna are parallel, while forearm pronation turns the hand to the palm backward position in which the radius crosses over the ulna to form an "X." (h) Dorsiflexion of the foot at the ankle joint moves the top of the foot toward the leg, while plantar flexion lifts the heel and points the toes. (i) Eversion of the foot moves the bottom (sole) of the foot away from the midline of the body, while foot inversion faces the sole toward the midline. (j) Protraction of the mandible pushes the chin forward, and retraction pulls the chin back. (k) Depression of the mandible opens the mouth, while elevation closes it. (l) Opposition of the thumb brings the tip of the thumb into contact with the tip of the fingers of the same hand and reposition brings the thumb back next to the index finger.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Atlantoaxial Joint
subject: Atlantoaxial Joint
description: The atlantoaxial joint is a pivot type of joint between the dens portion of the axis (C2 vertebra) and the anterior arch of the atlas (C1 vertebra), with the dens held in place by a ligament.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Temporomandibular Joint
subject: Temporomandibular Joint
description: The temporomandibular joint is the articulation between the temporal bone of the skull and the condyle of the mandible, with an articular disc located between these bones. During depression of the mandible (opening of the mouth), the mandibular condyle moves both forward and hinges downward as it travels from the mandibular fossa onto the articular tubercle.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Glenohumeral Joint
subject: Glenohumeral Joint
description: The glenohumeral (shoulder) joint is a ball-and-socket joint that provides the widest range of motions. It has a loose articular capsule and is supported by ligaments and the rotator cuff muscles.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Elbow Joint
subject: Elbow Joint
description: (a) The elbow is a hinge joint that allows only for flexion and extension of the forearm. (b) It is supported by the ulnar and radial collateral ligaments. (c) The annular ligament supports the head of the radius at the proximal radioulnar joint, the pivot joint that allows for rotation of the radius.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Hip Joint
subject: Hip Joint
description: (a) The ball-and-socket joint of the hip is a multiaxial joint that provides both stability and a wide range of motion. (b–c) When standing, the supporting ligaments are tight, pulling the head of the femur into the acetabulum.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Knee Joint
subject: Knee Joint
description: (a) The knee joint is the largest joint of the body. (b)–(c) It is supported by the tibial and fibular collateral ligaments located on the sides of the knee outside of the articular capsule, and the anterior and posterior cruciate ligaments found inside the capsule. The medial and lateral menisci provide padding and support between the femoral condyles and tibial condyles.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Knee Injury
subject: Knee Injury
description: A strong blow to the lateral side of the extended knee will cause three injuries, in sequence: tearing of the tibial collateral ligament, damage to the medial meniscus, and rupture of the anterior cruciate ligament.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Ankle Joint
subject: Ankle Joint
description: The talocrural (ankle) joint is a uniaxial hinge joint that only allows for dorsiflexion or plantar flexion of the foot. Movements at the subtalar joint, between the talus and calcaneus bones, combined with motions at other intertarsal joints, enables eversion/inversion movements of the foot. Ligaments that unite the medial or lateral malleolus with the talus and calcaneus bones serve to support the talocrural joint and to resist excess eversion or inversion of the foot.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

The Three Types of Muscle Tissue
subject: Muscle Tissue
description: The body contains three types of muscle tissue: (a) skeletal muscle, (b) smooth muscle, and (c) cardiac muscle.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

The Three Connective Tissue Layers
subject: Connective Tissue
description: Bundles of muscle fibers, called fascicles, are covered by the perimysium. Muscle fibers are covered by the endomysium.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Muscle Fiber
subject: Muscle Fiber
description: A skeletal muscle fiber is surrounded by a plasma membrane called the sarcolemma, which contains sarcoplasm, the cytoplasm of muscle cells. A muscle fiber is composed of many fibrils, which give the cell its striated appearance.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

The Sarcomere
subject: Sarcomere
description: The sarcomere, the region from one Z-line to the next Z-line, is the functional unit of a skeletal muscle fiber.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Motor End-Plate and Innervation
subject: Motor End-Plate
subject: Innervation
description: At the NMJ, the axon terminal releases ACh. The motor end-plate is the location of the ACh-receptors in the muscle fiber sarcolemma. When ACh molecules are released, they diffuse across a minute space called the synaptic cleft and bind to the receptors.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

The T-tubule
subject: T-tubule
description: Narrow T-tubules permit the conduction of electrical impulses. The SR functions to regulate intracellular levels of calcium. Two terminal cisternae (where enlarged SR connects to the T-tubule) and one T-tubule comprise a triad—a “threesome” of membranes, with those of SR on two sides and the T-tubule sandwiched between them.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Contraction of a Muscle Fiber
subject: Muscle Fiber
description: A cross-bridge forms between actin and the myosin heads triggering contraction. As long as Ca++ ions remain in the sarcoplasm to bind to troponin, and as long as ATP is available, the muscle fiber will continue to shorten.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Relaxation of a Muscle Fiber
subject: Muscle Fiber
description: Ca++ ions are pumped back into the SR, which causes the tropomyosin to reshield the binding sites on the actin strands. A muscle may also stop contracting when it runs out of ATP and becomes fatigued.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

The Sliding Filament Model of Muscle Contraction
subject: Muscle Contraction
subject: Filament
description: When a sarcomere contracts, the Z lines move closer together, and the I band becomes smaller. The A band stays the same width. At full contraction, the thin and thick filaments overlap completely.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Skeletal Muscle Contraction
subject: Skeletal Muscle Contraction
description: (a) The active site on actin is exposed as calcium binds to troponin. (b) The myosin head is attracted to actin, and myosin binds actin at its actin-binding site, forming the cross-bridge. (c) During the power stroke, the phosphate generated in the previous contraction cycle is released. This results in the myosin head pivoting toward the center of the sarcomere, after which the attached ADP and phosphate group are released. (d) A new molecule of ATP attaches to the myosin head, causing the cross-bridge to detach. (e) The myosin head hydrolyzes ATP to ADP and phosphate, which returns the myosin to the cocked position.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Muscle Metabolism
subject: Muscle Metabolism
description: (a) Some ATP is stored in a resting muscle. As contraction starts, it is used up in seconds. More ATP is generated from creatine phosphate for about 15 seconds. (b) Each glucose molecule produces two ATP and two molecules of pyruvic acid, which can be used in aerobic respiration or converted to lactic acid. If oxygen is not available, pyruvic acid is converted to lactic acid, which may contribute to muscle fatigue. This occurs during strenuous exercise when high amounts of energy are needed but oxygen cannot be sufficiently delivered to muscle. (c) Aerobic respiration is the breakdown of glucose in the presence of oxygen (O2) to produce carbon dioxide, water, and ATP. Approximately 95 percent of the ATP required for resting or moderately active muscles is provided by aerobic respiration, which takes place in mitochondria.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Types of Muscle Contractions
subject: Muscle Contractions
description: During isotonic contractions, muscle length changes to move a load. During isometric contractions, muscle length does not change because the load exceeds the tension the muscle can generate.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Atrophy
subject: Atrophy
description: Muscle mass is reduced as muscles atrophy with disuse.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Cardiac Muscle
subject: Cardiac Muscle
description: Intercalated discs are part of the cardiac muscle sarcolemma and they contain gap junctions and desmosomes.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Smooth Muscle Tissue
subject: Smooth Muscle Tissue
description: Smooth muscle tissue is found around organs in the digestive, respiratory, reproductive tracts and the iris of the eye.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Muscle Contraction
subject: Muscle Contraction
description: The dense bodies and intermediate filaments are networked through the sarcoplasm, which cause the muscle fiber to contract.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Motor Units
subject: Motor Units
description: A series of axon-like swelling, called varicosities or “boutons,” from autonomic neurons form motor units through the smooth muscle.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Prime Movers and Synergists
subject: Prime Movers
subject: Synergists
description: The biceps brachii flex the lower arm. The brachoradialis, in the forearm, and brachialis, located deep to the biceps in the upper arm, are both synergists that aid in this motion.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Muscle Shapes and Fiber Alignment
subject: Muscle Shapes
subject: Fiber Alignment
description: The skeletal muscles of the body typically come in seven different general shapes.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Overview of the Muscular System
subject: Muscular System
description: On the anterior and posterior views of the muscular system above, superficial muscles (those at the surface) are shown on the right side of the body while deep muscles (those underneath the superficial muscles) are shown on the left half of the body. For the legs, superficial muscles are shown in the anterior view while the posterior view shows both superficial and deep muscles.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Muscles of Facial Expression
subject: Muscles
description: Many of the muscles of facial expression insert into the skin surrounding the eyelids, nose and mouth, producing facial expressions by moving the skin rather than bones.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Muscles of the Eyes
subject: Muscles
subject: Eyes
description: (a) The extrinsic eye muscles originate outside of the eye on the skull. (b) Each muscle inserts onto the eyeball.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Muscles That Move the Lower Jaw
subject: Muscles
subject: Lower Jaw
description: The muscles that move the lower jaw are typically located within the cheek and originate from processes in the skull. This provides the jaw muscles with the large amount of leverage needed for chewing.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Muscles That Move the Tongue
subject: Muscles
subject: Tongue
description: Tongue muscles can be extrinsic or intrinsic. Extrinsic tongue muscles insert into the tongue from outside origins, and the intrinsic tongue muscles insert into the tongue from origins within it. The extrinsic muscles move the whole tongue in different directions, whereas the intrinsic muscles allow the tongue to change its shape (such as, curling the tongue in a loop or flattening it).
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Muscles of the Anterior Neck
subject: Muscles
subject: Anterior Neck
description: The anterior muscles of the neck facilitate swallowing and speech. The suprahyoid muscles originate from above the hyoid bone in the chin region. The infrahyoid muscles originate below the hyoid bone in the lower neck.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Posterior and Lateral Views of the Neck
subject: Posterior
subject: Neck
description: The superficial and deep muscles of the neck are responsible for moving the head, cervical vertebrae, and scapulas.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Muscles of the Neck and Back
subject: Muscles
subject: Neck
subject: Back
description: The large, complex muscles of the neck and back move the head, shoulders, and vertebral column.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Muscles of the Abdomen
subject: Muscles of the Abdomen
description: (a) The anterior abdominal muscles include the medially located rectus abdominis, which is covered by a sheet of connective tissue called the rectus sheath. On the flanks of the body, medial to the rectus abdominis, the abdominal wall is composed of three layers. The external oblique muscles form the superficial layer, while the internal oblique muscles form the middle layer, and the transverses abdominus forms the deepest layer. (b) The muscles of the lower back move the lumbar spine but also assist in femur movements.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Muscles of the Diaphragm
subject: Muscles of the Diaphragm
description: The diaphragm separates the thoracic and abdominal cavities.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Intercostal Muscles
subject: Intercostal Muscles
description: The external intercostals are located laterally on the sides of the body. The internal intercostals are located medially near the sternum. The innermost intercostals are located deep to both the internal and external intercostals.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Muscles of the Pelvic Floor
subject: Muscles of the Pelvic Floor
description: The pelvic floor muscles support the pelvic organs, resist intra-abdominal pressure, and work as sphincters for the urethra, rectum, and vagina.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Muscles That Position the Pectoral Girdle
subject: Muscles
subject: Pectoral Girdle
description: The muscles that stabilize the pectoral girdle make it a steady base on which other muscles can move the arm. Note that the pectoralis major and deltoid, which move the humerus, are cut here to show the deeper positioning muscles.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Muscles That Move the Humerus
subject: Muscles That Move the Humerus
description: (a, c) The muscles that move the humerus anteriorly are generally located on the anterior side of the body and originate from the sternum (e.g., pectoralis major) or the anterior side of the scapula (e.g., subscapularis). (b) The muscles that move the humerus superiorly generally originate from the superior surfaces of the scapula and/or the clavicle (e.g., deltoids). The muscles that move the humerus inferiorly generally originate from middle or lower back (e.g., latissiumus dorsi). (d) The muscles that move the humerus posteriorly are generally located on the posterior side of the body and insert into the scapula (e.g., infraspinatus).
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Muscles That Move the Forearm
subject: Muscles
subject: Forearm
description: The muscles originating in the upper arm flex, extend, pronate, and supinate the forearm. The muscles originating in the forearm move the wrists, hands, and fingers.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Intrinsic Muscles of the Hand
subject: Intrinsic Muscles of the Hand
description: The intrinsic muscles of the hand both originate and insert within the hand. These muscles provide the fine motor control of the fingers by flexing, extending, abducting, and adducting the more distal finger and thumb segments.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Hip and Thigh Muscles
subject: Hip
subject: Thigh Muscles
description: The large and powerful muscles of the hip that move the femur generally originate on the pelvic girdle and insert into the femur. The muscles that move the lower leg typically originate on the femur and insert into the bones of the knee joint. The anterior muscles of the femur extend the lower leg but also aid in flexing the thigh. The posterior muscles of the femur flex the lower leg but also aid in extending the thigh. A combination of gluteal and thigh muscles also adduct, abduct, and rotate the thigh and lower leg.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Intrinsic Muscles of the Foot
subject: Intrinsic Muscles of the Foot
description: The muscles along the dorsal side of the foot (a) generally extend the toes while the muscles of the plantar side of the foot (b, c, d) generally flex the toes. The plantar muscles exist in three layers, providing the foot the strength to counterbalance the weight of the body. In this diagram, these three layers are shown from a plantar view beginning with the bottom-most layer just under the plantar skin of the foot (b) and ending with the top-most layer (d) located just inferior to the foot and toe bones.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Muscles of the Lower Leg
subject: Muscles of the Lower Leg
description: The muscles of the anterior compartment of the lower leg are generally responsible for dorsiflexion, and the muscles of the posterior compartment of the lower leg are generally responsible for plantar flexion. The lateral and medial muscles in both compartments invert, evert, and rotate the foot.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Central and Peripheral Nervous System
subject: Central Nervous System
subject: Peripheral Nervous System
description: The structures of the PNS are referred to as ganglia and nerves, which can be seen as distinct structures. The equivalent structures in the CNS are not obvious from this overall perspective and are best examined in prepared tissue under the microscope.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

What Is a Nucleus
subject: Nucleus
description: (a) The nucleus of an atom contains its protons and neutrons. (b) The nucleus of a cell is the organelle that contains DNA. (c) A nucleus in the CNS is a localized center of function with the cell bodies of several neurons, shown here circled in red
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Optic Nerve Versus Optic Tract
subject: Optic Nerve
subject: Optic Tract
description: This drawing of the connections of the eye to the brain shows the optic nerve extending from the eye to the chiasm, where the structure continues as the optic tract. The same axons extend from the eye to the brain through these two bundles of fibers, but the chiasm represents the border between peripheral and central.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Somatic, Autonomic, and Enteric Structures of the Nervous System
subject: Somatic
subject: Autonomic
subject: Enteric Structures
subject: Nervous System
description: Somatic structures include the spinal nerves, both motor and sensory fibers, as well as the sensory ganglia (posterior root ganglia and cranial nerve ganglia). Autonomic structures are found in the nerves also, but include the sympathetic and parasympathetic ganglia. The enteric nervous system includes the nervous tissue within the organs of the digestive tract.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Parts of a Neuron
subject: Neuron
description: The major parts of the neuron are labeled on a multipolar neuron from the CNS.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Neuron Classification by Shape
subject: Neuron Classification
description: Unipolar cells have one process that includes both the axon and dendrite. Bipolar cells have two processes, the axon and a dendrite. Multipolar cells have more than two processes, the axon and two or more dendrites.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Other Neuron Classifications
subject: Neuron Classifications
description: Three examples of neurons that are classified on the basis of other criteria. (a) The pyramidal cell is a multipolar cell with a cell body that is shaped something like a pyramid. (b) The Purkinje cell in the cerebellum was named after the scientist who originally described it. (c) Olfactory neurons are named for the functional group with which they belong.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Glial Cells of the CNS
subject: Glial Cells
description: The CNS has astrocytes, oligodendrocytes, microglia, and ependymal cells that support the neurons of the CNS in several ways.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Glial Cells of the PNS
subject: Glial Cells
description: The PNS has satellite cells and Schwann cells.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

The Process of Myelination
subject: Process of Myelination
description: Myelinating glia wrap several layers of cell membrane around the cell membrane of an axon segment. A single Schwann cell insulates a segment of a peripheral nerve, whereas in the CNS, an oligodendrocyte may provide insulation for a few separate axon segments
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Testing the Water
subject: Testing the Water
description: (1) The sensory neuron has endings in the skin that sense a stimulus such as water temperature. The strength of the signal that starts here is dependent on the strength of the stimulus. (2) The graded potential from the sensory endings, if strong enough, will initiate an action potential at the initial segment of the axon (which is immediately adjacent to the sensory endings in the skin). (3) The axon of the peripheral sensory neuron enters the spinal cord and contacts another neuron in the gray matter. The contact is a synapse where another graded potential is caused by the release of a chemical signal from the axon terminals. (4) An action potential is initiated at the initial segment of this neuron and travels up the sensory pathway to a region of the brain called the thalamus. Another synapse passes the information along to the next neuron. (5) The sensory pathway ends when the signal reaches the cerebral cortex. (6) After integration with neurons in other parts of the cerebral cortex, a motor command is sent from the precentral gyrus of the frontal cortex. (7) The upper motor neuron sends an action potential down to the spinal cord. The target of the upper motor neuron is the dendrites of the lower motor neuron in the gray matter of the spinal cord. (8) The axon of the lower motor neuron emerges from the spinal cord in a nerve and connects to a muscle through a neuromuscular junction to cause contraction of the target muscle.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

The Sensory Input
subject: Sensory Input
description: Receptors in the skin sense the temperature of the water.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

The Motor Response
subject: Motor Response
description: On the basis of the sensory input and the integration in the CNS, a motor response is formulated and executed.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Cell Membrane and Transmembrane Proteins
subject: Cell Membrane and Transmembrane Proteins
subject: Transmembrane Proteins
description: The cell membrane is composed of a phospholipid bilayer and has many transmembrane proteins, including different types of channel proteins that serve as ion channels.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Ligand-Gated Channels
subject: Ligand-Gated Channels
description: When the ligand, in this case the neurotransmitter acetylcholine, binds to a specific location on the extracellular surface of the channel protein, the pore opens to allow select ions through. The ions, in this case, are cations of sodium, calcium, and potassium.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Voltage-Gated Channels
subject: Voltage-Gated Channels
description: Voltage-gated channels open when the transmembrane voltage changes around them. Amino acids in the structure of the protein are sensitive to charge and cause the pore to open to the selected ion.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Leakage Channels
subject: Leakage Channels
description: In certain situations, ions need to move across the membrane randomly. The particular electrical properties of certain cells are modified by the presence of this type of channel.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Graded Potentials
subject: Graded Potentials
description: Graded potentials are temporary changes in the membrane voltage, the characteristics of which depend on the size of the stimulus. Some types of stimuli cause depolarization of the membrane, whereas others cause hyperpolarization. It depends on the specific ion channels that are activated in the cell membrane.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

The Synapse
subject: Synapse
description: The synapse is a connection between a neuron and its target cell (which is not necessarily a neuron). The presynaptic element is the synaptic end bulb of the axon where Ca2+ enters the bulb to cause vesicle fusion and neurotransmitter release. The neurotransmitter diffuses across the synaptic cleft to bind to its receptor. The neurotransmitter is cleared from the synapse either by enzymatic degradation, neuronal reuptake, or glial reuptake.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Receptor Types
subject: Receptor Types
description: (a) An ionotropic receptor is a channel that opens when the neurotransmitter binds to it. (b) A metabotropic receptor is a complex that causes metabolic changes in the cell when the neurotransmitter binds to it (1). After binding, the G protein hydrolyzes GTP and moves to the effector protein (2). When the G protein contacts the effector protein, a second messenger is generated, such as cAMP (3). The second messenger can then go on to cause changes in the neuron, such as opening or closing ion channels, metabolic changes, and changes in gene transcription.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Early Embryonic Development of Nervous System
subject: Embryonic
subject: Nervous System
description: The neuroectoderm begins to fold inward to form the neural groove. As the two sides of the neural groove converge, they form the neural tube, which lies beneath the ectoderm. The anterior end of the neural tube will develop into the brain, and the posterior portion will become the spinal cord. The neural crest develops into peripheral structures.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Primary and Secondary Vesicle Stages of Development
subject: Primary and Secondary Vesicle Stages
description: The embryonic brain develops complexity through enlargements of the neural tube called vesicles; (a) The primary vesicle stage has three regions, and (b) the secondary vesicle stage has five regions.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Spinal Bifida
subject: Spinal Bifida
description: (a) Spina bifida is a birth defect of the spinal cord caused when the neural tube does not completely close, but the rest of development continues. The result is the emergence of meninges and neural tissue through the vertebral column. (b) Fetal myelomeningocele is evident in this ultrasound taken at 21 weeks.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

The Cerebrum
subject: Cerebrum
description: The cerebrum is a large component of the CNS in humans, and the most obvious aspect of it is the folded surface called the cerebral cortex.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Lobes of the Cerebral Cortex
subject: Lobes of the Cerebral Cortex
description: The cerebral cortex is divided into four lobes. Extensive folding increases the surface area available for cerebral functions.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Brodmann's Areas of the Cerebral Cortex
subject: Brodmann's of the Cerebral Cortex
description: Brodmann mapping of functionally distinct regions of the cortex was based on its cytoarchitecture at a microscopic level.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Frontal Section of Cerebral Cortex and Basal Nuclei
subject: Frontal of Cerebral Cortex
subject: Basal Nuclei
description: The major components of the basal nuclei, shown in a frontal section of the brain, are the caudate (just lateral to the lateral ventricle), the putamen (inferior to the caudate and separated by the large white-matter structure called the internal capsule), and the globus pallidus (medial to the putamen).
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

The Diencephalon
subject: Diencephalon
description: The diencephalon is composed primarily of the thalamus and hypothalamus, which together define the walls of the third ventricle. The thalami are two elongated, ovoid structures on either side of the midline that make contact in the middle. The hypothalamus is inferior and anterior to the thalamus, culminating in a sharp angle to which the pituitary gland is attached.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

The Brain Stem
subject: Brain Stem
description: The brain stem comprises three regions: the midbrain, the pons, and the medulla.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

The Cerebellum
subject: Cerebellum
description: The cerebellum is situated on the posterior surface of the brain stem. Descending input from the cerebellum enters through the large white matter structure of the pons. Ascending input from the periphery and spinal cord enters through the fibers of the inferior olive. Output goes to the midbrain, which sends a descending signal to the spinal cord.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Cross-section of Spinal Cord
subject: Cross-section of Spinal Cord
description: The cross-section of a thoracic spinal cord segment shows the posterior, anterior, and lateral horns of gray matter, as well as the posterior, anterior, and lateral columns of white matter
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Circle of Willis
subject: Circle of Willis
description: The blood supply to the brain enters through the internal carotid arteries and the vertebral arteries, eventually giving rise to the circle of Willis.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Dural Sinuses and Veins
subject: Dural Sinuses
subject: Veins
description: Blood drains from the brain through a series of sinuses that connect to the jugular veins.
contributor: Cut Rita Zahara
rights: Creative Commons

Cerebrospinal Fluid Circulation
subject: Cerebrospinal Fluid Circulation
description: The choroid plexus in the four ventricles produce CSF, which is circulated through the ventricular system and then enters the subarachnoid space through the median and lateral apertures. The CSF is then reabsorbed into the blood at the arachnoid granulations, where the arachnoid membrane emerges into the dural sinuses.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Dorsal Root Ganglion
subject: Dorsal Root Ganglion
description: The cell bodies of sensory neurons, which are unipolar neurons by shape, are seen in this photomicrograph. Also, the fibrous region is composed of the axons of these neurons that are passing through the ganglion to be part of the dorsal nerve root (tissue source: canine)
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Spinal Cord and Root Ganglion
subject: Spinal Cord and Root Ganglion
description: The slide includes both a cross-section of the lumbar spinal cord and a section of the dorsal root ganglion (see also [link]) (tissue source: canine).
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Nerve Structure
subject: Nerve Structure
description: The structure of a nerve is organized by the layers of connective tissue on the outside, around each fascicle, and surrounding the individual nerve fibers (tissue source: simian).
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Close-Up of Nerve Trunk
subject: Close-Up of Nerve Trunk
description: Zoom in on this slide of a nerve trunk to examine the endoneurium, perineurium, and epineurium in greater detail (tissue source: simian).
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

The Cranial Nerves
subject: Cranial Nerves
description: The anatomical arrangement of the roots of the cranial nerves observed from an inferior view of the brain.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Nerve Plexuses of the Body
subject: Nerve Plexuses
description: There are four main nerve plexuses in the human body. The cervical plexus supplies nerves to the posterior head and neck, as well as to the diaphragm. The brachial plexus supplies nerves to the arm. The lumbar plexus supplies nerves to the anterior leg. The sacral plexus supplies nerves to the posterior leg.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Receptor Classification by Cell Type
subject: Receptor Classification
subject: Cell
description: Receptor cell types can be classified on the basis of their structure. Sensory neurons can have either (a) free nerve endings or (b) encapsulated endings. Photoreceptors in the eyes, such as rod cells, are examples of (c) specialized receptor cells. These cells release neurotransmitters onto a bipolar cell, which then synapses with the optic nerve neurons.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

The Tongue
subject: Tongue
description: The tongue is covered with small bumps, called papillae, which contain taste buds that are sensitive to chemicals in ingested food or drink. Different types of papillae are found in different regions of the tongue. The taste buds contain specialized gustatory receptor cells that respond to chemical stimuli dissolved in the saliva. These receptor cells activate sensory neurons that are part of the facial and glossopharyngeal nerves.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

The Olfactory System
subject: Olfactory System
description: (a) The olfactory system begins in the peripheral structures of the nasal cavity. (b) The olfactory receptor neurons are within the olfactory epithelium. (c) Axons of the olfactory receptor neurons project through the cribriform plate of the ethmoid bone and synapse with the neurons of the olfactory bulb (tissue source: simian).
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Structures of the Ear
subject: Ear
description: The external ear contains the auricle, ear canal, and tympanic membrane. The middle ear contains the ossicles and is connected to the pharynx by the Eustachian tube. The inner ear contains the cochlea and vestibule, which are responsible for audition and equilibrium, respectively.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Transmission of Sound Waves to Cochlea
subject: Sound Waves
subject: Cochlea
description: A sound wave causes the tympanic membrane to vibrate. This vibration is amplified as it moves across the malleus, incus, and stapes. The amplified vibration is picked up by the oval window causing pressure waves in the fluid of the scala vestibuli and scala tympani. The complexity of the pressure waves is determined by the changes in amplitude and frequency of the sound waves entering the ear.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Cross Section of the Cochlea
subject: Cochlea
description: The three major spaces within the cochlea are highlighted. The scala tympani and scala vestibuli lie on either side of the cochlear duct. The organ of Corti, containing the mechanoreceptor hair cells, is adjacent to the scala tympani, where it sits atop the basilar membrane.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Hair Cell
subject: Hair Cell
description: The hair cell is a mechanoreceptor with an array of stereocilia emerging from its apical surface. The stereocilia are tethered together by proteins that open ion channels when the array is bent toward the tallest member of their array, and closed when the array is bent toward the shortest member of their array.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Cochlea and Organ of Corti
subject: Cochlea
subject: Organ of Corti
description: a given region of the basilar membrane will only move if the incoming sound is at a specific frequency. Because the tectorial membrane only moves where the basilar membrane moves, the hair cells in this region will also only respond to sounds of this specific frequency. Therefore, as the frequency of a sound changes, different hair cells are activated all along the basilar membrane. The cochlea encodes auditory stimuli for frequencies between 20 and 20,000 Hz, which is the range of sound that human ears can detect. The unit of Hertz measures the frequency of sound waves in terms of cycles produced per second. Frequencies as low as 20 Hz are detected by hair cells at the apex, or tip, of the cochlea. Frequencies in the higher ranges of 20 KHz are encoded by hair cells at the base of the cochlea, close to the round and oval windows ([link]). Most auditory stimuli contain a mixture of sounds at a variety of frequencies and intensities (represented by the amplitude of the sound wave). The hair cells along the length of the cochlear duct, which are each sensitive to a particular frequency, allow the cochlea to separate auditory stimuli by frequency, just as a prism separates visible light into its component colors.
contributor: Cut Rita Zahara
rights: Craetive Commons
type: Image

Frequency Coding in the Cochlea
subject: Frequency Coding
subject: Cochlea
description: The standing sound wave generated in the cochlea by the movement of the oval window deflects the basilar membrane on the basis of the frequency of sound. Therefore, hair cells at the base of the cochlea are activated only by high frequencies, whereas those at the apex of the cochlea are activated only by low frequencies.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Linear Acceleration Coding by Maculae
subject: Maculae
description: The maculae are specialized for sensing linear acceleration, such as when gravity acts on the tilting head, or if the head starts moving in a straight line. The difference in inertia between the hair cell stereocilia and the otolithic membrane in which they are embedded leads to a shearing force that causes the stereocilia to bend in the direction of that linear acceleration.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Rotational Coding by Semicircular Canals
subject: Semicircular Canals
description: Rotational movement of the head is encoded by the hair cells in the base of the semicircular canals. As one of the canals moves in an arc with the head, the internal fluid moves in the opposite direction, causing the cupula and stereocilia to bend. The movement of two canals within a plane results in information about the direction in which the head is moving, and activation of all six canals can give a very precise indication of head movement in three dimensions.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

The Eye in the Orbit
subject: Eye
subject: Orbit
description: The eye is located within the orbit and surrounded by soft tissues that protect and support its function. The orbit is surrounded by cranial bones of the skull.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Extraocular Muscles
subject: Extraocular Muscles
description: The extraocular muscles move the eye within the orbit.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Structure of the Eye
subject: Eye
description: The sphere of the eye can be divided into anterior and posterior chambers. The wall of the eye is composed of three layers: the fibrous tunic, vascular tunic, and neural tunic. Within the neural tunic is the retina, with three layers of cells and two synaptic layers in between. The center of the retina has a small indentation known as the fovea.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Photoreceptor
subject: Photoreceptor
description: (a) All photoreceptors have inner segments containing the nucleus and other important organelles and outer segments with membrane arrays containing the photosensitive opsin molecules. Rod outer segments are long columnar shapes with stacks of membrane-bound discs that contain the rhodopsin pigment. Cone outer segments are short, tapered shapes with folds of membrane in place of the discs in the rods. (b) Tissue of the retina shows a dense layer of nuclei of the rods and cones.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Retinal Isomers
subject: Retinal Isomers
description: The retinal molecule has two isomers, (a) one before a photon interacts with it and (b) one that is altered through photoisomerization.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Comparison of Color Sensitivity of Photopigments
subject: Color
subject: Photopigments
description: Comparing the peak sensitivity and absorbance spectra of the four photopigments suggests that they are most sensitive to particular wavelengths.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Ascending Sensory Pathways of the Spinal Cord
subject: Sensory Pathways
subject: Spinal Cord
description: The dorsal column system and spinothalamic tract are the major ascending pathways that connect the periphery with the brain.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Auditory Brain Stem Mechanisms of Sound Localization
subject: Brain Stem
subject: Sound
description: Localizing sound in the horizontal plane is achieved by processing in the medullary nuclei of the auditory system. Connections between neurons on either side are able to compare very slight differences in sound stimuli that arrive at either ear and represent interaural time and intensity differences.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Vestibulo-ocular Reflex
subject: Vestibulo-ocular Reflex
description: Connections between the vestibular system and the cranial nerves controlling eye movement keep the eyes centered on a visual stimulus, even though the head is moving. During head movement, the eye muscles move the eyes in the opposite direction as the head movement, keeping the visual stimulus centered in the field of view.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Segregation of Visual Field Information at the Optic Chiasm
subject: Optic Chiasm
description: Contralateral visual field information from the lateral retina projects to the ipsilateral brain, whereas ipsilateral visual field information has to decussate at the optic chiasm to reach the opposite side of the brain.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

The Sensory Homunculus
subject: Sensory Homunculus
description: A cartoon representation of the sensory homunculus arranged adjacent to the cortical region in which the processing takes place.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Topographic Mapping of the Retina onto the Visual Cortex
subject: Retina
subject: Cortex
description: The visual field projects onto the retina through the lenses and falls on the retinae as an inverted, reversed image. The topography of this image is maintained as the visual information travels through the visual pathway to the cortex.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Retinal Disparity
subject: Retinal Disparity
description: Because of the interocular distance, which results in objects of different distances falling on different spots of the two retinae, the brain can extract depth perception from the two-dimensional information of the visual field.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Ventral and Dorsal Visual Streams
subject: Ventral and Dorsal
description: From the primary visual cortex in the occipital lobe, visual processing continues in two streams—one into the temporal lobe and one into the parietal lobe.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Corticospinal Tract
subject: Corticospinal Tract
description: The major descending tract that controls skeletal muscle movements is the corticospinal tract. It is composed of two neurons, the upper motor neuron and the lower motor neuron. The upper motor neuron has its cell body in the primary motor cortex of the frontal lobe and synapses on the lower motor neuron, which is in the ventral horn of the spinal cord and projects to the skeletal muscle in the periphery.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Connections of Parasympathetic Division of the Autonomic Nervous System
subject: Parasympathetic
subject: Nervous System
description: Neurons from brain-stem nuclei, or from the lateral horn of the sacral spinal cord, project to terminal ganglia near or within the various organs of the body. Axons from these ganglionic neurons then project the short distance to those target effectors.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Autonomic Varicosities
subject: Autonomic Varicosities
description: The connection between autonomic fibers and target effectors is not the same as the typical synapse, such as the neuromuscular junction. Instead of a synaptic end bulb, a neurotransmitter is released from swellings along the length of a fiber that makes an extended network of connections in the target effector.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Comparison of Somatic and Visceral Reflexes
subject: Somatic and Visceral Reflexes
description: The afferent inputs to somatic and visceral reflexes are essentially the same, whereas the efferent branches are different. Somatic reflexes, for instance, involve a direct connection from the ventral horn of the spinal cord to the skeletal muscle. Visceral reflexes involve a projection from the central neuron to a ganglion, followed by a second projection from the ganglion to the target effector.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Genetika dan Sel
description: Open Educational Resource (OER) Unsyiah adalah satu satu Portal yang dikembangkan oleh Perpustakaan Universitas Syiah Kuala. OER Unsyiah berbasis Open Acces untuk siapa saja dan di mana saja. Bahkan Kami juga akan menerima kontribusi yang ingin ikut berpartisipasi dalam OER Unsyiah: http://uilis.unsyiah.ac.id/oer/contribution. Di sini, Kami menyediakan berbagai bentuk Course, seperti Textbook, Video, Audio, dan sebagainnya dengan berbagai bidang materi yang bervariasi. Namun, yang perlu diketahui bahwa OER Unsyiah berLisensi Creative Commons. Nah, bagi yang berkenan atau ingin mempelajari berbagai bidang materi mari kunjungi link UPT. Perpustakaan Unsyiah: http://uilis.unsyiah.ac.id/oer/ http://uilis.unsyiah.ac.id/ http://uilis.unsyiah.ac.id/oer/ https://www.facebook.com/groups/pustaka.unsyiah/ https://www.youtube.com/channel/UCvOxlI8WMHLUWuPTD80jNUw https://www.instagram.com/upt_perpustakaan_unsyiah/?hl=en
source: http://youtu.be/d_HGGC6xk9c
publisher: OER UNSYIAH published via YouTube.com
date: 2018-03-20T08:50:39.000Z
contributor: Miranda
contributor: Cut Rita Zahara
rights: Creative Commons License
type: Video

Logaritma
description: Open Educational Resource (OER) Unsyiah adalah satu satu Portal yang dikembangkan oleh Perpustakaan Universitas Syiah Kuala. OER Unsyiah berbasis Open Acces untuk siapa saja dan di mana saja. Bahkan Kami juga akan menerima kontribusi yang ingin ikut berpartisipasi dalam OER Unsyiah: http://uilis.unsyiah.ac.id/oer/contribution. Di sini, Kami menyediakan berbagai bentuk Course, seperti Textbook, Video, Audio, dan sebagainnya dengan berbagai bidang materi yang bervariasi. Namun, yang perlu diketahui bahwa OER Unsyiah berLisensi Creative Commons. Nah, bagi yang berkenan atau ingin mempelajari berbagai bidang materi mari kunjungi link UPT. Perpustakaan Unsyiah: http://uilis.unsyiah.ac.id/oer/ http://uilis.unsyiah.ac.id/ http://uilis.unsyiah.ac.id/oer/ https://www.facebook.com/groups/pustaka.unsyiah/ https://www.youtube.com/channel/UCvOxlI8WMHLUWuPTD80jNUw https://www.instagram.com/upt_perpustakaan_unsyiah/?hl=en
source: http://youtu.be/wMCwz3KjXzA
publisher: OER UNSYIAH published via YouTube.com
date: 2018-03-20T10:11:56.000Z
contributor: Cut Rita Zahara
rights: Creative Commons License
type: Video

The Nose and its Adjacent Structures
subject: Nose
description: Several bones that help form the walls of the nasal cavity have air-containing spaces called the paranasal sinuses, which serve to warm and humidify incoming air. Sinuses are lined with a mucosa. Each paranasal sinus is named for its associated bone: frontal sinus, maxillary sinus, sphenoidal sinus, and ethmoidal sinus. The sinuses produce mucus and lighten the weight of the skull.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Map of Mathematics Poster
subject: Mathematics
description: All of mathematics summarised in one poster.
contributor: Cut Rita Zahara
rights: Creative Commons
type: Image

Calculus -- The foundation of modern science
description: Easy to understand explanation of integrals and derivatives using 3D animations.
source: http://youtu.be/rjLJIVoQxz4
publisher: Physics Videos by Eugene Khutoryansky published via YouTube.com
date: 2014-04-11T01:43:34.000Z
rights: Creative Commons License

An Introduction to Sustainable Business
subject: Sustainable Business
description: Going green, green business, and sustainable business are topics on everyone’s mind. But what does all this mean exactly? A Primer on Sustainable Business answers that question and provides an introduction to the basics you need to know. We begin with an understanding of the background of the concept of sustainability and how it applies to the business world. In 1987, the Brundtland Commission put forth a “global agenda for change” with the purpose of “furthering the common understanding and common spirit of responsibility so clearly needed in a divided world.”Brundtland (1987). The report outlined the following description of sustainable development:
source: https://2012books.lardbucket.org/pdfs/an-introduction-to-sustainable-business
publisher: https:books.lardbucket.org
date: 2012
contributor: Baihaqi
rights: Creative Commons
format: PDf
language: English
type: Textbook

Basic Suturing: How to Suture
subject: Suturing
description: In this video, I demonstrate the surgeon's knot and the square knot and give some general beginner tips on how to suture.
source: http://youtu.be/DJMf0vN8fkw
publisher: Lifelong Nursing published via YouTube.com
date: 2017-09-14
contributor: Baihaqi
rights: Standard YouTube License This video represents licensed content on YouTube, meaning that the content has been claimed by a YouTube content partner.
format: Video
language: English
type: Tutorial

Drug Formulations
subject: Drug
description: This is a tutorial/lecture on Drug Formulations. We cover some topics important for classes such as Biochemistry and Pharmacology.
source: http://youtu.be/rvfABQpWoxE
publisher: TheSalmonellaPlace published via YouTube.com
date: 2012-11-30
contributor: Baihaqi
rights: Creative Commons

Intro To Psychology
subject: Psychology
description: Psychology is the scientific study of mind and behavior. The word “psychology” comes from the Greek words “psyche,” meaning life, and “logos,” meaning explanation. Psychology is a popular major for students, a popular topic in the public media, and a part of our everyday lives. Television shows such as Dr. Phil feature psychologists who provide personal advice to those with personal or family difficulties. Crime dramas such as CSI, Lie to Me, and others feature the work of forensic psychologists who use psychological principles to help solve crimes. And many people have direct knowledge about psychology because they have visited psychologists, for instance, school counselors, family therapists, and religious, marriage, or bereavement counselors.
source: https://ocw.mit.edu/ans7870/9/9.00SC/MIT9_00SCF11_text.pdf
publisher: http://www.openwa.org
date: -
contributor: Baihaqi
rights: Creative Commons
format: PDF
language: English
type: Textbook

Pharmacokinetics/ADME Of Drugs | Pharmacology Online Lecture-1 | For Upcoming D.Pharm & B.Pharm Exam
subject: Pharmacology
description: In this video , we have discussed about PHARMACOKINETICS OF DRUGS - ABSORPTION, DISTRIBUTION, METABOLISM, EXCRETION (ADME) IN BRIEF. Watch the video till the end to get complete information regarding pharmacokinetics of drugs. Topic discussed in the video :- Pharmacokinetics - the branch of pharmacology concerned with the movement of drugs within the body, the time course of its absorption, bioavailability, distribution, metabolism, and excretion or sometimes described as what the body does to a drug. It include four steps:- Absorption, Distribution, Metabolism, Excretion.
source: http://youtu.be/Ekn6QxC-g6o
publisher: LEARNINGPHARMACY.IN published via YouTube.com
date: 2017-12-26
rights: Creative Commons
format: Video
language: English

English Speaking Course in Hindi for Beginners English Speaking Tutorial
subject: English Speaking
description: If you just started learning English, you first need to know some basic rules of the language. Developing a solid foundation in English grammar will not only help you create your own sentences correctly but will also make it easier to improve your communication skills in both spoken and written English.
source: http://youtu.be/Bc953x2-7T0
publisher: Creative Commons published via YouTube.com
date: 2018-12-20
rights: Creative Commons License
format: Video
language: English