1. Keratinocytes - most abundant, in all layers
2. Melanocytes - pigment producing cells in stratum germanitivum & spinosum,
3. Langerhorn cells - phagocytic cells in stratum spinosum
4. Merkel cells - detect sensation, found in stratum germanitivum,

1. Germanitivum
2. Spinosum
3. Granulosum
4. Lucidum
5. Corneum

1. Skeletal (voluntary) muscle - moves the body by pulling on bones of the skeleton
2. Cardiac muscle - pushes blood through the arteries & veins
3. Smooth (involuntary) muscle - pushes fluids and solids along the digestive tract, among funtions in other systems

1. Excitability - respond to stimulation
2. Contractility - shorten actively to exert pull or tension
3. Extensibility - continue to contract over a range of resting lengths
4. Elasticity - rebound toward origina length after contraction

Skeletal muscles are contractile organs directly or indirectly attached to bones of the skeleton.

Functions:

• Produce skeletal movement
• Maintain posture & body position
• Support soft tissues (ab wall & pelvic cavity support visceral organs)
• Regulate  entering and exiting of material (muscle at orifices)
• Maintain body temp (muscle use releases heat - shivering)

1. The H band and I band get smaller
2. the zone of overlap gets bigger
3. the Z lines move closer together
4. the width of the A band remains constant

• Hypertrophy (enlargement) results from exhaustive stimulation because it causes the fibers to develop more mitochondria, a higher concentration of glycolyric enzymes, larger glycogen reserves, more myofibrils and more thick/thin filaments within each myofibril
• Atrophy is the opposite.  Too little stimulation results in a loss of size, tone, and power.

1. Fast fibers - contractions are supplied with energy anaerobically through glycolysis (glycogen converted to lactic acid), fatigue quickly because glyc. reserves are limited
2. Slow fibers - 3 times as long to contract as fast, but can contract longer without fatigue because their mitochondria are constantly making ATP through aerobic metabolism. The O₂ used to make ATP comes from the greater number of capillaries and myoglobin, which reserves oxygen
3. Intermediate fibers - properties between the two, physically similar to fast except more mitochondria, increased capillary supply and greater fatigue resistance

1. Parallel
2. Convergent
3. Pennate (feather) (Uni-, Bi-, Multi-)
4. Circular (guard entrances/exits of internal passageways)

1. The origin is stationary and the insertion moves, or the origin is proximal to the insertion
2. The aponeurosis is the origin and the tendon is attached to the insertion (if the muscle extends between a broad aponeurosis and a narrow tendon)
3. If there are multiple tendons on one end and a single at the other end, there are multiple origins and a single insertion

1. Agonists (aka prime movers) - a muscle whose contraction is chiefly responsible for producing a particular movement (ex. biceps brachii produces flexion of elbow)
2. Synergists - a muscle that assists the agonist through additional pull or stabilization. (termed fixator if it assists by preventing movement at a joint & stabilizing the origin of the agonist)
3. Antagonist - a muscle whose actions oppose that of the agonist (ex. triceps brachii extends elbow back into place)

First class lever (seesaw) - muscle used to raise the head

Second class lever (wheelbarrow) - calf muscle used to raise heel, force gets magnified

Third class lever - bicep used to raise forearm, speed and distance traveled are incread at the expense of force

Levers provide speed and versatility that could not be achieved otherwise

1. Skeleton muscle fibers are smaller in diameter from less myofibrils & less ATP, gylcogen, and myoglobin (leads to fatigue, less muscle strength and endurance)
2. Entire skeletal muscles become smaller in diameter  & less elastic (fibrosis decreases elasticity by developing fibrous connective tissue)
3. Tolerance for exercise decreases (quicker fatigue from above and less ability for thermoregulation)
4. Decreased ability to recover from muscular injuries (fewer myosatellite cells which facilitate repairs)

• Papillary layer - loose connective tissue with capillaries supplying the epidermis and axons of sensory nerves that monitor receptors in this layer and the epidermis
• Reticular layer - interwoven dense connective tissue surrounding blood vessels, hair follicles, nerves, sweat glands, and sebaceous glands

• The hair root plexus is a group of sensory nerves surround the base of the follicle, so that the movement of a single hair can be consciously felt
• The arrector pili is a smooth muscle also surrounding the follicle, which pulls on the follicle and elevates the hair (goose bumps, hair on end)

1. Apocrine sweat glands - only found in axillae (armpits), groin, nipples. Produce a viscous secretion, communicate via pheremones, influenced by hormones. (Related include mammary glands for milk & ceruminous glands for earwax)
2. Merocrine sweat glands - widespread, produce thin secretions of mostly water, controlled by nervous system, functions in thermoregulation, excretion, & some antibacterial use

• Fewer melanocytes (pale)
• Dry epidermis (less gland activity)
• Reduced blood supply
• Changes in fat & hair distribution
• Fewer active hair follicles (thinner, sparse hair)

• Support - structural framework for attachment
• Storage of minerals - 98% of calcium is in bones
• Blood cell production - red marrow in internal medullary cavities of bones
• Protection - delicate tissues and organs surrounded by skeleton
• Leverage - movement produced by skeletal muscles using bones as leverage

• ²/₃ of weight Calcium phosphate Ca₃(PO₄)₂, some of which converts to hydroxyoatite.  These inorganic compounds resist compression
• ¹/₃ of weight is collagen fibers, which are tough and flexible, and tolerate stretching and bending well
• About 2% of weight is osteocytes and other living cells
• Mix of inorganics and collagen gives intermediate properties, with some strength ad some flexibility.

1. Osteocytes - mature bone cells, which maintain the bone tissue, mostly through directing the release&deposition of calcium
2. Osteoblasts - inner/outer surfaces of bone, which secrete osteoid (organic components of bone matrix) that will mineralize. New bone creation is termed osteogenesis
3. Osteprogenitor cells - also on inner/outer surfaces, divide into osteoblasts when more are needed (ex. when bone is broken)
4. Osteoclasts - large, multinucleate cells, which secrete acid to dissolve the bony matrix. The erosion process is "osteolysis".   -clasts work in balance w/ -blasts.

• Compact bone - dense and solid, osteocyes arranged in concentric layers around a central canal, used where stresses come from one direction (usually conducts from one end to another)
• Spongy bone - arranged in an open network of struts and plates, not as massive as compact but able to resist stresses from multiple directions
• Matrix composition of both is the same, only the arrangement is different

• Periosteum - covering on outer surface of bone, to isolate and protect bone from surrounding tissue, provide a route and place of attachment of circulatory& nervous supply, actively participate in bone growth and repair, and attaches bone to the connective tissue network of the deep fascia
• Endosteum - lining on inside (medullary cavity)

1. Intramembranous ossification - mesenchymal cells differentiate into osteoblasts, which secrete osteoid and creates spongy bone. This will become compact bone if deposition of calcium continues
2. Endochondral ossification - turns a hyaline cartilage model into bone. The model begins to calcify, killing large chondrocytes.  The cells of the perichondrium differentiate into osteoblasts and begin to form more bone matrix. Capillaries & osteoblasts migrate inwards to the spaces left by chondrocytes.  The calcified model breaks down and the osteoblasts create spongy bone

• Calcium & phosphate salts, & other ions such as magnesium, citrate, carbonate & sodium (from diet)
• Vitamins A & C (from diet)
• Vitamin D (actually a group of related steroids) (from diet or synthesized in the skin in the presence of UV radiation)
• Parathyroid hormone, which simulates osteoblast/clast activity, increasing calcium absorption
• Calcitonin, which inhibits osteoclasts and inc. the rate of Ca lost (antagonist of pht)
• Growth hormone & thyroxine, which stimulate bone growth until puberty
• Sex hormones (estrogen & testosterone) stimulates faster osteoblast activity

• After the fracture, extensive bleeding occurs, and a large blood clot (fracture hematoma) develops
• An internal callus forms & spongy bone unites the inner edges while an external callus of cartilage & bone stabilized the outer edges
• The external callus becomes all bone & struts of spongy bone unite the broken ends
• The area is swollen with the reformation, but it will be remodeled over time until it looks the same.

1. Long bone - femur
2. Flat bone - parietal
3. Pneumatized bone - (hollow or with numerous air pockets) ethmoid
4. Irregular bone- vertebra
5. Short bone - (boxlike) carpal
6. Sesamoid - (form in tendons in reaction to stresses) patella

• a framework that supports and protects organs in the ventral body cavity
• houses special organs for taste, smell, hearing, balance, and sight
• surface area for attachment of muscles that adjust the positions of the head, neck & trunk, perform respiratory movements, & stabilize or position structures of the apendicular skeleton.

• frontal, sphenoid, ethmoid, maxillae
• sinuses (air pockets) lighten skull bones, produce mucus, and resonate during sound production

In infants, the sutures are not finished forming, and are still made of cartilage. The large cartilage areas, where multiple sutures meet, are called fontanels.  The four are:

1. Anterior fontanel - largest, at intersection of frontal, sagittal, and coronal sutures
2. Posterior fontanel - at intersection of lamboid and sagittal sutures
3. Sphenoidal fontanel - at intersection of coronal and squamous sutures
4. Mastoid fontanel - at intersection of lamboid and squamous sutures

• Functions: column of support to bear weight of head, neck & trunk, transfer this weight to lower appendicular skeleton, protect spinal cord, provide route for spinal nerves, and help maintain upright position
• Regions: Cervical (7 vertabrae), Thoracic (12 vertebrae), Lumbar (5 vertebrae), Sacral (5 fused vertebrae), Coccygeal (3-5 fused)

• Protects structures of the thoracic cavity
• Atachment point for muscles involved with respiration, the position of the vertebra column, and movements of the pectoral girdle and upper limbs

Some Lovers Try Positions That They Can't Handle

(Scaphoid, Lunate, Triquetrum, Pisiform, Trapezium, Trapezoid, Capitate, Hamate)

Female pelvis is:

• smoother/lighter & fewer markings for attachments because less muscle
• larger pelvic outlet
• less curvature of sacrum/coccyx
• wider, more rounded pelvic inlet
• broad, low pelvis
• widely fanning
• broader pubic angle

(all except first for child birth)

1. Synarthrosis - immovable
2. Amphiarthrosis - slightly moveable
3. Diarthrosis, or synovial - freely moveable

• Suture - immovable interlocking joint of the skull
• Gomphosis - fibrous synarthrosis that binds each tooth to the surrounding bony socket (periodontal ligament = fibrous connection)
• Synchondrosis - interposition of cartilage plate (ex. epiphyseal cartilage)
• Syntosis - fusion of bone (ex. frontal suture on frontal bone)

1. A joint capsule
2. Articular cartilages
3. A joint cavity filled with synovial fluid
4. A synovial membrae lining the joint capsule
5. Accesory structures
6. Sensory nerves and blood vessels that supply the exterior and interior of the joint

1. Provide lubrication, reducing friction within the capsule
2. Nurishes the chondrocytes by delivering nutrients when the fluid is circulated by motion
3. Acts as a shock absorber by evenly distributing a shock across the surface

• Linear - gliding of two opposing surfaces past each other. ex. carpal/tarsal bones
• Angular - Abduction (away from body), adduction (toward body), flexion (reduces angle between articulating elements), extension (increases angle between articulating elements), and circumduction (ex. moving arm in loop)
• Rotation - ex. shaking head no (right & left) or pronation/supination of hand
• Special - eversion/inversion, dorsiflexion/plantar flexion, lateral flexion, protraction/retraction, opposition, elevation/depression

1. Plane joint - gliding joints with slight sliding movement
2. Hinge joint - motion along a single plane, allowing flexion/extenson (elbow, knee)
3. Pivot joint - rotational motion along single plane (atlas/axis to turn head)
4. Condylar (ellipsoidal) joint - motion along two planes (fingers/toes go front/back, left/right)
5. Saddle joint - same as above except greater range (thumb)
6. Ball & socket - all combinations of movement (shoulder/hip)

1. Anterior longitudinal ligament - connects the anterior surfaces of the vertebral bodies
2. Posterior longitudinal ligament - parallel to above, but along the posterior surface of the vertebral bodies
3. Ligamentum flavum - connects the laminae of adjacent vertebrae
4. Interspinous ligament - connects the spinous processes of adjacent vertebrae
5. Supraspinous ligament - connects the tips of the spinous processes

1. Anterior flexion (bending forward)
2. Extension (bending backward)
3. Lateral flexion (bending to the side)
4. Rotation (twisting)

• Rheumatism indicates pain and stiffness of the skeletal or muscular systems, or both.
• Arthritis is a type of rheumatism that affects synovial joints

1. Support the organs in the pelvic cavity
2. Flex the joints of the sacrum & coccyx
3. Control movement of materials through the urethra and anus