Muscle and Skin

• protects
• regulates internal temp.
• contains sensory organs
• produces vitamin D

• blood vessels constrict
• vessels move away from the surface
• hair stands up on end to trap heat
• shiver, muscles contract

• sweat evaporates and cools body
• vessels dilate and move to the surface to release heat
• hair lays down

Epidermis

Epidermis

Dermis

Dermis

When your skin is exposed to UV rays, melanin, a pigment that absorbs and breaks down the UV rays you are exposed to, this increases the melanin production therefore darkening your skin color.

muscle pulls on bone.

raises lips

wrinkles forehead; raises eyebrows

close eyelid

pucker lips

alone: move neck side to side; together: flex neck

abducts upper arm

adducts upper arm

flex forearm

extend forearm

protracts scapula

flex trunk

elevate shoulder; extend neck

brings shoulder down and back to body

flex hip; extend lower leg

extend hip; flex lower leg

flex lower leg; flex thigh; laterally rotate thigh

dorsiflex foot

planterflex foot

hyperextend thigh; laterally rotate thigh

abducts thigh; medially rotate thigh

adducts thigh

• smooth
• cardiac
• skeletal

cardiac

smooth

skeletal

skeletal

• cardiac
• smooth

skeletal

skeletal

smooth

• actin- thinner
• myosin- thicker

• myosin- does not move
• actin- moves

Lactic acid is a product of anaerobic respiration that occurs when the body is short on oxygen; it builds up in the muscles when you excerise and don't take in enough oxygen, causes pain and cramping.

exercise rips muscle fibers, they rebuild themselves thicker and stronger.

tendons

ligaments