Skin

Question 1

Epidermis Layers

Answer 1

Stratum corneum (flattened keratinocytes- barrier), lucidum - thick hairless skin. granulosum- keratinocytes die. spinosum connected. basale = stem cells prolif of keratinocytes and melanocytes.

Question 2

langerhan cells

Answer 2

specialized macrophages w/in stratum spinosum that present antigens to t cells to activate immune system

Question 3

Dermis layers

Answer 3

papillary layer = loose ct. reticular layer- sweat glands, blood vessels and hair follicles.

Question 4

Merkel cells (discs)

Answer 4

sensory at epidermal dermal junction. connected to sensory neurons and presonsible for deep pressure and texture sensation.

Question 5

free nerve endings

Answer 5

pain

Question 6

meissners corpuscles

Answer 6

light touch

Question 7

ruffini endigs

Answer 7

stretch

Question 8

pascinian corpuscle

Answer 8

deep pressure and vibration

Question 9

hypodermis

Answer 9

fat and connective tissue

Question 10

Thermoregulation

Answer 10

sweating, controlled by ANS. postganglionic sympathetic neurons utilize ach innervate sweat glands and promote water secretion with certain ions onto skin. Heat is absorbed by body as molecules w/in H2o undergo a phase change to evaporate. vasodilation occurs to maximize heat loss.

Question 11

arrector pili

Answer 11

contract in cold traps layer of heated air in skin. arterioles that feed skin capillaries constrict.

Question 12

white vs brown fat

Answer 12

white fat insulates, brown fat is in infants less efficient etc and more heat released as fuel is burned