integument-lecture 5

how many layers does the dermis have?

two, papillary and reticular

papillary layer

superficial layer, contains dermal papillae, capillaries, and nerve axons

reticular layer

deep layer, dense IR connective tissue, hair follicles, sweat glands, and sebaceous glands

subcutaneous layer

aka hypodermis

deep to the dermis

has adipose and major blood vessels

is the subcutaneous layer apart of the integument?

no, but it helps stabilize it

hair growth cycle step 1

active

lasts 2-5 years

grows 0.33 mm/day

hair growth cycle step 2

regression

undergoes regression then transitions

hair growth cycle step 3

resting

hair loses its attachment to the follicle and becomes a club hair

hair growth cycle step 4

reactivation

club hair is lost and the hair matrix begins producing a replacement hair

what is hair made of?

keratin

vellus hair

covers most of the body

intermediate hair

covers arms and legs

terminal hair

hair on the head

function of hair

1. proctection from uv

2. insulation

3. guards nose and ears

4. sending impulses to brain

5. arrector pili muscles

how is hair color determined?

melanin production by melanocytes

glands function

lubricates epidermis, excretes waste, and assists in thermoregulation

true/false epidermis is vascular

false, it is avascular

sebaceous gland location

everywhere besides palms/soles, mainly on forehead/face, and upper back

sebaceous gland function

secretes oily sebum and provides lubrication

sweat glands function

produces watery solution by merocrine secretion

apocrine sweat glands

axillae, groin, and nipples

secretes pheromones

merocrine (eccrine) sweat glands

palms and soles

thermoregulation

thin watery secretions

special apocrine glands

ceruminous (ear wax) and mammary glands (milk production)

when injury occurs where does defense begin?

reticuloendothelial system (macrophages consume invading bacteria)

in which way does repair occur?

from the basale up

how is damaged dermis restored?

by repair to CT (fibroblasts)

can infected tissue be repaired?

no, it is in the inflammatory state