Epithelial Tissue: skin annexes

Question 1

describe melanocytes

Answer 1

round body shaped cells
makes melanin granules

Question 2

where do melanocytes rest

Answer 2

underneath or in between stratum germinativum stem cells

Question 3

describe process of melanocytes

Answer 3

sends finger like projections with developing melanin granules
projections are phagocytize
budding tentacles come out and pinches off (form of vesicle)
goes into cell and releases melanin
melanocytes make umbrellas to cover cells of stratum spinosum (to protect from uv rays)
active process

Question 4

name the 2 types of melanocytes

Answer 4

eumelanin - brown
pheomelanin - red (more cysteine bonds)

Question 5

why do we have hair

Answer 5

thermoregulation (sweat, hair stands up and air between hair creates heat)
protection
sensation (whiskers)
goosebumps (communication)

Question 6

describe sebaceous gland (location)

Answer 6

at neck of polysebaceous unit

Question 7

describe hair shaft

Answer 7

visible
follow it down to follicle

Question 8

name and describe parts of hair shaft

Answer 8

medulla - animals dont have one
cortex
cuticle
flat keratinized cells

Question 9

describe hair follicle

Answer 9

around where hair shaft becomes continuous with follicle and then follicle becomes continuous with bulb

Question 10

describe hair bulb

Answer 10

invagination of connective tissue (dermal papilla)
super vascularized - with nerves

Question 11

why does pulling hair hurt

Answer 11

firing nerves in dermal papilla

Question 12

what does arrector pili cause

Answer 12

goosebumps

Question 13

what is glassy membrane

Answer 13

basement membrane
separates connective tissue from epithelial tissue

Question 14

what gives hair colour

Answer 14

melanocytes on BM

Question 15

describe CT sheath

Answer 15

wraps around hair bulb and comes inside (dermal papilla)

Question 16

name layers of hair follicle

Answer 16

connective tissue sheath
glassy membrane
external root sheath
internal root sheath
cuticle of hair shaft
cortex

Question 17

describe internal root sheath

Answer 17

henle’s layer - flat cells
huxley’s layer - trichohyalin granules
cuticle of IRS = flat

Question 18

describe sebaceous gland

Answer 18

non squamous stratified epithelium
polygonal (round cells)

Question 19

what does sebaceous gland have (what is inside cells)

Answer 19

lipid droplets containing cholesterol, phospholipids, triglycerides and glycogen
look empty bc ethanol dissolves fats

Question 20

what is sebaceous gland stimulated and inhibited by

Answer 20

stimulated by androgens
inhibited by estrogens

Question 20

what does sebaceous gland make

Answer 20

sebum (pheromones, bacteriostatic permeability)
released when cell dies

Question 21

what is acne

Answer 21

sebaceous glands starting to work

Question 22

describe what happens during sebaceous gland secretion

Answer 22

base layer of stem cells (dark pink) can differentiate into cells that make fats
stem cells and major glands make lipids - make so many that cell explodes and releases its contents and dead cells
dead cells enucleated - contents being emptied into shaft

Question 23

describe holocrine secretion

Answer 23

sebaceous gland
contents of cell and dead cell - everything is secreted

Question 24

describe apocrine secretion

Answer 24

some tissue stays intact - mix of holo and mero

Question 25

describe merocrine secretion

Answer 25

opposite of holocrine
just cellular contents (secretory product) - gland stays intact

Question 26

describe sweat gland

Answer 26

merocrine secretion
simple tubular gland
myoepithelial cells sit on BM

Question 27

what are myoepithelial cells

Answer 27

specialized cells for contractility

Question 28

describe how sweat gland secretes

Answer 28

myoepithelial cells contract and pushes sweat and makes it to excretory gland
and sweat pore
sweat pools in lumen of gland

Question 29

what does sweat gland secrete

Answer 29

water
urea
ammonia
NaCl

Question 30

what is purpose of sweat gland

Answer 30

thermoregulation by evaporative cooling

Question 31

describe excretory portion of sweat gland

Answer 31

in hypodermis and dermis
smaller and darker stain
compound stratified cuboidal cells (2 layers)

Question 32

describe secretory portion of sweat gland

Answer 32

in hypodermis
simple columnar/pyramidal when H&E stain
actually has 2 layers but can only be seen with special stain that stains myosin

Question 33

why is lumen of excretory portion smaller

Answer 33

reduce volume of lumen so sweat comes out faster - still same pressure