Skin and Glands

Question 1

what does vasculature do when there is an increase in core temperature?

Answer 1

decrease smooth muscle tone –>vasodilation

core t decreases

Question 2

langerhans cell

Answer 2

apc/dendritic cell; endocytose antigens and transport to lymph nodes initiating immune response
-pale staining among keratinocytes

Question 3

layer of not true stem cells, with mitosis and melanocytes

Answer 3

stratum basale

Question 4

layer with channels for nutrient flow, and spine-like desmosome connections; mitosis occurs here but not past here

Answer 4

stratum spinosum

Question 5

layer with two types of granules

Answer 5

stratum granulosum

Question 6

what are the two types of bodies in granulosum?

Answer 6

1. keratohyalin: dark staining aggregate of keratin bound by protein
2. lamellar bodies: lipid granules that provide water proofing to skin

Question 7

layer sometimes present in thick skin like palms and soles; clear dead cells

Answer 7

s. lucidum

Question 8

layer with no internal organelles; protein crosslinking on inner membrane gives strength

Answer 8

s corneum

Question 9

order of epidermal strata (top to bottom)

Answer 9

corneum, lucidum, granular, spinosum, basale

Question 10

how do basal cells change to toughen the epithelium as they become keratinocytes?

Answer 10

• crosslink cytoplasmic proteins

- lipids secreted outside cell form waterproof barrier

Question 11

what layer of skin is the main source of strength?

Answer 11

DERMIS

Question 12

two dermal layers

and layer that follows

Answer 12

top: papillary layer
bottom: reticular layer
then hypodermis below

Question 13

papillary vs reticular dermis

Answer 13

papillary layer interlocks with overlying epidermis and reticular has larger collagen bundles

Question 14

where do largest hair follicles begin?

Answer 14

hypodermis

Question 15

thick vs thin skin

Answer 15

thin has no lucidum and a thin corneum

Question 16

how does melanocyte system lead to pigmentation?

Answer 16

pigment is due to the melanocyte at base of basale layer

• melanocytes make melanin and packages it into melanosomes
• keratinocytes pinch off these melanosomes

Question 17

melanin in pale skin v dark skin

Answer 17

• in pale skin, melanosomes break down quickly so highest [] is in basal
• darker skin has bigger more resistant melanosomes so highest [] is in spinosum – not more melanocytes, just bigger/more melanosomes

Question 18

three common accessory organs

Answer 18

pacinian corpuscle
meissners corpuscle
merkel cells

Question 19

looks like large onion, senses rapid vibration

Answer 19

pacinian corpuscle

Question 20

tornado in papillae of dermis extending into epidermis

Answer 20

meissners corpuscle

-senses light touch, change in texture, and low freq vibration (closer to surface than pacinian)

Question 21

senses sensitivity, sustained pressure

in s. basale near sweat ducts

Answer 21

merkel cell

Question 22

rete ridges

Answer 22

epidermal thickenings that extend downward between dermal papillae

Question 23

temperature control

capillaries vs large vessels

Answer 23

capillaries restrict and dilate in the dermis

while large vessels provide radiant heating

Question 24

evaporative cooling

Answer 24

sweat gland base secretes sweat

• myoepithelial cells surround tube and squeeze w muscle properties
• up the tube some ions are resorbed

Question 25

histology of sweat glands
dark cells
light cells
frothy outer cells

Answer 25

dark - protein secreting
light - ion pumping cells
frothy - myoepithelial cells

Question 26

myoepithelial cells

Answer 26

have properties of muscle and can squeeze

ex: sweat gland lining

Question 27

anatomy of hair follicle

Answer 27

outer to inner –> outer root sheath, inner root sheath, cuticle, cortex, medulla

Question 28

outermost layer of hair shaft

Answer 28

cuticle

Question 29

what produces signals to drive growth of hair follicle?

Answer 29

dermal papillae

Question 30

why does hair turn grey?

Answer 30

melanocytes are present in shaft –> as we age, precursors begin to die out

Question 31

unicellular exocrine gland

Answer 31

goblet cell

Question 32

modes of secretion

Answer 32

exocrine - secrete into duct
endocrine - no ducts; sit on basement membrane and secrete into blood stream
paracrine - affect nearby cells

Question 33

three types of exocrine secretion

Answer 33

merocrine, apocrine, holocrine

Question 34

merocrine secretion

Answer 34

cells make granules, transport them to PM, and release into duct

Question 35

apocrine secretion

Answer 35

larger granules than merocrine that take a little PM with them

Question 36

holocrine secretion

Answer 36

whole cells break down and release their material

Question 37

salivary gland two cell types

Answer 37

mucous secreting - lighter staining due to glycosylated protein

serous secreting - low glycosylation so darker staining

Question 38

two pieces of pathway out of salivary gland

Answer 38

mucous and serous secretions are released into lumen which becomes intercalated (constricted)
then into striated duct which alters product with mitochondria

Question 39

why is striated duct of salivary gland striated?

Answer 39

mitochondria that are modifying secretion product

Question 40

which organ has no ducts and just secretes hormones into surrounding tissue to be absorbed by vessels

Answer 40

thyroid