Integument

Question 1

name 5 functions of the skin

Answer 1

protection. body temp. vitamin d. excretion. sensory.

Question 2

what does keratinocyte refer to. why?

Answer 2

epidermal cells because the IF is keratin and it will eventually kill the cell.

Question 3

what are the differences between thin and thick skin

Answer 3

thin- low trauma areas. hair. only 4 layers. thick- high trauma areas. no hair. 5 layers. very thick stratum corneum

Question 4

what is the deepest layer of epidermis?

Answer 4

basal layer (stratum basale)- one layer thick. mitotically active stem cells that produce all cells above it. cuboidal or low columnar. then contain a cap of melanin that protects them from UV damage.

Question 5

what is the second deepest layer of the epidermis?

Answer 5

spinous layer (stratum spinosum)- several layers thick (thickest) of cells held together by desmosomes. tonofibrils are groups of keratin that are anchored to the attachement plaques of desmosomes

Question 6

what is the third deepest layers of the epidermis?

Answer 6

granular layer (stratum granulosum) 3-5 layers of granular cells. granules contain keratohyalin which compacts the tonofibrils together. they also contain lamellar bodies that release a waterproofing seal

Question 7

what is the least deep layer of the epidermis?

Answer 7

stratum corneum- many layers of dead, keratinized cells. deep cells still held together by desmosomes but superficial cells are not

Question 8

ketosis pilaris

Answer 8

when keratin builds up in hair follicles

Question 9

melanocytes

Answer 9

found in the basal layer, they secrete melanin. their cytoplasm is clear and they have tiny processes that extend out to give their melanin

Question 10

langerhans cells

Answer 10

exist in all layers. they capture and present antigens to t cells. responsible for allergic dermatitis.

Question 11

merkel cells

Answer 11

also found in the basement layer, they are touch receptors for fine touch and texture. usually associated with a nerve.

Question 12

what are the two layers of the dermis

Answer 12

papillary and reticular. papillary is superficial with more loose CT that interdigitates with epidermis (dermal papillae or dermal ridges). contains blood vessels, mast cells, fibroblasts, nerves and macrophages. the reticular layer is dense irregular CT with more fibers and less cells. it is thicker than the papillary layer. blood vesses, nerves and glands are also present.

Question 13

what creates finger prints?

Answer 13

dermal ridges

Question 14

what is the point of the dermal ridges/dermal papillae?

Answer 14

to strengthen the dermal/epidermal junction

Question 15

what is the hypodermis?

Answer 15

fat cells and CT deep to the dermis

Question 16

describe the anatomy of a hair follicle

Answer 16

surrounded by a tube of epithelium. bottom of the follicle is the hair bulb, which contains dermal papillae. the dermal papillae has the blood supply for the hair. the cells around the papillae are the hair matrix, and they create the hair. melanocytes are also in the matrix and responsible for hair color.

Question 17

sebaceous gland

Answer 17

a gland that secretes sebum via holocrine secretion, often found associated with hair and arrector pili muscles. simple branched acinar structure.

Question 18

sweat glands

Answer 18

simple coiled tubular. myoepthelial cells assist with secretion. merocrine. 2 types- eccrine and apocrine

Question 19

eccrine sweat glands

Answer 19

secretory portion- simple cuboidal with myoepthelium. duct portion- stratified cuboidal (2 layers). primary function is evaporative cooling. dark cells- granules. clear cells- electrolytes

Question 20

apocrine sweat glands

Answer 20

found in axillary and anogenital region. large lumens. “socially offensive.” contain pheromones.

Question 21

mammilary glands

Answer 21

compound tubuloalveolar. alveoli are simple cuboidal or columnar. modified sweat glands. become more active during pregnancy and after birth. secretion is both merocrine and apocrine. secreted into lactiferous ducts which drain into lactiferous sinuses

Question 22

messiners corpuscle

Answer 22

pinecone. fine touch and texture. dermal ridge

Question 23

pacinian corpuscle

Answer 23

deep in dermis. pressure and vibrations. onion.