Integument (7)

Question 1

integument

contents

Answer 1

skin
sweat glands
sebaceous glands
hair
nails

Question 2

functions of skin

Answer 2

1. protect from microorganisms/dehyrdation
2. reg of body temp by sweat
3. reception by sensory nerve endings
4. absorption of UV to form vit D
5. excretion by sebaceous/sweat glands

Question 3

thin skin

Answer 3

covers most of body surface

has hair follicles + arrector pili musclse + sebaceous + sweat glands

Question 4

thick skin

Answer 4

palm of hand and soles of feet
has sweat glands only

Question 5

skin layers

Answer 5

1. epidermis-superficial/epithelial
2. dermis- deeper CT layer

epidermis is avascular

Question 6

epidermis cells

Answer 6

in general: stratified squamous keratinized avascular

keratinocytes-most common
nonkeratinocytes

Question 7

keratinocytes

Answer 7

epithelial cells

provide physical barrier/is protective

continuous skin renewal by mitotic activity at night @ basal layer cells»accumulate keratin filaments as migrate to surface

evolve and desquamate every 25-30 days

Question 8

nonkeratinocytes

Answer 8

langerhans cells
merkel cells
melanocytes

Question 9

langerhans cells

Answer 9

from precurosrs in bone marrow > blood stream> epidermis mainly @stratum spinosum and superficial dermis

defensive cells

have cytoplasmic processes and Birbeck granules (tennis racket)

Question 10

langerhan cell function

Answer 10

attach to antigens entering skin > travel to lymph node to interact w/ lymphocytes

Question 11

merkel cells

Answer 11

@ base of hair follicles and fingertips
@stratum basale of epidermis

mechanoreceptors to enhance sensory perception

Question 12

melanocytes

Answer 12

@stratum basale and superficial dermis
-from neural crest

syn melanin (protect skin DNA from UV radiation)

Question 13

melanin pathway

Answer 13

1. RER syn tyrosinase (enzyme)
2. golgi packs it into melanosomes
3. tyrosinase activated by UV light
4. tyrosine > melanin via tyrosinase @melanosomes
5. melanosomes released into ECS of spinosum > phagocytosed by keratinocytes
6. move to supranuclear region to protect chromosomes from UV

Question 14

differences in skin pigmentation

Answer 14

1. tyrosinase activity
2. # of melanin granules
3. size of granules
4. granule distribution
5. rate of melanin breakdown

Question 15

vitiligo

Answer 15

loss of pigment so white patches

due to dec or complete loss of melanocytes

autoimmunity or self destruction of melanocytes

Question 16

albinism

Answer 16

melanocytes present but not syn melanin due to defect or absence of tyrosinase

Question 17

malignant melanoma

Answer 17

causes: hereditary, light skin, xs sunlight exposure

ABCDE of melanoma

Question 18

strata of thick skin

Answer 18

1. corneum (superficial)
2. lucidum
3. granulosum
4. spinosumm
5. basale (deep)

can lucy get a spin bike

Question 19

stratum basale

thick skin

Answer 19

columnar shape w/ desmosomes, rests on basement membrane w/ hemidesmos

most intense mitotic activity so layer of cell renewal

melanocytes and merkel cells reside

Question 20

basal cell carcinoma

Answer 20

pearly papule

slow growing and rarely metastasize so treatable via surgery

Question 21

stratum spinosum

thick skin

Answer 21

interdigitating processes/intercellular bridges held by desmosomes to keep cells from sep so bind and protect

spiny appearance/zipper/prickley

bundles of intermed filaments, langerhans cells, membrane coated granuels

IFs= tonofilaments + cytokeratin

Question 22

stratum granulosum

Answer 22

keratohyalin granules (soft keratin protein) + membrane coating granules (lamellar bodies lipids)

waterproofs skin surface via exocytosis of lipid rich substance form sheet

Question 23

lamellar bodies contents

Answer 23

1. glycosphingolipids
2. phospholipid
3. ceramide

Question 24

stratum lucidum

Answer 24

subdivision of stratum corneum w/ keratin filaments
NO organelles/nuclei aka non-viable cells
protective

Question 25

stratum corneum

Answer 25

thick layer w/ keratin filaments + amorphous matrix (will thicken w/ friction aka callus) flat/desiccated/keratinized dead cells so no nuclei or organelles **protective** desquamates easily bc no desmos b/t cells to bind

Question 26

strata of thin skin

Answer 26

1. thin corneum 2. discontinous lucidum 2. discontinuous granulosum 3. thin spinosum 4. stratum basale

Question 27

ichthyosis

Answer 27

hyperkeratosis = fish scales presentation

Question 28

papillary layer | dermis

Answer 28

superficial loose CT layer of dermis for **defense** dermal papillae interdigitate w/ epidermal ridges (more prominent in high mechanical stress aka palms and soles)

Question 29

papillary layer contents | dermis

Answer 29

LCT cells= fibroblasts, macrophages, plasma cells, mast cells +reticular fibers +elastic fibers +Meissner corpuscles= mechanoreception +abundant capillary loops for nutrition and thermoreg

Question 30

reticular layer | dermis

Answer 30

dense irregular coll CT reticular layer for **tensile strength** w/ collagen bundles thick elastic fibers for stretch/resilence

Question 31

reticular layer contents | dermis

Answer 31

proteoglycans (rich in dermatan sulfate) +fibroblasts, mast cells, lymphocytes, macrophages, fat cells +hair follicles, arrector pili muscles, sebaceous glands, sweat glands +pacinian corpuscles to detect deep pressure/vibrations

Question 32

hypodermis

Answer 32

superficial fascia not a part of skin base/root of hair follicules

Question 33

eccrine sweat glands

Answer 33

ordinary sweat glands, scattered thru skin/body expel waste via merocrine secretion -have myoepithelial cells to assist -inn by postganglionic sympathetic fibers simple coiled tubular shape

Question 34

apocrine sweat glands

Answer 34

@ axilla, areola of nipple, anal region merocine excretion, influenced by hormones and sympathetics | don't start until puberty

Question 35

sebaceous glands

Answer 35

syn sebum (natural cold cream) to soften skin -influenced by hormones, active at puberty holocrine secretion

Question 36

hair follicle structure

Answer 36

1.bulb @ base (encloses dermal papilla) 2.cortex keratinized 2.medulla w/ mod keratinization 3.cuticle keratinized 4.internal root sheath w/ some keratiniz 5.glassy membrane 6.CT | external root sheath not a part of hair

Question 37

dermis contents

Answer 37

1. collagen (tensile strength) 2. immune cells (defense) 3. capillaries (nutrition/thermoreg) 4. glands (thermoreg/excrete waste) 5. nerve fiber terminals (sensation) 6. elastic fibers (stretch)

Question 38

arrector pili muscles | hair follicles

Answer 38

smooth muscle contract to raise hair follicles and conserve body heat attaches to hair follicle midway/obliquely + cradles sebaceous gland

Question 39

nail structure

Answer 39

1. nail fold + eponychium 2. root 3. nail plate (dense keratinz) rest on nail bed (strat squamous) 4. matrix (growth happens) 5. hyponychium