skin histology module Flashcards

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1
Q

thick skin does not have

A

hair follicles, sebaceous glands, arrector pili muscles

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2
Q

where is thick skin

what does it lack

A

palms and plantar

lacks hair follicles, sebaceous glands

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3
Q

what is thin skin

what does it lack

A

lacks a stratum lucidum

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4
Q

most superficial layer of skin

A

epidermis

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5
Q

shape of cells in epidermis

A

stratified squamous keratinized epithelium

also melanocytes, langerhans and merkel cells

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6
Q

regeneration of epidermis

A

constant - about every 30 days
carried out by mitotic keratinocytes
cells normally divide at night

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7
Q

desmosomes

A

connect kerotinocytes together

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8
Q

hemidesmosomes

A

connect keratinocyte to basement membrane

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9
Q

where are melanocytes?

A

stratum basale

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10
Q

function of melanocytes

A

synthesize melanin in melanosomes

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11
Q

what does melanin do

A

protect against tissue damage and degradation patters

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12
Q

_____ increases production and changes of melanocytes

A

sunlight

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13
Q

where are langerhans cells located

A

primarily in the stratum spinosum

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14
Q

shape of langerhans cells

A

comma like appearance, appears pale

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15
Q

function of langerhans cells

A

antigen presenting cells in immune responses to contact antigens/allergies and some skin grafts

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16
Q

birbeck granules

A

inside langerhans cells - cytoplasmic organelles that look like tennis racket

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17
Q

where are merkel cells

A

stratum basale enar areas of well vascularized, richly innervated connective tissue

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18
Q

function of merkel cells

A

receive afferent nerve terminals and are believed to function as sensory mechanoreceptors

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19
Q

stratum basale

A

deepest layer of the epidermis

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20
Q

composition of stratum basale

A

keratinocytes, melanoyctes, langerhans, merkel

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21
Q

stratum spinosum

A
  • keratinocytes connected by desmosomes

- mitotically active in deeper region

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22
Q

keratinocytes membrane coating granules

A

in the superficial regions of the stratum spinosum, the contents of the granules are released into the intercellular spaces in the form of lipid-containing sheets that are impermeable to water and many foreign substances

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23
Q

stratum granulosum

A

most superficial layer in which nuclei are still present

3-5 (10-12 nm thick) layers of flattened keratonocytes with keratohyalin granules

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24
Q

keratohyalin granules

A
  • in stratum granulosum
  • contain histidine and cystine rich proteins which bind the keratin filaments together
  • not membrane bound
25
Q

stratum lucidum

A
  • clear homogenous layer just superficial to stratum granulosum
  • found only in thick skin - palmar and plantar
26
Q

cells if stratum lucidum

A

consists of keratinocytes that have neither nuclei nor organelles but have keratin filaments and eleidin

27
Q

eleidin

A

transformation product of keratohyaline

28
Q

stratum corneum

A
  • most superficial layer
  • 15-20 layers of flattened, non nucleated “dead cells”
  • squames that are 14 polygon shaped
29
Q

outermost layer of stratum corneum

A

squames that are continuously shed by desquamation

30
Q

layers of the epidermis

A
corneum
lucidum
granulosum
spinosum
basale

come lets get some beer

31
Q

layers of the dermis

A

papillary and reticular

what beer? PbR

32
Q

the dermis is composed of dense, irregular connective tissue with _________ and ______

A

type 1 collagen fibers and elastic fibers

33
Q

papillary layer

A
  • superficial thin layer of connective tissue that interdigitates with epidermal ridges of the epidermis
  • forms dermal papillae where meissner corpuscles and capillary loops may be found
  • contains delicate collage fibers (type 1 and III_
  • contains anchoring fibrils (type VII collagen), microfibrils (fibrillin) and elastic fibers
34
Q

meissner corpuscles

A

fine touch receptors

35
Q

reticular layer

A
  • deep layer of dermis
  • major portion of dermis
  • dense bundles of collagen fibers (type 1) and thick elastic fibers
  • arteries, veins, and lymphatics are present
  • location of sweat glands and their ducts
  • pacinian corpuscles and nerves
  • in thin skin, contains hair follicles, sebaceous glands and arrector pili muscles
36
Q

corpuscles of papillary layer

A
  • contains capillary loops and meissner corpuscles (fine touch)
37
Q

corpuscles of reticular layer

A

pacinian corpuscles (pressure receptors) and kraus end bulbs

38
Q

arrector pili muscle

A
  • smooth muscle
  • under sympathetic control
  • contracts to elevate hair - goose bumps
39
Q

name for sweat gland

A

eccrine

40
Q

eccrine sweat gland

A
  • simple coiled tubular glands present in skin throughout the body
41
Q

shape of sebaceous gland

A

acinar

stratified cuboidal

42
Q

secretory unit of eccrine sweat gland

A
  • embedded in dermis:
  • dark cells contain mucinogen rich secretory granules
  • clear cells secrete a watery electrolyte rich material
  • myoepithelial cells are scattered in beneath clear cells, they contract and aid in expressing the glands secretions into the duct
43
Q

how do sweat glands secrete sweat?

A

contraction of myoepithelial cells

44
Q

dark cells

A

line the lumen of the gland in eccrine sweat unit

45
Q

clear cells

A

rich in mitochondria and glycogen, contain intercellular canaliculi that extend to lumen of gland

46
Q

location of apocrine sweat gland

A

anus, axilla, areola, cerumen of external ear

47
Q

function of apocrine sweat gland

A
  • empty viscous odorless secretions into hair follicles near sebaceous gland ducts
  • bacteria act on these secretions to produce odors unique to a person
48
Q

what makes apocrine glands smell

A

not secretions, but bacteria that digest secretions

49
Q

structure of sebaceous gland

A

secretory unit - branched acinar

duct - empties into neck of a hair follicle

50
Q

location of sebaceous gland

A

face, forehead, scalp

absent in thick skin (palms and soles)

51
Q

function of sebaceous gland

A

holocrine glands that release sebum - oily secretion and degenerating epithelial cells

52
Q

types of secretion mechanisms

A

holocrine - sebaceous
merocrine - eccrine and salivary
apocrine - lactating mammary

53
Q

holocrine secretion

A

release entire secretory cell and its contents

54
Q

merocrine secretion

A

exocytosis

55
Q

apocrine secretion

A

release part of apical cytoplasm

56
Q

myofibroblast

A

contains high amounts of actin and myosin for contraction

contracts during wound healing

57
Q

meissners corpuscles

A
  • in dermal papillae of thick skin, eyelids, lips, and nipples
  • function in fine touch perception
58
Q

pacinian corpuscles

A
  • in dermis and hypodermis and in the connective tissue of the mesenteries and joints, especially being abundant in the digits and breasts
  • perceive pressure, touch, and vibration
59
Q

shape of cells in dermis

A

stratified cuboidal epithelium in sweat glands