skin histology module

Question 1

thick skin does not have

Answer 1

hair follicles, sebaceous glands, arrector pili muscles

Question 2

where is thick skin

what does it lack

Answer 2

palms and plantar

lacks hair follicles, sebaceous glands

Question 3

what is thin skin

what does it lack

Answer 3

lacks a stratum lucidum

Question 4

most superficial layer of skin

Answer 4

epidermis

Question 5

shape of cells in epidermis

Answer 5

stratified squamous keratinized epithelium

also melanocytes, langerhans and merkel cells

Question 6

regeneration of epidermis

Answer 6

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

Question 7

desmosomes

Answer 7

connect kerotinocytes together

Question 8

hemidesmosomes

Answer 8

connect keratinocyte to basement membrane

Question 9

where are melanocytes?

Answer 9

stratum basale

Question 10

function of melanocytes

Answer 10

synthesize melanin in melanosomes

Question 11

what does melanin do

Answer 11

protect against tissue damage and degradation patters

Question 12

_____ increases production and changes of melanocytes

Answer 12

sunlight

Question 13

where are langerhans cells located

Answer 13

primarily in the stratum spinosum

Question 14

shape of langerhans cells

Answer 14

comma like appearance, appears pale

Question 15

function of langerhans cells

Answer 15

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

Question 16

birbeck granules

Answer 16

inside langerhans cells - cytoplasmic organelles that look like tennis racket

Question 17

where are merkel cells

Answer 17

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

Question 18

function of merkel cells

Answer 18

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

Question 19

stratum basale

Answer 19

deepest layer of the epidermis

Question 20

composition of stratum basale

Answer 20

keratinocytes, melanoyctes, langerhans, merkel

Question 21

stratum spinosum

Answer 21

• keratinocytes connected by desmosomes

- mitotically active in deeper region

Question 22

keratinocytes membrane coating granules

Answer 22

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

Question 23

stratum granulosum

Answer 23

most superficial layer in which nuclei are still present

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

Question 24

keratohyalin granules

Answer 24

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

Question 25

stratum lucidum

Answer 25

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

Question 26

cells if stratum lucidum

Answer 26

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

Question 27

eleidin

Answer 27

transformation product of keratohyaline

Question 28

stratum corneum

Answer 28

- most superficial layer - 15-20 layers of flattened, non nucleated "dead cells" - squames that are 14 polygon shaped

Question 29

outermost layer of stratum corneum

Answer 29

squames that are continuously shed by desquamation

Question 30

layers of the epidermis

Answer 30

``` corneum lucidum granulosum spinosum basale ``` come lets get some beer

Question 31

layers of the dermis

Answer 31

papillary and reticular | what beer? PbR

Question 32

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

Answer 32

type 1 collagen fibers and elastic fibers

Question 33

papillary layer

Answer 33

- 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

Question 34

meissner corpuscles

Answer 34

fine touch receptors

Question 35

reticular layer

Answer 35

- 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

Question 36

corpuscles of papillary layer

Answer 36

- contains capillary loops and meissner corpuscles (fine touch)

Question 37

corpuscles of reticular layer

Answer 37

pacinian corpuscles (pressure receptors) and kraus end bulbs

Question 38

arrector pili muscle

Answer 38

- smooth muscle - under sympathetic control - contracts to elevate hair - goose bumps

Question 39

name for sweat gland

Answer 39

eccrine

Question 40

eccrine sweat gland

Answer 40

- simple coiled tubular glands present in skin throughout the body

Question 41

shape of sebaceous gland

Answer 41

acinar stratified cuboidal

Question 42

secretory unit of eccrine sweat gland

Answer 42

- 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

Question 43

how do sweat glands secrete sweat?

Answer 43

contraction of myoepithelial cells

Question 44

dark cells

Answer 44

line the lumen of the gland in eccrine sweat unit

Question 45

clear cells

Answer 45

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

Question 46

location of apocrine sweat gland

Answer 46

anus, axilla, areola, cerumen of external ear

Question 47

function of apocrine sweat gland

Answer 47

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

Question 48

what makes apocrine glands smell

Answer 48

not secretions, but bacteria that digest secretions

Question 49

structure of sebaceous gland

Answer 49

secretory unit - branched acinar | duct - empties into neck of a hair follicle

Question 50

location of sebaceous gland

Answer 50

face, forehead, scalp | absent in thick skin (palms and soles)

Question 51

function of sebaceous gland

Answer 51

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

Question 52

types of secretion mechanisms

Answer 52

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

Question 53

holocrine secretion

Answer 53

release entire secretory cell and its contents

Question 54

merocrine secretion

Answer 54

exocytosis

Question 55

apocrine secretion

Answer 55

release part of apical cytoplasm

Question 56

myofibroblast

Answer 56

contains high amounts of actin and myosin for contraction | contracts during wound healing

Question 57

meissners corpuscles

Answer 57

- in dermal papillae of thick skin, eyelids, lips, and nipples - function in fine touch perception

Question 58

pacinian corpuscles

Answer 58

- 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

Question 59

shape of cells in dermis

Answer 59

stratified cuboidal epithelium in sweat glands