Integument

Front 1

origin of melanocytes?

Back 1

neural crest

Front 2

Apocrine sweat glands:
associated with?
when are they fxnl?
innervation?
how do they release product?

Back 2

assoc w hair follicles
fxnl after puberty
innervated by adrenergic fibers
release by merocrine secretion

Front 3

in what layer of the skin are apocrine sweat glands located?

Back 3

reticular dermis

Front 4

where will you NOT find thin skin?

Back 4

palms of hands, soles of feet.

Front 5

where are mitotically active keratinocytes located?

Back 5

s. basale and deep portion of s. spinosum

Front 6

what do langerhans' cells do?

Back 6

play role in immune response as Ag presenting cells

Front 7

Describe granules of Merkel cells

Back 7

80nm, dense cored, neurosecretory, resemble those of adrenal medulla and carotid body

Front 8

What do Pacinian corpuscles look like, where are they located, and what do they do?

Back 8

large, ovoid, found in deeper dermis, respond to pressure and vibration

Front 9

What do lamellar bodies do?

Back 9

contribute to formation of intercellular epidermal water barrier

Front 10

What kind of receptors are Meisner's corpuscles? Where are they located.

Back 10

touch receptors, responsive to low freq stimuli in papillary dermis of hairless skin

Front 11

T/F: There are desmosomal connections between keratinocytes and melanocytes

Back 11

F. But they do interact by cytocrine secretion (melanocytes --> keratinocytes)

Front 12

T/F: melanocytes contain more melanin granules than keratinocytes

Back 12

F

Front 13

T/F: melanocytes are found in approximately equivalent numbers in all races

Back 13

T

Front 14

What is the fxn of Merkel cells?

Back 14

fxn in cutaneous sensation

Front 15

What type of skin is represented by PROMINENT s. corneum, robust s. granulosum and distinct s. lucidum?

Back 15

THICK SKIN (thin skin has less prominent s. corneum, poorly developed granulosum and no obv s. lucidum)

Front 16

What type of skin covers most of the body surface?

Back 16

THIN SKIN

Front 17

What type of skin is found on palms of hands/soles of feet?

Back 17

THICK SKIN

Front 18

Name three things that thin skin contains that thick skin does not.

Back 18

hair follicles, sebaceous glands, and arrector pili muscles (all assoc with hair, and thick skin is assoc w palms and soles which have no hair)

Front 19

Epidermis is developmentally derived from....?

Back 19

ectoderm

Front 20

what type of cell makes up >90% of epidermis?

Back 20

keratinocytes

Front 21

regenerative capacity of skin? High/low?

Back 21

highly regenerative (replaced every ~30days)

Front 22

What is responsible for our fingerprints?

Back 22

the epidermal ridges formed by dermal papillae on which the epidermis rests.

Front 23

Name and describe deepest layer of dermis.

Back 23

s. basale, simple cuboidal cells resting on basal lamina and attached to it by anchoring fibrils and hemidesmosomes

Front 24

what is the most mitotically active layer of the epidermis?

Back 24

s. basale (contains stem cells from which new keratinocytes are derived and rise to upper strata)

Front 25

Where are melanocytes and Merkel's cells located?

Back 25

s. basale

Front 26

What is the most prominent layer of the epidermis and what does it look like?

Back 26

s. spinosum, several cell layers thick, called spinous or prickle cell layer (shrinking and desmosome cnxns give this look) areas of memb thickening due to desmosomes called nodes of bizzozero

Front 27

What happens to the cells of the epidermis as they rise and mature?

Back 27

cytoplasm increases, become more flattened

Front 28

what important proteins do the cells of s. granulosum contain?

Back 28

keratohyalin (granules) and keratin (filaments). responsible for waterproofing of the skin

Front 29

what is filaggrin?

Back 29

protein that aggregates keratin filaments in the s. corneum. its presence is a marker of keratinocyte apoptosis

Front 30

what is the most superficial layer of epidermis in which cells are nucleated?

Back 30

s. granulosum

Front 31

what layer of epidermis is found only in thick skin?

Back 31

s. lucidum (just superficial to s. granulosum)

Front 32

cells of s. lucidum are rich in what important substance?

Back 32

eleidin (a metabolite of keratohyalin)

Front 33

what is the most superficial layer of epidermis? what type of skin is it found in?

Back 33

s. corneum, only in THICK skin
(aka SQUAMES, shed by desquamation)

Front 34

Characteristics of s.basale keratinocytes

Back 34

basophilic (lots of free ribosomes), long axis perpendicular to s.basale, lots of tonofilaments (int/keratin), high metabolic activity

Front 35

Characteristics of s.spinosum keratinocytes

Back 35

more eosinophilic, inc. tonofilaments, cuboidal, central nuc, in upper layer, start to synth keratohyalin and lamellar bodies

Front 36

What are lamellar bodies?

Back 36

membrane coating granules, fuse with PM and spill glycolipid sheets from within onto surface of cell (for waterproofing)
mostly in s.granulosum

Front 37

Characteristics of s. granulosum keratinocytes

Back 37

lg amts of keratohyalin granules (no membrane), flattened, lots of lamellar bodies

Front 38

Characteristics of s.lucidum keratinocytes

Back 38

weakly eosinophilic, extremely flat, no nuc, densely packed filaments in electron dense matrix

Front 39

Characteristics of s.corneum keratinocytes

Back 39

eosinophilic, lg amts of keratin, very flat, no nuc,

Front 40

What layer of epidermis are melanocytes found?

Back 40

s.basale

Front 41

Melanosomes contain melanin within melanocytes. What other protein is in melanosomes?

Back 41

tyrosinase - UV sensitive enzyme involved in melanin synthesis

Front 42

What type of melanin is responsible for brown/black pigments? reddish-yellow pigments?

Back 42

eumelanin, pheomelanin (this is most apparent in the hair)

Front 43

Brief description of melanogenesis

Back 43

1. vesicle surrounded by membrane: premelanosome. orderly arrangement of tyrosinase at periphery
2. ovoid melanosome vesicle, parallel filaments w cross-striations on which melanin is deposited
3. increased melanin formation
4. melanin fills vesicle, cytocrine secretion into keratinocyte

Front 44

Explain cytocrine secretion and name the cell that uses it

Back 44

exocytosis with concomitant endocytosis. transfer of melanosomes to keratinocytes with v. little cytoplasm transfer

Front 45

What is lacking in Addison's disease?

Back 45

cortisol from adrenal cortex, too much ACTH --> increase in pigmentation

Front 46

What causes albinism?

Back 46

inability of mellanocytes to synthesize melanin due to absence of tyrosinase or inability of cells to take up tyrosine

Front 47

What disease is marked by degeneration & disappearance of entire melanocytes?

Back 47

vitiligo

Front 48

What are Langerhans' cells?
What layer are they located in?

Back 48

immune response, delayed hypersensitivity rxns, s. spinosum (originate in bone marrow)

Front 49

Describe and name granules of langerhans' cells.

Back 49

paddle shaped, Birbeck granules, involved in activation of Tcells

Front 50

What cells are characterized by a lack of desmosomal connections, lack of tonofilaments and an indented nuc?

Back 50

Langerhans' cells

Front 51

What do Merkel's cells do? Where are they located?

Back 51

role in perception and local endocrine cntrl, located in s.basale and concentrated where sensory perception in acute (fingertips)

Front 52

How do Merkel's cells differ ultrastructurally with Langerhans' cells?

Back 52

Merkel's contain tonofilaments and desmosomes and have a lobed nucleus (vs. indented) Both types of cells, however, stain clear on H&E

Front 53

origin of dermis?

what are the layers?

Back 53

mesoderm

papillary and reticular layers

Front 54

What types of CT are present in dermis?

Back 54

dense, irregular CT containing type I collagen and thick elastic fibers

Front 55

what layer of dermis contains capillary loops? what do they do?

Back 55

papillary dermis, caps nourish but do not enter epidermis

Front 56

What are Meissner's corpuscles? In what layer of the skin are they located?

Back 56

fine touch sensory receptors of the papillary dermis

Front 57

What are langer's lines? Where are they located?

Back 57

dense bundles of type I collagen and thick elastic fibers oriented into regular lines of tension (if you cut along these lines, it heals better)

Front 58

Which layer of dermis is:
thicker?
most cellular?
has most leukocytes?

Back 58

Reticular layer is thicker
Papillary layer is most cellular
Reticular layer has more leukocytes

Front 59

What are pacinian corpuscles?

Back 59

pressure receptors in Reticular dermis

Front 60

What are Krause's end-bulbs?

Back 60

Cold and pressure receptors in reticular dermis

Front 61

in what area of the dermis are hair follicles and glands found?

Back 61

reticular layer of dermis of thin skin

Front 62

what type of nerves are sensory receptors of the skin?

Back 62

peripheral terminals of afferent nerves

Front 63

What types of things do EFFERENT nerve endings supply in the skin?

Back 63

blood vessels, arrector pili muscles and sweat glands

Front 64

What type of nerve ending lack a connective tissue of Schwann cell investment?

Back 64

free nerve endings

Front 65

Where do free nerve endings terminate and what kind of info do they relay?

Back 65

terminate in s.granulosum and relay info abt fine touch, heat and cold, esp found around hair follicles that serve as mechanoreceptors (cats whiskers)

Front 66

What type of nerve endings are enclosed in a CT capsule? What are the 3 types of this category?

Back 66

encapsulated nerve endings, Pacinian corpuscles, Meissner's corpuscles, Ruffini's corpuscles

Front 67

What are Pacinian corpuscles?
where are they found?

Back 67

encapsulated nerve endings, myelinated, in deeper area of reticular dermis (esp fingertips, joints, periosteum, internal organs)
(organized multilayer capsule)

Front 68

What are Meissner's corpuscles? Where are they found?

Back 68

encapsulated nerve endings, unmyelinated, located in papillary dermis in hairless skin
(irreg lamellae)

Front 69

What do Meissner's corpuscles convey?

Back 69

touch reception, low freq vibrations

Front 70

What are Ruffini's corpuscles? Where are they found?

Back 70

encapsulated nerve endings, unmyelinated endings of myelinated fibers, spiral path, in reticular dermis, hypodermis and CT of mesenteries, joints, digits and breasts

Front 71

What do Ruffini's corpuscles convey?

Back 71

pressure and touch reception

Front 72

How are epidermal skin appendages derived? Name 3 things that fall under this category.

Back 72

derived from downgrowths of epidermal epithelium during development.
include hair follicles (and hair), sebaceous glands and apocrine sweat glands

Front 73

What is the pilosebaceous apparatus?

Back 73

consists of hair follicle and its assoc. sebaceous and apocrine sweat glands

Front 74

Name the 3 parts of the hair follicle.

Back 74

Infundibulum, Isthmus, Inferior segment

Front 75

Where does the infundibulum extend?

Back 75

from the surface opening of the follicle to the opening of its sebaceous gland (part of the pilosebaceous canal thru which sebum is discharged)

Front 76

Where does the isthmus extend?

Back 76

from infundibulum to level of insertion of the arrector pili muscle in reticular layer of dermis.

Front 77

What is the arrector pili muscle?

Back 77

attaches to dermal sheath around hair follicle, extendes superfic. to underlie sebaceous gland, inserts into papillary layer, is SMOOTH MUSCLE. elevates the hair

Front 78

Where does the inferior segment extend?

Back 78

extends from arrector pili muscle to the dermal papilla at bottom of the bulb

Front 79

What is the dermal papilla of the hair follicle?

Back 79

tuft of highly vascularized loose connective tissue at the base of the bulb

Front 80

What are the matrix cells of the bulb of the hair follicle?

Back 80

represent the germinative layer of the follicle, divide and account for hair growth, and differentiate into keratin producing cells and internal root sheath

Front 81

What are the 3 layers of the internal root sheath? and describe

Back 81

CUTICLE(innermost) - squam cells, touches hair shaft
HUXLEY's layer (middle)
HENLE's layer (outermost) - designated external root sheath

Front 82

Where in the hair follicle are melanocytes located?

Back 82

in the base of the bulb

Front 83

What are the 3 layers of hair? What type of skin is it found in?

Back 83

Medulla (innermost) (only in thick hairs)
Cortex
Cuticle (outermost)
found in THIN SKIN

Front 84

Describe the cortex of a hair

Back 84

contains cuboidal cells
undergo differentiation into keratin-filled cells

Front 85

Describe the cuticle of the hair. What layer of the hair follicle is it continuous with?

Back 85

contains squamous cells, outermost layer of hair, contiguous with the cuticle of the internal root sheath.

Front 86

What part of the hair follicle are sebaceous glands an outgrowth of?

Back 86

the external root sheath

Front 87

T/F: There is one sebaceous gland associated with each hair follicle.

Back 87

F. There are usually several glands assoc. with each hair follicle

Front 88

What part of body are sebaceous glands most abundant?

Back 88

face, forehead, scalp (greasy areas)

Front 89

What type of secretion do sebaceous glands use and what do they secrete?

Back 89

holocrine (release entire cytoplasm upon secretion) secretion of SEBUM

Front 90

What is the function of sebum?

Back 90

coats hair follicle and surface of skin to provide bacteriostatic, emollient, barrier, and phermonal fxn

Front 91

Describe steps of sebum production

Back 91

1. mitotically active cells @ periphery of acini divide
2. daughter cells synthesize lipid-rich secretory product in cytoplasm
3. nuc shrink, cells disintegrate, secretory product released into pilosebaceous canal

Front 92

Name purpose and types of sweat glands

Back 92

purpose: body temp regulation, rid body of waste
types: eccrine and apocrine

Front 93

T/F: Eccrine sweat glands are NOT associated with hair follicles

Back 93

T and they are formed from downgrowths of epithelium

Front 94

What composes the secretory unit of eccrine sweat glands?

Back 94

dark cells, clear cells and myoepithelial cells

Front 95

Describe dark cells?

Back 95

line lumen of eccrine sweat glands, contain secretory granules, and a mucous-rich material

Front 96

Describe clear cells

Back 96

underlie dark cells, rich in mito adn glycogen, contain intercellular canaliculi which extend into lumen, secrete watery, electrolyte-rich material

Front 97

Describe myoepithelial cells

Back 97

form incomplete layer btwn clear cells and basal lamina of eccrine sweat glands, contract and aid in gland's secretions into the duct

Front 98

Which type of sweat gland has a more narrow duct and which has a larger duct?

Back 98

eccrine have a narrow duct, apocrine have larger ducts

Front 99

what type of cells are found in the duct of an eccrine sweat gland and what does it do?

Back 99

lined by stratified cuboidal, serve to modify secretory product by absorbing electrolytes and excreting ions, urea, lactic acid, drugs, etc

Front 100

What are apocrine sweat glands always assoc with?

Back 100

hair follicles

Front 101

Where are apocrine sweat glands typically found on the body?

Back 101

axilla, areola and perianal region and ceruminous (wax) glands of ear

Front 102

Which type of glands are not active until puberty?

Back 102

apocrine sweat glands. they are responsive to hormonal influences

Front 103

In what layer of skin are apocrine sweat glands located?

Back 103

reticular dermis or hypodermis, enveloped by myoepithelial cells

Front 104

How are apocrine sweat glands innervated?

Back 104

adrenergic fibers

Front 105

Which type of gland is associated with emotional sweating?

Back 105

apocrine sweat glands

Front 106

What layers of skin form the nail bed?

Back 106

s. basale and s.spinosum are continuous with the nail bed

Front 107

What is another name for the fold of skin covering the proximal end of the nail and aka the cuticle? What layer of skin is it continuous with?

Back 107

eponychium, continuous with the s.corneum

Front 108

Where do nails grow from?

Back 108

mitoses of cells in the matrix of the nail root