Integument Flashcards
what is the integument?
skin + appendages (nails, claws, hair, sweat glands, sebaceous glands)
what does the integument do?
barrier for protection
provides immunologic information
conveys sensory information
excretion —> waste products
thermoregulation –> blood flow, sweating/panting
what are the 3 skin layers?
epidermis, dermis, hypodermis
top ———————– bottom
what is the hypodermis?
is loose CT with fat
NOT A PART OF SKIN LAYERS
fat storage
contains large blood vessels —> superficial fascia
what is the rete apparatus?
is the interdigitations of epidermal ridges and dermal ridges (papillae)
attach epidermis to dermis
what is some general information about the epidermis?
stratified squamous keratinized epithelium —> means cells on top are dead
avascular –> b/c epithelial tissue
continuously renewed by mitosis
what is the difference between thick skin and thin skin?
DEPENDS ON THICKNESS OF THE EPIDERMIS
describe thick skin/the characteristics
-glabrous, smooth, non hairy
found on the palm and soles
LACKS HAIR FOLLICLES/SEBACEOUS GLANDS
describe thin skin
hairy
3-4 layers of epidermis
found on most of body
HAS HAIR FOLLICLES, SEBACEOUS GLANDS, AND SOMETIMES SWEAT GLANDS
what is the main cell in the epidermis?
keratinocytes
name the layers of the epidermis from superficial to deep
-stratum corneum
-stratum lucidum
-stratum granulosum
-stratum spinosum
-stratum basale
move up as they age
C.L.G.S.B
cats love great soggy boots
what is the stratum basale? what is another name for it?
aka stratum germanitivum
basophilic cytoplasm
cells lie on basement membrane
actively dividing cells
what are some stratum basale characteristics?
large nucleus
abundant free ribosomes
produce intermediate filaments (keratin) = tonofilaments
bundled into tonofibrils in stratum basale and stratum spinosum
contains desmosomes and hemidesmosomes
where are melanocytes located?
stratum basale
describe melanocytes
-no desmosomes
-number of melanocytes are the same in all groups, but their distribution varies
describe stratum spinosum. why is it called the prickle cell layer?
multiple cell layers
cell layer adjacent to s. basale mitotically active
prickles are where desmosomes are still clinging on
cuboidal or slightly flattened cells with a central nucleus
what are the nodes of bizzozero in the stratum spinosum
cells bound together by filament-filled cytoplasmic spines and desmosomes
where are langerhans cells located?
what are they?
stratum spinosum
are specialized macrophages —> b/c they just live in the skin
describe the stratum granulosum
is 3-5 layers of cells
last layer with nuclei
lysosomal enzymes digest organelles
TWO TYPES OF GRANULES: keratohyalin (arrows) and lamellar granules (bodies)
what are the lamellar bodies associated with in the stratum granulosum?
discharges a lipid-rich content —> acts to serve as a barrier for foreign materials –> water proofs the skin
produced in: golgi apparatus
what are the purpose of keratohyalin granules in the stratum granulosum?
made by ribosomes and are associated with tonofibrils to help strengthen them
describe stratum lucidum
likely just an artifact
only in thick skin
no nuclei or organelles
contain densely packed keratin
clear, thin eosinophilic layer of extremely flattened cells
describe stratum corneum
-15-20 layers of flattened, non-nucleated, keratinized cells with thick membranes and no organelles
-more layers in thick skin
in the deep layers: cells held together by desmosomes
in the superficial layers: cells lose desmosomes and undergo desquamation
describe the dermis
has CT that layers deep to the epidermis
is separated from stratum basale by a basement membrane
is vascularized
nourishes epidermis
what are tension lines/cleavage lines/langer lines?
IN THE DERMIS
is a pattern of distribution of type 1 collagen fibers
determines tension and wrinkle lines in skin
determines pace and nature of wound healing
what are the two layers of the dermis?
papillary and reticular
describe the papillary layer
has loose CT, interdigitates with epidermis, RETE APPARATUS
-contains collagen fibers (type 1 and 3)
-contains elastic fibers
-contains anchoring fibrils that extend from the basal lamina into the papillary layer
describe the reticular layer
dense, irregular CT
NOT AN ABUNDANCE OF RETICULAR FIBERS JUST A RETICULAR NETWORK
type 1 collagen fibers, thick elastic fibers, smooth muscle (arrector pilli)
epidermally derived glands (b/c same color)
hair follicles
what are derived from the epithelium of the epidermis?
claws, nails, hair, sweat glands, and sebaceous glands
define hair
elongated keratinized structures derived from invaginations of epidermal epithelium
describe sebaceous glands
-produce sebum (waxy texture) —> hair follicle has to have sebum on it for it to be healthy
-located all over body (except palms, soles, sides of feet)
-most abundant on face, forehead and scalp
-lie within fibrous sheath surrounding each hair follicle
-cradled by arrector pilli muscles
what type of secretions do sebaceous glands do? describe the secretion
holocrine secretion –> destruction of the cell
what is the bottom layer of sebaceous glands called? describe it
acinus layer –> is the basal layer of undifferentiated flattened epithelial cells that rest on the basal lamina
packed with lipid filled vacuoles
what are the two types of sweat glands?
eccrine and apocrine sweat glands
describe eccrine sweat glands
are simple coiled tubular glands
ducts open on skin surface –> NOT ASSOCIATED WITH HAIRS
invaginations of epithelium into dermis/hypodermis
location species-specific
merocrine secretion
what is merocrine secretion?
exocytosis, cells not damaged during secretion
describe apocrine sweat glands
open into canals of the hair follicles just superficial to the entry of the sebaceous gland ducts
contain pheromones
at axilla/around anus: secrete milky product, odorless until metabolized by bacteria
difference between apocrine and eccrine sweat glands on histology slides
apocrine have big lumens –> bc secretory product is stored here
