Anatomy of the Integumentary System Flashcards
What does hirsute skin mean
hairy skin (covers most of the body)
what does glaborous skin mean
hairless skin (palm, sole, flexor aspects)
Histology of skin (superficial to deep)
epidermis
dermis
hypodermis/panniculus
5 layers of the epidermis
Stratum:
- corneum
- lucidum
- granulosum
- spinosum
- basale
Cells making up the epidermis
Other term for stratum basale
stratum germinativum (because it is the source of all epidermal cells)
How long is the typical cycle of cells from basale to corneum?
25-45 days
How many rows is stratum basale?
single row of stem cells
how many rows is stratum spinosum?
8-10 layers of spiny cells and weblike system of prekeratin filaments
what is abundant in the stratum spinosum
melanin granules and dendritic cells
Where do merkel cells hang out
stratum basale
where do langerhans cells hang out
stratum spinosum
how many layers is stratum granulosum?
3-5 layers of flat cells rich in lipids and filaggrin (water sealant)
How many rows are in the stratum lucidum?
a few rows of flat dead keratinocytes (palms and soles)
How many rows is stratum corneum?
20-30 rows of dead flat keratinized membranous sacs (dust)
Intercellular matrix is composed of
How many types of corpuscles are in the epidermis?
one, the merkel cell
What are the proteins in the epidermis?
keratine and fillagrin
what are the 4 types of cells in the epidermis?
keratinocytes, melanocytes, merkel cells, langerhan cells
What are the corpuscles of the dermis?
pacinian, meissner, and free nerve endings
What does the pacinian corpuscle sense?
pressure/vibrationwh
What does the Meissner corpuscle sense?
light touch
What does the Merkel’s corpuscle sense?
touch
What does the free nerve ending sense?
heat
What happens in bullous pemphigoid
autoantibodies form against antigens beneath the basale layer of the epidermis at the dermoepidermal junction
What happens in pemphigus vulgaris
autoantibodies form against antigens in the intercellular spaces of the epidermis leading to decreased adhesion of the cells and skin breakage
What happens in psoriasis
the rate of epidermal turnover is increased, not enough time for differentiation/maturation of cells
What happens in atopic dermatitis
mutations in filaggrin in the epidermis
melanocytic nevi is defined as
a benign collection of melanocytes
Basal cell carcinoma is composed of
cells that resemble the basal layer keratinocytes
What are the two layers of the dermis
Papillary and reticular
What does the papillary layer of the dermis do
-anchorage and metabolic support
-forms papillae that bulge into epidermis creating finger prints
what does the papillary layer of the dermis consist of
-collagen and elastic fibers and blood vessels
-capillary loops
-corpuscles (not merkel’s)
Which layer makes up 80% of the dermis
reticular layer
what is the reticular layer of the dermis made up of
thick collagen fibers: strength, resiliency
elastic fibers: stretch/recoil
glandular stuff
What are the cells of the dermis
fibroblasts, macrophages, sometimes mast cells and WBCs
What do fibroblasts do
- make most of extracellular matrix of connective tissue
- wound repair
- influenced by steroid hormones, diet, stress, vit C
What are keloids formed by
hyperactive fibroblasts leading to excessive collagen production
What are hypertrophied scars formed by
hyperactive fibroblasts, but more regulated than in keloids
What do mast cells do
- defense (especially around blood vessels)
- excrete vesicles containing histamine
- inflammation
- result in localized response like urticaria or generalized like anaphylactic shock
What do cleavage lines result from
collagen fibers arranged in bundles forming tension/cleavage lines
3 pigments of skin color
Melanin: yellow, reddish, brown, black
Carotene: yellow, orange
Hemoglobin: pinkish
What is the hypodermis made up of?
loose connective tissue, mostly aerolar/adipose
What is the hypodermis responsible for?
- shock absorption
- thermal insulation
- metabolic energy
-production of Vit C and conversion of hormones
What is a lipoma
benign tumor of fat
What happens in erythema nodosum
inflammation of hypodermis
What are the appendages of the skin
- sweat glands
- sebaceous glands
- hairs and follicles
- nails
What are the 2 types of sudoriferous glands
- eccrine: palms, soles, forehead
- apocrine: axilla, perianal, areolae, periumbilical
What are the 2 types of specialized apocrine glands
ceruminous glands (earwax) and mammary glands (breast milk)
What is the function of hair
alerting to bugs, guarding scalp from trauma, heat loss, sun
anatomy of hair
What is damaged/removed for hair to stop growing
dermal papilla
What is responsible for goosebumps
arrector pili (smooth muscle attached to hair follicle)
What are the 4 phases of hair growth
anagen/growng
catagen/involuting
telogen/resting
exogen/shedding
What does acne vulgaris result from
plugging of hair follicle as a result of abnormal keratinization
Structure of a nail
Functions of the skin
protection, temperature regulation, sensation, metabolic functions, blood reservoir, excretion, social communication
Rubor =
red
Calor =
hot
Tumor =
swelling
Dolor =
pain
What is inflammation
a protective response intended to eliminate cause of cell injury (acute or chronic)
4 steps of inflammation
vasoconstriction, vasodilation, vascular permeability, neutrophil margination
What happens in margination
What happens in diapedesis
what are the 4 outcomes of inflammation
- healing
- scarring
- abscess formation
- chronic inflammation
what is the primary cell involved in acute inflammation
neutorphils
what is the primary cell involved in chronic inflammation
lymphocytes
5 Rs of inflammation
- Recognition of agent
- Recruitment of leukocytes
- Removal of agent
- Regulation of response
- Resolution
Do permanent cells regenerate/replicate?
no (neurons/cardiac muscle)
Labile cells
- epi cells, stem cells
- regenerate thru life
stable cells
- hepatocytes, endothelium
- low level replication thru life
Primary union healing
- clean wounds
- surgical incision
Secondary union healing
- large tissue injuries
- larger scars
