Integumentary System Flashcards
Major functions (4)
- physical/immunological protection
- thermoregulation
- sensation
-metabolic function ( vit D, stores fat)
Tissue Composition
1- epithelium
2- connective tissue
3- smooth muscle
4- nerve
Epithelium
covers surface, forms boundary
Connective tissue
supports epithelium- strength/resilant
Smooth muscle
controls blood vessel diameter (blushing), hair position (hair up/down)
Nerve
controls smooth muscle
generates sensation (tactile/temp etc)
stims exocrine glands
Structure of skin
Epidermis (TOP)
dermis- nerves, muscle, connective tissue
hypodermis - fat reserves (BOTTOM)
How to dermis and epidermis connect?
Epidermal ride + dermal papilla interlock (peak-and-valley) - RESIST shearing stress
Structure of epidermis (7)
- Stratum Corneum (superficial)
-stratum lucidum
-stratum granulosum
-stratum spinosum - stratum germinativum
- dermal papilla
-dermis
Stratum Germinativum
aka stratum basale (large basal cells)
-attached to basil lamina
- stem cells divide –> new keratinocytes
-
Stratum Spinosum
Made up of Keratinocytes –> contain tonofilaments (protein)
desmosomes (space in between) - attach keratinocytes together
last layer keratinocytes can divide
Stratum Granulosum
production of keratohyalin and keratin
secrete lipids - fill spaces bt/wn kertinocytes (water- repellent )
Stratum Lucidum
CLEAR LAYER
large amounts of keratin & thick plasma membranes
ONLY FOUND in volar skin
Stratum Corneum
layers of dead cell - continous shed
water repellant barrier
protect against abrasion
Thick vs think skin
Thin skin - thin stratum corneum
- less clear layers
- dermal papillae/epidermal ridges less developed
Dermis - Papillary layer
-thin layer
-areolar connective tissue
- increase area of contact w epidermis
-has nerve endings
Dermis- Reticular layer
- thick layer
- dense, irregular c. tissue
- elastic fibres
lines of cleavage
differently aligned collagen fiber bundles in the body
- align along lines of tension
Hypodermis structure
superficial fascia
stabalizes position of skin
loose connective tissue- stores fat
merkel cells
specialized skin cell
least common type
located in basal layer (stratum germinativum) - touch sensation
langerhans cells
originate in bone marrow - migrate to epidermis
phagocyte - immune response
Melanocyte
in between keratinocyte -produced melanin
Skin colour
blood supply to dermis
oxygenated hemoglobin- pink skin hue
deoxygenated hemoglobin- blue skin hue
blood vessel dilation (increase blood flow)- redness
three pigments
Carotene (yellow/orange)
pheomelanin (red/yellow)
melanin (brown/black)
melanin
in darker skin- melanosomes are lager, keratinocytes persist to more superficial layers if skin (pigmentation)
Exocrine glands
1) sweat - merocrine (eccerine) secretion –> exocytosis no cell death
2) sebaceous glands - secrete oily lipid –> coats hair and skin surface
-holocrine secretion –> secretory product invades cell which burst for product release CELL DEATH)
Sweat glands (2)
simple coiled tube glands
1) apocrine sweat glands - odiferous sweat –> Merocrine mechanism, specific to body region, secrete water, electrolytes, lipids, proteins (emotional stress/arousal)
2) Merocrine glands- normal sweat glands –> widespread, regulate body temp, secrete water/electolytes
Special apocrine sweat glands (2)
1) Ceruminous glands
modified sweat glands
secrete waxy cerumen (ear wax) via merocrine secretion
2) Mammary glands
specialized for milk production
apocrine secretion–> product released with shedding + no cell death
regulated by sexual/pituitary hormones
hair
covers all body surfaces except volar skin
uv protection/ thermal insulation
touch sensation/particle filtration
anatomy of a hair follicle
LOOK AT DIAGRAM
Types of hair (3)
1) Vellus hair - peach fuzz
2) Intermediate hairs- hairs of limbs, distribution based on sex hormones
3) terminal hairs - more pigmented, sclap, eyebrows etc
Hair growth cycle
Scalp-
2-6 years, rest = 3 months (no growth)
