integumentary system Flashcards
(24 cards)
what are the general functions of the integumentary system?
- physical and chemical protection
- synthesis of vitamin D
- involved in body temperature regulation and cutaneous sensation
location function and histology of papillary layer of dermis
location: deep to stratum basale of epidermis, superficial to reticular layer of dermis
function: has dermal papillae which contain capillaries, pain receptors and touch receptors
histology: areolar CT
location structure function and histology of epidermis
location: most superficial layer of the skin
structure: made up of 5 strata in thick skin, only 4 in thin skin
function: barrier to: physical damage, UV radiation, chemical exposure, water loss, etc.
histology: keratinized, stratified squamous epithelium
location function and histology of reticular layer of dermis
location: superficial to the hypodermis and deep to the papillary layer of the dermis
function: collagen allows it to be strong and resilient, elastin allows the stretch-recoil, holds water
histology: dense irregular CT
layers of the epidermis from superficial to deep? characteristics/appearances?
- stratum corneum (multiple layers of flattened, dead, interlocking keratinocytes. water resistant)
- stratum lucidum (appears glassy. thick skin only, like palms and feet)
- stratum granulosum (most superficial “living” layer)
- stratum spinosum (keratinocytes are bound together by desmosomes)
- stratum basale (deepest, basal layer. contains melanocytes)
what are keratinized cells held together by?
desmosomes
where does keratin production begin and then increase?
begins in stratum spinosum, increases in stratum granulosum
function, location, histology of hypodermis
function: anchors skin to underlying tissues, insulation, energy storage
location: just deep to dermis, superficial to fascia (CT that covers the skeletal muscles)
histology: mostly adipose tissue, or subcutaneous fat
compare and contrast the layers, location, and presence/absence of various structures in thick vs thin skin
layers:
thick has all 5
thin has 4 (no lucidum)
location:
thick=feet and palms
thin=everywhere else
structures:
thick=no hair follicles
thin=has hair
describe the process of keratinization and the function of keratin
process:
1. living keratinocytes are produced in the stratum basale by stem cells.
2. when new cells are produced, the older cells begin to get pushed up to the surface of the skin. as the cells migrate upwards, they begin to undergo changes.
3. in the stratum spinosum and stratum granulosum, the keratinocytes begin to produce a protein called keratin. the keratin begins to fill the cells and makes them rigid and hard.
4. the cells begin to flatten as they lose their nuclei and organelles. the keratin (and other proteins) in the cells forms a water-resistant barrier.
5. the cells in the stratum lucidum and stratum corneum are now considered fully dead and keratinized. the most superficial cells are continuously flaked off/shed and replaced by newer cells from below.
function: protection!
describe the process of function of melanin formation and the function of melanin
process: melanin is produced by melanocytes in the stratum basale and packaged into melanosomes that can pass into other cells
function: UV protection
structure and function of dermal papillae?
structure: made up of areolar CT and epidermal ridges. contain capillaries, sensory receptors, and sometimes lymphatic vessels
function: sensory function, nutrient supply, and helps anchor epidermis and dermis together
structure location and function of hair?
structure: composed mainly of dead, hard keratinized cells
location: root is deep in the dermis
function: warmth, sensation, protection
structure, location, and function of nails
structure: contains hard keratin
location: on fingertips and toe-tips
function: protection, enhanced dexterity, support, defence
structure function and location of sebaceous glands (function of secretions?)
structure: simple branched alveolar glands
function: secretion of sebum (oil and cell fragments)
location: dermis (typically reticular layer)
function of sebum: softens and lubricates hair and skin, is bactericidal
structure function and location of merocrine sudoriferous glands
structure: simple, coiled, tubular
function: secretes sweat to regulate temperature
location: found all over body (most common type), especially on palms, soles of feet, and forehead
function and location of apocrine sudoriferous glands
function: sweat in response to emotional stress
location: mainly in axillary and genital regions
structure function and location of ceruminous glands
structure: coiled, tubular
function: protect ear from particles entering it and to keep ears moist
location: lining of external ear canal
structure function and location of mammary glands
structure: modified sweat glands
function: milk secretion
location: contained within the hypodermis
