C5 8-13 Flashcards
6 functions of the skin
Protection, temperature regulation, cutaneous sensation, metabolic functions, blood reservoir, excretion
Describe the functional relationship of arrector pili muscles to the hair follicles and the evolutionary significance of these muscles in humans.
Each hair follicle is associated with a muscle called arrector pili. When these muscles contract they pull the hair upright. Animals with significant amounts of hair use these to look larger and trap warm air in their fur. In humans, arrector pili are mostly vestigial, but do have a small function in forcing sebum out of hair follicles.
Apocrine sweat gland
FOUND IN: dermis, axillary/anogenital areas, less numerous type of sweat gland; SECRETE: water, salts, vit C, metabolic wastes, dermicidin (microbe killing peptide), proteins, fatty acids (more viscous than eccrine) ALSO: vaporizes less readily than eccrine
Eccrine glands
FOUND IN: dermis, all over body, abundant on the palms, soles of feet and the forehead SECRETE: water, salts, vit C, metabolic wastes, dermicidin (microbe killing peptide) ALSO: vaporizes more readily than apocrine, very good for cooling
3rd degree burn
A burn that involves the entire thickness of the skin; also called full thickness burn (epidermis and dermis)
1st degree burn
A burn in which only the epidermis is damaged
Pore
The surface opening of the duct of a sweat gland
Malignant
Life threatening; pertains to neoplasms that spread and lead to death, such as cancer
2nd degree burn
A burn in wich the epidermis and the upper region of the dermis are damaged
Arrector pilli
Tiny, smooth muscles attached to hair follicles; contraction causes the hair to stand upright
Rule of nines
Method of computing the extent of burns by dividing the body into a number of areas, each accounting for 9%
Sudoriferous gland
Epidermal gland that produces sweat
Hypodermis
SC tissue just deep to the skin; consists of adipose plus some areolar ct
Sweat facts
Has a 4-6 ph acid mantle which keeps bacteria from growing on skin. Controlled by sympathetic nervous system. Distributed over entire skin surface.
Skin function: Protection
Chemical barriers, physical/mechanical barriers/biological barriers
Skin function: Temperature regulation
Sweat cools, vasodilation/vasoconstriction, protects body from temp variation
Skin function: Cutaneous sensation
Detection of touch, pressure, pain, temp. Protects by being able to respond to harmful stimuli.
Skin function: Metabolic function
Sythesizes vitamin D, produces melanin and keratin, stores lipids
Skin function: Blood reservoir
Can store 5% of the body’s blood volume when it is not needed (like during exercise)
Skin function: Excretion
The body eliminates limited amounts of nitrogen-containing wastes in sweat. Salts and water also get sweated out.
Skin function: Protection: Chemical Barriers
Acid mantle: Low ph of skin secretions (sweat/lactic +fatty acids/epithleal cells) creates an acid mantle which is anti-fungal/antibacterial. Human defensin: skin cells also secrete natural antibiotics. Cathelicidins: antimicrobial peptides secreted by neutrophils/macrophages when skin is injured.
Skin function: Protection: Physical/mechanical barriers
Multiple layers resist abrasion, ect.
Skin function: Protection: biological barriers
immune system cells respond to antigens: Dermal macrophages dispose of viruses and bacteria. Langerhan’s cells
Why are burns life threatening?
Immediate threat: loss of body fluids containing proteins and electrolytes resulting in dehydration/electrolyte imbalance which can cause renal shutdown/circulatory shock. Later, infection is a danger.
When are burns considered critical?
2nd degree over 25% of body, over 10% of body with 3rd degree, or 3rd degree burns of face/hands/feet
Basal cell carcinoma?
Least malignant and most common, 80% of skin cancer. Stratum basale cells proliferate invading dermis/hypodermis. Most often on high sun exposure areas (face). Slow growing, rarely metastasizes.
Squamous cell carcinoma?
Second most common, happens in areas of sun-exposed skin. Happens in keratinocytes.
Malignant melanoma?
Cancer of the melanocytes; can begin wherever there is pigment. Cancerous melanocytes grow rapidly and metastasizethrough the lyphoid system. If detected early survival chances are good. Most dangerous skin cancer.
ABCDE for recognizing melanomas
Asymmetry(two sides don’t match) / Border irregularity(border has indentations) / Color(several present) / Diameter (>6mm) / Elevation
- Describe the interaction between sunlight and vitamin D3 synthesis.
When exposed to UV radiation, epidermal cells convert a steroid into vit D3.
The liver then converts D3 into an product used by the kidneys to synthesize the hormone calcitriol which is essential for the absorption of calcium and phosphorus by the small intestine.
