HSA MA Ch. 9 Integumentary System

the skin takes up how much of your weight

15%

5 functions of the skin

protects against microorganisms, regulates temp/heat, secretion/excretion, absorption/sensation, perception

what does the brain do when it senses the body is becoming too warm?

it sends messages to the surface vessels to dilate which allows heat from the blood to escape and therefore cool the body

if heat has to be retained what happens to the vessels?

they constrict to trap heat in the blood to reduce loss of heat so that body can remain at temp of adequate level

hair follicles

allow for absorption of materials; this allows it to be used for treating certain conditions like anti motion sickness patches (on the skin behind ear) and in paste form on the chest to treat certain heart conditions, the advantages are “timed release,” which spreads medication evenly over a long period

skin’s function of excretion

eliminates water and salt and minute amount of other waste products

skin is composed of 3 layers+functions

epidermis: top layer; contains cells that produce pigment (melanin) +protect immune system

dermis: middle layer; contains nerve endings, oil, hair follicles, sweat glands, blood vessels

subcutaneous tissue: made of fat (for insulation and cushion), connective tissue, and larger blood vessels 

why do wrinkles occur?

as ppl age, elastic fibers in dermis increase while collagen in dermis decreases, this makes support for epidermis decreased therefore producing wrinkles

4 major organs of skin

1. sweat glands: found in dermis

2. sebaceous (oil) glands: found in dermis; are in or near hair follicle

3. hair

4. nails

acne

forms by the sebaceous glands get plugged by overgrowth of cell leading to formation of too much oil

goosebumps

occur bc of the arrector pili muscle which is attached to hair follicle when it contracts bc of cold emotions (like fear or awe), it pulls the hair upright and creates the raised bump on the skin

hard keratin

found in nails and hair; more permanent than soft and does not drop off so has to be cut

soft keratin

found in epidermis

melanocytes

protect underlying skin from damage by the sun; in light skin ppl melanin found bottom of epidermis wheras darker skin has them throughout epidermis

freckles

small areas of melanin pigment

albinism

little to no pigment; this means no pigment in eyes which means sun and artifical light cannot be filtered out so will have sensitive eyes; also have to protetc skin more bc more suseceptible to skin cancer

carotene

yellow pigment

Skin is often used to test and diagnose disorder and disease, for ex:

allergy testing and TB testing

ABCDEs of melanoma

A- asymmetric (one half is unlike the other)

B- border (blurry and/or jagged edges)

C- color (more than one shade of color)

D- diameter (greater than 6 mm)

E- evolving ( watch for changes over time)