Chapter 5 Integumentary System (Intro integumentary (5 majors funtions…
superficial partial- thickness (1st degree) a. epidermis only
b. reddening due to increased blood flow
c. mild pain
d. common sunburns
e. heals in a few days-2 weeks
Deep partial- thickness burns (2nd degree) a. epidermis and some dermal damage
b. reddening and blistering caused by blood vessel damage
c. moderate pain
d. common to physical contact with hot objects
e. heals in 2-6 weeks without scars unless infected.
Full- thickness burns (3rd degree) a. epidermis, entire dermis and potentially subcutaneal damage
b. dry, leathery tissue with red or black color
c. severe pain
d. caused by prolonged heat or chemical contact
e. healing rarely occurs due to lack of surviving skin cells, skin replacements (grafts) are usually needed, usually extensive scarring
-autographs: transplant from yourself
Homographs- temporary transplant from cadaver
5-9 How skin responds to injury and repairs itself (Regulation of body temperature= normally near 98.6 degrees F set point)
- Heat production is mostly a by- product of a cellular metabolism.
- Heat loss is controlled : by regulating dermal blood flow.
A. Vasodilation- increases dermal blood flow, which also increases heat loss.
B. Vasconstriction- decreases derma blood flow which decreases heat loss
- Heat loss is by 4 methods
-most heat loss by this mode
-infrared heat rays move from area of high (the blood) to areas of low heat (the environment)
-less heat loss
-heat moves by physical contact
- the reason the seat you sit in is warm when you stand up
-heat loss to surrounding air
-increases as air movement increases. that is why turning on a fan cools your body
-heat loss varies
- if heat increases our sweating increases, so we lose more heat by evaporating the sweat on the surface of our skin.
- Low body temperature require heat loss to be minimized a. The hypothalamus signals for sweating to decrease (decreasing heat loss by evaporation) and dermal vasoconstriction (decreasing heat loss by radiation).
b. Usually this brings the body temperature back to normal.
- If the body temperature remains low after the above action.
a. Heat must be produced
b. Shivering occurs and the tiny muscle contractions involved produce heat.
Problems in temperature regulation
Hyperthermia-elevated body temperature
2 common causes
-humid air decreases evaporation
-air temperature exceeds body temperature, thus heat is gained not loss
Hypothermia- low body temperature
-very dangerous if core body temperature drops below 94 F
-limbs can withstand about 65 F because they contain no vital organs.