exam 3 chapter 9 Flashcards
homeostasis
refers to temperature regulation and other biological processes that keep certain body variables within a fixed range
set point
single value that the body works to maintain
(water, oxygen, glucose, etc.)
negative feedback
processes that reduce discrepancies from the set point
allostasis
refers to the adaptive way in which the body anticipates needs depending on the situation
basal metabolism
energy used to maintain a constant body temperature while at rest
poikilothermic (ectothermic)
refers to the idea that the body temperature matches that of the environment
(cold-blooded)
homeothermic (endothermic)
refers to the use of internal physiological mechanisms to maintain an almost constant body temperature
(requires energy and fuel)
mammals have evolved to have a constant temperature of …?
98 Fº / 37 Cº
preoptic area/anterior hypothalamus (POA/AH)
receives input from temperature receptors throughout the body
immune system delivers …
prostaglandins and histamines
- causes shivering, increased metabolism, and fever
fever
reflects an increased body temperature set point, directed by the hypothalamus
functions of fever
bacteria grows less vigorously, immune system works harder
fever of above what temperature hurts body more than it helps
103 Fº
(109 Fº is life threatening)
cytokines
small proteins that attack intruders but also stimulate the vagus nerve
water constitutes what percent of the mammalian body
70%
water can be conserved by…
-excreting concentrated urine
-decreasing sweat and other autonomic responses
vasopressin
hormone that raises blood pressure, helps to compensate for decreased water volume
vasopressin water regulation pathway
posterior pituary gland, vasopressin, elevate blood pressure
osmotic thirst
results from eating salty foods
hypovolemic thirst
resulting from loss of fluids due to bleeding or sweating