Homeostasis Flashcards
(24 cards)
physiological and behavioral systems are responsible for … the maintenance of a stable, balanced, internal environment
homestasis
changes in the internal environment can affect … the psychological process that induces or sustains a certain behavior
motivation
is the regulation of the body temp
thermoregulation
generate their own heat through internal processes, like metabolism and muscular activity
- this gives organisms an advantage they aren’t tied to certain environments
endotherms
who get most of their heat from the environment
- both try to maintain their temps within an ideal range for optimal functioning of cells: too hot and proteins lose their correct shape and malfunction, too cool and chemical reactions in the body occur too slowly
ectotherms
in keeping with thermoregulation… if a desired value, the set point, is deviated from, compensatory action begins. Once the desired value is reached, it feeds back and turns the system off
… systems are the primary homeostatic mechanism
The set zone refers to the range of tolerance in a system
negative feedback
- receptors in the skin, body core, and hypothalamus detect temp and transmit that information to the spinal cord, brainstem and hypothalamus
- if body temp is outside the set zone, these neural regions can initiate physiological and behavioral responses to return temp to the set zone
basic mammalian thermoregulatory system
physiological systems show … monitored by more than one mechanism
redundancy
there are 2 separate thermoregulatory systems in the rat hypothalamus:
- the … of the hypothalamus controls the physiological responses to cold, such as shivering and constriction of blood vessels
- the … controls behavioral regulation of temp, such as turning on heat lamps or cooling fans
pre-optic area (POA)
lateral hypothalamus
behavioral regulation of temp:
1. change … of the body surface (like huddling or extending limbs)
- change external … (by using clothing or nests)
- change … (moving into sun or shade)
- exposure
- insulation
- surroundings
thermoregulation through behavior is especially important to … but exhibited by endotherms as well
ectotherms
skin surface
body core
hypothalamus/POA
receptors
spinal cord
brainstem
hypothalamus/POA
neural regions
behavioral responses
- shivering
- heat-seeking/avoiding behaviors
physiological responses
- constriction or dilation of blood vessels
- sweating
- respiration
- thyroid hormone secretion
effectors
land animals must prevent dehydration – excessive water loss
fluid regulation
the fluid part of the body contained within cells (inside)
intracellular compartment
the fluid in the space outside of cells, divided between interstitial fluid (fluid between cells) and blood plasma (outside)
extracellular compartment
water is always moving between these compartments to ensure our cells:
have the water they need for processes
molecules of a substance (solute) dissolved in another substance (solvent) will move until a uniform concentration is achieved
diffusion
passive movement of solvent through a semipermeable membrane between solutions of different solute concentration until both sides become equal
osmosis
the force that pushes or pulls water across the membrane
osmotic pressure
if the extracellular fluid is … concentrated than 0.9% water will move out of the cells to the extracellular space
MORE
if the extracellular fluid is … than 0.9% NaCl, water will move into cells
LESS
both conditions can cause cells to :
not work properly or can be damaging
