Homeostatis and Feedback Mechanism Flashcards
refers to the relatively stable state inside the body of an animal.
Homeostasis
These conditions remain stable because of physiologic processes that result in ____ relationships.
negative feedback
Homeostatic mechanisms keep the body in _____ by constantly adjusting to the changes that the body’s systems encounter.
dynamic equilibrium
A change in the internal or external environment is called a ____ and is detected by a ___; the response of the system is to adjust the activities of the system so the value moves back toward the set point.
stimulus; receptor
Two examples of factors that are regulated homeostatically are ___ and ____
temperature; water content
The goal of homeostasis is the maintenance of equilibrium around a point or value called a ____
set point
Any homeostatic process that changes the direction of the stimulus is a ____. It may either increase or decrease the stimulus, but the stimulus is not allowed to continue as it did before the receptor sensed it. In other words, if a level is too high, the body does something to bring it down, and conversely, if a level is too low, the body does something to make it go up.
negative feedback loop
maintains the direction of the stimulus, possibly accelerating it. Few example exist in animal bodies, but one is found in the cascade of chemical reactions that result in blood clotting, or coagulation. As one clotting factor is activated, it activates the next factor in sequence until a fibrin elot is achieved. The direction is maintained, not changed.
positive feedback loop
Animals that do not control their body temperature are called ___ .
ectotherms
_____ are animals with constantly varying internal temperatures.
poikilotherms
An animal that maintains a constant body temperature in the face of environmental changes is called a ____
homeotherm
The processes of homeostasis and temperature control are centered in the ____ of the advanced animal brain.
hypothalamus
It maintains the set point for body temperature through reflexes that cause vasodilation or vasoconstriction, as needed for shivering or sweating
Hypothalamus
the diffusion of water across a membrane in response to osmotic pressure caused by an imbalance of molecules on either side of the membrane
Osmosis
is the process of maintenance of salt and water balance (osmotic balance) across membranes within the body’s fluids, which are composed of water, plus electrolytes and non-electrolytes
Osmoregulation
a solute that dissociates into ions when dissolved in water.
electrolyte
