whats animal physiology
its the study of how animal structures and systems function to maintain their life, how they exchange materials with the environment and maintain internal stability
what is homeostasis
its the maintenance of stable chemical and physical conditions inside cells, tissues and organs even though there are changes in the outside environment
why is homeostasis important for animals
because cellular processes can only function within narrow ranges of temp., ph, ion concentration and water balance
what type of deedback mechanism maintains homeostasis
negative feedback
what is negative feedback
a mechanism that a change in a variable triggers responses that reverse the change and restore the system back to its set point
components of a negative feedback loop
sensor - detects change
control center - processes information
effector - carries out the response
what are three environment factors that animals must regulate
- energy and nutrients
- temperature
- water and ions
what determines the rate of diffusion
Rate of diffusion =
k × A × (P2 − P1) / D
Where:
k = constant
A = surface area
P2 − P1 = concentration/partial pressure gradient
D = diffusion distance
three structural features that maximixe diffusion
1 - large surface area
2 - short diffusion distance
3 - maintaining a steep gradient
what is a countercurrent exchange
a mechanism where two fluids flow in opposite directions so that the gradient can be maintained across the entire exchange surface
why is countercurret exchange efficient
because it maintains a continous gradient, this allows for maximal transfer of heat or gases
example of countercurrent exchange
fish gills or heat exchange in animal limbs
what is osmoregulation
its the regulation of water and ion concentrations in bodily fluids
what are osmoconformers
they are animals whos internal osmolarity matches the environment
what are osmoregulators
animals that actively control internal salt concentration regardless of environmental conditions
freshwater fish osmotic challenge
bodily fluids are more concentrated than water therefore water enters body and ions diffuse out
how do freshwater fish compensate
they produce large volumes of filuted urine and actively uptake ions through gills
marine fish osmotic challenge
bodily fluids are less concentrated than seawater the results of this are water leaves the body and salt enters the body
what is diffusion
diffusion is passive movement of molecules from high concentration to low concentration
how do marine fish compensate
they drink seawater and excrete salt through gill chloride cells
diffusion is efficient over what distances
short distances only
what is bulk flow
movement of fluids driven by pressure differences
bulk flow is used for?
long-distance transport (blood circulation)
what is the function of circulatory systems
to move oxygen, nutrients, wastes and signals throughout the body
