Homeostasis and temperature regulation (Endotherms (mechanisms for…
Homeostasis and temperature regulation
The alveoli in mammalian lungs provide a large respiratory surface area but do not permit countercurrent exchange. Inhaled fresh air contains some CO2, but levels are higher in the lungs, so more CO2 is exhaled than inhaled; similarly, O2 levels are higher in fresh air, leading to an influx of O2.
a unique structure that affords birds the most efficient respiration of all terrestrial vertebrates. Unlike the mammalian lung, which ends in blind alveoli, the bird lung channels air through tiny air vessels called parabronchi, where gas exchange occurs. Air flows through the parabronchi in one direction only. This flow is similar to the unidirectional flow of water through a fish gill.
The great increase in diffusion surface area that gills provide enables aquatic organisms to extract far more oxygen from water than would be possible from their body surface alone.
meaning oxygenated water and blood move in the same direction. This route allows for only a 50% maximum for oxygen
The % saturation levels of oxygen in the fish’s blood will begin to increase but will never be higher that the % saturation levels of oxygen in the water. The % saturation level of oxygen will always be higher in the water
meaning oxygenated water (which has a higher partial pressure for oxygen than the fish’s blood) and blood move in opposite directions.
Cephalopod, mollusk, annelids, vertebrates
blood conveyed directly to organs
high pressure, rapid flow
don't have a true body city
less well regulated
organs bath in it
thermogenesis: 2 types shivering/non shivering
heat transfer mechanism used in animals
all sub. Have a heat of vap. The amount of energy needed to change them from a liquid to a gas phase
Water has a high heat of vap, and many org use water as a cooling source
trans. Of heat brought about by the movement of gas or a liquid. Maybe externally caused by the wind or due to density differences related to heating and cooling
small organisms have a relatively larger surface area for their mass, and they gain or lose heat more readily to the surroundings
larger the surface area relative to overall mass, the greater the conduction of heat.
transfer of heat by electromagnetic radiation, like the sun, does not require direct contact. Heat is trans. From hotter bodies to colder bodies by radiation
conditions that are constantly fluctuating and being monitored
Concentrations of glucose and oxygen
DO NOT HELP TO MAINTAIN HOMEOSTASIS. HIGHLY UNSTABLE
The effector drives the value of the controlled variable even farther from the set point
effectors act to change the value of the variable
gets it back to the set point
in-between endo and ecto
low metabolic mate
mechanisms for temperature homeostasis: behavior
source of heat is external (the sun)
mechanisms for temperature homeostasis: evaporative cooling (sweating/panting ), dilating/constricting the BV to increase or decrease heat exchange
INVERSE relationship: btwn body size and metabolic rate and O2 consumption
effect of body size
disadvantages: high metabolic rate required high and constant energy intake
advantages: sustained high energy activity
source of heat is internal (increasing metabilic rate or shivering )
based on a set point, regardless of external influencers
allow body temp to conform to the environment