Circulation Flashcards
(84 cards)
What do unicellular organisms use to exchange material with their environment directly
diffusion
when is diffusion efficient
small distances
How do protosomes exchange material with their environment
through diffusion, they live in aquatic environments with thin body walls
what do gastrovascular cavities do
minimize diffusion distances for digestion and circulation
what are the three components of a CS
circulatory fluid, interconnecting vessels, muscular pump
what are the two types of CS
open and closed
what does a CS do?
connects fluid that surrounds cells with organs that exchange gases, nutrients, wastes
What are open Cs
no distinction between blood and IF (hemolymph)
What organisms have open systems
insects, arthropods, molluscs
what are some characteristics in an open CS
internal fluid is circulated through body cavity, pressure rapidly dissipates (requires a faster heart rate or accessory hearts)
what is a closed Cs
blood is confined to vessels and is distinct from IF
where do substances move between in a closed CS
blood —> IF, IF —> cells
what is a key characteristic of closed CS
more efficient at transport (maintain pressure gradients)
What are arteries
carry blood away from the heart to capillaries
what are veins
return blood from capillaries to heart
what are capillary beds and their function
networks of capillaries, sites of chemical exchange between blood and IF
What animals use single circulation, how many heart chambers do they have?
fish, rays, sharks, two or more chambers
Single circulation pathway
Atrium, Ventricle, Gill capillary beds, Body capillary beds
what is a disadvantage of single circulatio
low pressure, no fresh perfusion to the heart
How many chambers do amphibian hearts have
3, 2 atria and 1 ventricle
what is the pathway of double circulation in amphibians
the ventricle pumps blood into a forked artery that goes into the pulmonary and systemic circuit
what can amphibians do to their bloodflow
can shut off the blood flow to lungs when underwater
how many heart chambers do mammals and birds have
four (2 atria, 2 ventricles)
What is the function of the systemic circuit
carries oxygen rich blood from heart to the rest of the body