Lecture 14 - Circulation Flashcards
When are circulatory systems needed?
when diffusion distances are too big
how is the medium moved in diffusion only circulation?
cilia
how does diffusion only circulation work?
•uses direct uptake from
environment
Thickness of tissue
layers is limited
What is often used other than circulator systems to transport nutrients?
Gastrovascular cavity
•diffusion of nutrients etc over short distance
When Are circulatory systems needed?
needed when diffusion distances are too big
two types circulatory systems?
•open or closed
describe the Annelid circulatory system?
-Closed system
- has Many contractile
vessels
how much of the body volume of vertebrates is blood?
5-10%
Where is Single circuit blood flow found?
fish
in Single circuit blood flow what does the pressure in the gills depend on?
•pressure in gills depends
on pressure in rest of body
What changes with heart contraction in a Single circuit blood flow?
volume of the circuit
key features of Amphibian/Reptilian blood flow?
Double circuit ventricle undivided •some mixing of blood •equal pressure •skin & lungs both receive blood (not reptiles)
What are the defining features of Mammalian/Avian blood flow?
complete division of ventricle •differential pressure in pulmonary & systemic circuits •most effective O2 delivery system
In the mammalian system is the distribution of blood to organs equal?
distribution of blood to
organs not equal or
constant
When does contraction occur?
systole
