1/ overview of the CV block Flashcards
what does the CVS help transport around the body?
- O2 and CO2
- nutrients
- metabolites
- hormones
- heat
how many time does the heart beat in a lifetime? (70 years)
2,5 billion in 70 years
how is the CVS “flexible” in its function?
- pump can vary output
- vessels can redirect blood
- vessels can store blood
the two sides of the heart can be considered as two different pumps fitted in parallel/ series?
series
what does this fitting imply about the output?
output of both pumps must be equal
how are most of the vascular beds fitted?
parallel
what does that allow?
- allows for the oxygenation of all tissues (in series, the first ones would get more O2)
- allows regional redirection of blood
which vessels act as the “taps” controlling resistance?
arterioles
flow =
delta P/ Rh
what does this allow?
allows control of resistance (and therefore flow, fractional distribution of blood) to each vascular bed
what are the characteristics of elastic arteries?
= aorta, wide lumen, elastic wall, muscle used to dampens pressure variations
what are the characteristics of muscular arteries?
muscular arteries, wide lumen, strong non-elastic wall, low resistant conduit
what are the characteristics of the arterioles?
narrow lumen, thick contractile wall, they control resistance and therefore flow, allow regional redirection of blood
what are the characteristics of the capillaries?
exchange vessels, narrow lumen, thin wall
what are the characteristics of venules and veins?
capacitance vessels, wide lumen, distensible wall, low resistance conduit & reservoir, allows fractional distribution of blood between veins & rest of circulation (esp. heart)
