Flashcards in CVS Session 1- Intro To The CVS Deck (19)
What is the purpose of the CVS?
To supply all cells in the body with their metabolic needs.
How does 98% of exchange between capillaries and tissues occur?
Which two molecules can diffuse straight through the lipid bilayer?
Oxygen and carbon dioxide.
Which 3 molecules are hydrophilic and therefore travel down a concentration gradient and diffuse through small pores in capillaries?
Lactate, glucose, amino acids.
What three factors does the rate of diffusion depend on?
The greater the conc. gradient the ............ The rate of diffusion.
The greater the number of capillaries the .............the area and the ............ The rate of diffusion.
What is the diffusion resistance dependent on? (3)
The nature of the barrier
The nature of the molecule
The path length
What is the min and max blood flow in the brain and is there a change?
What is the min and max blood flow to the heart. Is there a change?
Yes- can increase according to demand.
What is the min and max blood flow to the kidneys and is there a change?
No because the kidneys require a constant perfusion in order to carry out their function.
What is the min and max blood flow to the gut and liver and is there a change?
It can increase when digestion is required.
What is the min and max blood flow to the skin and is there a change?
Yes, changes according to thermoregulation
What is the min and max blood flow to muscle and is there a change?
Yes it can change according to increased exercise.
What is the average cardiac output at rest and during exercise of a 70kg man?
What is the role of arterioles and pre-capillary sphincters in blood flow regulation?
They ensure blood flow is distributed appropriately by restricting flow to easily perfusable parts so that blood is driven to parts that are less easily perfused.
What is the role of veins in blood flow regulation?
They have capacitance and act as a temporary store of blood.
Why are veins able to regulate blood flow in this way?
Because they have thin walls that are easily distended or collapsed.