Function of CVS Flashcards
Functions of CVS
Bulk flow system
- O2
- Nutrients
- metabolites
- hormones
- heat
Main function of CVS
To supply oxygen to tissues
What organ of the body receives the most blood flow?
Abdo organs
Equation for pressure difference
MAP - CVP
What does MAP stand for?
Mean arterial pressure
What does CVP stand for?
Central venous pressure
Equation for flow
Flow = difference in pressure / resistance
What is the pressure controlled by?
Radius
What vessels act as taps and therefore control resistance to each vascular bed?
Arterioles
Different vessels of the body
- Arteries
- Arterioles
- Capillaries
- Venules
- Veins
Most vascular beds are in parallel, and therefore….
- All tissues get oxygenated blood
2. Allows regional redirection of blood
What vascular beds are arranged in serial rather than parallel?
Anterior pituitary and hypothalamus
Liver and gut
Where does the right side of the heart pump blood to?
The lungs
Where does the left side of the heart pump blood to?
Systemic circulation
Example of an elastic artery
Aorta
Features of the elastic artery / aorta
Wide lumen Elastic wall Thick wall Low resistance so easy for blood to get through Dampens pressure variations
Classification of blood vessels
Elastic arteries Muscular arteries Resistance vessels Exchange vessels Capacitance vessels
Features of muscular arteries
Wide lumen
Strong non elastic wall so can withstand pressure variations
Low resistance conduit
More than one of these
What are the resistance arteries?
Arterioles
Features of resistance arteries
Narrow lumen
Thick contractile wall = can constrict or dilate
A lot smaller than arteries
High resistance
Made up of smooth muscle and therefore control the redirection of blood
Control resistance and therefore flow
What do resistance arteries allow?
Regional redirection of blood
Resistance of resistance arteries
High
What are exchange vessels?
Capillaries
Features of exchange vessels
Narrow lumen
Thin wall
One layer thick
Small barrier to diffusion
What are the capacitance vessels
Venules and veins
Features of capacitance vessels
Wide lumen Distensible wall Low resistance conduit and reservoir Has smooth muscle but much less than the arteries etc Essentially store blood
What do capacitance vessels allow?
Fractional distribution of blood
Name parts of the heart
Septum Myocardium Ventricles Atrium Vena cava Pulmonary trunk Valves Chordae tendinae Papillary muscle
Where is the septum found?
Up the middle of the heart
What is the myocardium?
Wall of the heart
Which side of the heart has a thicker myocardium and why?
Left side thicker
Has to pump blood around the systemic circulation
What are the ventricles?
Pumping chambers
What valves are in the heart?
Aortic
Pulmonary
Tricuspid
Mitral
How many cusps does the tricuspid valve have?
3
What are the chordae tendinae attached to?
Capillary muscle
Function of chordae tendinae
Passive valves so only pressure changes are the valves opening and shutting
Stops valves from turning inside out
