Function of the CVS Flashcards
What type of system is the CVS?
Bulk flow
What 4 things is the CVS responsible for getting around the body?
- O2 and CO2
- Nutrients
- Metabolites
- Hormones
What homeostatic aspect is regulated by the CVS?
Heat
In what ways is the CVS flexible?
- Pump output can vary
- Vessels can redirect blood
- Vessels can store blood
Describe the structure of the largest vessels of the CVS?
- Exist in series like an electrical circuit
- Output is equal
How do vascular beds exist with reference to eachother?
In a parallel circuit
What can occur to allow some beds to get more blood than others?
Regional redirection (vaso dilation/constriction in some vessels)
Why are the hypothalamas and anterior pituitary gland in series and not parallel?
- Blood travels through the hypothalamus first
- Picks up hormone secretions that work directly on the pituitary
What is the hierarchal order of organs by their O2
used?
Abdominal Organs
30%
Skeletal Muscles
20%
Brain
18%
Other
14%
Heart
10%
Kidney
6%
Skin
2%
What is the hierarchal order of organs by their cardiac output used?
Abdominal Organs
24%
Skeletal Muscles
20%
Brain
13%
Other
10%
Heart
4%
Kidney
20%
Skin
9%
What is the equation for pressure difference?
Pressure difference = mean arterial pressure - central venous pressure
What happens to flow when pressure increases?
Flow increases
What is the equation for flow?
Flow = change in pressure/resistance
What effect does radius of vessel have on the resistance?
Radius^4 so has a huge effect
What do arterioles act as by controlling resistance through radius?
Taps to each organ vascular bed
Describe the properties of the aorta
- Large elastic wall
- Wide lumen
How does the elasticity of the aorta aid in pumping blood?
- Gains elastic energy when stretches in response to systole
- Elastic walls can recontract to increase pressure and therefore flow
Describe the properties of the arteries
- Muscular
- Wide lumen
- Low resistance
What is the name given to the type of vessels that arterioles are?
- Resistance vessels
What are the properties of arterioles?
- Narrow lumen
- Thick contractile wall
- Can control resistance and therefore flow
What is the function of capillaries?
Exchange vessels
What are the properties of capillaries?
- Narrow lumen
- Thin wall
What is the name given to the type of vessels that venules and veins are?
- Capacitance vessels
Describe the properties of veins and venules
- Wide lumen
- Low resistance
What is the function of the interatrial septum?
Seperates left and right atrium
What type of valves are the aortic and pulmonary valves?
Semi lunar
What is the mitral valve?
- Also known as bicuspid as it has two cusps
- Left AV valve
What is the tricuspid valve?
- Right AV valve
What are the chordae tendinae?
Connective tissue fibres that connect the AV valves with the papillary muscle
What is the function of the chordae tendinae and the papillary muscle?
- Stop the AV valve from inverting
- Is passive so allows the valve to shut but not go too far
