Overview of the Function of the CVS Flashcards
What are the functions of the CVS? (5)
Distribute things around the body : O2 and CO2 , nutrients, metabolites, hormones and heat.
State the equation that defines flow
Flow = Δ pressure / resistance
How can the pressure difference be defined in the cardiovascular system
Pressure difference = mean arterial pressure - central venous pressure
How can the resistance be determined?
Determined by the radius4 of the vessel
Describe the arrangement of the CVS in series
The heart pumps are in series therefore output is equal between the right and left side of the heart, this important to avoid the accumulation of blood.
Describe the arrangement of the CVS in parallel
Most vascular beds are parallel; therefore, all the tissues get oxygenated blood.
This also allows the redirection of blood.
What are the 2 exception of the parallel vascular bed layout?
- Hypothalamus and anterior pituitary gland - hypothalamus controls release of
hormones from anterior pituitary gland
Hypothalamus -> Ant Pit
- Gut and the liver - absorption in the gut and stored in the liver
LV ->Liver
LV ->Gut -> Liver
Explain the structure and function of elastic arteries
- Wide lumen
- Elastic wall – extra elastic fibres in the tunica media
- Dampens the pressure variation due the ability to stretch
Explain the structure and function of muscular arteries
- Wide Lumen
- Strong no-elastic wall – muscular wall
- Low resistance conduit – easy for the blood to flow out of them
Explain the structure and function of resistance vessels
Arterioles • Narrow lumen • Thick contractile wall • Control resistance by contracting therefore control flow • Allow regional redirection of blood
Explain the structure and function of exchange vessels
Capillaries
• Very narrow lumen
• One cell thick wall to allow exchange with ease
Explain the structure and function of capacitance vessels
Veins and venules
• Wide lumen
• Distensible walls to allow the storage of blood
• Allow the fractional distribution of blood (how much blood is sitting in the veins and venules compared to the rest of the circulation) between veins and venules and the rest of the circulation especially the heart.
