Introduction to the cardiovascular system Flashcards
Name six reasons why we need the cardiovascular system
- Temperature regulation
- Pump blood through lungs & carry oxygen
- Transport nutrients to muscles & organs
- Circulates hormones & immune mediators
- Connection to lymphatic system
- Human Reproduction
Define Passive diffusion and what does Ficks Law state?
Passive diffusion is the random, undirected thermal movement of molecules.
- The time needed to diffuse a given distance is proportional to the square of the distance. This is known as Ficks Law.
- t α d2
What is the diffusion range?
• Diffusion is fast in µm but very time consuming over distances >1 mm and inappropriate for transport throughout the body.
Describe the movement of blood through the heart - circulation
- Blood returns to the heart from the veins via the right atrium and is pumped through the lungs by the right ventricle.
- Blood returns to the heart from the lungs via the left atrium and is pumped through the body by the left ventricle.
What creates a pressure difference with distant blood vessels?
What is the pressure in the aorta and large veins?
- Output of blood at high pressure creates a pressure difference with distant blood vessels…
- Aorta >100 mmHg
- Large veins 5-10 mmHg
- Pressure difference drives blood flow
What is systole and diastole?
Systole = contraction Diastole = relaxation
Define cardiac output
• Cardiac output = volume of blood ejected from the heart per minute, typically around 5 litres/min.
Where does the cardiac output go and what about the oxygen consumption
On image
What is the cardiac output equation?
Cardiac output = heart rate x stroke volume (amount of blood in each beat).
What controls blood flow and determines blood pressure?
What is the blood flow equation?
Blood flow and blood pressure is critical for correct bodily functioning
Controlling the resistance of the vessels gives some control of blood flow
Blood flow is:
1. proportional to pressure across blood vessel
2. inversely proportional to resistance of blood vessel
on image
Describe the pressure profile of the circulation
On image
Why does blood slow down in capillaries?
On image
What are the four main functional groups of blood vessels?
flow.
Resistance vessels. Arterioles - Control arterial BP & regulate local blood flow.
Exchange vessels, Capillaries - Nutrient delivery to cells tissue water & lymph formation removal of metabolic waste.
Capacitance vessels, Venules & Veins - Control filling pressure & provide reservoir of blood.
Describe the distribution of blood volume
On image
Describe the structure of arteries and veins
On image
