Overview of the function of the cardiovascular system

Question 1

What is the cardiovascular system >

Answer 1

The cardiovascular system is a bulk flow system which transports carbon dioxide and oxygen around the body.

Question 2

What other components does the cardiovascular system transport?

Answer 2

The cardiovascular system also transports
- nutrients
- hormones
- metabolites
- heat

Question 3

What vessels store blood?

Answer 3

The veins and venules are capable of storing blood. At rest they store 2/3 of our bodies blood.

Question 4

Can the heart vary it’s output?

Answer 4

Yes the heart can vary it’s output. Exercise can make your heart beat faster and the strength of the contraction can increase to pump more oxygen around the body.

Question 5

What is the function of arterioles?

Answer 5

Arterioles contrle the redirection of blood. They can be reffered to as resistance vessels. They can change diameter and therefore change how much blood flow is going through the vascular beds.

Question 6

What is the heart?

Answer 6

The heart is 2 pumps that work together

Question 7

What is the function of the right side of the heart?

Answer 7

The right side of the heart pumps blood into the pulmonary circulation (lungs), where gas exchange occurs. There is oxygen diffusing into the blood and carbon dioxide diffusion out of the blood. All blood pumped into the lungs must go to the left side of the heart.

Question 8

What is the function of the left side of the heart?

Answer 8

The left side of the heart pumps blood into systemic circulation (blood supply to all body tissue). The diffusion here is the same but in the opposite way. Oxygen diffuses from the blood into the tissue and organs and cardbon dioxide diffuses from the tissue and organs back into the blood

Question 9

Why is it important that the output of the right side of the heart should be equal to the output to the left side of the heart?

Answer 9

The output of the right side of the heart must be equal to the output of the left side of the heart. If the right side was pumping more blood then the left side blood will start to accumulate in the lungs

Question 10

How are vascular beds arranged ?

Answer 10

Vascular beds are arranged in parallel (receive oxygenated blood at the same time). These include head, legs, arms. The gut and liver are arrnaged in series, nutrients abosrbed in the gut can be passed onto the liver to be metabolised. Liver has it’s own blood supply in parallel.

Question 11

What does parallel arrangement allow?

Answer 11

The parallel arrangement allows the regional redirection of blood. For example, if you are doing exercise the amount of blood going to liver and gut can be decreased and the amount of blood going to you arms will increase.

Question 12

What is darcys law?

Answer 12

flow = difference in pressure/resistance

Question 13

What is mean arterial pressure ?

Answer 13

Pressure varys on the left hand side, this is referred to as mean arterial pressure. This can increase during exercise

Question 14

What is central venou pressure ?

Answer 14

Central venous pressure is on the right hand side

Question 15

How can you get redirection of blood flow?

Answer 15

To get redirection of blood flow you need to change resistance of vessels. This is influenced by the diameter of the blood vessels in which you are trying to push the blood through.

Question 16

What is the main function of arteries ?

Answer 16

Arteries are major blood vessels that carry blood away from the heart

Question 17

What are capillaries ?

Answer 17

capillaries are the smallest blood vessels. This is where the exchange of carbon dioxide and oxygen takes place.

Question 18

What are veins and venules?

Answer 18

These are on the left-hand side. These are often referred to as capacitance vessels. They store blood. When this blood is needed forces can push the blood back to the right side of the heart.

Question 19

What is fractional distribution of blood?

Answer 19

The proportion of blood in veins and venules vs the rest of your systemic circulation

Question 20

What is the structure of the AORTA?

Answer 20

• It is one of the two elastic arteries in your body
• Wide lumen: Therefore has a low resistance
• Thick elastic walls
• Damp pressure variations

Question 21

What is the structure of ARTERIES?

Answer 21

• Wide lumen
• Strong, thick, non elastic walls
• Known as muscular arteries

Question 22

What is the structure of ARTERIOLES?

Answer 22

• Known as resistant vessels
• Narrow lumen
• Thick contractile wall, contains muscle that can contract and relax. This controles the resistance and how much blood will flow through these vessels. This is how the redirection of the blood flow is controlled.

Question 23

What is the structure of capillaries?

Answer 23

• Small in size
• narrow lumen
  -Thin wall
• They are exchange vessles. They have a very large surface area to volume ratio which easily allows oxygen to diffuse from the blood into the tissue organs and then allow carbon dioxide to go the other way.

Question 24

What is the structure of veins and venules ?

Answer 24

• These are known as capacitance vessels. They store the blood
• Have a wide lumen which helps their ability to store blood
• Low resistance to the flow of blood
• They have a thin distensible wall. This can increase in size and therefore help it’s ability to store blood
• Allows fractional distribution of blood

Question 25

What is the role of the septum?

Answer 25

The left and right pump of the heart is seperated by the septum. It also seperates the atria.

Question 26

What is the role of atrium?

Answer 26

Atrium is the receiving chamber. Blood from the systemic circulation will come back to the right atrium. Blood returning from the lungs will come back to the left atrium.

Question 27

What is the role of the ventricles ?

Answer 27

The ventricles are the pumping chambers. They are inferior to the atrium. Blood is pumped from the left ventricle into the aorta which goes of to the systemic circulation. Deoxygenated blood will fill into the right ventricle where it's pumped into the pulmonary circulation.

Question 28

What is the role of the pulmonary trunk ?

Answer 28

The deoxygnated blood exits the ventricle and enters pulmonary trunk. The pulmonary trunk bifurcates into left and right pulmonary artery. These carry blood to the left and right lung respectively.

Question 29

What is the role of the pulmonary veins?

Answer 29

Once the blood has been oxygenated it returns to the left atrium via the pulmonary veins. There is four of these: left, right, superior and inferior pulmonary vein.

Question 30

Where is the aortic valve located?

Answer 30

The aortic valve is located between the left ventricle and the aorta

Question 31

Where is the pulmonary valve located?

Answer 31

The pulmonary valve is located between the right ventricle and the pulmonary trunk

Question 32

When is the aortic and pulmonary valves open?

Answer 32

The pulmonary and aortic valve is open when the heart is in systole (when the blood is being squeezed out of the ventricles into the aorta and the pulmonary trunk).

Question 33

When is the pulmonary valve and aortic valve closed?

Answer 33

Pulmonary and aortic valve is closed when the heart is in diastole (When the heart chambers are filling with blood)

Question 34

Where is the tricuspid valve located?

Answer 34

The tricuspid valve is located between the right atrium and the right ventricle. It has 3 cusps

Question 35

Where is the mitral valve located?

Answer 35

The mitral valve is located between the left ventricle and the left atrium. It has 2 cusps.

Question 36

What is the role of the mitral and tricuspid valve>

Answer 36

The role of the mitral valve and tricuspid valve is to prevent regulation of blood from the ventricles back into the atrium. Chordae tendinae prevent the valves from inverting. These valves open and close due to changed in the pressure in the heart