Cardiovascular system

Question 1

What does it mean by the heart being a double circulatory system?

Answer 1

Transport oxygen, nutrients and hormones
Removes waste products

Question 2

What is the Pulmonary circuit?

Answer 2

carries deoxy blood to lungs and carries oxy blood to heart

Question 3

what is the systemic circuit?

Answer 3

carries oxy blood to muscles/around body and carries deoxy blood back to the heart

Question 4

What is the passage of blood?

Answer 4

Deoxy blood enters heart through superior/inferior vena cava, into the right atrium.
Blood passes through the tricuspid valve into the right ventricle.
The deoxy blood gets forced out through the pulmonary artery to the lungs.

After diffusion of blood at the lungs, oxy blood travels through pulmonologist vein into the left atria.
Oxy blood passes through the bicuspid valve into the left ventricle.
It gets forced out through the aorta, where it circulates to the muscles and organs.
The oxygen gets used up and diffuses into deoxygenated blood.

Question 5

What is the SA node?

Answer 5

Located in the right atrium wall.
It generates the electrical impulses and fires it through the atria walls causing them to contract.

SA node is known as the pacemaker as its firing rate determines the heart rate.

Question 6

What is the AV node?

Answer 6

Collects the impulse of SA node and delays it for approx 0.1 seconds to allow the atria to finish contracting.
It then releases the impulse to the Bundle of His

Question 7

What is the Bundle of His?

Answer 7

Located in the septum.
Splits the impulse in two, ready to be distributed into each separate ventricle.

Question 8

What is the Bundle of Branches?

Answer 8

It carries impulse to the base of each ventricle

Question 9

What are Purkinjie Fibres?

Answer 9

Distributed the impulse through the ventricle walls causing them to contract.
Once the electrical impulses journey is complete, the atria and ventricles relax as the heart re-fills with blood.
This process signifies one heartbeat

Question 10

What is the cardiac muscle classed as?

Answer 10

Myogenic.
- it has the capacity to generate its own electrical impulses that passes through the muscular wall forcing them to contract

Question 11

What is the cardiac cycle?

Answer 11

Process of the cardiac muscle contraction and the movement of blood through its chambers.
One complete cardiac cycle represents the sequence of one single heart beat.

Question 12

What is diastole?

Answer 12

As the atria and ventricles relax, they expand and draw blood into the atria.
Pressure in the atria increases opening AV valves.
Blood passively enters the ventricles.
SL valves are closed to prevent blood from leaving the heart.

Question 13

What is atria systole?

Answer 13

Atria contract, forcing remaining blood into ventricles

Question 14

What is ventricular systole?

Answer 14

Ventricles contract, increasing pressure, closing the AV valves to prevent back flow of blood into the atrium.
SL valves are forced open as the blood is ejected from the ventricles into the aorta and pulmonary artery.

Question 15

What is cardiovascular effiency?

Answer 15

Can be measured by looking at the HR and SV
Cardiac Output.
Improving these will maximise aerobic performance and help us like an active, balanced and healthy lifestyle.

Question 16

What is sub maximal?

Answer 16

a low to moderate intensity of exercise within a performer’s aerobic capacity

Question 17

What is maximal?

Answer 17

a high intensity of exercise above a performer aerobic capacity that will induce fatigue

Question 18

What is SV response to venous return?

Answer 18

SV increases in proportion to exercise intensity until a plateau is reached at approx 40-60.
This corresponds to sub maximal intensity exercise.
Stroke volume is able to increase due to:
venous return
frank-starling mechanism

Question 19

What is increase venous return?

Answer 19

This is the volume of blood that returns from the body to the heart.
During exercise venous return increases, meaning there is a greater volume of blood returning to the heart.
This is due to the muscle pump.

Question 20

What Frank-Starling Mechanism?

Answer 20

It shows how SV is dependent on venous return. An increased volume of blood returning to the heart means and increased end-diastolic volume in the ventricles and therefore a greater stretch on the ventricle walls.
The greater stretch increases the force of ventricular contraction, ejecting a lager volume of blood from the ventricles.
The lower the HR, the more time available to maximise this effect.

Question 21

What is cardiacs output response to exercise?

Answer 21

It is the product of HR and SV and therefore the recovery is a combination of the two.
Q increases in line with exercise intensity and plateus during minimal exercise.
In recovery, there is a rapid decrease followed by a slower decrease to resting levels.

Question 22

What are the 3 main sources of info that determine the action of CCC?

Answer 22

Neural control
Intrinsic control
Hormonal control

Question 23

What is vascular shunting mechanisms?

Answer 23

• The redistribution of blood flow to a different part of the body is controlled by VSM.
• Arterioles lead to the capillary beds, which brings the blood in close contact with organ and muscle cells.
• The exchange of O2 and nutrients with CO2 and waste products.
• The blood flow is controlled by pre-capillary sphincters at the entrance of the bed.

Question 24

Why is blood flow redistributed to the organs at rest?

Answer 24

• Arterioles to the organs vasodilate (inc blood flow), and arterioles to muscles vasoconstrict (limiting blood flow)
• PCS dilate, opening the capillary beds to allow more blood flow to the organ cells, while constricting, closing the capillary beds to the muscle cells.

Question 25

What happens to blood flow redistribution during exercise?

Answer 25

• Arterioles and PCS surrounding muscle cells dilate, allowing maximal blood flow, nutrients and gaseous exchange.
• blood flow to organs is reduced due to constriction of PCS serving those particular capillary beds.

Question 26

What is vasomotor control?

Answer 26

• Vascular shunt mechanism is under the control of vasomotor control centre (VCC) in the medulla oblongata.
• The smooth muscle in the walls of the arterial blood is always in a slight state of contraction, known as vasomotor tone.
• When sensory info is received the VCC alters the level of stimulation sent to the arterioles and PCS at different sites in the body.

Question 27

What is the VCC

Answer 27

• It receives info from chemoreceptors regarding chemical changes, such as CO2 and lactic acid rising during exercise.
• Baroreceptors regarding pressure changes of the arterial walls.