Unit 1 - Anatomy and physiology for health and exercise - the cardiovascular system

Question 1

What are the four chambers of the heart called?

Answer 1

• 2 upper chambers: atria (atrium in singular)
• 2 lower, larger chambers: ventricles

Question 2

What is the name of the predominant tissue of the heart?

Answer 2

The cardiac muscle or myocardium

Question 3

What do atrioventricular vales do?

Answer 3

The Atrioventricular valves are Mitral and Tricuspid valves located between the atrium and ventricles. Their main functions is to “prevent the backflow of blood from the ventricles into the atrium during the ventricular contraction (systole).

Question 4

What is the function of the coronary arteries?

Answer 4

Coronary arteries supply blood to the heart muscle. Like all other tissues in the body, the heart muscle needs oxygen-rich blood to function. Also, oxygen-depleted blood must be carried away. The coronary arteries wrap around the outside of the heart.

Question 5

What factors can lead to damage these coronary arteries and dysfunction and therefor limit blood flow to sections of the heart?

Answer 5

Mineral, protein and fatty deposits can build up in the walls of the arteries.

These hard mineral deposits reduce the elasticity of the arteries so they cant stretch in response to blood flow and increased blood pressure can result.

Sudden heart attack can often be a result of one of these deposits bursting, releasing their contents and initiating a rapid colouring process to stop the blood from escaping the artery.

Question 6

What can a forming blood clot stop?

Answer 6

it can stop blood flow which results in oxygen deprivation to a section fo the heart.

The body responds with a rapid increase in heart rate to try and dislodge the blockage and re-establish blood flow.

This very rapid beating, oxygen-deprived heart, is what is experienced during a heart attack.

Question 7

What is blood pressure?

Answer 7

A measure of the force that the blood applies to the walls of the arteries as it flows through them.

Question 8

How is blood pressure measured (what unit measure is used)?

Answer 8

Blood pressure is measured in millimetres of mercury (mmHg), using two numbers.

Question 9

What is the optimal blood pressure, with respect to cardiovascular risk?

Answer 9

Below 120 mmHg for systolic and 80 mmHg for diastolic pressure.

120/80

Question 10

What is hypertension?

Answer 10

It’s the clinical term used to describe a high blood pressure of 140/90 mmHg or higher

Question 11

What is the short-term effect of exercise on blood pressure?

Answer 11

It increases blood pressure.

Question 12

What is a central element to the heart’s conduction system, by which it directs the course of electrical activity (action potential) through the tissues of the heart?

Answer 12

Two small bundles of fibres located in the right atrium:

• the sinoatrial (SA) node
• the atrioventricular (AV) node

Question 13

What is the sinoatrial node?

Answer 13

The SA node is a collection of elf excitable cells; they require no neural input and are the site where cardiac action potentials begin.

Here, action potential spread across both atria and thus, they will contract first.

Question 14

By what is the flow of action potentials to the ventricles controlled?

Answer 14

Via the AV node which is located at the base of the right atrium.

Its function is to slow down the action potential and give the atrial time to contract.

From here the action potential travels down a specialised nerve bundle before branching off into two bundles in the central wall of the heart (the septum).

Question 15

What is the central wall of the heart called?

Answer 15

The septum

Question 16

Describe the cardiac cycle.

Answer 16

The cardiac cycle describes all the activities of the heart through one complete heartbeat—that is, through one contraction and relaxation of both the atria and ventricles.

A contraction event (of either the atria or ventricles) is referred to as systole, and

a relaxation event is referred to as diastole.

Question 17

Give a brief summary of the cardiac cycle.

Answer 17

• Relaxation (diastole): of the atria allows blood to refill them form the pulmonary veins and vena cava.
• Atrial systole (contraction): stimulation form the SA node causes the atria to contract and push any remaining blood into the ventricles.
• Ventricular systole (contraction): the ventricles contract causing a rise in pressure. This closes off the AV valves and directs the blood to be ejected from the heart via the pulmonary artery and aorta.
• Relaxation (diastole): the atria relax followed by the ventricles until all four chambers are in diastole and the cardiac cycle begins over again.

Question 18

Apart from the SA node dictating the basic rhythm of the heartbeat, how else is the heart cycle regulated?

Answer 18

Regulation of the cardiac cycle is also achieved via the autonomic nervous system. This is primarily directed by the medulla oblongata of the brain.
The sympathetic and parasympathetic divisions of the autonomic system regulate heart rhythm by affecting the same intrinsic impulse conducting mechanisms that lie within the heart in opposing ways.

Question 19

What is cardiac output?

Answer 19

It is the work done by the heart and is defined as the volume of blood pumped from the heart every minute.

The determinants of cardiac output are stroke volume (SV) and heart rate (HR).

Question 20

What is stroke volume and heart rate?

Answer 20

The amount of blood ejected from the ventricles every beat and heart rate is the number of times the heart beats in a minute.

Question 21

What is the formula to calculate cardiac output?

Answer 21

CO = SV x HR

(cardiac output = stroke volume x heart rate)

Question 22

Name the 5 types of vessels in the circulatory system.

Answer 22

• arteries
• arterioles
• capillaries
• venules
• veins

Question 23

What is the main feature of arteries?

Answer 23

They carry blood away from the heart.

The pressure exerted on them is considerably higher than in other vessels.

Question 24

What are arterioles?

Answer 24

As the arteries branch and subdivide, they become smaller. The smallest of these arteries are the arterioles. Although microscopic, they still contain smooth muscle and elastic fibres, albeit in relatively small amounts.

Question 25

What is the main purpose of arterioles?

Answer 25

To regulate blood flow to the capillary beds.

Question 26

What are Capillaries?

Answer 26

the smallest of blood vessels. They serve to distribute oxygenated blood from arteries to the tissues of the body and to feed deoxygenated blood from the tissues back into the veins.

Just about every cell in the body will have a capillary nearby, although areas of high metabolic activity will tend to have a higher density.

Exercise will increase capillary density in trained muscle

Question 27

What are venules?

Answer 27

a very small blood vessel in the microcirculation that allows blood to return from the capillary beds to drain into the larger blood vessels, the veins.

They have small amounts of smooth muscle tissue and elastic fibres.

Question 28

What are veins?

Answer 28

Veins are the blood vessels that carry deoxygenated blood from parts of our body back to the heart.

The pressure of blood within the veins is relatively low, and whilst veins are comprised of the same basic constituents as arteries (i.e. smooth muscle and elastic fibres), the proportions tend to be lower when compared to an artery of a similar size.

One of the major distinguishing features is that they are equipped with non-return valves. These are needed because blood pressure in the veins may be insufficient to overcome gravity, thus valves help prevent reversed blood flow or pooling of blood in the limbs.

Question 29

What are the benefits of exercise on the cardiovascular system in healthy individuals, like a regular exercise training programme including aerobic and endurance-based resistance training?

Answer 29

• increased growth of cardiac muscle • larger stroke volume
• lower heart rate for the same relative pre-trained exercise intensity
• stronger and more elastic arteries
• improved blood cholesterol markers
• increased network density of capillary beds
• increased haemoglobin count in the blood
• lower blood pressure in the long term

Question 30

What risks carries exercise in certain population groups with regard to the cardiovascular system?

Answer 30

• increased blood pressure, especially during high-intensity work, breath-holding and use of Valsalva techniques
• increased risk of lightheadedness or postural hypotension in some clients