The cardiovascular system

Question 1

What makes up the cardiovascular system and what is its function

Answer 1

The cardiovascular system is made up of the heart and blood vessels. The heart is the pump that circulates the blood through the vessels. The vessels are the major transport system responsible for transporting nutrients and oxygen to tissues and removing urea and carbon dioxide. It also transports hormones involved in homeostasis.

Question 2

What are arteries

Answer 2

Arteries are thick muscular blood vessels that carry high pressure oxygenated blood away from the heart.

Question 3

What are veins

Answer 3

Veins are thin walled blood vessels which carry low pressured deoxygenated blood towards the heart

Question 4

What are capillaries

Answer 4

Capillaries are small vessels that distribute blood and connect arteries to veins. They are usually found in capillary beds connected by venules and arterioles. They are regulated by precapillary sphincters

Question 5

What colour is the blood in the arteries and the veins

Answer 5

Arteries have oxygenated bright cherry red blood. Veins have deoxygenated dark cherry red blood

Question 6

Where is the heart located and where can you palpate it

Answer 6

The heart is located in the thoracic cavity behind the breastbone (sternum). With the apex projecting to the left, so you can palpate it in the 5th intercostal space to the left.

Question 7

How many litres of blood does the heart pump in a day

Answer 7

The heart pump 9000 litres of blood a day

Question 8

How big is the heart

Answer 8

it is 12-14cm long and 9-11cm wide but it can increase with age due to it being harder to pump the blood round the vessels which have fatty deposits.

Question 9

How does the heart change during pregnancy

Answer 9

The heart is pushed up the chest during pregnancy and increases on size (known as hypertrophy) due to the increase in blood volume

Question 10

What is the pericardium

Answer 10

The pericardium is a tough membrane that surrounds the heart

Question 11

What are the functions of the pericardium

Answer 11

It anchors the heart to the sternum and top of diaphragm in position. It also produces pericardial fluid which lubricates and prevents trauma from rubbing other structures. It also acts as a shock absorber

Question 12

Name the three layers of the heart

Answer 12

The myocardium is the thick muscle layer responsible for pumping blood
The epicardium is the outer layer
The endocardium in the inner layer and lines heart chambers

Question 13

What is cardiac tamponade

Answer 13

Cardiac tamponade is a condition caused by either an infection or trauma to the heart causing an increased amount of pericardial fluid. This increases pressure on the heart which stops effective pumping and requires a needle decompression to remove it.

Question 14

What is the role of the coronary arteries

Answer 14

The coronary arteries supply oxygenated blood to the myocardium

Question 15

What is coronary artery disease

Answer 15

Coronary artery disease is caused by the arteries narrowing due to a buildup of fatty deposits which turns into plaque and limits blood flow and causes angina. Smoking, a fatty diet and some health conditions increase the risk.

Question 16

When might midwives encounter coronary artery disease

Answer 16

Women don’t always experience the symptoms particularly those with diabetes due to damaged nerve endings because of the constantly high sugar levels. Pregnancy puts extra strain on the heart which may cause them to experience angina for the first time.

Question 17

How many chambers are in the heart

Answer 17

The heart has four chambers. Two upper thin and elastic collecting chambers called atria and two lower thick and muscular lower pumping chambers called ventricles.

Question 18

How many valves are there in the heart

Answer 18

Between the atria and ventricles there are two atrioventricular valves. The Tricuspid on the right and the bicuspid on the left. There are two semilunar valves to prevent backflow the pulmonary valve on the right and the aortic valve on the left.

Question 19

Label a diagram of the heart

Answer 19

Check using notes should include 4 chambers, tricuspid valve, bicuspid valve, pulmonary valve, aortic valve, pulmonary artery, vena cava, aorta and pulmonary vein.

Question 20

Explain how the pulmonary circuit works

Answer 20

The right side of the heart collects deoxygenated blood from the vena cava and pumps it through the pulmonary arteries to the lungs to become oxygenated. It returns through the pulmonary vein to the left side.

Question 21

Explain how the systemic circuit works

Answer 21

The oxygenated blood is pumped into the aorta round the organs

Question 22

What is systole

Answer 22

Systole is contraction of the heart chambers

Question 23

What is diastole

Answer 23

Diastole is relaxation of the heart chambers

Question 24

What happens during atrial systole

Answer 24

The atria collect blood from the vena cava and pulmonary veins and contracts forcing it through the atrioventricular valves into the ventricles.

Question 25

What happens during ventricular systole

Answer 25

The ventricles fill with blood and contract ejecting it into the pulmonary artery and aorta and then undergo diastole as the stria contract again.

Question 26

What is bradycardia

Answer 26

Bradycardia is when the resting HR is less than 60 bpm, it is usually in athletes and patients on beta blockers

Question 27

What is tachycardia

Answer 27

Tachycardia is a resting HR above 100bpm usually due to stress infection or haemorrhage

Question 28

What is the tunica externa

Answer 28

The tunica externa is the outer protective layer that anchors the vessel in place

Question 29

What is the tunica media

Answer 29

The tunica media is the smooth muscle inner layer which allows regulation of blood flow through vasoconstriction/dilation.

Question 30

What is the endothelium

Answer 30

The endothelium is the innermost layer which is one cell thick and easily damaged by cigarette toxins, blood sugar and raised BP. It periodically folds in on itself to form valves.

Question 31

What is the skeletal muscle pump

Answer 31

The skeletal muscle pump helps to return deoxygenated blood under low pressure to the heart by the calf muscles compressing veins during movement which increases pressure aided by the semilunar valves to prevent backflow.

Question 32

Why is thrombosis an issue during pregnancy

Answer 32

To prepare for bloodloss the liver produces more plasma proteins which increases risk of thrombosis as it makes the blood hypercoagulable.

Question 33

What is vischows triad

Answer 33

Vischows triad is three factors that predispose thrombosis: hypercoagulable blood, endothelial injury and circulatory stasis

Question 34

Why is it important to exercise during pregnancy and what are the risks of not

Answer 34

To active the skeletal muscle pump to avoid a DVT which may compromise bloodflow. The clot may become dislodged and embolise and travel to the heart to become a pulmonary embolism leading to a heart attack or stroke.

Question 35

Summarise the cardiovascular changed during pregnancy

Answer 35

``` Upwards displacement of heart Hypertrophy Lower BP in 2nd trimester 50% increase in blood volume Weight gain due to increased blood volume ```