Heart And Circulatory System

Question 1

What are the 3 distinct layers of the heart wall?

Answer 1

Epicardium (outer)
Myocardium (middle)
Endocardium (inner)

Question 2

What separates the right and left ventricle?

Answer 2

Thick interventricular septum

Question 3

What separates the right and left atria?

Answer 3

Thin interatrial septum

Question 4

The right atrium receives what type of blood and from where?

Answer 4

Deoxygenated/venous blood from the superior and inferior vena cava

Question 5

When blood travel from the right atrium to right ventricle, which valve does it pass through?

Answer 5

Tricuspid valve

Question 6

From the right atrium, which valve does the blood travel through and where does it end up?

Answer 6

Blood travels through tricuspid valve into right ventricle. Then travels through the pulmonary valve and enters the right and left pulmonary arteries. The deoxygenated blood then travels to the lungs for gas exchange.

Question 7

Where does oxygenated blood enter the heart?

Answer 7

From the lungs, through the left and right pulmonary veins and into the left atrium

Question 8

Which valve connects the left atrium and the left ventricle?

Answer 8

Mitral (bicuspid) valve - oxygenated blood travels through this

Question 9

From the left ventricle, how does the oxygenated exit the heart?

Answer 9

Through the aortic semilunar valve, the aorta, and to the rest of the body

Question 10

What is the cardiac cycle of deoxygenated blood through the heart?

Answer 10

1. Enters through superior and inferior vena cava to the right atrium
2. Deoxygenated blood leaves the right atrium through the tricuspid valve into the right ventricle
3. Blood exists the right ventricle through the pulmonary valve and exists the heart through the left and right pulmonary arteries
4. The deoxygenated blood then travels to the lungs for gas exchange.

Question 11

What is the cardiac cycle of oxygenated blood through the heart?

Answer 11

1. Enters the left atrium through the left and right pulmonary veins
2. Oxygenated blood travels through the mitral (bicuspid) valve into the left ventricle
3. Exists the left ventricle through the aortic semilunar valve into aorta.
4. The oxygenated blood then travels to the rest of the body.

Question 12

What is the period of diastole in the cardiac cycle

Answer 12

A period of relaxation in the cardiac cycle when the heart fills with blood.
80% of blood flows directly through the atria into the ventricles before contraction.

Question 13

What is the systole period in the cardiac cycle?

Answer 13

The phase of contraction of the hearts ventricles, forcing blood out of the heart.

Question 14

Which valve will close during systole of the left ventricle?

Answer 14

Mitral valve will close to prevent back flow into left atrium

Question 15

Which valve will close during systole of the right ventricle?

Answer 15

Tricuspid valve will close to prevent back flow into right atrium

Question 16

Which ventricle has thicker walls and why?

Answer 16

Left ventricle due to the increased pressure required to pump blood to rest of body.

Question 17

Which valve prevents back flow from the aorta into the left ventricle?

Answer 17

Aortic semilunar valve

Question 18

What is pericarditis?

Answer 18

Inflammation of the pericardial sac

Question 19

How many pints of blood does the heart pump 24/7?

Answer 19

8 pints

Question 20

What encloses and protects the heart and forms the wall of the pericardial cavity which contains the pericardial fluid?

Answer 20

Pericardial sac / Parietal pericardium

Question 21

What is the parietal pericardium composed of?

Answer 21

Outer fibrous and inner serous layer

Question 22

Which layer of the parietal pericardium secretes the pericardial fluid and what is its function

Answer 22

Inner serous layer
Pericardial fluid acts to reduce friction as the heart beats

Question 23

Which layer of the heart wall is responsible for contraction?

Answer 23

Myocardium; thick middle layer, composed of thick cardiac muscle

Question 24

What is endocarditis?

Answer 24

Inflammation of the endocardium (smooth inner layer of the wall, lining of heart and internal structures.

Question 25

What can endocarditis be triggered by?

Answer 25

Very rare; but bacteria can enter the blood stream through the mouth and then end up in the heart

Question 26

What connects cardiac muscle cells together?

Answer 26

Intercalated discs

Question 27

What do intercalated discs consist of and what are their functions?

Answer 27

- Fascia adherens and demosomes; hold cardiac muscle cells end to end. - Gap junctions; allow ions to pass between cardiac muscle cells, transmitting nerve impulses.

Question 28

What do grooved depressions indicate on the surface of the heart?

Answer 28

Partitions between the 4 chambers. Also contain the cardiac vessels that supply blood to heart wall.

Question 29

In which direction does the blood flow in the veins?

Answer 29

Blood flows towards the heart

Question 30

In which direction does the blood flow within the arteries?

Answer 30

Away from the heart.

Question 31

What are the components of the conduction system of the heart?

Answer 31

Sinoatrial node Atrioventricular node Bundle of His Purkinje fibres

Question 32

Where is the Sinoatrial node located?

Answer 32

Right atrium near the superior vena cava opening

Question 33

During diastole what does the Sinoatrial node exhibit?

Answer 33

Spontaneous depolarisation (pacemaker potential)

Question 34

Where does each heartbeat begin?

Answer 34

Sinoatrial (SA) node (hearts pacemaker)

Question 35

What does a wave of depolarisation result in?

Answer 35

Atrial systole (heart pumps blood out) This converges at the atrioventricular (AV) node.

Question 36

Which node delays the electrical impulses, for how long and why?

Answer 36

Atrioventricular (AV) node. 0.1-0.2 seconds. To give the atria time to fully empty the ventricles.

Question 37

Where conducts the impulses from the atrioventricular node and what are they?

Answer 37

Bundle of His. Specialised muscle fibres that conduct electrical impulses from the AV node.

Question 38

What are the specialised nerve cells within the heart and what is the main function?

Answer 38

Purkinje fibres. Sends electrical impulse received from the AV node to the bundle of His, to the ventricles. This coordinates contraction of the ventricles, ventricular systole.

Question 39

What is pulmonary circulation?

Answer 39

Transportation of deoxygenated blood from right ventricle, out the pulmonary valve and left and right pulmonary arteries, to lungs to be oxygenated, back to the left atrium through the left and right pulmonary veins. - pulmonary truck (arteries, veins, capillaries)

Question 40

What is systemic circulation?

Answer 40

Transportation of oxygenated blood from the left ventricle through the aortic valve into the aorta, the oxygenated blood transports and delivers to the body and collects carbon dioxide. The deoxygenated blood travels back to the heart through the superior and inferior vena cava into the right atrium.

Question 41

What happens in the capillaries?

Answer 41

Rapid rate of gas exchange between blood and tissues; oxygen, nutrients, waste products.

Question 42

What is the primary role of platelets in blood?

Answer 42

Clotting mechanisms

Question 43

What’s the primary role of red blood cells?

Answer 43

Transport oxygen

Question 44

What does blood pressure measure?

Answer 44

The force exerted by circulating blood on vessel walls

Question 45

What type of vessel carries oxygenated blood away from heart?

Answer 45

Arteries

Question 46

What type of vessel carries deoxygenated blood to the heart?

Answer 46

Veins

Question 47

What is the hearts own circulation known as?

Answer 47

Coronary circulation

Question 48

What does the cardivascular system control?

Answer 48

Homeostasis

Question 49

Why is pulmonary circulation unnecessary in utero?

Answer 49

Foetal blood is oxygenated from the placenta

Question 50

What serves as the connection between the foetus and placenta in foetal circulation?

Answer 50

Umbilical cord

Question 51

What is venous blood?

Answer 51

Deoxygenated

Question 52

In foetus circulation, the venous blood returning to the right atrium is deflected into the left atrium through what?

Answer 52

Foramen Ovale

Question 53

In foetus circulation, the blood in the left ventricle is diverted away from the pulmonary arteries, to the aorta, through the what?

Answer 53

Ductus arteriosus

Question 54

What are the 5 types of blood vessels

Answer 54

Arteries Arterioles Capillaries Venules Veins

Question 55

Function and structure of arteries in circulatory system

Answer 55

- Transport oxygenated blood (not pulmonary system) away from heart. - Blood flows under high pressure. - Thin elastic muscular walls. - Strong muscular walls to withstand pressure.

Question 56

Function of arterioles

Answer 56

Last small branch of artery system. Act as control valves to release blood into capillaries.

Question 57

Function and structure of capillaries

Answer 57

- Exchange nutrients, hormones, waste, oxygen, electrolytes between blood and tissues. - Smallest and most abundant in body. - Walls are endothelium 1 cell layer thick.

Question 58

Function of venules

Answer 58

Collect blood from capillaries

Question 59

Function and structure of veins in circulatory system

Answer 59

- Transports deoxygenated blood from tissues back to heart. - Contains valves to prevent back-flow/pooling. - Rely on the skeletal muscle and respiratory pump. - Less muscular and elastic compared to arteries but still same 3 layers.

Question 60

What determines the blood flow through capillaries?

Answer 60

Precapillary sphincter muscles Constriction or dilation of arteries or arterioles.

Question 61

3 types of capillaries

Answer 61

Continuous - no perforations Fenestrated - small perforations Discontinuous - large openings

Question 62

What is the blood brain barrier?

Answer 62

Boundary between circulating blood and the brain

Question 63

Functions of the blood brain barrier?

Answer 63

Highly selective and protects the brain from foreign substances and maintains constant environment for brain.

Question 64

How are large molecules, immune cells, bacteria and viruses prevented from passing the blood brain barrier?

Answer 64

Brain capillaries are not fenestrated and their endothelial cells are tightly packed.

Question 65

Capillary beds

Answer 65

Networks of capillaries supplying organs

Question 66

Major arteries

Answer 66

Pulmonary artery Aorta

Question 67

Major veins

Answer 67

Pulmonary vein Superior vena cava Inferior vena cava

Question 68

Pulmonary arteries

Answer 68

Carry deoxygenated blood to the lungs from the right atrium.

Question 69

Aorta

Answer 69

Carry oxygenated blood to the rest of the body. Ascending aortic arch - upper body Descending aortic arch - lower body

Question 70

Pulmonary vein

Answer 70

Returns oxygenated blood from the lungs into left atrium.

Question 71

Superior vena cava

Answer 71

Receives deoxygenated blood from upper body and drains into right atrium.

Question 72

Inferior vena cava

Answer 72

Receives deoxygenated blood from lower body and drains into right atrium.