Cardiovascular System

Question 1

What are the roles of the cardiovascular system?

Answer 1

1. Transports fluids, nutrients, waste products, gases and hormones throughout the body.
2. Exchange materials between blood, cells and extracellular fluid.
3. Plays a part in the immune response, blood pressure and regulation of body temperature.

Question 2

Describe fibrous pericardium

Answer 2

Tough, fibrous outer layer. Prevents distention; acts as an anchor.

Question 3

Describe serous pericardium.

Answer 3

Thin, transparent, inner later. Simple squamous epithelium.

Question 4

What are the two types of serous pericardium?

Answer 4

Parietal: lines the fibrous outer layer.
Visceral: covers the heart surface.
Both are continuous and have a pericardial cavity between them filled with pericardial fluid.

Question 5

What are the three layers of tissue that make up the wall of the heart?

Answer 5

1. Epicardium: serous membrane; smooth outer surface.
2. Myocardium: middle layer composed of cardiac muscle cells - contractability.
3. Endocardium: smooth inner surface of heart chambers

Question 6

What are the muscles that make up the wall of the heart?

Answer 6

Pectinate muscles: muscular ridges in auricles & right atrial wall.
Trabeculae carne: muscular ridges & columns on inside walls of ventricles.

Question 7

What are the atria in the heart?

Answer 7

Right atrium: three major openings to receive blood returning from the blood.
Left atrium: four openings that receive blood from pulmonary veins.

Question 8

What are the ventricles in the heart?

Answer 8

Atrioventricular canals: openings between atria and respective ventricles.
Right ventricle: opens to the pulmonary trunk.
Left ventricle: opens to aorta - very muscular wall.
Interventricular septum: between the two ventricles.

Question 9

What are the great vessels?

Answer 9

Superior vena cava (blood into right atrium)
Aortic arch (blood out of left ventricle)
Right pulmonary veins )blood into left atrium)
Pulmonary trunk (blood out of right ventricle)
Left pulmonary veins (blood into left atrium)
Inferior vena cava (blood into right atrium)

Question 10

Describe the atrioventricular valves

Answer 10

Each valve has leaf-like cusps that are attached to cone-shaped papillary muscles by tendons (chordae tendinae).
Right side: tricuspid
Left side: bicuspid
When the valve is open, blood flows from atrium to ventricle.

Question 11

Describe the semilunar valves

Answer 11

Right (pulmonary). Left (aortic).
Each cusp is shaped like a cup.
When cusps are filled, the valve is closed to stop backflow.

Question 12

What are the features of arteries?

Answer 12

Elastic, muscular, arterioles.
Take blood away from the heart.
Contain blood under pressure.

Question 13

What are the features of veins?

Answer 13

Large, medium, small, venules
Take blood towards the heart
Thinner walls than arteries & contain less elastic tissue and smooth muscle.
Valves to prevent backflow.

Question 14

Why are capillaries important?

Answer 14

They are the site of exchange with tissues (interstitial fluid).

Question 15

What is the tunica intima?

Answer 15

The innermost layer of endothelium cells surrounding an artery or vein

Question 16

What is the tunica media?

Answer 16

Layers of smooth muscle cells arranged circularly around the blood.

Question 17

What is vasoconstriction?

Answer 17

Smooth muscles contract, decrease in blood flow.

Question 18

What is vasodilation?

Answer 18

Smooth muscles relax, increase in blood flow.

Question 19

What is the tunica externa (adventitia)?

Answer 19

The external layer surrounding the blood vessel, connective tissue?

Question 20

What is the structure of capillaries?

Answer 20

Capillary beds - networks for exchange.
Wall consisting of endothelial cells (simple, squamous epithelium), basement membrane and a thin layer of connective tissue.

Question 21

What are the functions of blood?

Answer 21

1. Transport: gases, nutrients, waste products, processed molecules, hormones, enzymes.
2. Regulation: pH and osmosis
3. Maintenance of body temp.
4. Protection against foreign substances.
5. Blood clotting

Question 22

What is the structure of a red blood cell?

Answer 22

No nucleus and bi-concave shape to increase surface area and oxygen carrying capacity.

98. 5% of oxygen from the lungs is attached to haemoglobin protein.
99. 5% is dissolved in plasma.

Question 23

What is the difference between pulmonary and systemic circulation?

Answer 23

Pulmonary circulation is the process of gas exchange in the lungs. Systemic circulation is the capillary exchange in the body/cells.

Question 24

What is the process of pulmonary circulation?

Answer 24

Deoxygenated blood enters the right atrium and flows into the right ventricle and exits heart through the pulmonary trunk. Blood travels to the right and left lung - gas exchange. Oxygenated blood travels in the left or right pulmonary veins and enters the left atrium.

Question 25

What is the process of systemic circulation?

Answer 25

Oxygenated blood enters left atrium and flows into the left ventricle. Left ventricle contracts and pushes blood out of the heart through the aorta. Blood is delivered to all cells and tissues in the body for gas/nutrient/fluid exchange. Blood travels back to the heart and re-enters right atrium through vena cava.

Question 26

What is the order of blood flow through the heart?

Answer 26

1. Vena cava, right atrium, tricuspid valve. 2. Right ventricle, pulmonary semilunar valves. 3. Pulmonary trunk. 4. Pulmonary arteries, lung tissue. 5. Pulmonary veins, left atrium. 6. Bicuspid valve. 7. Left ventricle, aortic semilunar valves. 8. Aorta to body tissues or coronary arteries.

Question 27

What is the difference between systole and diastole?

Answer 27

Systole is the repetitive contraction of the heart chambers and diastole is the relaxation of them.

Question 28

What is the role of the nervous system in the cycle and control of blood flow?

Answer 28

Maintains blood pressure and thus blood flow. Re-routed blood flow.

Question 29

What is the role of hormones in the cycle and control of blood flow?

Answer 29

Epinephrine (adrenaline) from adrenal gland - increase HR & SV, vasoconstriction in response to stress or exercise.

Question 30

What are the nodes of the heart?

Answer 30

``` Sinoatrial node (SA) - pace maker Atroventricular node (AV) ```

Question 31

What is the process of the conducting and pumping system?

Answer 31

1. Action potentials originate in the SA node and travel across the wall of the atrium to the AV node. 2. Action potentials pass through the AV node and along the AV bundle, through the fibrous skeleton and into the interventricular septum. 3. The AV bundle divides into right and left bundle branches and action potentials descend each branch. 4. Action potentials are carried by the Purkinje fibres from the bundle branches to the ventricular walls & papillary muscles.

Question 32

How does capillary exchange work?

Answer 32

Cells are bathed in interstitial fluid. Diffusion across these cells requires a pressure gradient. The products come via the capillaries and CVS and move through diffusion. Oxygen, hormones, nutrients diffuse from a high concentration in the capillary to a low concentration in the interstitial fluid.

Question 33

What substances are lipid soluble?

Answer 33

Oxygen, carbon dioxide, steroid hormones, fatty acids.

Question 34

What substances are water soluble?

Answer 34

Amino acids, glucose.

Question 35

What affects the movement of fluid from capillaries?

Answer 35

Capillary permeability, blood pressure, and osmotic pressure.

Question 36

What role does capillary exchange play in the lymphatic system?

Answer 36

Fluid moves out of capillaries into interstitial (intercellular) space and most returns to capillaries. The fluid which remains in tissues is picked up by the lymphatic system then eventually returned to venous circulation.

Question 37

What part of the heart controls pulse?

Answer 37

Left ventricle

Question 38

What is stroke volume and heart rate measured in?

Answer 38

Heart rate: beats per minute (BPM) | Stroke volume: mLs

Question 39

How do we determine cardiac output and what is it measured in?

Answer 39

Cardiac output = heart rate x stroke volume. | It is measured in Litres.