Week 5 - Cardiovascular System

Question 1

Describe the purpose of the cardiorespiratory system

Answer 1

Transport O2 and nutrients to tissues
Removal of CO2 wastes from tissues
Regulation of body temperature

Question 2

What are the two major adjustments of blood flow during exercise

Answer 2

Increased cardiac output
Redistribution of blood flow from inactive organs to active muscle

Question 3

What are the main aspects of the circulatory system

Answer 3

Heart: creates pressure to pump blood
Arteries & arterioles: carry blood away from heart
Capillaries: Exchange of O2, CO2, and nutrients with tissues
Veins and venules: carry blood towards the heart

Question 4

What is the difference between the pulmonary circuit and systemic circuit

Answer 4

Pulmonary circuit is the right side of the heart. Pumps deoxygenated blood to the lungs via pulmonary arteries. Returns oxygenated blood to the left side of the heart via pulmonary veins
Systemic circuit is the left side of the heart. Pumps oxygenated blood to the whole body via arteries. Returns deoxygenated blood to right side of heart via veins

Question 5

What are some wall components of blood vessels

Answer 5

Smooth muscle
Collagen
Elastin
Endothelium

Question 6

Define resistance to flow

Answer 6

Resistance = measure of hinderance or opposition to blood flow through a vessel caused by friction between the blood in the vessel wall

Question 7

What factors affects blood flow

Answer 7

Directly proportional to the pressure difference between the two ends of the system
Inversely proportional to resistance
Blood flow = changes in pressure / resistance

Question 8

What factors influence resistance

Answer 8

Length of vessel
Viscosity of the blood
radius of the vessel (greatest influence)

Question 9

Define arterivenous difference

Answer 9

Amount of O2 that is taken up from 100ml of blood
Increases during exercise due to increased O2 uptake in tissues

Question 10

What is Ficks equation

Answer 10

VO2 = cardiac output x a-vO2 difference

Question 11

How does the central command affect the cardiovascular system

Answer 11

Initial signal to drive cardiovascular system comes from higher brain centres
Fine-tuned by afferent feedback from receptors (from mechanoreceptors of heart and muscle)

Exercise pressor reflex (feedback to medulla oblongata to amend CV response to exercise)

Question 12

Why is there a continued increased in systolic BP with exercise when baroreceptors work to maintAIN BP homeostasis

Answer 12

The baroreflex is reset during exercise. Central command and exercise pressor reflex both play an active role in resetting baroreflex.

Question 13

Define myocardial infarction

Answer 13

Blockage in coronary blood flow results in cell damage
Exercise training protects against heart damage during an MI

Question 14

What are the consecutive layers in the heart

Answer 14

Epicardium (lubricative outer covering)
Myocardium (muscular contractions)
Endocardium (protective inner layer)

Question 15

What factors affect the electrical stimulation of the myocardium

Answer 15

Sinoatrial node
Atrioventricular node
Bundle Branches
Purkinje fibres

Question 16

Describe the conduction system of the heart

Answer 16

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

Question 17

What are the main aspects of the electrocardiogram (ECG)

Answer 17

P wave: Atrial depolarisation
QRS complex: Ventricular depolarisation and atrial repolarisation
T wave: Ventricular repolarisation

Question 18

Define atherosclerosis

Answer 18

Fatty plaque that narrows coronary arteries.
Reduces blood flow to myocardium

Question 19

How does exercise training protect the heart

Answer 19

Reduces heart attacks
Improves heart’s antioxidants capacity
Improves function of ATP sensitive potassium channels

Question 20

Define the terms chronotropic and inotropic

Answer 20

Chronotropic: Heart rate increases
Inotropic: Contractility increases

Question 21

What is the main metabolic vasodilator in coronary blood vessels

Answer 21

Adenosine, also beta-adrenergic vasodilation

Question 22

What is the process during conduction system of the heart

Answer 22

1. Action potentials originate in the sinoatrial (SA) node and travels across the wall of the atrium from the SA node to the atrioventricular (AV) node
2. Action potentials pass through the AV node and along the atrioventricular (AV) bundle, which extends from the AV node, through the fibrous skeleton, into the interventricular septum
3. The AV bundle divides into right and left bundle branches, and action potentials descend to the apex of each ventricle along the bundle branches
4. Action potentials are carried by the Purkinje fibres from the bundle branches to the ventricular walls

Question 23

How is heart rate regulated during exercise

Answer 23

Parasympathetic nervous system:
- via vagus nerve which slows HR by inhibiting SA and AV node

Sympathetic nervous system:
- via cardiac accelerator nerves which increases HR by stimulating SA and AV nodes

Question 24

What are the main valves in the heart located

Answer 24

Atrioventricular valves
Tricuspid (Right atrium & right ventricle)
Mitral (left atrium & left ventricle)

Semilunar Valves:
1. Pulmonary (right ventricle & pulmonary artery)
2. Aortic (left ventricle & aorta)

Question 25

What does a segment in S-T ECG diagram indicate

Answer 25

Myocardial ischemia