Cardiovascular physiology

Question 1

What are the functions of the cardiovascular system?

Answer 1

Delivery of oxygen and other nutrients.
Removal of carbon dioxide and other waste products.
Support thermoregulation and control body fluid balance.
Hormone transport.
Regulation of immune function.

Question 2

Outline the gross structure of the heart.

Answer 2

Two atria above two ventricles.

Greater muscle mass in left ventricle.

Question 3

Describe the functions of the right and left heart.

Answer 3

Right heart - Receives deoxygenated blood which it pumps to the lungs.
Left heart - Receives oxygenated blood from the lungs and pumps to all other tissues in the body.

Question 4

List the four valves in the heart.

Answer 4

Atrioventricular (Tricuspid and bicuspid)

Semilunar (Pulmonary and aortic)

Question 5

List the order of cardiac conduction

Answer 5

1. SA node
2. Right atrium
3. AV node
4. Purkinje fibres
5. Left atrium
6. Bundle of his
7. AV bundle branches
8. AV right bundle branches

Question 6

What do the different waves in the ECG trace represent?

Answer 6

P wave - Atrial depolarisation
QRS - Ventricular depolarisation
T wave - Ventricular repolarisation

Question 7

What are tachycardia and bradycardia?

Answer 7

Tachycardia > 100bpm

Baradycardia < 60bpm

Question 8

What is Henry’s law?

Answer 8

When a mixture of gas is in contact with liquid each gas dissolves in the liquid in proportion to it’s partial pressure and solubility until equilibrium is achieved and the gas partial pressure are equal in both locations.

Question 9

How is oxygen transported in the blood? (2 ways)

Answer 9

Dissolved in plasma, 3mL per L of blood.

Bound to haemoglobin men 150g/L women 130g/L

Question 10

What is the equilibrium equation for haemogolbin and oxygen binding?

Answer 10

Hb4 + 4O2 <> Hb4O8

Question 11

How much oxygen does each gram of haemoglobin hold?

Answer 11

1.34mL

Question 12

How is carbon dioxide transported in the blood? (three ways, include percentages)

Answer 12

Dissolved in blood - 7%
Carbamino compounds - 23%
Bicarbonate ions - 70%

Question 13

What is the equation for the formation of bicarbonate ions from carbon dioxide and water?

Answer 13

CO2 + H2O <> H2CO3 <> HCO3- + H+

Question 14

What is blood pressure?

Answer 14

The pressure exerted by blood on vessel walls.

Question 15

What are the two equations for MABP?

Answer 15

2/3DBP + 1/3SBP

DBP + 0.33(SBP-DBP)

Question 16

What is cardiac output? What is the equation?

Answer 16

Total volume of blood pumped by the ventricle per minute.

Q = HR x SV

Question 17

What is stroke volume? What is the equation?

Answer 17

The volume of blood pumped during one beat.

SV = EDV - ESV

Question 18

What is heart rate variability? Why can it be beneficial?

Answer 18

Variation in time interval between heart beats.

Beneficial in response to stimuli

Question 19

Outline the autonomic control of heart rate.

Answer 19

Sympathetic - Increase heart rate and ionotropism

Parasympathetic - Decrease heart rate and ionotropism

Question 20

What benefits have been associated with high heart rate variability?

Answer 20

Good emotional regulation
Well being
Information processing

Question 21

What negative consequences have been associated with low heart rate variability?

Answer 21

Depression, anxiety, poor emotional regulation
IBS
Ageing
Cardiac mortality

Question 22

What is VO2?
What is the equation?
What are the determinants?

Answer 22

The difference between the volume of gas inhaled and volume of gas exhaled per unit of time.
VO2 = [(Vi x FiO2)-(Ve x FeO2)]/T
Blood flow and oxygen extraction

Question 23

What is the fick equation?

Answer 23

VO2 = Q x (Ca02-Cv02)

Question 24

Define maximal oxygen uptake.
How do you measure it?
What are you looking for?

Answer 24

The maximum ability to take in, transport and utilise oxygen during exercise.
Ramp/Step incremental test.
Looking for: Plateau of oxygen consumption, RER > 1.10, HR within 10 of predicted max, RPE > 17

Question 25

What is lactate threshold and turnpiont?

Answer 25

Threshold - The first increase above baseline

Turnpoint - Point at which there is a sudden increase in lactate.

Question 26

Outline the response to increasing exercise intensity.

Answer 26

Increased blood pressure - This rise is larger in the systolic than in the diastolic.
Increase in cardiac output - Increase in HR is linear until exhaustion. Stroke volume increases then levels off.

Question 27

What is the shape of the oxyhaemoglobin dissociation curve?

Answer 27

Sigmoidal

Question 28

What factors affect haemoglobin O2 affinity?

Answer 28

Acidity - Increases during exercise. Affinity of Hb decreases. More O2 delivered to acidic sites.
Partial pressure of CO2 - Rises during exercise, affinity of Hb decreases. Harder a tissue is working the more O2 will be unloaded.
2,3 BPG - Formed during glycolysis. Helps unload O2 by binding with Hb.
Temperature - Affinity of Hb decreases. More O2 delivered to warm muscle.

Question 29

Expain how there is increased oxygen utilisation during exercise?

Answer 29

Increased O2 extraction from blood.
Dilation of peripheral vascular beds.
Increased Q.
Increase in pulmonary blood flow.
Increase in ventilation.