Lecture 10 Part 2

Question 1

What does endurance training increase?

Answer 1

Heart rate, cardiac output, stroke volume, end systolic residual volume, ejection function and cycle time

Question 2

What is the fold change from endurance training from normal?

Answer 2

By a 5-fold change

Question 3

What is one way of measuring the cardiac efficiency?

Answer 3

Buy the pressure-volume loop

Question 4

What happens when you get an electrical excitation?

Answer 4

Increase in ventricular volume and increased in ventricular pressure (valves opens and blood exists the heart)

Question 5

What = the total loop area (the mechanical work of the heart)?

Answer 5

Mitral valves open, aortic valve closes, aortic valve opens and mitral valves closes

Question 6

What increases per ventricle volume?

Answer 6

Ventricle contraction increases per ventricle volume

Question 7

What does endurance training incorporate?

Answer 7

Combinations of beta-receptor signalling and distension

Question 8

What happens short term in endurance training?

Answer 8

Chamber distension occurs due to increased venous return - increased preload

Question 9

What is activated in short term endurance training?

Answer 9

Frank starling and brainbridge mechanisms

Question 10

What happens to the ventricles in short term in endurance training?

Answer 10

Activates stronger contraction by the frank-starling mechanism

Question 11

What happens to the atrium short term in endurance training?

Answer 11

Contributes to increased heart rate by the brainbridge reflex

Question 12

What happens to the heart during longer term endurance training?

Answer 12

There can also be structural remodelling of the heart

Question 13

What does chamber distension result in?

Answer 13

A larger radius over time

Question 14

What does laplace’s law mean?

Answer 14

Reduces ventricular pressure. Pressure = wall tension/ radius

Question 15

What is the stimulus of chamber sustension over a period of time?

Answer 15

It is greater over a period of time

Question 16

What can ventricular pressure be accommodated by?

Answer 16

By increasing the muscle mass

Question 17

How chamber distension result into a larger radius?

Answer 17

Increase in preload results in sarcomeres being added in series, cells increase in size, length not width

Question 18

What is the process of a larger radius called?

Answer 18

Eccentric cardiac hypertrophy

Question 19

What are some cardiac physiological adaptations in action?

Answer 19

Increased in cardiac output, stroke volume, heart rate and decrease in peripheral vascular resistance

Question 20

What is the increase in blood volume from a normal person to someone who is pregnant?

Answer 20

35-50% increase in blood volume, 50% up to 9 months

Question 21

What mechanism is increased in pregnancy?

Answer 21

Preload - as the metabolic demands of the organ systems are increasing all the time

Question 22

What can happen to the ventricle during pregnancy?

Answer 22

You can have a dilated ventricle - which is responses by eccentric remodelling

Question 23

What is important to know about dilated ventricles in pregnancy?

Answer 23

That they are reversed 1-3 months post partum

Question 24

What is increased during strength exercise training?

Answer 24

Increased after load

Question 25

Describe the changes that occur in strength exercise training?

Answer 25

Increased in wall stress as the force in which the ventricles has to contract is higher, and increase in after load

Question 26

What is increase wall stress in the cardiac ventricles inversely proportional to?

Answer 26

The thickness of the diameters and radius

Question 27

What is done to counter the increase in mass due to the induced wall stress?

Answer 27

Sarcomeres are added in parallel - the process Is called concentric cardiac hypertrophy

Question 28

What happens if the physiological changes are over ridden?

Answer 28

It results in cardiac dysfunction or even heart failure

Question 29

Define heart failure?

Answer 29

An inability to pump enough blood to meet metabolic demand

Question 30

What are the symptoms for heart failure?

Answer 30

Decreased SV, CO, Decreased BP, oedema and exercise intolerance

Question 31

What is the most common cause of heart failure?

Answer 31

Ischaemic heart disease, which is a build up of plaque material that blocks the flow of blood, the block can be complete or it can be partial

Question 32

What can coronary artery damage result to?

Answer 32

Result to phenotypic alteration of vascular cells

Question 33

What does alteration vascular cell result in?

Answer 33

Results in the formation of an atherosclerotic and fibrotic plaque restricting blood flow to the myocardium

Question 34

What does ischaemia cause?

Answer 34

Dysregulation of the cardiomyocytes

Question 35

What is the process from a heart attack to increased sympathetic drive?

Answer 35

Decrease in cardiac EC coupling, cardiac output, BP, and baroreceptor input

Question 36

What happens to the feedforward responses from the heart attack?

Answer 36

Increase in circulating catecholamines - overstimulation, more SR ca2+ and leakiness of ca2+ sparks through the RYR2 receptors

Question 37

How is the there an overload of SR ca2+ ?

Answer 37

From phospholamban phosphorylation

Question 38

What does beta-signalling overstimulation induce?

Answer 38

Induces ca2+ dysregulation

Question 39

What does a large increase in ca2+ increase?

Answer 39

Increases the membrane potential of the cell

Question 40

What happens when the whole membrane potential is increased?

Answer 40

It can start to cause arrhythmias which disrupts the while cell. Different cells can access a ca2+ wave but cardiomyocytes in sarcomeres cannot

Question 41

What is tissue level EC coupling compounded by? - from a feed forward response

Answer 41

Infarcted tissue leading to fibrosis, loss of contractile tissue again increasing risk of electrical dysregulation (arrhythmias)

Question 42

What is the treatment for severe heart failure?

Answer 42

Often involves trying to reduce the preload and after load

Question 43

What are examples of treatment for heart failure?

Answer 43

Diuretics - reduce plasma volume, ACE inhibitors - reduce vasconstriction, beta blockers - inhibit catecholamines overstimulation

Question 44

What are some potential integrated physiological mechanisms?

Answer 44

Improved respiration, improved skeletal muscle function and improved blood pressure, maintain glucose and homeostasis and reduce sarcopenia

Question 45

What can sarcomeric protein mutations over time lead to?

Answer 45

Dilated cardiomyopathy or hypertrophic cardiomyopathy