Lecture 12 - Control of cardiac output

Question 1

What is cardiac output?

Answer 1

The volume of blood ejected by each ventricle per minute

Question 2

What is heart rate?

Answer 2

Number of heart beats per minute

Question 3

What is stroke volume?

Answer 3

The volume of blood ejected by each ventricle per beat

Question 4

What is the formula for cardiac output?

Answer 4

Cardiac output = heart rate x stroke volume

Question 5

What are some factors that affect heart rate?

Answer 5

Atrial reflex
Hormones
Venous returnW

Question 6

What are some factors affecting stroke volume?

Answer 6

Filling time
Autonomic innervation
Hormones
Vascular tone

Question 7

What are chronotropic effects?

Answer 7

Factors that affect the heart rate

Question 8

What is the process of the innervation of the heart?

Answer 8

Sensory cells detect a change needs to be made and a signal is sent to the medulla oblongata in cardioregulatory centre

Question 9

What are the two centres within the cardioregulatory centre?

Answer 9

Cardioinhibitory and cardioregulatory centre

Question 10

Where are chemoreceptors?

Answer 10

In the carotid artery and medulla oblongataW

Question 11

Where are baroreceptors?

Answer 11

In carotid artery and aorta

Question 12

What do chemoreceptors detect?

Answer 12

CO2
pH

Question 13

What do baroreceptors detect?

Answer 13

Pressure

Question 14

What type of chronotropic effect does parasympathetic have?

Answer 14

Negative
Lowers heart rate
Reduces CO

Question 15

What type of chronotropic effect does sympathetic have?

Answer 15

Positive
Increases heart rate
Increases cardiac output

Question 16

What does the parasympathetic division do in control of pacemaker cells?

Answer 16

Opens potassium ion channels
Causes faster repolarization

Question 17

What is venous return?

Answer 17

Stretches the pacemaker cells which increases heart rate

Question 18

What is the formula for stroke volume?

Answer 18

End diastolic volume - end systolic volume

Question 19

What is preload?

Answer 19

The degree to which ventricular muscle cells are stretched at the end of diastole
Directly proportional to end diastolic volume
Dependent on ventricular filling time

Question 20

What is contractility?

Answer 20

The force produced by ventricular muscle cells during systole at a given period
Has chronotropic and inotropic effects

Question 21

What is afterload?

Answer 21

The force the ventricle needs to overcome to open the semilunar valve and eject blood

Question 22

What division are positive inotropic effects?

Answer 22

Sympathetic

Question 23

What division are negative inotropic effects?

Answer 23

Parasympathetic

Question 24

What are some factors affecting venous return?

Answer 24

Posture - blood pools in legs, decreases venous return
Skeletal muscle pump - movement of skeletal muscle constricts veins, increases VR
Respiratory pump - increases venous return

Question 25

What do vaso dilation and constriction do in relation to afterload?

Answer 25

Dilation = reduces afterload
Constriction = increases afterload

Question 26

What does sympathetic division do in control of pacemaker?

Answer 26

Opens sodium ion channels
Causes depolarisation