lecture 10 - controlling heart & blood pressure

Question 1

What structure generates pressure for the systemic circulation?

Answer 1

The left ventricle

Question 2

What drives blood flow between arteries and veins?

Answer 2

A high pressure difference between high pressure arteries, less pressured arterioles and low pressure veins

Question 3

What is the symbol for blood flow?

Answer 3

Q

Question 4

What is the equation for blood flow?

Answer 4

Q= ΔP/R (flow=change in pressure/resistance)

Question 5

What is blood flow proportional to?

Answer 5

Change in pressure in a vessel, and Mean Arterial Pressure

Question 6

What is blood flow inversely proportional to?

Answer 6

Resistance in a vessel

Question 7

What is the equation for Mean Arterial Pressure, in terms of Q and R ?

Answer 7

MAP=QR (mean arterial pressure=blood flow * resistance)

Question 8

What is mean arterial pressure proportional to?

Answer 8

Blood flow and resistance

Question 9

What is the equation for Mean arterial pressure, in terms of CO and TPR?

Answer 9

MAP=CO*TPR (mean arterial pressure = cardiac output * total peripheral resistance)

Question 10

What is the equation for cardiac output?

Answer 10

CO=SV*HR (cardiac output = stroke volume * heart rate)

Question 11

What is the unit for stroke volume?

Answer 11

L/beat

Question 12

What is the unit for cardiac output?

Answer 12

L/min

Question 13

What is control centre of blood pressure homeostasis?

Answer 13

The brain stem

Question 14

What is the afferent input to the brain stem that regulates blood pressure?

Answer 14

From the CNS and periphery

Question 15

What is the efferent output to the brain stem that regulates blood pressure?

Answer 15

To the heart and blood vessels

Question 16

What part of the nervous system is involved in blood pressure homeostasis?

Answer 16

Autonomic - Parasympathetic and sympathetic

Question 17

What type of receptor are involved in detecting blood pressure change?

Answer 17

Baroreceptors

Question 18

What type of receptor are baroreceptors?

Answer 18

Stretch receptors

Question 19

Where are baroreceptors found?

Answer 19

Buried in the walls of blood vessels

Question 20

How does baroreceptor signalling work?

Answer 20

They send a constant signal to the brain, with the frequency of the action potentials changing as as blood pressure changes

Question 21

Which parts of the body have the highest concentration of baroreceptors?

Answer 21

The carotid sinus and aortic arch

Question 22

Why does the carotid sinus have a high concentration of baroreceptors?

Answer 22

Located on the carotid artery, meaning blood pressure to the brain can be carefully managed.

Question 23

Why is there a high concentration of baroreceptors on the aortic arch?

Answer 23

To measure blood pressure immediately as the blood leaves the heart

Question 24

What nerve is responsible for parasympathetic decrease of heart rate?

Answer 24

the vagus nerve

Question 25

What nerve is responsible for sympathetic increase in heart rate?

Answer 25

The sympathetic cardiac nerves

Question 26

Where does the vagus nerve target?

Answer 26

The SA and AV nodes

Question 27

Where do the sympathetic cardiac nerves target?

Answer 27

The SA and AV nodes

Question 28

How do vagus and sympathetic cardiac nerves alter contraction by signalling the AV node?

Answer 28

They alter the pause between atrial and ventricular contraction, altering heart rate

Question 29

How does the sympathetic nervous system increase the force of heart contraction?

Answer 29

The sympathetic cardiac nerves synapse with the conduction cells on the ventricles of the heart, increasing the force with which the muscle contracts.