Cardio Physiology 7-9

Question 1

What type of pressure is in the arteries?

Answer 1

Pulsatile pressure

Question 2

This is a critically important determinant of blood flow.

Answer 2

Mean arterial blood pressure

Question 3

High pressure in systemic arteries are due to? (2 things)

Answer 3

Ventricular contraction and ejection of blood

Question 4

How does ejection of blood maintain blood flow?

Answer 4

The balance between blood flow in and out determines blood flow.

Blood flow in - arteries are occupied = arterial pressure increases = arterial blood volume increases

Blood flow out - arteries are being emptied = arterial pressure is decreasing = arterial blood volume is decreasing as well

Question 5

What is the nature of the blood pressure of veins and why?

Answer 5

Veins have a very low pressure, and it has a low pressure so that it can get pumped back to the right atrium.

Question 6

What creates a driving force for blood flow?

Answer 6

The difference in pressure between the artery and veins (artery = high pressure, veins = low pressure)

Question 7

This describes how blood flows in a single vessel.

Answer 7

Haemodynamics

Question 8

What is the equation for blood flow? Explain.

Answer 8

Blood flow = Change in pressure over Resistance

Blood flow is dependent on changes in pressure, and inversely proportional to changes in resistance (eg: when blood flow increases - resistance decreases because that means blood vessel diameter is increasing)

Question 9

What are the 2 determinants of blood pressure?

Answer 9

Cardiac output and arterial resistance/TPR

just think of equation

Question 10

What are the 2 determinants of cardiac output?

Answer 10

Stroke volume and heartrate

Question 11

This is the volume of blood released in each heartbeat. (which also refers to the strength of the contraction, because the stronger the contraction, the higher the volume)

Answer 11

Stroke volume

Question 12

________ is variable due to changes in heart rate and/or stroke volume.

Answer 12

Cardiac output

Question 13

Where is the mean arterial blood pressure coordinated in the brain?

Answer 13

The medulla oblongata/brainstem

Question 14

Where are the 2 locations where we would usually find baroreceptors in the heart?

Answer 14

Carotid sinus and aortic arch

Question 15

This activates the parasympathetic inputs in the SA and AV node to decrease blood pressure when it’s increased,

Answer 15

Vagus nerve (parasympathetic = rest and digest)

Question 16

These increase the heart rate and force of contraction to increase blood pressure.

Answer 16

Sympathetic nerves

Question 17

What afferent signal do baroreceptors send to the brain?

Answer 17

Changes in blood pressure (because baroreceptors detect changes in blood pressure)

Question 18

How does signaling through the vagus nerve affect the heart?

Answer 18

The heart will relax. Slows heart rate.

Cardiac output and stroke volume would decrease therefore blood pressure would decrease.

The cardiomyocytes would relax because more Ca2+ being pumped back into SR

Question 19

How does signaling through the sympathetic trunk ganglion affect the heart?

Answer 19

The heart will be active. Speeds up heart rate.

Cardiac output and stroke volume will increase so blood pressure will also increase.

There will be more contractions because of the pressure so more Ca2+ would be released from SR

Question 20

Cardiac blood is distributed to:

Answer 20

all organs

Question 21

The branching of the arterial network within the systemic circulation establishes what kind of flow?

Answer 21

Regional flow - so flow is divided among regional circulations

Question 22

What is the distribution of cardiac output to organs during exercise?

Answer 22

Increased blood flow to muscle, skin and heart

Decreased blood flow to GI tract and kidneys

Constant blood flow to brain

Question 23

This circulation has an increased cardiac output, constant mean arterial pressure, and decreased total peripheral resistance during exercise.

Answer 23

Systemic circulation

Question 24

These are the resistance vessels of the vascular system. They are lined with smooth muscle and determine blood pressure.

Answer 24

Arterioles

Question 25

Blood flow to an organ or region is controlled by adjusting the ___________ and _____.

Answer 25

arteriolar tone and radius (resistance) The bigger the radius, the larger the blood flow (because less resistance) The smaller the radius, the smaller the blood flow (because more resistance)

Question 26

What is the rule of 16?

Answer 26

R (resistance) = 1/r^4 Small changes to the lumen of the arteriole will decrease or increase the blood flow/resistance by a factor of 16

Question 27

Fine vascular control depends on:

Answer 27

High arterial pressure - high pressure means better control of flow/vascular flow

Question 28

Most blood is found where?

Answer 28

Systemic veins

Question 29

What kind of system allows for blood to be redistributed depending on the needs of the body?

Answer 29

Parallel redistribution system - basically what amount goes in is the same amount that will go out. So keeps volume of blood in those organs constant.

Question 30

This is the extent to which a vessel allows deformation in response to an applied force.

Answer 30

Compliance

Question 31

What is the equation for compliance?

Answer 31

Compliance = change in volume / change in pressure

Question 32

This is a neurologically induced contraction of the smooth muscle in veins to push blood onto arteries that have been punctured to ensure blood pressure keeps going.

Answer 32

Venoconstriction

Question 33

In the upright position, venous volume below the heart _________ and venous volume above the heart _________.

Answer 33

increases; decreases

Question 34

These counteract venous pooling and allow a more even distribution of weight in the veins.

Answer 34

Venous valves

Question 35

This acts to stiffen veins, and makes them less compliant and prone to pooling.

Answer 35

Muscle tone - so a low muscle tone = less blood flow to certain areas of the body and excessive amounts in some = usually leads to fainting

Question 36

What increases venous return to the heart when you're standing upright?

Answer 36

Skeletal muscle contractions. Basically just engaging your muscles more helps the veins to pump the blood back into the heart

Question 37

This states that the more stretched muscle fibres are before a contraction, the stronger the contraction will be.

Answer 37

Starling's Law of the Heart

Question 38

Increased venous return means increased:

Answer 38

stroke volume (heart beats stronger because the muscles are engaged before the contraction, so the contraction of the heart will be stronger)

Question 39

These are thin-walled vessels that have high compliance compared to arteries.

Answer 39

Veins

Question 40

What are the mechanisms that counter venous pooling in the legs? (2)

Answer 40

Venous valves and changing the muscle tone of the legs

Question 41

This tells us that the more the walls of the heart contract before contraction, the stronger the contraction and greater stroke volume we'll have.

Answer 41

Starling's Law of the Heart

Question 42

What generates pressure for the systemic circulation?

Answer 42

Left ventricle