Feedback Control in the CV System

Question 1

What is blood pressure?

Answer 1

The outwards (hydrostatic) pressure exerted by the blood on blood vessel walls

Question 2

What is Systemic Systolic Arterial Blood Pressure?

Answer 2

The pressure exerted by the blood on the alls of the aorta & systemic arteries when the heart contracts

Question 3

What is Systemic Diastolic Arterial Blood Pressure?

Answer 3

The pressure exerted by the blood on the walls of the aorta & systemic arteries when the heart relaxes

Question 4

What is the ideal normal arterial blood pressure for adults under 80?

Answer 4

Systolic 90-129mmHg
Diastolic 60-80mmHg

Question 5

What is hypertension?

Answer 5

Clinical blood pressure of 140/90 mmHg or higher & day time average of 135/85 mmHg or higher

Question 6

What is Pulse Pressure?

Answer 6

Difference between systolic & diastolic blood pressures

Question 7

How do you calculate pulse pressure?

Answer 7

Systolic - Diastolic

Normal pp is 30-50mmHg

Question 8

What is MAP?

Answer 8

The average arterial blood pressure during a single cardiac cycle, which involves contraction & relaxation of the heart

Question 9

What is the simplest way to estimate MAP?

Answer 9

[(2x Diastolic) + Systolic]/3

Question 10

What is the normal range of MAP?

Answer 10

70-105mmHg

At least 60mmHg is required to perfume vital organs like brain, heart & kidneys

Question 11

Why must MAP be regulated within a narrow range?

Answer 11

Pressure high enough to perfume vital organs
But
Low enough to not damage blood vessels or place extra strain on heart & other organs

Question 12

What happens to baroreceptor firing when MAP increases?

Answer 12

Increases
Vice Versa

Question 13

What does NTS stand for?

Answer 13

Nucleus Tractus Solitarus

Question 14

How does the Baroreceptors send afferent impulses to the CV control centre in the medulla of brain?

Answer 14

CV control centre receives CVS afferent information
NTS is site of 1st synapse for all CVS affects in medulla
NTS integrates & relays information to other regions that control pathway of 2 divisions of ANS to heart & blood vessels

Question 15

By regulating what can regulate MAP?

Answer 15

Heart rate, Stroke volume , Systemic vascular resistance
Increasing these increases MAP

Question 16

What is Authorhythmicity?

Answer 16

The hearts ability of beating rhythmically in the absence of external stimuli

Question 17

What nervous system is heart rate modified by?

Answer 17

Autonomic Nervous System

Question 18

What is it called when the heart rate accelerates?

Answer 18

Tachycardia

Question 19

What is it called when the heart rate slows?

Answer 19

Bradycardia

Question 20

What receptors does noradrenaline act on?

Answer 20

Beta 1 receptors

Question 21

What receptors does acetylcholine act on?

Answer 21

M2 receptors
Muscarinic

Question 22

How does stroke volume increase?

Answer 22

When the contractile strength of the heart is increased

Question 23

How does the sympathetic nervous system increase stroke volume?

Answer 23

Sympathetic nerves innervate the ventricular myocardium & stimulation increases force of contraction & stroke volume

Question 24

What law is intrinsic control of stroke volume?

Answer 24

Starlings

Question 25

What is systemic vascular resistance regulated by?

Answer 25

Vascular smooth muscles

Question 26

What is the main site of SVR?

Answer 26

Arterioles

Question 27

What does contraction of VSM cause?

Answer 27

Vasoconstriction & increases SVR & MAP

Question 28

What does relaxation of VSM cause?

Answer 28

Vasodilation & decreases SVR & MAP

Question 29

In VSM what neurotransmitter acts on alpha receptors?

Answer 29

Noradrenaline

Question 30

Vasomotor Tone

Answer 30

Vascular smooth muscles are partially constricted at rest

Question 31

What causes Vasomotor tone?

Answer 31

Tonic discharge of sympathetic nerves resulting in continuous release of noradrenaline

Question 32

What happens to SVR if sympathetic discharge is increased?

Answer 32

It increases

Question 33

What happens to SVR if sympathetic discharge decreases?

Answer 33

It decreases

Question 34

What happens to baroreceptors if high arterial blood pressure is sustained (re-set)?

Answer 34

They will only fire again if there is an acute change higher than the already new steady level