CV Physiology

Question 1

Where are the arterial baroreceptors located?

Answer 1

Carotid Sinus (Internal Carotid)
Aortic Arch
Preglomerular Arteriole (Kidney)

Question 2

The activation of the SNS results in the INCREASE of…?

Answer 2

Heart Rate
Cardiac contractility
TPR
Venous Tone

Question 3

The activation of the SNS results in the DECREASE of…?

Answer 3

AV Conduction Time

Question 4

The activation of the PNS results in…?

Answer 4

Increased AV Conduction Time

Decreased Heart Rate (NOT CONTRACTILITY)

Question 5

Where are the chemoceptors located?

Answer 5

Aortic bodies

Carotid bodies

Question 6

Why is BP lower at night?

Answer 6

Less sympathetic activity

Controlled mainly by renin-angiotensin system

Question 7

Why is BP lower during the summer?

Answer 7

Increased vasodilation
Increased sweating
Loss of body weight
Decrease in BP

Question 8

What is the “Population Paradox?”

Answer 8

In a population, more deaths occur in the larger number of people at moderate risk than in the small number of people at highest risk

Question 9

Describe the BP changes that occur with age

Answer 9

Systolic BP increases over the lifespan

Diastolic BP increases until 60 y.o and then decreases

Question 10

Does the pericardium play a role in ventricular compliance in a normal heart? Why?

Answer 10

No. Pericardium only plays a role in ventricular compliance when the pericardium is fibrosed/scarred or inflamed (pericarditis)

Question 11

Contractility can be increased by…

Answer 11

SNS activation
Caffeine
Adrenaline

Question 12

Contractility is decreased by

Answer 12

Acidosis

Hypercapnia

Question 13

What is the mean circulatory filling pressure? What is the normal pressure?

Answer 13

It is the pressure in the vessels when the heart stops pumping and the blood settles. This pressure depends on blood volume and compliance. Normally 7mmHg

Question 14

What does the vascular function curve describe? What pattern is observed?

Answer 14

the change in venous pressure as CO changes.

As CO increases, venous pressure decreases

Question 15

What does the cardiac function curve describe? What pattern is observed?

Answer 15

the change in CO as venous pressure changes.

As CO increases, venous pressure increases

Question 16

What substances does the endothelium produce to alter smooth muscle activity?

Answer 16

Endothelin (vasoconstrictor)
NO (vasodilator)
PGE (vasodilator/constrictor & other functions)

Question 17

What factors determine normal heart size?

Answer 17

Body size
Genetics
Blood pressure
Angiotensin II/Catecholamines
Athletic Conditioning

Question 18

List the causes of LV Hypertrophy

Answer 18

Hypertension, Aortic Stenosis (Concentric Hypertrophy)
Mitral and aortic regurgitation, ventricular septal defect (eccentric hypertrophy)
After MI
Cardiac Injury (myocarditis)
Obesity, diabetes, renal failure
Infiltration (e.g. amyloid; amyloidosis)

Question 19

What are the epidemiological consequences of LV hypertrophy?

Answer 19

Increased risk (2-3 times) of atrial fibrillation, stroke, cardiac failure, ischaemic heart disease

Question 20

What are the functional consequences of LV hypertrophy?

Answer 20

Diastolic dysfunction (less compliance)
Increased LAP and pulmonary vein pressure
Pulmonary congestion
Dehydration

Question 21

What is the treatment for LVH?

Answer 21

Target underlying condition:
Reduce BP
Valve replacement/repair
Weight loss

Question 22

What are the causes of LV Remodelling?

Answer 22

Occurs following MI

• Renin-Angiotensin-Aldosterone
• Adrenergic
• Cytokines
• Endothelin

Question 23

What are the causes of RV Hypertrophy?

Answer 23

Congenital (switching of great vessels),
Pulmonary artery hypertension (lung disease, pulmonary embolus, chronic left heart failure),
Right heart disease (pulmonary stenosis/regurgitation, tricupsid regurgitation)

Question 24

What are the causes of oedema?

Answer 24

• Decreased osmotic pressure (due to loss of plasma proteins - liver failure)
• Increased venous pressure (due to heart failure)
• Blocked lymphatics (due to cancer)
• Increased capillary permeability (due to infection)

Question 25

True or false:

Oedema (pulmonary or systemic) is due to high arterial pressure, not venous pressure

Answer 25

False.

Oedema is due to high venous pressure

Question 26

What are the causes of heart failure?

Answer 26

• Ischaemic heart disease (MI)
• Valvular heart disease
• Hypertension
• Congenital heart disease (shunts/rearranged anatomy)
• Cardiomyopathy
• Cor pulmonale
• Pericardial disease (thickening/fluid in pericardium)

Question 27

What are the clinical features of LH failure?

Answer 27

SOB, fatigue, tachycardia, lung “creps”

Question 28

What are the clinical features off RH failure?

Answer 28

Oedema (esp. peripheral), liver congestion

Question 29

What are the inappropriate adaptations that occur in response to heart failure?

Answer 29

• Fluid retention (activated by the renin-angiotensin system to increase CO)
• Sympathetic NS activity (baroreflex to increase CO)

Question 30

What are the mechanisms for right heart failure?

Answer 30

• Global heart disease
• Specific RH disease (RV cardiomyopathy, right-sided shunts, pericardial disease, pulmonary hypertension, cor pulmonale, pulmonary embolism)
• Left Heart Failure (e.g. mitral stenosis which leads to pulmonary venous hypertension (possibly due to diastolic heart failure), pulmonary congestion, chronic hypoxia leading to pulmonary vasoconstriction, pulmonary arterial hypertension leading to right heart failure)