Cardiology

Question 1

What are three functions of the pericardium?

Answer 1

“It is the layer on the outside of the heart

1. Provides support ‘sports bra to the heart’
2. Allows the heart to not overfill.
3. Limits the filling of the heart in diastole”

Question 2

What are the four components of a cardiac cycle?

Answer 2

1. Isovolumic contraction - no change in volume - all valves shut
2. Ejection
3. Isovolumic relaxation - semilumar valves fill up, all vavles are shut again.
4. Diastole - filling of the heart

Question 3

What are the three phases of diastole?

Answer 3

1. Rapid filling (blood has been waiting)
2. Diastasis
3. Atrial contraction (depolarization, pushes the last residual blood)

Question 4

Systole

Answer 4

accumulates blood -> the contraction of the chambers of the heart (especially the ventricles) to drive blood into the aorta and pulmonary artery

Question 5

What does the left aortic sinus gives rise to?

What does the right aortic sinus gives rise to?

Answer 5

The left coronary artery

The right coronary artery

Question 6

Chronotropy
Inotropy
Lusitropy
Dromotropy

Answer 6

rate of contraction/min, increased by sympathetic, decreased by parasympathetic
pertaining to cardiac contractile force.
the ability of the heart to fill; another word for myocardial relaxation
pertaining to the speed of impulse transmission.

Question 7

List 5 factors to increase the myocardial oxygen demand/consumption

Answer 7

Heart Rate
Contractility (Ionotropy)
After load
Preload
Conduction velocity (Dromotropy)
(the opposite decreases myocardial oxygen demand/consumption)
Distensibility 
Synergy

Question 8

List at least 4 ways to enhance contractility (inotropy)

Answer 8

1. Increase affinity of Troponin C for calcium
2. Increase extracellular concentration of calcium ions (IV Ca)
3. β adrenergic receptor agonist (increases cAMP)
4. Stimulate the sympathetic nervous system (catecholamines)
5. Stimulate the RAAS (renin-angiotensin-aldosterone system)
6. phosphodiesterase inhibitors
7. Blockade of the Na/K ATPase pump

Question 9

What structures undergo dilation in a PDA?

Answer 9

• Pulmonary artery (post PDA)
• Pulmonary capillaries
• Pulmonary vein
• Left atrium and ventricle
• beginning of aorta

Question 10

List the steps that increase contractility after beta receptor activation of a myocardial cell

Answer 10

• epinephrine/norepinephrine

Question 11

List 3 arterial receptors that mediate vasoconstriction

Answer 11

Alpha 1 adrenergic receptor
Angiotensin II receptor
Endothelin receptor

Question 12

What cardiac events are associated with S1?
What cardiac events are associated with S2?
What cardiac events are associated with S3?

What cardiac events are associated with S4?

Answer 12

Associated with closure of the A/V valves
Associated with closure of the semilunar valves
Associated with filling
(Normal in horse & cow)
Associated with atrial contraction
(Normal in horse & cow)

Question 13

How do starling’s forces promote edema?

Answer 13

Starling’s forces effect the direction of fluid movement controlled by balance between blood pressure and osmotic pressure.
If blood pressure is too high or osmotic pressure is too low, edema will form.

Question 14

What happens with premature beats?

Answer 14

• cause Tachyarrhythmias –> a heart rythym with premature beats causing the heart rate to speed up
• -> increase in oxygen demand, decrease in filling time, decrease in time for coronary blood flow

Question 15

premature beats

Answer 15

They represent cells that are normally non-automatic that have acquired automaticity
(usually due to disease causing myocardial dilation)

Question 16

How does tachycardia affect myocardial performance?

Answer 16

Part of myocardial performance is the amount of O2 required for contraction
- this is effected by wall stress, contractility and heart rate. If heart rate increases, more O2 is required.

Question 17

Factors that promote venous dilation

Answer 17

ANS (M3 receptor/G-alpha-i)
Naturitic peptides
Adenosine
Nitric Oxide
Endothelium derived relaxation factor
Prostacyclin (activates G-alpha-s)
Bosantin (Endothelin receptor blocker)
Bradykinin

Question 18

Cause of heart murmurs

Answer 18

• Leaky valves
• Stenotic valves
• abnormal communications (shunts, A/V)

Question 19

Blood pressure

Answer 19

Cardiac ouput x Arterial resistance

Question 20

Cardiac Output

Answer 20

Stroke volume x heart rate

Question 21

Arterial resistance is proportional to…

Answer 21

Arterial tone (vasocontrition/vasodilation)
Stroke volume
Compliance/stiffness of the arterial tree

Question 22

Factors that promote venous constriction

Answer 22

• ANS
• Renin/angiotensin system
• Arganine vasopressin
• Endothelin

Question 23

Endothelin

Answer 23

a peptide produced and secreted by endothelial cells that induces vasoconstriction

Question 24

Adenosine

Answer 24

energy storage molecule used by most organisms (vasodilator)

Question 25

Ectopic beats

Answer 25

When other areas of the heart initiate a heart beat. The appearance of the ECG does change.