Cardiac Cycle

Question 1

diastole

Answer 1

• relaxation phase of cardiac activity -
• reflects the lowest pressure in the arteries (just before heart begins to contract again)

Question 2

systole

Answer 2

• cardiac contraction - squeezing -
• reflects the highest pressure in the arteries (when heart contracts)

Question 3

Defective valves that leak or do not open completely cause what?

Answer 3

unusual turbulance resulting in abnormal sounds or murmurs - hole in septum - abnormal blood flow

Question 4

Describe the cycle of a heart beat

Answer 4

1. atria relaxed and filling with blood
2. AV valves open as the pressure of blood in the atria increases and the ventricles are relaxed
3. Blood flows into the ventricles, almost emptying the atria
4. The conduction system stimulates the atrial muscles to contract, forcing any remaining blood into the ventricles
5. The atria relax
6. The two ventricles begin to contract and the pressure increases in the ventricles
7. The AV valve closes
8. For a brief moment, all valves are closed, the ventricular myocardium continues to build up pressure, this is the isovolumetric phase (no change in blood volume in the ventricles)
9. Then the increasing pressure opens the semilunar valves; blood is forced into the aorta and pulmonary arteries (note that the contraction must be strong enough to overcome the opposing pressure in the artery to force the valve open)
10. At the end of the cycle, the atria have begun to fill again, the ventricles relax, the aortic valve and pulmonary valves close to prevent backflow of blood, and the cycle repeats.

Question 5

What happens during ventricular systole

Answer 5

•During ventricular systole, the surge of blood expands the arteries allowing palpation of pulses. Felt at Radial

Question 6

The apical pulse refers to what?

Answer 6

the rate measured at the heart itself

Question 7

•A pulse deficit is what?

Answer 7

a difference in the rate between the apical pulse and the radial pulse

Question 8

•Cardiac function may be measured in a number of ways:

Answer 8

1. Cardiac output
2. Stroke volume
3. Cardiac reserve- refers to the ability of the heart to increase output in response to increased demand. Meet the needs of the body as that changes
4. Preload
5. Afterload

Question 9

Stroke Volume- SV

Answer 9

• The volume of blood pumped per beat
• Each heart beat is considered a stroke
• Dependant on HR and SV

Question 10

Cardiac Output- CO

Answer 10

• The volume of blood pumped over one minute. (about 5L) •
• CO = SV X HR Decrease in SV and CO - congestive Heat failure

Question 11

Preload

Answer 11

•The volume of blood in the ventricle before contraction

Question 12

Afterload

Answer 12

The volume of blood in the ventricle after contraction

Question 13

hypertension

Answer 13

high blood pressure

Question 14

How is hypertension measured? What numbers indicate hypertension

Answer 14

• HTN is measured by consistent elevation in BP, either: •
• Systolic > 140mmHg •
• Diastolic > 90mmHg

Question 15

Blood pressure

Answer 15

• is the pressure exerted by circulating blood upon the walls of the blood vessels. •
• Blood pressure depends on cardiac output and peripheral resistance

Question 16

Baroreflex

Answer 16

• Changes in blood pressure are detected by the baroreceptors and relayed to the vasomotor control center in the medulla, which adjusts the distribution of blood to maintain normal blood pressure stretch
• These reflexes help regulate short-term blood pressure

Question 17

•There are two ways the SNS increases BP:

Answer 17

1. SNS act on the beta-adrenergic receptors in the heart to increase both rate and contractility
2. SNS promotes vasoconstriction epinephrine and norepinephrine

Question 18

What are the three important hormones from the Kidnes which contributes to control BP

Answer 18

• Antidiuretic hormone (ADH);
• Aldosterone;
• renin-angiotensin-aldosterone system. (RAAS).

Question 19

Antidiuretic hormone (ADH)

Answer 19

increases water reabsorption in the kidneys, ↑ blood volume. ADH also causes vasoconstriction, decreases sweat vassopressin

Question 20

Aldosterone

Answer 20

↑ blood volume by ↑ reabsorption of sodium and water Adrenals hormone

Question 21

The renin-angiotensin-aldosterone system. (RAAS).

Answer 21

Angiotensin II is a powerful vasoconstrictor Kidney hormone