Cardiovascular System

Question 1

Cardiac Valves Blood Flow

Answer 1

Question 2

Cardiac Valves Blood Flow Mnemonic

Answer 2

Toilet Paper My Ass

Triscupid

Pulmonic

Mitril

Aortic

Question 3

Heart Sounds

Answer 3

Question 4

Heart Sounds Mnemonic

Answer 4

APE To Man

• Aortic
• Pulmonic
• Erbs Point
• Triscupid
• Mitral

Question 5

Wiggers Diagram

Answer 5

Question 6

A Wiggers diagram, showing the cardiac cycle events occuring in the left ventricle. In the atrial pressure plot: wave “a” corresponds to atrial contraction, wave “c” corresponds to an increase in pressure from the mitral valve bulging into the atrium after closure, and wave “v” corresponds to passive atrial filling. In the electrocardiogram: wave “P” corresponds to atrial depolarization, waves “QRS” correspond to ventricular depolarization, and wave “T” corresponds to ventricular repolarization. In the phonocardiogram: The sound labeled 1st contributes to the S1 heart sound and is the reverberation of blood from the sudden closure of the mitral valve (left A-V valve) and the sound labeled “2nd” contributes to the S2 heart sound and is the reverberation of blood from the sudden closure of the aortic valve.

Answer 6

Question 7

Renin-Angiotensin-Aldosterone System (RAAS)

Answer 7

The renin-angiotensin-aldosterone system (RAAS) is a signaling pathway responsible for regulating the body’s blood pressure.

Stimulated by low blood pressure or certain nerve impulses (e.g. in stressful situations), the kidneys release an enzyme called renin. This triggers a signal transduction pathway: renin splits the protein angiotensinogen, producing angiotensin I. This is converted by another enzyme, the angiotensin-converting enzyme (ACE), into angiotensin II.

Angiotensin II not only causes blood vessels to narrow (vasoconstriction), it also simultaneously stimulates the secretion of the water-retaining hormone vasopressin (also called AVP) in the pituitary gland (hypophysis) as well as the release of adrenaline, noradrenaline and aldosterone in the adrenal gland.

Whereas adrenaline and noradrenaline enhance vasoconstriction, aldosterone influences the filtration function of the kidneys. The kidneys retain more sodium and water in the body and excrete more potassium. The vasopressin from the pituitary gland prevents the excretion of water without affecting the electrolytes sodium and potassium.

In this way, the overall volume of blood in the body is increased: more blood is pumped through constricted arteries, which increases the pressure exerted on the artery walls – the blood pressure.

Question 8

Renin Angiotensin Aldosterone System

Answer 8

The renin-angiotensin-aldosterone system (RAAS) plays an important role in regulating blood volume and systemic vascular resistance, which together influence cardiac output and arterial pressure. As the name implies, there are three important components to this system: 1) renin, 2) angiotensin, and 3) aldosterone. Renin, which is primarily released by the kidneys, stimulates the formation of angiotensin in blood and tissues, which in turn stimulates the release of aldosterone from the adrenal cortex.

Renin is a proteolytic enzyme that is released into the circulation primarily by the kidneys. Its release is stimulated by:

• sympathetic nerve activation (acting through β1-adrenoceptors)
• renal artery hypotension (caused by systemic hypotension or renal artery stenosis)
• decreased sodium delivery to the distal tubules of the kidney.