Cardiac physiology and murmurs

Question 1

Describe the pathway of blood circulation
starting at VC

Answer 1

DeO2 blood enters via IVC/SVC
Enters right atrium
^ pressure opens tricuspid valve -> right ventricle
^ pressure opens pulmonary valve -> pulmonary arteries -> lungs

O2 enters via pulmonary veins
enters left atrium
^ pressure opens mitral valve -> left ventricle
^ pressure opens aortic valve -> aorta -> body

Question 2

What is the Endocardium

Answer 2

Innermost layer of the heart wall
lines heart valves and cavities
regulates heart contractions

Question 3

What is the Myocardium

Answer 3

Middle layer of the heart wall,
composed of cardiac muscle fibers.
Causes heart contractions

Question 4

What is the Epicardium

Answer 4

Outermost layer of the heart wall aka visceral pericardium
Thin layer of connective tissue and fat that serves as an additional layer of protection

Question 5

What are the pectinate muscles

Answer 5

muscular ridges located in the atria of the heart, specifically in the right atrium and auricle. They increase the surface area.

Question 6

What are the Chordae tendineae

Answer 6

Cord-like tendons that connect the papillary muscles to the tricuspid valve and mitral valve in the heart.Prevent the valve from prolapsing during the ventricular systole.

Question 7

What are the Trabeculae carneae

Answer 7

Muscular columns in the right/left ventricles.
Provide additional ventricular valve support
Help maintain the SV + CO

Question 8

What are Papillary muscles

Answer 8

Located in the ventricles.
Attach to AV valves cusps via chordae tendineae
Contract to prevent inversion/prolapse during systole (or ventricular contraction)

Question 9

What is the interventricular septum

Answer 9

Muscular wall that separates the ventricles of the heart. Wall of cardiac tissue that comprises muscular and membranous tissue

Question 10

Components of systole

Answer 10

Isovolumetric contraction
Rapid ejection
Reduced ejection

Question 11

Components of diastole

Answer 11

Isovolumetric relaxation
Rapid filling
Reduced filling

Question 12

Cardiac output eq

Answer 12

CO= HR x SV
vol of blood pumped in one min

Question 13

Stroke volume eq

Answer 13

SV = EDV - ESV

Question 14

Mean arterial pressure eq

Answer 14

MAP = DP + 1/3(SP - DP)

Question 15

What happens during isovolumetric contraction

Answer 15

Wave of ventricular depolarisation - QRS complex
AV valves close -> S1 sound
no change in volume as pressure hasn’t exceeded aorta yet

Question 16

What happens during isovolumetric relaxation

Answer 16

Start of diastole
SL valves close -> S2 sound
no vol change as atrial pressure has not exceeded ventricles yet.

Question 17

What occurs during rapid ejection

Answer 17

SL valves open
dec. ventricular volume but pressure is still greater than aorta

Question 18

What occurs during reduced ejection

Answer 18

T wave - repolarised ventricles
ventricular vol decreases more slowly

Question 19

What occurs during rapid filling

Answer 19

isoelectric ECG
AV open, ^ vol in ventricles

Question 20

What occurs during reduced filling

Answer 20

^ ventricular vol slows
No atrial contraction

Question 21

What occurs during atrial systole

Answer 21

P wave - atrial excitation
atria contract to ^ ventricular volume

Question 22

What causes the S1 heart sound

Answer 22

AV valves closing during start of ventricular contraction

Question 23

What causes the S2 heart sound

Answer 23

SL valves closing during isovolumetric relaxation

Question 24

What causes the S3 heart sound

Answer 24

Rapid filling and expansion of ventricles
During early diastole (rapid filling)
Pathology - congestive heart failure

Question 25

What causes the S4 heart sound

Answer 25

Forced atrial contractions pushing blood into stiff ventricles During late diastole (atrial systole) Pathology - atrial hypertrophy/stiff ventricles (HTN, Cardiomyopathy, ischaemia)

Question 26

What is a heart murmur

Answer 26

Caused by turbulent flow through valves whooshing/rasping heard during heartbeat

Question 27

Types of murmurs

Answer 27

Systolic murmur Diastolic murmur Continuous murmur

Question 28

When does a systolic murmur occur

Answer 28

Heart pumping blood to the rest of the body

Question 29

When does a diastolic murmur occur

Answer 29

Heart relaxes btw beats to fill with blood

Question 30

When does a continuous murmur occur

Answer 30

Throughout the heartbeat

Question 31

Murmur heard in Aortic stenosis

Answer 31

Ejection systolic murmur

Question 32

Murmur heard in Aortic regurg

Answer 32

Early diastolic murmur

Question 33

Murmur heard in Mitral stenosis

Answer 33

Mid diastolic murmur

Question 34

Murmur heard in Mitral regurg

Answer 34

Pansystolic murmur

Question 35

Murmur heard in patent ductus arteriosus

Answer 35

continuous "machinery" murmur

Question 36

What is aortic stenosis

Answer 36

Narrow, inflexible aortic valve Blood enters through small opening in systole difficult entry to aorta

Question 37

What is aortic regurg

Answer 37

Valve leaflets floppy, improper valve closure Leak blood into ventricle during diastole

Question 38

What is Mitral stenosis

Answer 38

Narrow, inflexible mitral valve Difficult for blood to travel atria -> ventricle during diastole (mid)

Question 39

What is mitral regurg

Answer 39

Floppy mitral valve leaflets cause backflow of blood during systole

Question 40

What is a patent ductus arteriosus

Answer 40

Hole in the heart btw Aorta and pulmonary artery Mixing of blood, free flow btw lungs, aorta and pulmonary artery.