Case 11

Question 1

What is membrane excitability?

Answer 1

The ability of a cell membrane to undergo changes in electric potential in response to stimuli. This allows for generation and spreading of action potentials

Question 2

Hyperkalemia?

Answer 2

High blood potassium levels

Question 3

Hypokalemia?

Answer 3

Low blood potassium levels

Question 4

Symptoms of hyperkalemia?

Answer 4

Irregular heart rhythms (arrhythmia)
Muscle weakness
Nausea
Fatigue
Tingling or numbness

Question 5

Symptoms of hypokalemia?

Answer 5

Muscle weakness or cramps
Fatigue
Irregular heartbeat (arrhythmia)
Constipation
Numbness or tingling
Increased urination

Question 6

What is aortic stenosis?

Answer 6

Narrowing of aortic valve opening

Question 7

What is aortic regurgitation?

Answer 7

Leaking of blood backward from aorta into left ventricle

Question 8

What is mitral regurgitation?

Answer 8

Backflow of blood from left ventricle into left atrium through mitral valve during contraction

Question 9

What is mitral stenosis?

Answer 9

Narrowing of mitral valve (which separates left atrium and left ventricle)

Question 10

What is coronary heart disease?

Answer 10

When coronary arteries (which supply heart) become narrowed or blocked, often due to fatty deposits

Question 11

What is myocardial infarction?

Answer 11

Heart attack

Question 12

What is hypertension?

Answer 12

High blood pressure

Question 13

What are cardiomyopathies?

Answer 13

Group of diseases which lead to structural and functional abnormalities of heart muscle

Question 14

Describe embryonic cardiac development process?

Answer 14

1) Heart develops from the mesoderm
2) Week 3: Heart tube formed, made of 2 segments, primitive atrium and primitive ventricle
3) Week 4+5: Formation of atria and ventricles
4) Week 5 + 6: Formation of heart valves
5) Week 5 - 8: Development of heart septa and formation of coronary vessels
6) Week 8: Maturation. Heart is complete. It is the first organ to be completed.

Question 15

Describe fetal circulation?

Answer 15

1) Oxygen and nutrients from mother blood diffuse into placental blood diffuse into fetal blood at placenta
2) Umbilical vein returns the oxygenated blood back to the foetus after placenta
3) Blood distributed around body
4) In heart, foreman ovale and ductus arteriousus are shunts so blood avoids lungs
5) Umbilical arteries return deoxygenated blood to arteries

Question 16

What is a normal heart beat?

Answer 16

70 per minute

Question 17

What are cardiomyocytes?

Answer 17

Cells in heart which contract

Question 18

Explain cardiac cycle?

Answer 18

1) Blood enters atria
2) Atrial contraction and atrioventricular valves open
3) Blood flows into ventricles
4) AV valves close (to prevent backflow) and ventricles contract
5) Pressure in ventricles exceeds pressure in arteries, so semi lunar valves open
6) Blood leaves heart and goes to lungs and body
7) Ventricles relax

Question 19

Sinoatrial node?

Answer 19

Natural pacemaker in right atrium

Question 20

Atrioventricular node?

Answer 20

Located between atria and ventricles

Question 21

Bundle of His?

Answer 21

Divides into bundle branches, transmitting signals to ventricles

Question 22

Purkinje fibres?

Answer 22

Network of fibres which distribute signals through ventricles

Question 23

Describe process of conduction of impulses?

Answer 23

1) Sinoatrial node initiates signals, causing atria to contract
2) Signals reach AV node
3) There is a delay, allowing ventricles to fill
4) Bundle of His conducts signals to bundle branches and purkinje fibres
5) Rapid signal transmission through purkinje fibres triggers synchronised ventricular contraction, so loud is pumped effectively

Question 24

What are natriuretic peptides?

Answer 24

Hormones released by the heart in response to increased blood pressure and volume
Regulate fluid balance, blood pressure and cardiovascular homeostasis
They promote vasodilation and increased urine production

Question 25

Cardiac output?

Answer 25

Total volume of blood pumped by the heart per minute

Question 26

Stroke volume?

Answer 26

Volume of blood ejected by left ventricle in one contraction

Question 27

Venous return?

Answer 27

Blood flow returning to heart from systemic circulation

Question 28

End Diastolic volume (EDV)?

Answer 28

Maximum amount of blood in heart during cardiac cycle Blood volume in ventricles just before next contraction

Question 29

End Systolic volume (ESV)?

Answer 29

Minimum volume of blood in heart during cardiac cycle Blood volume in ventricles just after contraction

Question 30

Ejection fraction?

Answer 30

Percentage of blood pumped out of the ventricle with each contraction

Question 31

Ejection fraction?

Answer 31

Percentage of blood pumped out of the ventricle with each contraction

Question 32

Describe intracellular fluid?

Answer 32

Found inside cells Rich in potassium, magnesium and phosphate ions Contains proteins and nucleic acids

Question 33

Describe extracellular fluid?

Answer 33

Outside cells Eg interstitial fluid and plasma Higher in sodium and chloride ions, contains bicarbonate ions

Question 34

What is oedema?

Answer 34

Swelling caused by a build up of fluid

Question 35

Physiological factors which form oedema?

Answer 35

Increased capillary permeability Changes in osmotic pressure Lymphatic obstruction Increased hydrostatic pressure of blood Sodium and water retention

Question 36

What is heart failure?

Answer 36

Heart is unable to pump blood effectively This leads to insufficient oxygen and nutrients reaching tissues

Question 37

Common causes of heart failure?

Answer 37

Coronary heart disease (blocked blood vessels which supply heart) Myocardial infarction (heart attack) Hypertension (high blood pressure) Valvular heart diseases Cardiomyopathies (abnormalities of heart)

Question 38

Signs and symptoms of heart failure?

Answer 38

Dyspnea (shortness of breath) - especially during exercise or when lying down Fatigue and weakness Oedema (swelling) in legs, ankles or abdomen due to fluid retention Persistant coughing Pink, frothy sputum Heart arrhythmias Reduced exercise tolerance Excessive urination at night

Question 39

Function of furosemide and why used to treat heart failure?

Answer 39

Inhibits sodium and water re absorption at loop of henle in kidneys Reduces fluid overload (reducing blood pressure)

Question 40

Function of glyceryl trinitrotoluene (GTN) and why used to treat heart failure?

Answer 40

Vasodilator Reducing blood pressure (reduced workload on heart)

Question 41

Function of carvedilol and why used to treat heart failure?

Answer 41

Blocks beta adrenergic receptors Reduces heart rate and O2 demand of heart muscle Dilates blood vessels

Question 42

Function of rampipril and why used to treat heart failure?

Answer 42

Blocks formation of angiotension II (from angiotension I) This is a vasoconstrictor So rampipril acts as a vasodilator

Question 43

What is atrial fibrillation?

Answer 43

Disorder characterised by irregular and rapid heartbeats Atria quiver rather than contracting

Question 44

What are anticoagulants?

Answer 44

Medications which help prevent blood clot formation

Question 45

Why would an atrial fibrillation patient be given anticoagulants?

Answer 45

Stagnant blood in atria increases risk of clot formation, which could break loose and travel to other parts of body.

Question 46

What is pericardium?

Answer 46

A double walled sac surrounding the heart

Question 47

What are the 2 layers of the pericardium?

Answer 47

Fibrous (outer) and Serous (inner)

Question 48

What are the 3 layers of the heart wall?

Answer 48

Epicardium (outer), Myocardium (middle), Endocardium (inner)

Question 49

What is tricuspid valve?

Answer 49

Right atrium to right ventricle

Question 50

What is bicuspid/mitral valve?

Answer 50

Left atrium to left ventricle

Question 51

What is pulmonary semilunar valve?

Answer 51

Valve linking right ventricle and pulmonary artery

Question 52

What is aortic semi lunar valve?

Answer 52

Valve linking left ventricle and aorta

Question 53

What is superior vena cava?

Answer 53

Drains deoxygenated blood from upper body into right atrium

Question 54

What is inferior vena cava?

Answer 54

Drains deoxygenated blood from lower body into right atrium

Question 55

What is aorta?

Answer 55

Distributes blood from left ventricle around body

Question 56

Describe blood flow through heart and lungs?

Answer 56

1) Deoxygenated blood enters right atrium via vena cava 2) It moves through tricuspid valve into right ventricle 3) Contraction sends blood through pulmonary valve into pulmonary artery 4) Blood goes to lungs 5) Blood leaves lungs via pulmonary vein back into left atrium 6) Passes through bicuspid/mitral valve into left ventricle 7) Pumped out of ventricle through aortic valve into aorta, then out into body