Heart And Lung

Question 1

What are functions of the cardiovascular system?

Answer 1

Transport of oxygen, nutrients, antibodies, hormones, waste products and heat

Question 2

Discuss the arterial vs venous structure

Answer 2

Arterial: endothelium lining lumen, basement membrane, elastic layer, smooth muscle, elastic layer and connective tissue
Venous: endothelium lining lumen which contains valves, basement membrane, smooth muscle and connective tissue

Question 3

How is blood pressure maintained?

Answer 3

1) cardiac output

2) resistance to blood flow

Question 4

What detects blood pressure changes?

What controls blood pressures?

Answer 4

Baroreceptors detect arterial BP
Chemoreceptors detect O2 and CO2 levels

Sympathetic nerve increased BP by increasing heart rate and vasoconstriction
Parasympathetic nerve decreases BP by decreasing heart rate and vasodilation

Question 5

What additional inputs are there to BP?

Answer 5

Increased by RAAS, angiotensin and ADH from kidney. And adrenaline/noradrenaline
Decreased by ANP and nitric oxide

Question 6

What causes cardiovascular disease?

Answer 6

Formation of artherosclerosis plaques: deposits of lipid and matrix proteins in the arterial wall causing narrowing of the lumen and reduced blood supply

Question 7

What causes coronary heart disease?

What is CHD?

Answer 7

Cardiovascular disease, vasospasm, anaemia and arrhythmias

Failure of coronary circulation to meet demands of the heart. Lack of oxygen causes ischaemia

Question 8

What is a myocardial infarction?

Answer 8

End point of CHD

Caused by prolonged ischaemia

Question 9

What is stable angina?

Answer 9

Partial occlusion of the cardiac artery

Unable to supply oxygen if demand is increased

Question 10

What is acute coronary syndrome?

Answer 10

Rupturing of plaque causes unstable angina and myocardial infarction

Question 11

How can acute coronary syndrome be diagnosed?

Answer 11

ECG

Biochemical marker; cardiac enzymes, myoglobin and troponins

Question 12

What are the four main cardiac enzymes?

Answer 12

Alanine aminotransferase(ALT)
Aspartate aminotransferase (AST)
Lactate dehydrogenase (LDH)
Creatinine kinase (CK)

Question 13

Where is myoglobin found?

Answer 13

Present in cytoplasm of all muscle cells. Haem protein for oxygen transport

Question 14

What are the troponin proteins?

How are they useful markers?

Answer 14

Troponin T: binds to tropomyosin
Troponin I: inhibitor if ATPase
Troponin C: binds calcium

Troponin T and I are markers of cardiac damage. I is more specific as skeletal form of T known to cross react

Question 15

What affects detection time of cardiac markers in serum?

Answer 15

Size
Cellular location
Plasma clearance

Question 16

Discuss heart failure

Answer 16

Failure of heart output to meet demand
Symptoms: shortness of breath, fatigue and oedema
Causes: cardiomyopathy, inflammation, valvular heart disease and ischaemiac heart disease
Diagnosed by ECG and brain natriuretic peptide

Question 17

What is brain natriuretic peptide?

Answer 17

Peptide released by ventricles in response to stretching
Increased in cardiac failure
Useful rule out test as if negative = not heart failure

Question 18

What is hypertension?

What are the markers?

Answer 18

BP >140/90
Risk factor for CVD or CHD

No direct biochem markers, can diagnose the endocrine causes

Question 19

What is thrombotic disease?
What can it cause?
How can venous thrombus be biochemically detected?

Answer 19

Formation of blood clot in artery or vein due to coagulation

Can break away to from an embolus:
Arterial; MI, stroke or TIA
Venous: DVT or pulmonary embolus

D dimer(fibrin degradation product)

Question 20

What is the function of the respiratory system?

How is it regulated?

Answer 20

Gas exchange and acid-base regulation

Respiratory centre in medulla controls rate and depth of breathing. Driven by CO2 concentration

Question 21

How can lung function be monitored?

Answer 21

Blood gases pCO2 and pO2: measure gas exchange

pH, PCO2 and HCO3: acid base balance

Question 22

What are the key disorders of respiration?

Answer 22

Hypercapnia: increase PCO2
Hypocapnia: decreased PCO2
Hypoxemia: decreased O2
Type 1 respiratory failure: normal PCO2 and decreased PO2
Type 2: increased PCO2 and decreased PO2
Hyperventilation: normal PO2 and decreased PCO2

Question 23

What are the common causes of respiratory failure?

Answer 23

Type 1: pneumonia, PE, COPD, ARDS
Type 2: COPD, exhaustion and opiates
Type 3: anxiety, salicylate and hypoxaemia

Question 24

Name some other respiratory disorders

Answer 24

Cystic fibrosis
Alpha-1 antitrypsin deficiency: no inhibition of neutrophil elastase
Carbon monoxide poisoning