Heart And Lung Flashcards
What are functions of the cardiovascular system?
Transport of oxygen, nutrients, antibodies, hormones, waste products and heat
Discuss the arterial vs venous structure
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
How is blood pressure maintained?
1) cardiac output
2) resistance to blood flow
What detects blood pressure changes?
What controls blood pressures?
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
What additional inputs are there to BP?
Increased by RAAS, angiotensin and ADH from kidney. And adrenaline/noradrenaline
Decreased by ANP and nitric oxide
What causes cardiovascular disease?
Formation of artherosclerosis plaques: deposits of lipid and matrix proteins in the arterial wall causing narrowing of the lumen and reduced blood supply
What causes coronary heart disease?
What is CHD?
Cardiovascular disease, vasospasm, anaemia and arrhythmias
Failure of coronary circulation to meet demands of the heart. Lack of oxygen causes ischaemia
What is a myocardial infarction?
End point of CHD
Caused by prolonged ischaemia
What is stable angina?
Partial occlusion of the cardiac artery
Unable to supply oxygen if demand is increased
What is acute coronary syndrome?
Rupturing of plaque causes unstable angina and myocardial infarction
How can acute coronary syndrome be diagnosed?
ECG
Biochemical marker; cardiac enzymes, myoglobin and troponins
What are the four main cardiac enzymes?
Alanine aminotransferase(ALT) Aspartate aminotransferase (AST) Lactate dehydrogenase (LDH) Creatinine kinase (CK)
Where is myoglobin found?
Present in cytoplasm of all muscle cells. Haem protein for oxygen transport
What are the troponin proteins?
How are they useful markers?
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
What affects detection time of cardiac markers in serum?
Size
Cellular location
Plasma clearance
Discuss heart failure
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
What is brain natriuretic peptide?
Peptide released by ventricles in response to stretching
Increased in cardiac failure
Useful rule out test as if negative = not heart failure
What is hypertension?
What are the markers?
BP >140/90
Risk factor for CVD or CHD
No direct biochem markers, can diagnose the endocrine causes
What is thrombotic disease?
What can it cause?
How can venous thrombus be biochemically detected?
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)
What is the function of the respiratory system?
How is it regulated?
Gas exchange and acid-base regulation
Respiratory centre in medulla controls rate and depth of breathing. Driven by CO2 concentration
How can lung function be monitored?
Blood gases pCO2 and pO2: measure gas exchange
pH, PCO2 and HCO3: acid base balance
What are the key disorders of respiration?
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
What are the common causes of respiratory failure?
Type 1: pneumonia, PE, COPD, ARDS
Type 2: COPD, exhaustion and opiates
Type 3: anxiety, salicylate and hypoxaemia
Name some other respiratory disorders
Cystic fibrosis
Alpha-1 antitrypsin deficiency: no inhibition of neutrophil elastase
Carbon monoxide poisoning
