cardiovascular and respiratory diseases

myocardial infarction

plaque ruptir or blood clot occludes one or more arteries supplying myocardium, depriving O2 and nutrients meaning reduced active area of contraction during systole

acute and chronic effects of MI on the heart

immediate - tissue hypoxia, decreased rhythmic contractions, decreased BP and CO, tissue necrosis and inflammation

chronic - widespread inflammation, increased fibrosis, hypertrophy and ventricle dilation causing decreased systolic pressure and CO

cardiac fibrosis

increased collagen deposition by myofibroblasts impairs diastolic function

can be diffuse (e.g. hypertension) or localised (e.g. MI)

fibres covalently crosslinked by glycosylation increasing stiffness

slower C2+ reuptake in heart failure

reduced SERCA activity/decreased SERCA expression slows reuptake

phospholamban (PLB) acts as a break on SERCA pump, expression does not change in HF meaning same PLB to less SERCA

PLB phosphorylation relieves SERCA inhibition, HF displays hypophosphorylation

cardiomyopathies

broadly affect the structure and function of muscle cells or structure of the myocardium

often caused by mutations in myofilaments producing hypercontractile phentoype

channelopathies

occur due to mutations in ion channels creating aberrations in electrical properties

often caused by mutations in genes coding for Iks (slow) and Ikr (rapid) potassium channel subunits or sodium channel subunit

produces long QT interval due to delayed repolarisation of the ventricles

chronic obstructive pulmonary disease (COPD)

airway remodelling - inflammation, increased mucus production and airway fibrosis

alveolar destruction - inflammation and emphysema

affects terminal airways - alveolar ducts and sac, respiratory bronchioles

asthma

trigger invokes airway inflammation

causes bronchial swelling, mucus hypersecretion and airway muscle constriction

narrowing of airways causes wheezing, cough, shortness of breath and chest tightness

treated with anti-inflammatory and bronchodilator inhalers

bronchodilators

B2 agonists activate beta adrenergic receptors to signal for smooth muscle relaxation

corticosteroids

reduce inflammation, swelling of the airways and mucus production