Question

Part C

Emma’s COPD has caused pulmonary hypertension and subsequent failure of the right ventricle. What are the roles of the venous pressure and capillary hydrostatic pressure causing edema

Part D

Emma right ventricular failure has cause decrease in cardiac output. Explain which hormonal system will be activated and how it compensates for this

Answer 1

Part c : edema is accumulation of fluid in the interstitial space , simply swelling of tissue . Emma has copd , due to which she developed pulmonary hypertension and right ventricle failure . Pulmonary hypertension is a condition in which blood from right ventricle is not able to pass through the lungs due to narrowing of pulmonary arteries. So blood remains in right ventricle not being able to pump causing right ventricle failure . Which cause increased venous pressure, which inturn increases capillary hydrostatic pressure. So when capillary hydrostatic pressure increases, the fluid escapes into interstitium, causing edema formation. During right heart failure we can see edema formation in abdomen , that is ascites and in ankle and leg  due to increased venous and hydrostatic pressure.  

Part d ). Decreased cardia output will be sensed by macula densa cells in juxta glomerular apparatus of kidney wich cause renin secretion, which inturn activates angiotensinogen in liver to angiotensin 1 and into angiotensin 2 by angiotensin converting enzyme , angiotensin 2 binds with at 2 receptors in the heart , thereby increasing cardiac contractility and increasing heart rate , which will help in increasing cardiac output, sympathetic system also gets activated increasing cardiac output ,but this is a relieving mechanism only in the initial stages, because renin activation also cause increased sodium and water absorption by aldosterone and adh secretion which increases work load and afterload is also increased and can cause angina , so this should be treated earlier.