Which of the following is a characteristic of G-CSF activity that must be taken into account to assure similar biologic function?
A) Activation of a specific cell-surface receptor
B) Display of cross-species functionality
C) Downregulation of cell growth
D) Production by endothelial cells
E) Stimulation of megakaryocytic cell production
A. G-CSF works by binding to the G-CSF receptor on progenitor cells.
By elimination:
B. Cross species functionality is not required.
C. Upregulation of granulocyte growth is what G-CSF would do
D. G-CSF is not produced by endothelial cells
E. Megakaryocyte production is stimulated by IL11 (Oprelvekin)
a patient who is hemorrhaging, which of the following is an adaptive response that helps to maintain mean arterial pressure?
A) Increased end-systolic volume
B) Increased venous compliance
C) Inhibition of secretion of ADH (vasopressin)
D) A fluid shift from interstitial to vascular compartment
E) Release of atrial natriuretic peptide
D. Fluid shift from interstitial to vascular compartment. This helps maintain the blood volume in the vasculature.
By elimination:
A. Increased ESV indicates decline in the cardiac pump activity.
B. Increased compliance would reduce the arterial blood volume by sequestering it in the veinous system. Venoconstriction is the adaptive response in hemorrhage.
C. Inhibition of ADH would lead to further volume loss.
E. ANP will cause further volume loss through natriuresis.
Which of the following cell types initiates the repair mechanism neccessary to resolve the proteinuria and hematuria in strep glomerulonephritis?
1. erythrocytes
2. juxtaglomerular cells
3. mesangial cells
4. plasma cells
5. polkissen (whats that??)
6. proximal tubule epithelial cells
please explain
3. Mesangial cells. They have contractile functions, synthesise collagen for the basal lamina and also have phagocytic function. (as per Kaplan)
1. RBC have no role in repair.
2. JGA cells merely secrete renin. They do undergo hypertrophy in case RBF decreases, e.g. renal artery stenosis, or clamping of the renal artery.
4. Plasma cells have no role in repair.
5. Polkissen cells are mesangial cells located near the JGA, and are hence extraglomerular mesangial cells. Their function is unclear. They are thought to secrete erythropoetin.
6. PTC cells can't help in glomerulonephritis.
