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Blood Pressure
Maintaining blood pressure
| Question | Answer |
|---|---|
| State the pressure gradients from the aorta to capillaries | 60mmHg (90mmHg to 30mmHg) |
| State the pressure gradients across the capillary bed | 15mmHg (30mmHg to 15mmHg) |
| State the pressure gradients from the capillaries to the heart | 15mmHg (15mmHg to 0mmHg) |
| State the formula for flow | Flow = difference in pressure / resistance |
| Factors affecting blood flow | Sympathetic nerves, hormones and local factors i.e. metabolic and endothelial |
| Factors affecting blood pressure | Blood volume, total peripheral resistance, cardiac output |
| Mean arterial pressure = | diastolic pressure + 1/3 pulse pressure |
| Metabolic controls that dilate blood vessels | decrease O2, increase CO2, decrease pH, increase prostaglandins, increased osmolarity, increased nitric oxide |
| Metabolic controls that constrict blood vessels | increase endothelin |
| Nerves that constrict the blood vessels | Sympathetic |
| Hormones that constrict the blood vessels | alpha receptors, ADH, angiotensin II |
| Hormones that dilate the blood vessels | beta receptors, ANP (atria natriuretic peptide) |