Blood Flow in the Capillaries

1. Exchange of Gases and Nutrients
1. diffusion - all molecules move DOWN the concentration gradient (from HIGH to LOW) into or out of the blood
2. oxygen/nutrients (blood ------> body cells)
3. carbon dioxide/ wastes (body cells ------> blood)
2. Fluid Movements
1. Hydrostatic pressure - force of the capillary wall on the blood itself
• filtration pressure - the pressure forcing fluid and solutes through capillary clefts
2. Osmotic pressure - force driving fluid in the direction of HIGHER solute concentration
• movement out: Hydrostatic pressure > Osmotic difference
• movement in : Hydrostatic pressure <>
3. Normal fluid movement - 1.5 ml/min in the entire body
3. Circulatory Shock
1. Circulatory shock - blood pressure gets so low that blood will not flow adequately
2. Hypovolemic shock - circulatory shock resulting from loss of fluid (bleeding, diarrhea, burn)
• heart rate increases rapidly
• general vasoconstriction of vessels
3. Vascular shock - extreme vasodilation causes sudden drop in blood pressure
• snake and spider bites with NE blockers
• septicemia - bacterial infection
4. Cardiogenic shock - heart is unable to provide sufficient blood pressure

Category: Physiology Notes