CAS BI 315 Lecture Notes - Lecture 12: Skeletal Muscle, Osmosis, Varicose Veins
Document Summary
Open system in most animals: liquid, not blood, sloshes around in response to muscular movement, blood and interstitial fluid = hemolymph, no vessels. Closed: blood vessels distinct from the interstitial fluid, all vertebrates and some invertebrates. An open system cannot adapt to the size of the animal, and the separate gas exchange limits the size of the organism. Viscosity increases with erythrocytes and is bad for the heart (more work), so this can cause an enlarged heart. Example: it"s a hot day and the person is exercising and drinking tons of water, so the crit goes up from exercise and sweat. Then the water being drunk normalizes the crit, but if they drink too much water the crit will go too low. Bp is formatted as (max when heart contracts/min when heart relaxes) Arteriole: distributes blood, but there is no exchange here.