Circulation. The Presence of a Circulatory System:. Reduces the distance a substance must travel to enter or leave a cell. Uses “Blood” to carry these molecules to the cells.
O2 diffuses from the air in the lungs (or similar structures) across epithelium to the “blood” which carries it to all parts of the body.
Once in the capillaries, O2 diffuses across epithelium again to the tissues.
CO2, of course, moves in the opposite direction.
closed system = higher pressures
low O2to body
low pressureto body
high pressure & high O2to body
What’s the adaptive value of a 4 chamber heart?
4 chamber heart is double pump = separates oxygen-rich & oxygen-poor blood; maintains high pressure
birds & mammals
Pressure is greatest in the arteries, lowest in veins
Interstitial fluid flows back into capillaries due to osmosis
Fluid & solutes flows out of capillaries to tissues due to blood pressure
BP > OP
BP < OP
85% fluid returns to capillaries
15% fluid returns via lymph
What do bluevs.redareas represent?
to neck & head& arms
1 complete sequence of pumping
heart contracts & pumps
heart relaxes & chambers fill
ventricles pumps blood out
atria refill with blood
It’s more than just red stuff.
The fluid portion of blood.
Water accounts for over 90%
Electrolytes- to maintain osmotic balance, buffer
So, if blood is 55% plasma, the rest must be ….._________
Erythrocytes-also called Red Blood Cells (RBCs)
So, what about those cells?
also called white blood cells (WBCs)
Actually spend most of their
time in interstitial fluid and
the lymphatic system.
Provides immediate but temporary “plug”
2. Release clotting factors which catalyze the reaction:
Fibrin aggregates to form the clot