Blood carries hemoglobin which carries O2 and CO2.
O2 and CO2 are transported by diffusion.
- Oxygenated Blood
- Is bright red in color.
- Deoxygenated Blood
- Is dark red in color.
- Appears blue through our skin and in educational models.
- Hemoglobin
- A protein used to transport oxygen.
- Contains 4 heme molecules that bind to O2 and CO2.
-
- Gas molecules bind to Fe (iron) molecules in the heme.
CO2 is primarily transported in the form of HCO3-.
CO2 is non-polar and can seep through cellular membranes.
- Carbonic Anhydrase
- An enzyme.
- Facilitates two-way reactions to bind CO2 and O2 back and forth.
- Concentration of CO2 drives which way the reaction occurs.
Ions are more soluble in water. CO2 forms acid in your blood and lowers pH. Must be kept in balance.
Hearts
Evolution of Hearts
- Atrium partial septate (separation)
- Atrium complete septate (separation)
- Ventricle partial septate (separation)
- Ventricle complete septate (separation)
- Two-Chambered Hearts
- Most Fishes
- Single circuit
- Single atrium and single ventricle
- Most fishes don't have lungs so they don't have a need for a dedicated lung circuit.
- Lung Fishes
- Have a modified circulatory system
- Double atrium, deoxygenated and oxygenated blood is mixed.
- Three-Chambered Hearts
- Amphibians
- Have a double circuit.
- Oxygenated blood and deoxygenated blood mix.
- Pulmonary Circuit
-
Heart > Lung > Heart
- Systemic Circuit
- All of body tissue.
-
Heart > Rest of Body > Heart
- Three-Chambered Heart with Septum
- Reptiles
- Partially divided ventricle
- Four-Chambered Heart
- Crocodiles, birds, mammals
- Oxygenated blood and deoxygenated blood are kept completely separate.
- Human Heart Four-Chambered Heart
- Body to right atrium
- Atrium to right ventricle
-
- Ventricle away to lungs
- Lungs back to left atrium
- Atrium to left ventricle
- Aorta from left ventricle out to the body.
Heartbeats
- Diastolic
- When your heart is at rest between beats.
- Systolic
- When your heart is actively beating.
- Blood Pressure
- Pressure exerted on blood vessel walls varies between systolic (max) and diastolic (min).
- Coronary Tissues
- Heart muscles