1. Circulation and Gas Exchange

2. The Respiratory System
GETS oxygen for the body
GETS RID of carbon dioxide
Characteristics/Requirements of ALL Gas Exchange Mechanisms:
MOIST membranes
Close spacing of gas and blood for easy diffusion
High surface area-to-volume ratio
An animal’s respiratory surfaces must be large enough to provide oxygen and expel carbon dioxide for the entire body

3. Countercurrent Exchange- blood & water flow in opposite directions

4. Tracheae The respiratory system used by insects
Tracheae are air tubes that branch throughout the insect body
The finest branches of the tracheae extend to the surface of nearly every cell, where gas is exchanged by diffusion

5. Human Respiratory System

6. Open vs. Closed Circulatory Systems
In open circulatory systems, hemolymph bathes the internal organs directly
Insects, arthropods, mollusks
In closed circulatory systems, blood is confined to vessels
Blood exchanges materials with the ISF bathing the cells
Earthworms, squids, octopuses, vertebrates

7. Open vs. Closed Circulatory Systems

8. REPTILES (EXCEPT BIRDS) Pulmocutaneous circuit
FISHES
AMPHIBIANS
REPTILES (EXCEPT BIRDS)
MAMMALS AND BIRDS
Systemic capillaries
Lung capillaries
Lung and skin capillaries
Gill capillaries
Right
Left
Systemic circuit
Pulmocutaneous circuit
Pulmonary circuit
Systemic circulation
Vein
Atrium (A)
Heart: ventricle (V)
Artery
Gill circulation A V
Systemic aorta
Right systemic aorta
Figure 42.4
Vertebrate circulatory systems

9. Double Pump
Right side pumps to the lungs and back to left atrium (PULMONARY CIRCUIT)
Left side pumps to the entire body and returns blood to right atrium (SYSTEMIC CIRCUIT)
Oxygenated & deoxygenated blood never mix!

10. The mammalian cardiovascular system
Pulmonary
vein
Right atrium
Right ventricle
Posterior
vena cava
Capillaries of
abdominal organs
and hind limbs
Aorta
Left ventricle
Left atrium
artery
Capillaries
of left lung
head and
forelimbs
Anterior
of right lung
Figure 42.5 1 10 11 5 4 6 2 9 3 7 8