1. Animal Form and Function
Axolotl – salamander native to shallow ponds in Mexico. External Gills! Structure/Function
Circulation and Gas Exchange Refer to pg in Holtzclaw, Ch 42 in Campbell and media resources

2. LEARNING GOAL: HOW DO ANIMALS EXCHANGE GASES AND TRANSPORT THEM INTERNALLY? WHAT ARE VARIOUS STRUCTURE/FUNCTION EXAMPLES ACROSS THE ANIMAL KINGDOM?

3. Learning Intentions You must know:
The circulatory vessels, heart chambers, and route of mammalian circulation.
How red bloods cells (RBCs) demonstrate the relationship of structure to function.
The general characteristics of a respiratory surface.
The pathway a molecule of oxygen takes from the air until it is picked up by the hemoglobin of a red blood cell.

4. Today: The circulatory vessels, heart chambers, and route of mammalian circulation.
You must exchange gas, wastes, and nutrients at the cellular level by diffusion!
Two solutions:
1) Keep all cells in contact with environment
Gastrovascular Cavity
2) Move fluid around to tissues/cells for exchange
Circulatory System

5. Gastrovascular Cavity

6. What are the three components of a Circulatory System?

7. What are the three components of a Circulatory System?
Blood (Circulatory Fluid)
Vessels (Tubes)
Heart (Pump)
Note differences in open vs closed. Open: blood and lymph are combined as hemolymph. Cavities called synuses. Arthropods and Molluscs. Closed: Blood in vessels. Blood separate from interstitial fluid. Annelids. Cephalopods, All Vertebrates.

8. In closed circulation you have:
Arteries – carry blood away from heart
Thick, lots of smooth muscle
Arterioles are smaller
Capillaries – Gas/Nutrient/Waste Exchange
Microscopic
Walls are one-cell layer thick (significance?)
Veins – carry blood back to the heart
Have valves to prevent backflow
Venules are smaller
The heart has atria and ventricles

10. Try This! True or False? Capillary beds:
Are the site of nutrient and oxygen delivery to tissues
Have a total cross-sectional area much smaller than the total cross-sectional area of major arteries
Join arterioles and venules

11. Try This! True or False? Capillary beds:
Are the site of nutrient and oxygen delivery to tissues TRUE!
Have a total cross-sectional area much smaller than the total cross-sectional area of major arteries FALSE!
Join arterioles and venules TRUE!

12. Variations!

13. Variations!

14. Try This! True or False?
The three-chambered hearts of amphibians and nonbird reptiles:
a. Allow substantial separation of pulmonary and systemic circulation
b. Are facultative, allowing variation in blood flow through the heart
c. Are inferior to the four-chambered hearts of birds and mammals, limiting the evolutionary success of amphibians and nonbird reptiles

15. Try This! True or False?
The three-chambered hearts of amphibians and nonbird reptiles:
a. Allow substantial separation of pulmonary and systemic circulation TRUE!
b. Are facultative, allowing variation in blood flow through the heart TRUE!
c. Are inferior to the four-chambered hearts of birds and mammals, limiting the evolutionary success of amphibians and nonbird reptiles FLASE!
Point out to students that the intermediate three-chambered heart evolved almost 400 million years ago. The extent of mixing of oxygen-rich and oxygen-poor blood in the circulatory systems of animals with three-chambered hearts varies considerably. Three-chambered hearts are facultative, rather than inferior, and are able to adjust blood flow depending on circumstances. Blood from the lungs may be diverted when the lungs are not the primary site of oxygen uptake: when the animal is submerged or when oxygen is taken up across gills or skin.

16. Take a moment to read and understand the Path of Circulation on Page 239 in Holtzclaw

17. The Cardiac Cycle – Systole (contraction) and Diastole (Relaxation)

18. The Cardiac Cycle – Read Heart Rate on Page 240 in Holtzclaw

23. Blood Pressure: Read 42.2 on page 240 in Holtzclaw
Analyze the graphs

24. Blood Pressure
What happens to cross-sectional surface area, velocity, and pressure as you move through the circulatory system?

25. Activity: Measuring Blood Pressure!
Experimental, not diagnostic!!!

29. Learning Intentions Do you know:
The circulatory vessels, heart chambers, and route of mammalian circulation.