What are the two systems with bulk flow in the “moving gases in animals” diagram?
A: Ventilation (first step)
C: Circulation (of blood)
Why do many animals, like giraffes, need a circulatory system? (Why isn’t diffusion good enough?). Explain with reference to Fick’s Law.
Diffusion= k ((area x gradient)/distance)
Distance is a big problem in giraffes so as that increases, diffusion decreases (dividing by a bigger number).
Usual diffusion distance: micrometers: 10^-6 m
Giraffes: many meters
Rate of transfer of gases and nutrients would essentially be zero over such a large distance.
Circulatory system links exchange surfaces with cells in the body to minimize the distance substances have to diffuse across.
Picture the circulatory system and how it runs in the middle of the body, decreasing distance between cells and other organs/diffusion locations. If it wasn’t there, the distance would be much greater to cross.
At the tissues, O2 again diffuses…
At the tissues, O2 again diffuses only a short distance from blood in capillaries to cells
What is a closed circulatory system?
Blood flows through connected blood vessels, pumped by muscular hearts.
There is nowhere is the system for the blood to “flow freely”.
The blood flows through vessels to supply tissues with nutrients
Ex. Human circulatory system
What is an open circulatory system?
Blood flows through a muscular vessel that acts as a pump.
Blood empties into an open body cavity (opening) to supply the tissues with nutrients, and is returned to the circulation
What are the advantages of a closed circulatory system (2)?
1) Can generate enough pressure to maintain a high flow rate
2) Can localize blood to tissues that need it most
What are the disadvantages of a closed circulatory system (3)?
1) Requires many more structures (arteries, capillaries, veins)
2) Diffusion distance is larger (across blood vessel walls as well as the tissues’ cell membranes)
3) Require more food and energy
What are the advantages of an open circulatory system (2)?
1) Hemolymph comes into direct contact with the tissues, so very small diffusion distance
2) Doesn’t require as many blood vessels
What are the disadvantages of an open circulatory system (2)?
1) Low hemolymph pressure so flow rates might be low
2) Cannot localize hemolymph to specific tissues
In vertebrates, what accomplishes internal transport
A closed circulatory system called the cardiovascular system
Cardiovascular system
Transports blood, oxygen, nutrients, hormones, and wastes throughout the body
Which of these is true: All blood moving away from your heart is:
1) Traveling in veins
2) Traveling in arteries
3) Deoxygenated
4) Oxygenated
5) In systemic circulation
6) In pulmonary circulation
2) Traveling in the arteries
Systemic circulation
Movement of blood between the heart and the rest of the body.
Deliver oxygen and nutrients to body tissues
Remove carbon dioxide and metabolic wastes
1) Left side of the Heart (left atrium and left ventricle)–ends with the right side when deoxygenated blood is delievered back
2) Arteries – carry oxygenated blood to the body
3) Capillaries – exchange of gases, nutrients, and wastes with tissues
4) Veins – return deoxygenated blood to the heart
Pulmonary circulation
Movement of blood between the heart and the lungs for gas exchange
1) Right side of the Heart (right atrium and right ventricle)
2) Pulmonary arteries – carry deoxygenated blood to the lungs
3) Lung capillaries – where gas exchange occurs
4) Pulmonary veins – carry oxygenated blood back to the heart
Picture the cardiovascular system diagram in the slides. Make a box in the middle around the heart and the lungs. This is the pulmonary system
Of human, fish, and frog vertebrate circulatory systems, which is the most evolved?
None are more evolved than another
Each is highly evolved to thrive in their own environment
Hemoglobin
Carries oxygen in the blood from the lungs to the tissues
How might oxygen and carbon dioxide be carried in the blood?
Most CO2 is dissolved in the plasma, in the form of bicarbonate ion
Most oxygen is bound to hemoglobin
What does the circulatory system do?
Move gases more quickly around the body using bulk flow
What does “hemoglobin % saturation” mean?
The amount of hemoglobin molecules that are carrying oxygen
Ex. 50% hemoglobin saturation means 50% of hemoglobin molecules are carrying )2
What does hemoglobin do when a high amount of oxygen is present?
Hemoglobin picks up oxygen in the lungs when a high amount of oxygen is present and delivers it to body tissues
What does hemoglobin do when a low amount of oxygen is present?
Hemoglobin drops off oxygen in the tissues when a low amount of oxygen is present in the tissues
The tissues are actively respiring, using up oxygen, so the blood near them has a ______ pO2
Lower pO2
Partial pressure of oxygen, think of this as the concentration
When oxygen is bound to hemoglobin, the oxygen is stuck in the red blood cell–…
When oxygen is bound to hemoglobin, the oxygen is stuck in the red blood cell–NOT accessible to the tissue that is actively respiring
At the tissues, hemoglobin needs to _______ _______ _____ ____ _______, so that it can diffuse into the cells there, so the cells can use it
At the tissues, hemoglobin needs to release oxygen into the blood, so that it can diffuse into the cells there, so the cells can use it
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Lecture 6-1: Introduction10
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Lecture 6-2: Animal Form and Function; Exchange with Environment46
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Review Questions Week 621
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Lecture 7-1: Exchange with the environment and homeostasis continued29
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Lecture 7-2: Exchange with the environment: Thermoregulation, salt and water balance57
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Review Question Week 748
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Lecture 8-1: Gas exchange in aquatic animals7
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Lecture 8-2: Circulation50
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Week 9 Pre-Reading Questions14
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Week 8 Review Questions58
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Lecture 9-16
