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BIOL 446 Physiological Ecology > Exam 2: Circulation and Gas Exchange > Flashcards

Exam 2: Circulation and Gas Exchange Flashcards

(70 cards)

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1
Q

What is the most important purpose of circulation?

A

Movement of gases

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2
Q

How is oxygen solubility affected in water?

A

Decreased significantly

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3
Q

How does oxygen move?

A

High partial pressure to low (high conc. to low)

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4
Q

How does temperature affect O2 solubility in water?

A

Solubility of O2 decrease with temperature in water

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5
Q

How does water affect oxygen diffusion?

A

Oxygen can only diffuse distances of 1 mm in water due to decreased solubility

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6
Q

How is the low diffusion capability of O2 accommodated by bodies?

A

Move oxygen using convection

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7
Q

What powers movement of oxygen from the atmosphere to the mitochondrion?

A

A cascade of oxygen partial pressure that decreases from atmosphere to mitochondrion

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8
Q

What are invaginated breathing structures?

A

breathing structures inside the body

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9
Q

What is a con of invaginated breathing structures?

A

requires active ventilation to bring gas inside

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10
Q

What are envaginated breathing structures?

A

breathing structures inside the body

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11
Q

What is a benefit of evaginated breathing structures?

A

energy is not required to bring gas to respiration structures

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12
Q

What is a con of evaginated breathing structures?

A

Breathing structures aren’t protected

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13
Q

What is a pro of invaginated breathing structures?

A

breathing structures are protected

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14
Q

What are RAM ventilators?

A

Fish that breath by moving in a way that forces water over their gills

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15
Q

What causes tidal gas exchange to occur?

A

The partial pressure of blood leaving lungs in lower than air in the lungs

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16
Q

What is tidal gas exchange?

A

Air enters and exits through the same tube

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17
Q

Why is tidal exchange successful despite mixing high and low O2 air?

A

Because air is practically infinitely available in the atmosphere so partial pressure of O2 in blood in always lower

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18
Q

How does countercurrent exchange gas exchange work?

A

Partial pressure of blood leaving the gills is higher than the water leaving the gills which maintains a gradient

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19
Q

Which form of gas exchange is most efficient?

A

Countercurrent exchange

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20
Q

Why do fish need countercurrent gas exchange?

A

Because O2 availability in water is really low

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21
Q

How does salinity affect solubility of O2?

A

O2 solubility decreases as salinity increases

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22
Q

How does crosscurrent gas exchange occur?

A

Vessels run perpendicular to the flow of oxygenated fluid and have slight mixing that causes decrease in partial pressure of oxygen in blood going down the fluid flow; However oxygen concentration in the fluid also decrease

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23
Q

What organisms employ crosscurrent gas exchange?

A

Birds

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24
Q

Is tidal exchange or cross current exchange more efficient and why?

A

cross current because mixing of oxygen partial pressures is minimized

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25
Why do birds employ crosscurrent gas exchange?
Flight has very high energy requirements and it is best to use aerobic respiration
26
What is the pulmonary circuit?
circulatory circuit that carries deoxygenated blood from the heart to the body
27
What is the systemic circuit?
circulatory circuit that carries oxygenated blood from the heart to the body
28
What is systole?
contraction of the myocardium
29
What is diastole?
relaxation of myocardium
30
What are the steps of four chambered heart contraction
Atria and ventricles are diastole -> atria systole pushes blood into ventricles -> ventricle systole pushes blood out of heart and atria diastole brings blood back in -> ventricle diastole
31
What is cardiac output measured by?
The volume of blood leaving the heart per minute
32
What is stroke volume?
The volume of blood pump per beat
33
What controls stroke volume?
Strength/size of cardiac muscle
34
What controls the heart beat of neurogenic hearts?
The nervous system
35
How do system do neurogenic hearts employ to function?
Central pattern generators
36
What controls the heart beat of myogenic hearts?
Muscle cells that generate pacemaker potentials
37
What kind of polarization generates pacemaker potentials? Why?
Hyperpolarization because the hyperpolarization threshold slows the generation of the potential; creates delay between each contraction
38
Does blood leave for lungs using the left or right ventricle?
right
39
Does blood leave for the body using the left or right ventricle?
right
40
How are four chambered hearts unique from other hearts?
The two sides of the heart do not mix
41
Where does systemic circulation actually occur?
Capillary beds
42
What is the structure and function of arteries?
Lined with smooth muscle, they carry fast moving blood out of the heart
43
What is the structure and function of veins?
Not as robust as arteries, carry blood back to the heart with the help of some muscle
44
What are two forms of control of blood distribution?
Precapillary sphincters and arteriovenous anastomoses
45
What are precapillary sphincters?
Muscle that pinch off blood flow to capillaries
46
What is the purpose of arteriovenous anastomoses?
They are vessels that bypass capillary beds
47
What is ultrafiltration?
Transfer of fluid to tissues from capillaries increases solute concentration in blood vessels
48
How does osmotic pressure change from the arterial to venous end of the circulatory system?
Highest at the arterial end and lowest and the venous end
49
What is the Starling-Landing hypothesis?
Loss of osmotic pressure in the circulatory system due to fluid filtration
50
How does body size affect cardiac output?
Smaller animals have higher cardiac outputs due to high heartrates, despite having a lower stroke volume
51
What function of blood distribution is unique to three chambered hearts?
Selective distribution; controls where blood flows in the body
52
What organisms have three chambered hearts?
amphibians and reptiles
53
How is an amphibian heart structured?
2 atria and 1 ventricle with a ridge in the center to prevent blood mixing
54
How are reptile hearts structured?
Have 2 atria and 2 ventricles; ventricles are loosely connected
55
How does blood flow through amphibian hearts?
blood comes from lungs into one atria, body into another atria, and both exit from one ventricle, then go to lungs and body
56
How does blood flow through reptile hearts?
Similar to four chambered with blood mixing
57
How is a crocodilian heart structured?
Four chambered heart with two aortas and two ventricles
58
What is the foramen of panizza?
Connects crocodilian ventricles
59
What does the foramen of panizza do?
Opens under pressure, when a crocodile is diving, and diverts blood flow away from the lungs
60
What is the structure of a fish heart?
two chambers
61
What is a con of having a two chambered heart?
oxygen inputted by the gils is used by the body before it returns to the heart
62
Why is a lack of oxygen supply to heart tissue not an issue for fish?
Because they have ectotherms and thus low oxygen requirements
63
64
How do fish conduct gas exchange besides using gills?
Specialized gas exchange organs
65
What is ventilation-perfusion matching?
When fish change blood flow to certain areas based on oxygen concentration in water
66
What kind of hearts do arthropods have?
multiple tubular hearts
67
What kind of circulation do arthropods exhibit?
open circulation
68
What is hemolymph?
arthropod circulatory fluid
69
What is the function of hemolymph?
to cycle hormones and nutrients NOT oxygen
70
How do arthropods get access to oxygen?
Pores called trachea bring oxygen into the body then into tracheoles embedded in tissues

BIOL 446 Physiological Ecology (8 decks)

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