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Partial Pressure
the pressure exerted by a articular gas in a mixture of gases
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Describe Tracheal System
- consists of tiny branching tubes that penetrate the body
- Respiratory and circulatory systems are separate
- Instead of taking oxygen in and transporting it to cells that need it, they have a series of tubes/canals that brings the air to the cell
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Gas diffusion increases with _____ and decreases with ______
- increases with surface area
- decreases with distance
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Gills have large ____ and small _____
large area, small distance
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Requirements of gills
circulate water to exchange gases
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In water the solubility of gases
is lower than it is in air
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Why is countercurrent exchange used in fishes/underwater?
to maximize efficiency of extracting oxygen
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Co-Current Exchange
- flow in same direction
- as they most left-right, start to equilibrate
- but only 50% of ink/gas is extracted
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Countercurrent Exchange
- flows in opposite directions
- 100% of ink/gas is extracted this way
- much more efficient
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Lungs are
an infolding of the body surface
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Circulatory system of birds
- they never stop breathing
- unidirectional flow of air: clean and dirty air do not mix
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How does a mammal breathe?
- inhale air, rib cage expands
- exhale air, rib cage gets smaller
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What kind of breathing do mammals have?
discontinuous breathing (unlike birds)
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Open circulatory system
circulatory fluid bathes all the cells, taken up by heart and pumped throughout body
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Closed circulatory system
fluid never leaves the body, travels from one organ to the next
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What is the advantage of a closed circulatory system over an open one?
- this system has pressure, which allows heart to be able to overcome gravity
- pumps to head and forces blood to come back from feet
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Single Circulation vs. Double circulation
- single— blood only passes through heart once
- double— two pumps, blood goes out of heart, goes up to lungs, comes back, pressurized by heart again, and travels at high pressure throughout the rest of the body
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Amphibians are special because they have (advantage)
- 3 chambered heart instead of 2
- advantageous because it allows them to divert blood where need when they are underwater
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Purpose of valves in the heart?
- help keep the blood where it should be
- due to amount of pressure generated, don’t want blood to travel backwards anywhere you don’t want it
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How does the heart work?
by contracting/squeezing itself
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Cardiac output (and what it depends on)
- volume of blood pumped into the system circulation per minute
- Depends on both heart rate and stroke volume
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Heart rate
number of bets per minute, aka pulse
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Stroke Volume
amount of blood pumped into a single contraction
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If stroke volume is lower than usual and you need same amount of cardiac output, what happens?
heart rate is increased
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Pacemaker is regulated by?
sympathetic (speeds up) and parasympathetic (slows down) divisions
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Structural difference between arteries and veins
arteries have a lot of muscle surrounding them, whereas veins do not have that much muscle around them
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What are capillaries?
smallest blood vessels that connect arterioles and venules
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How are arteries and veins different?
Arteries carry blood away from heart, veins bring blood back to heart
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Area vs. Speed vs. Pressure in Capillaries
- Huge surface area
- Speed is very slow - same amount of blood is being distributed into many capillaries, needs to be slow to equilibrate
- Pressure decreases gradually as area decreases
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at lower pH, hemoglobin ________
releases more oxygen
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What happens when hemoglobin picks up CO2
- reacts with water, acidifies the blood
- (the more CO2, the more acidic the blood becomes)
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What is the Bohr shift?
- when CO2 produced during cellular respiration lowers blood pH and decreases affinity of hemoglobin for O2
- so hemoglobin retains less O2 at lower pH
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Why/how do fetus’ steal oxygen from their mothers?
Because fetal hemoglobin has a higher affinity for oxygen than adult hemoglobin does
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How does the body measure how much CO2 is in our body?
by looking at the pH
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Describe process of acclimatization when there is low oxygen present?
- Low oxygen, high CO2, pH drops
- pH sensors in blood/fluids detect that
- trigger a response (breathe more deeply to bring in more O2 and release more CO2 until pH returns to normal)
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What does the hemoglobin dissociation curve show?
how much oxygen hemoglobin can carry at a particular partial pressure concentration
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The partial pressure of oxygen is maximal in ____ and minimal in ______
lungs, tissues at rest
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