Respiration Flashcards
What is respiration?
the process in which oxygen is exchanged for CO2 across external environment and cells
What is mitochondrial respiration?
the oxygenic process that involves the production of ATP by oxidizing carbohydrates, amino acids, or fatty acids in which oxygen is consumed and CO2 is produced
How is diffusion across respiratory surfaces maximized?
increased surface area
thin surfaces
How does Fick’s law of diffusion apply to respiration?
the rate of diffusion is increased when the surface area of membrane is maximized and the distance for diffusion is minimized
= larger SA and thinner surface
What are major challenges to respiration for aquatic organisms?
O2 is 30x less soluble in water than air = significantly less O2 available to aquatic organisms
O2 is 10000x less mobile in water than air = requires more energy to move the water
Why is O2 consumption and metabolic rate higher in smaller, unicellular organisms?
because they rely solely on diffusion for gas exchange = it’s fast and efficient
What do larger organisms require for respiration?
bulk flow and gas exchange = a close relationship between respiration and circulation
What is ventilation?
when medium (air/water) is moved over a respiratory surface
How does gas exchange occur in larger organisms?
ventilation of air/water across respiratory surfaces
How are gases moved throughout a larger organism’s body?
the circulatory system
What are 3 non-directional ventilation strategies
non-directional ventilation across thin surface
non-directional ventilation across thick surface
tidal ventilation (kinda bidirectional)
What organisms use nondirectional ventilation across thin surfaces?
cutaneous respiration in frogs
Describe non-directional ventilation across thin surfaces
medium flows over respiratory surface at random to the flow of blood
concentration of O2 in medium is steady and blood picks up O2 from medium quickly = efficient
Describe non-directional ventilation across thick surfaces
medium flows over respiratory surface at random to the flow of blood
concentration of O2 in medium is steady and blood slowly picks up O2 from medium = not very efficient
Describe tidal ventilation
medium with high O2 is inhaled, medium flows across respiratory surface, medium with low O2 is exhaled
efficient because bringing high O2 medium over respiratory surface and pushing low O2 medium out
What are the 3 types of unidirectional ventilation?
concurrent flow - medium flows with blood flow
countercurrent flow - medium flows against blood flow
crosscurrent flow - medium crosses over blood flow
Which type of unidirectional ventilation is really uncommon in nature?
concurrent flow - not very efficient
Which type of unidirectional ventilation is really most common in aquatic organisms?
countercurrent
Which type of unidirectional ventilation do birds use?
crosscurrent
describe concurrent ventilation
medium flows in same direction as blood flow in respiratory surface
as blood picks up O2 from medium, medium decreases in O2 = eventually they plateau together at mid level of O2
describe countercurrent ventilation - why is it so efficient?
medium flows in opposite direction of blood flow in respiratory surface
as blood uptakes O2, medium continues moving along and allows fresh O2 to come in contact with blood
this method ensures that respiratory surface is always being ventilated by medium with fresh O2
describe crosscurrent ventilation - why is it so efficient?
medium flows across blood flow in respiratory surface
as medium flows across capillaries, blood uptakes O2
what is the most efficient strategy for ventilation?
crosscurrent
What is the purpose of ventilation?
to reduce formation of static boundary layers and ensure gas exchange