Respiratory Physiology Pt 1 Flashcards
Why is O2 needed for energy production?
because O2 acts as the terminal acceptor in the mitochondria electron transport chain. If it is not present, ETC won’t work and thus respiration is compromised. ATP cannot be produced without the ETC
external vs cellular respiration
external: gas exchange between environment and mito. First goes through the lungs, then blood, then tissues. cellular: just mito processes
ideal gas law
PV=nRT. Units in mmHg.
T/F O2 can be taken up directly
false O2 cannot be taken up directly. It must be dissolved in aqueous media
concept of partial pressures
the partial pressure of one gas equal the total pressure of the mixture TIMES the fractional composition of that gas. EVERY GAS IS INDEPENDENT. If you change the parital pressure of one gas, no effect on the DIFFUSION of a dif gas.
Henry’s Law
Gas dissolving ability = Pgas x S gas
S= solubility
P= pressure
factors that affects how much gas dissolves in a fluid
1) number of collisions of gas with fluid surface. Dependent on CONCENTRATION and thus PRESSURE
2) solubility of gas in the fluid.
solubility of a gas ___ with increasing temperature. Why?
DECREASES with increasing temp. Because the gas molecules gain kinetic energy and are less likely to become liquids
solubiltiy ____ with increasing pressure
INCREASES with increasing pressure, because there are more gas molecules within the area.
How does gas solubiltiy and temperature affect aquatic animals
they are in a bit of a predicament because O2 solubility DECREASES with increasing temperature, yet their METABOLIC RATE INCREASES with increasing temp, so they need more O2, but it’s hard to dissolve it.
most abundant atmospheric gas
nitrogen
primary chemical reaction of CO2 that allows it to be transported in the blood
CO2 + H2O 00> H2CO3 –> H+ + HCO3-
its catalyzed by carbonic anhydrase and allows CO2 to be transported in the blood primarily as HCO3-
3 ways CO2 is transported
1) dissolved CO2 (v little
2) HCO3-
3) carbamino CO2
Which law determines the rate of diffusion of a gas
FICKS LAW determines that the RATE OF DIFFUSION= [ΔP(A)(D)/ ( Δx)]
D= diffusion coefficient- affected by molecular weight, permebility and temp
Δx = distance between two regions
P= partial pressure gradient
3 challenges for O2 delivery
1) animal size: limits to diffusion, large animals cannot actively rely on diffusion
2) habitats: O2 levels differ
3) metabolic requirements: thermoregulation, flight.
3 types of external exchange systems
1) diffusion of gases across body surface (cutaneous)
2) circulate external media through the body (sponges) (tracheal)
3) diffusion of gases across specialized membrane (vertebrates) (gills and lungs)
as organisms grow larger, the ratio of SA to volume ____
decreases.
as the SA:vol ratio decreases, the capacity for diffusion ___
decreases. this is because there is limited SA available for diffusion, and the large volume increases diffusion distance.
large animals cannot rely on diffusion. instead, they rely on __ ___
bulk flow
methods of bulk flow
1) pumps
2) convection currects
3) propulsion by cilia
benefits and drawbacks of terrestrial habitats and microhabitats.
benefits: very little variation in atmospheric PO2 as long as you stay at the same altitude.
drawbacks: water loss(dehydration) might result in decreased ability to exchange gases. there may also be dessication.
- microhabitats are nice because youre protected from dessication (habitat destruction), temp extremes and predation, but there may be PO2 drops and large amounts of PCO2. ex/ prairie dogs.
Benefits and drawbacks of aquatic habitats
benefits: turbulent environments provide a high O2 environment
drawbacks:
1) high density of water may cause problems with the convection of O2. Diffusion of O2 is slower
2) turbulence may result in instability
3) pollution can lead to dessication
- causes algal blooms and microbes deplete O2 sources.
4) estuaries and lagoons may have huge fluctuations in temp and salinity, affecting water difusion
diffusion of gases across a body surface or the ability to circulate external media through the body both involve diffusion through an _____.
INTEGUMENT.
problems with cutaneous respiration
1) severe restriction in body size
2) restriction of ecological niches. skin must remain moist in order to dissolve gases.
what is tracheal breathing
Tracheal Breathing. Insects, and some other invertebrates, exchange oxygen and carbon dioxide between their tissues and the air by a system of air-filled tubes called tracheae. Tracheae open to the outside through small holes called spiracles
T/F insects that use tracheal breathing implement a circulatory system
false. tracheal tubes allow for direct delivery of oxygen to respiring tissues. there is no need for gas transport by a circulatory system.
Tracheoles (branches from the trachea) are the tubes that truly reach the tissues
why is unidirectional flow of water favored in internal gills?
Its often difficult to blow out the water back the way it came because water is much more viscous compared to air, which is normally used in tracheal systems (that allow for tidal ventilation)
Where does gas exchange actually occur
in the secondary lamellae of the gill filament.
In gills, discuss the direction of water and blood flow
water and blood flow in opposite directions, like a counter current exchanger system. this facilitates a large O2 pressure gradient for good gas exchange. Lots of diffusion. prevents equilibrium from being reached.
Oxygen poor blood is always running INTO the gill filament, and oxygen enriched blood is sent out of the filament into the tissues
explain the double pump system in the gills of a telost fish
1) buccal pump: for pressure
2) opercular pump: for suction.
water gets sucked in, and when the mouth closes, the operculum pulls to create a suction and draw water across the arches and lamellae.
With unidirectional ventilation, which ways can blood flow relative to the medium?
in unidirectional gill ventilation, remember that the water never loops back and leaves through the opening.
thus, there are 3 ways
1) concurrent flow; blood flows in same direction as water
2) countercurrent flow; blood flows in opposite directions as water
3) crosscurrent flow; blood flows ACROSS the respiratory surface and across the flow of medium
explain how adult frogs are able to go in between different methods of respiration
adult frogs have lungs and still undergo cutaneous respiration. the absolute and relative contributions of pulmonary respiration increase with temperature. frogs exhibit GREATER increase in pulmonary O2 and cutaneous CO2 release as temp or activity increases.
many vertebrates use their thorax to pump air into their lungs (ex/ diaphragm), but frogs use their mouths. how?
the expand the mouth with their mouth closed, suck in air through nostrils, air enters lungs, and then blow out through mouth. the mouth flap creates pressure to pump air in and out.
mechanisms of air flow. How does it get to the lungs?
1) suction: ex/ diaphragm. Pumps in frogs. Compression/rebound of thorax in snakes, or expansion of thorax is lizards.
2) Bellows. Seen in birds. this is a one-way pass throguh exchange area in RIGID LUNGS that do not change in volume.
Describe bird ventilation through bellows
- involves rigid parabronchi that does not change in volume
bellows= airsacs on either side of parabronchi. Airsacs produce pressure changes which pull air in through parabronchi and out.
It requires two cucles of inhalation and exhalation in order to get O2 to the tissues.
1) expansion of the chest during the first inhalation causes fresh air to flow through the bronchi to the posterior air sacs
2) compression of the chest during the first exhalation pushes the fresh air from the posterior air sacs (BELLOWS) into the lungs
3) expansion of the chest during the second inhalation causes stale air to flow from the lungs into the ANTERIOR air sacs
4) compression of the chest during the second exhalation pushes stale air from the anterior air sacs out via the trachea.
general evolutionary trends seen in lung structure
1) theres been an expansion of surface area within the lungs to increase efficiency to support higher rates of O2 consumption. As body size increased, lung size expanded with in and there is thus a relationship with increased metabolic rate. More O2 consumption= larger lungs = higher MR in larger animals.
2) Branching airways
3) specialization of machinery for ventilation ex/ lungfish
4) circulation efficiency. Separation of systemic and pulmonary circulations ex/ some species have two hearts to deal with deoxy and oxy blood
outline the possible orientations of medium and blood flow in the lung structure (3)
1-nondirectional ventilation where the medium is fully mixed and there is a thin respiratory surface.
2) nondirectional ventilation where the medium is poorly pixed and there is a thicker respiratory surface, preventing complete diffusion
3) tidal ventilation. the respiratory surface kind of encapsulates the medium and it leaves through the same portion of the respiratory surface.
3 important pressurs that influence the stretch of the lungs so that they fill the thoracic cavity
1) atmospheric pressure: exerted by the weight of the gas in the atmosphere on objects on the earths surface HIGHER THAN INTRALEURAL PRESSURE
2) intra-albeolar pressure. pressure within the alveoli, same as atmospheric pressure
3) intrapleural pressure: pressure exerted within the pleural sac. usually less than atmospheric pressure, allows for favorable gradient.
transmural pressure gradient across LUNG WALL vs trans mural pressure gradient across THORACIC wall
across lung= intra-alveolar pressure- intrapleural pressure
thoracic wall= atmospheric pressure - intrapleural pressure.
explain boyles law and how pressure varies with volume
pressure varies inversley with volume. Note how during expiration, volume shortens but pressure in lungs increases
intra-alveolar pressure is ____ during inspiration and ____ during experiation. What about intra pleural pressure?
intra-alveolar pressure is NEGATIVE during inspiration and POSITIVE during experiation.
