respiration Flashcards
at equilibrium what can you say about partial pressures and concentrations of gases in aqueous and gaseous phase
the concentration of gases is not the same but the partial pressures is the same
O2 moves into the cell by diffusion because
PO2 in the interstitial fluid is greater than PO2 in the cell
O2 in a cell is used for oxidative phosphorylation in mitochondria so its concentration in the cell is low
CO2 moves out of the cell because
PCO2 in the cell is greater than PCO2 in interstitial fluid (product of oxidative phosphorylation)
Difference in exchange of gasses for aquatic animals and terrestrial animals
Aquatic animals exchange with dissolved gasses, and its environment will be in equilibrium with atmospheric gas
Terrestrial animal is exchanging gases directly with the atmosphere
The surface of the lungs is covered with water so the movement of gases between phases is taking place here
Problems with gases only moving by diffusion
Diffusion is slow
Partial pressure drops off with the square of the distance
what is the solution to diffusion being too slow and Partial pressure drops off with the square of the distance
increase surface area on which gases can exchange → lungs and gills
Reduce distance gases must travel
Insects tracheal system
Network of air-filled tubes
Increases surface area of gas exchange
Fish gills
Lots of close proximity capillaries
Countercurrent exchange
Water and blood flow in opposite directions
Brand-new oxygenated water is meeting blood that is leaving the capillaries
Partial pressures equilibrate better
contain arterioles, capillaries, and venules
Frogs
gas exchange
Exchange gases through skin
Lungs
Create positive pressure to force air into their lungs \
how do frogs create positive pressure to force air into their lungs
Expands buccal cavity and brings in air
Glotis opens and buccal cavity contracts → lungs expand
Buccal cavity expands and lungs contract
Glotis closes and buccal cavity contracts
Birds respiration
When they inhale they fill up air/posterior sacs
Exhale sends gas from sacs to the lungs and exchange gases at capillaries then send to anterior sacs and out
why is bird respiration more efficient than human respiration
humans have remaining air from previous inhale/exhale cycle
Birds don’t have that issue due to one way direction of air across the parabronchi
why do mammals not have the one way passage of air
the trachea and bronchioles don’t participate in gas exchange
Mammalian lungs
The nose, mouth, and pharynx all lead to the __ which connects to the __
Larynx, trachea
Trachea
stiff large tube
Stiff to maintain open passage
how does air flow in humans?
describe where it passes through
Air enters the thoracic cage and divides into two major bronchi
Each bronchus leads to a lung
The bronchi branch into smaller tubules called bronchioles
The bronchioles are wrapped in smooth muscle
Bronchioles continue to branch into smaller and smaller tubes that lead into the alveoli
Alveoli covered in capillaries
Alveolus
One alveoli
Most of the alveolus is just air (hollow)
at the terminals of bronchioles
covered in capillaries
Air sacs clustered at the tips of the tiniest bronchioles
pharynx
intersection where the paths for air and food cross
links mouth and nose to larynx and esophagus
What happens when food is swallowed
The larynx (upper part of respiratory tract) moves upward and tips the epiglottis over the glottis
This allows food to go down the esophagus to the stomach
what is the glottis and what is its resting state
The glottis is the opening of the trachea, or windpipe
Typically the glottis is open which allows for breathing
The epithelium lining the major branches of the respiratory tree(system of air ducts) is covered by is Cilia and thin film of mucus
the Purpose of mucus and cilia is
Traps dust pollen and other particulate contaminants
the beating cilia move the mucus upward to the pharynx where it can be swallowed into the esophagus
Plays a crucial role in cleansing the respiratory system
what prevents surface tension from collapsing alveoli(alveoli is hollow)
Surfactant
Mixture of phospholipids and proteins
Breaks up water strictures and prevent too much surface tension
How do humans breathe
inhalation and exhalation
Negative pressure breathing
Diaphragm contracts(moves down)
Increasing the volume of the lung (Patm>Plung –> air moves into lung)
Exhalation
Diaphragm relaxes (moves up)
Decrease the volume of the lung (Patm<Plung –> air moves out the lung)
uses diaphragm and rib muscles
what pressure keeps the lungs inflated
lungs are Suspended in our pleural cavity
Partial pressure inside pleural cavity is slightly less than in the lung
If pleural cavity or lung was punctured the lung would
deflate
collapsed lung
Control of respiration is done
Primarily through
monitoring CO2 not O2
and especially through monitoring pH
When CO2 levels rise, blood pH falls in cerebrospinal fluid
Sensors in major blood vessels detect decrease in blood pH
Medulla receives signals from major blood vessels
Signals from medulla to rib muscles and diaphragm increase rate and depth of ventilation
why does CO2 level in the blood affect pH
Carbonic anhydrase turns CO2 and H2O into carbonic acid which lowers pH
What occurs during respiration
gases move due to partial pressure differences
In atmosphere there is a lot of O2 and not a lot of CO2
O2 is breathed in and CO2 is released
when you inhale what is the partial pressure difference that is observed
you are inhaling used air along with the new air so there is a slightly higher PCO2 and lower PO2 in alveoli when inhaled
Oxygen just moves down partial pressure difference
blood entering the alveolar capillaries is going through what circulation
pulmonary circulation (lung)
in the alveoli, blood entering the alveolar capillaries from pulmonary circulation(old gas) has what sort of gas concentration
higher PCO2 and lower PO2 (compared to inhaled)
this is blood returning from systemic circulation (deoxygenated)
the air in the alveolar space(inhaled/new air) has what sort of pressure differences and how does it move
higher PO2 and lower PCO2
down pressure gradient
O2 moves into the blood and CO2 moves into the alveolar space(out the blood)
Why are alveoli highly susceptible to contamination and what is its defense measure
They lack cilia or significant air currents to remove particles from their surface
They do have white blood cells that patrol the alveoli and engulf foreign particles
Neurons mainly responsible for regulating breathing are in the
Medulla oblongata
Near the base of the brain
in the body tissues/where the systemic capillaries meet the body tissues, what is the pressure gradient like
blood entering the systemic capillaries from the pulmonary veins and systemic arteries has a high PO2 and low CO2
the interstitial fluid in the tissues have high PCO2 and low PO2 which results in O2 movement into the interstitial fluid and CO2 into the blood
as blood moves up the pulmonary arteries and systemic veins, what is the pressure like? where do the gases move
PCO2 is high and PO2 is low
CO2 leaves alveolar capillaries and is exhaled out while O2 is maintained in capillaries as old air to be used again
what comes first, the pulmonary veins or pulmonary arteries?
pulmonary veins
what comes first, systemic arteries or systemic veins
systemic arteries
If a molecule of CO2 is released into
the blood in your left toe is exhaled from your nose, it
must pass through all of the following except
a. the pulmonary vein.
b. the trachea.
c. the right atrium.
d. the right ventricle
a. pulmonary vein
it already went through pulmonary vein and needs to go through pulmonary artery
The amount of O2 that can directly dissolve in the blood is very low. So, we evolved
Erythrocytes (red blood cells)
Erythrocytes (red blood cells) and its function
Filled with hemoglobin that bind blood
When O2 goes into a red blood cell it binds to hemoglobin, due to this it no longer contributes to the partial pressure, allowing O2 to continue flowing in
They greatly increase the amount of O2 that can be carried in the circulatory fluid
contain respiratory pigment, hemoglobin which can carry four O2 molecules
Why is hemoglobin especially efficient at delivering O2 to tissues actively consuming O2
it can bind 4 O2
Where Co2 production is greater, the hemoglobin releases more O2(pH increases)
As the partial pressure of O2 increases, the amount of O2 bound to hemaglobin will increase
The binding of the first O2 increases the affinity for O2 binding of the next and so on
If only 7% of the CO2 released by respiring cells is transported in solution in blood plasma, what happens to the rest of it
The rest diffuses from plasma into erythrocytes and reacts with water to form H2CO3.
Minimizes change in blood pH
Most of CO2 is converted to carbonic acid by the enzyme carbonic anhydrase in the erythrocytes
Carbonic acid is pumped out of the cell and dissociates to ions that can diffuse out easier
