Respiratory Physiology Flashcards
Diffusion only works for ______ organisms. Give one metric which explains this
Small
The surface area to volume ratio gets much smaller as mass increases
List 5 strategies for gas exchange, and an example for each
1) Diffusion (water or air)– Bacteria
2) Bulk flow of water – Sponge
3) Bulk flow of air – Insect
4) Diffusion/gas transport– Leech/Earthworm
5) Ventilation/ gas transport– Vertebrate
How much oxygen does air have per volume compared to water? What does this mean?
1/30 as much oxygen
Need a higher flow rate of water!
What strategy do amphibians employ?
Diffusion/gas transport alone or in combination with ventilation/gas transport (skin, or both skin and lungs)
Name two amphibians
Frog and salamander
What happens when amphibians transition from tadpoles to frogs?
Go from using gills to lungs
Name and discuss three factors that affect the efficiency of gas exchange
1) Distance between blood flow and medium (thinner membrane= better!)
2) Tidal ventilation vs constant ventilation (tidal ventialtion= breathing, not as good as constant exposure)
3) Direction of flow countercurrent is more efficient than crosscurrent, which is more efficient than concurrent
How efficient is a countercurrent exchanger? How about a simple lung
80-90% efficient, vs. 20-25% efficient
What do underwater animals use for gas exchange with the environment?
Gills
Name four types of underwater creatures that have gills
Molluscs, Cephalopods (squids), Crustaceans (lobsters)
Name one creature that maintains embryonic external gills
Axolotl
What kind of pump do sharks use to ventilate gills (what body part does it use also)?
Buccal Pump (Mouth)
Name two factors that increase the efficiency of fish gills at oxygen extraction. Name two key parts
Buccal-Opercular Pump
Countercurrent Flow in gills
Primary lamella, secondary lamella
How frequently do fish breathe compared to humans?
Five times more often!
What openings facilitate bulk flow of air in insects? Can they be opened and closed?
Spiracles
Yes
What openings does a spider have? What kind of a lung does the spider have? What is special about this lung? What is one internal part of this lung?
Spiracles
Book lung
It increases surface area!
Lamallae
What kind of a mechanism do reptiles use to ventilate their lungs? Describe.
Suction-pump mechanisms. Movements of abdominal muscles and limbs open and close the lungs
Bird lungs are very ________ and can extract a ______ percentage of oxygen from the air. They use ________ ventilation, and have both _______ and lungs ___________.
Efficient high continuous air sacs lungs
List the parts of the air pathway from mouth to the end
Mouth/nostril, pharynx, larynx, trachea, primary bronchi, secondary bronchi, tertiary bronchi, bronchioles, terminal bronchioles
What fills most of the chest cavity?
the lungs
Where is the trachea located? What is it made of? How many rings? what is on the side facing the esophagus?
In front of the esophagus
Hyaline cartilage
16 to 20 incomplete rings
Smooth muscle
What lines the inside of the trachea? What do we call the smooth muscle at the back of the trachia?
respiratory epithelium
Trachealis muscle
What does the respiratory epithelium do? Why?
Produces and transports mucus. To capture foreign particles and pathogens
Where do we find the respiratory epithelium? What does it have, what do they do, and in what direction?
In nose, trachea and bronchi. Cilia in nose beat down toward pharynx. Cilia and trachea and bronchi beat upwards toward mouth. They can move particles at 1-2 cm per minute!
What is one disorder of the epithelial cells in the lungs? Describe it in detail
Cystic Fibrosis: If there is a mutation in the CFTR, then Cl transport across the membrane is defective, and as a result, water transport is defective as well. The mucus produced by the epithelial cells has less water, so it is thick and sticky and obstructs the airways.
What landmark surgery occured in 2011? What was the object made of?
First synthetic trachea transplant. Articial windpipe made of porous glass and stem cells
What are the three layers that cover the lung, from inside to out. What is their function?
Visceral pleura, pleural cavity filled with intrapleural fluid, parietal pleura.
Protection!
State Boyle’s Law. Why is it important for the lungs?
P1V1= P2V2. So that when we expand the chest cavity, the lungs fill with air, and vice versa
What happens if we puncture the chest cavity? (official term and description)
Pneumothorax. Now, instead of being at greater than atmospheric pressure, the pressure in the lung equilibriates with atmospheric pressure, and the lung collapses!
What are the structures in the conducting zone?
Trachea, bronchi, bronchioles, terminal bronchioles
What are tthe structures in the respiratory zone?
Respiratory bronchioles, alveolar ducts, alveolar sacs
What is the surface are of the lung equal to?
A tennis court (760 sq. feet)
How many alveolar sacs are there?
8*10^6
What surrounds the alveolar sacs?
Capillaries
How thick is the epithelial cell wall of the alveolar sacs?
One cell thick!
Discuss gas transport as we go deeper and deeper into the lung
Convection and bulk air flow through the bronchiles, then diffusion through the alveoli
What is another disease of the lung? How does it work?
Asthma. Bronchioles constrict due to smooth muscle, and may also have inflamed/enlarged linging. Makes it difficult for air to travel to alveoli!
How thick is the alveolo-capillary membrane?
0.5 micrometer
Name the four layers of the alveolo-capillary membrane (from gas to blood)
Surface film, alveolar epithelium, interstitial space, capillary endothelium
Name the three cell types of the Alveoli (along with description)
1) Type I alveolar cells- 97% of total, where gas exchange occurs!
2) Type II alveolar cells- secrete SURFACTANT
3) Alveolar duct cells- wandering macrophages that remove debris
What is surfactant composed of? What is its function? When does it start being made?
- Detergent-like substance- consists of DPPC, phospholipids (mostly), lipproteins
- A thin layer of alveoli causes surface tension that collapses the alveoli when people exhale. The surfactant decreases the surface tension and stops the alveoli from collapsing.
- Surfactant is produced late in fetal life, so it can be an issue if born too early!
What law governs the collapse of alveoli? What is the effect that surfactant has specifically? Give the equation
Law of Laplace: Air from smaller ones flows into larger ones if surface tension is too high, collapsing smaller ones.
P=2T/r
______________ is the _____ cause of death in _______ infants. Due to a _________ and ______ collapse
Neonatal Respiratory Distress Syndrome
leading, premature
lack of surfactant, alveoli collapse
What do we use to counter Neonatal Respiratory Distress Syndrome?
synthetic surfactant, ventilator
Name two synthetic surfactants
Exosurf
Alveofact (cow lung, also use pig lung)
What lung condition results from smoking? Describe it
Emphysema (“smoker’s lung”)- alveoli start breaking up and collapsing, creating large open pockets. This reduces surface area, and reduces gas exchange!
What was the first working replacement lung implanted in?
a Rat
What determines airflow into and out of lungs?
Pressure differences: air moves into lungs when pressure inside is less than atmospheric pressure. Air moves out when pressure inside is greater than atmospheric pressure.
What is atmospheric pressure?
760 mm Hg
What two muscles move during inhalation? How about exhalation?
Inhalation: External intercostal, diaphragm
Exhalation: Internal intercostal, diaphragm
Where are the intercostal muscles located? Describe the movement of the intercostal muscles during breathing
Located between ribs. External intercostal moves ribs up and out during inhalation, internal intercostal moves ribs down and in during inhalation.
How does the diaphragm work during breathing?
Moves down during inhalation, and up during exhalation
What do we perform to help a choking person? How does it work?
Heimlich Maneuver: we thrust in and up to move the diaphragm and compress the lungs, creating a pressure that pushes the foreign object out
Define 6 metrics of lung volumes and capacities
1) Tidal volume: air moved during quiet breathing (.5L)
2) Inspiratory reserve volume (IRV): amount of air that can be inhaled beyond tidal volume (3L)
3) Expiratory reserve volume (ERV): amount of air that can exhaled over and above the tidal volume (1L)
4) Vital capacity: Total amount of air inhaled and exhaled= tidal volume+ IRV+ERV
5) Residual volume: Amount of air left in lungs and airways after maximal exhalation (1.2L)
6) Total capacity: vital capacity+residual volume
How do we measure lung volumes?
spirometry
Name 4 more metrics of breathing
1) Forced expiratory volume (FEV): how much you can breathe out in 1 second (usually 80% of vital capacity)
2) Minute ventilation rate (MVR): amount of air moved in a minute
3) Dead space: Volume of non-respiratory airways
4) Alveolar ventilation: Total volume of fresh air entering alveoli= (tidal volume-dead space)*breathing rate
What is more effective, rapid, shallow breathing or slower, deeper breathing? Why?
We find that slower, deeper breathing is more effective. Use Alveolar Ventilation equaiton, find with shallower breathing the air doesn’t get a chance to move beyond the dead space!
Name one area that is dead space? What animal has a lot of dead space because of this?
the Trachea
some birds
What are the two deviations from normal breathing rate called? What changes do we see within the alveoli?
Hyperventilation- getting more air in
Hypoventilation- not getting as much air in
We find that during hyperventialtion, the partial pressure of O2 rises and that of CO2 falls. During hypoventilation, the partial pressure of O2 falls and that of CO2 rises.
What do we call the matching of the blood flow and air flow into the lung? How does it work?
Ventilation-Perfusion Coupling
Pulmonary blood vessels constrict in response to low O2 levels (opposite of everywhere else in body), this makes it so blood only flows to well oxygenated areas of the lung.
What is one change that occurs in the lung in response to exercise?
Capillaries at the top of the lung open up (they are normally closed at rest)
What is one difference between the top and bottom of the lung?
The top has a higher ventilation to blood-flow ratio
What is perfusion?
The distribution of blood throughout the lung
What does the lung do if there is decreased blood flow to a region of the lung? How?
Decreases airflow to that region. Via bronchoconstriction
What does the lung do if there is decreased airflow to a region of the lung?
Decreases blood flow via vasoconstriction
What is the primary carrier of oxygen in human blood (cell and molecule)
Red blood cells
Hemoglobin
How much does hemoglobin increase the oxygen-carrying capacity of the blood by? How many hemoglobin molecules does each RBC have? How many oxygen molecules does each hemoglobin/RBC carry? How much O2 is in a liter of blood? What percent of it is bound to hemoglobin?
50 fold 280 million hemoglobin molecules 4 oxygen molecules per hemoglobin, 1 billion oxygen molecules per RBC 200 ml of O2 per Liter of blood 98% of oxygen in blood bound to hemoglobin
Describe the structure of hemoglobin.
1 alpha subunit and one beta subunit make up a globin. 2 globins per hemoglobin. Heme is an iron containing porphyrin group, 4 per hemoglobin.
What percentage of the body’s iron is in hemoglobin?
65% of the total
What is the oxygen carrier in hemolymph? What is its color? What is the metal?
Hemocyanin
Blue color!
Copper
Hemocyanin is the ______ most popular carrier molecule. It is found in __________ and ____________. Unlike hemoglobin, it is usually ____________.
Second
Mollusks and crustaceans
Free-floating
What is one practical use of hemolymph? What do we harvest it from?
It is very sensitive at detecting bacteria. We harvest it from horseshoe crabs.
What is another oxygen-binding molecule in humans? Where is it found? How many O2 does it bind?
Myoglobin
Skeletal Muscle
Binds 1 O2
What do we use to measure saturation of oxygen-carrier vs. partial pressure of gas?
a Dissociation Curve
Myoglobin has a __________ affinity for oxygen than hemoglobin, so its dissocation curve is shfited __________
Higher, left
What law governs the partial pressure of gasses? What does it say?
Dalton’s Law: the total pressure is the sum of all partial pressures
What percent of air is oxygen? So what is oxygen’s partial pressure at sea level?
21% (so 160 mm Hg)
As we go higher, the ________ pressure decreases, so the _____________ of oxygen decreases as well
overall atmospheric pressure
partial pressure of oxygen
If we are calculating the partial pressure in alveoli, what do we have to account for? How do we do this?
The partial pressure of moisture in the air. We subtract this number from the total pressure
List the partial pressures of O2 and CO2 in the…
- Air
- Alveoli
- Cells
Air: 160, 0.3 mm Hg
Alveoli: 105, 40 mm Hg
Cells: 40, 46 mm Hg
*all read o2, co2
List the partial pressures of oxygen and co2 in arteries and veins
Arteries: 100, 40 mm Hg
Veins: 40, 46 mm Hg
What is the mitochondrial partial pressure of o2?
5 mm Hg
Where do we operate on the hemoglobin oxygen-dissociation curve? What does this mean?
We work only on the upper part of the curve, which means that we are always at saturation
What is one difference between adult and embryonic hemoglobin? (structural and consequence) Why is this the case.
Embryonic has 2 alpha and 2 gamma subunites
Adult has 2 alpha and 2 beta subunits
The gamma subunits bind oxygen more strongly!
Because maternal blood in placenta has less O2 than fresh air in lungs
What is the disease where babies keep synthesizing the gamma subunits?
Thalassemia
Name four factors that decrease the affinity of hemoglobin for O2. Which way does this shift the dissociation curve?
1) Acidity
2) Partial pressure of O2
3) Temperature
4) DPG or organophosphates
Shifts RIGHT!
As acidity increases, the affinity of hemoglobin for O2 ________. This is called the _______. Why does this occur? When does it occur, and why is this a good thing?
Decreases
BOHR EFFECT
The protons bind to hemoglobin and alter its conformation
This occurs during exercise (increased metabolism), good b/c O2 dissociates more easily in needy tissues!
How is DPG produced? What two factors accelerate its production?
As DPG increases, O2 affinity _________. Why is this a good thing?
It is a byproduct of glucose metabolism in red blood cells. Low partial pressure of CO2 (???) and high pH accelerate production.
Decreases
DPG helps in unloading of O2 in tissues!
Discuss the relationship between DPG and altitude, and one consequence
DPG is produced at high altitude. However, fetal DPG cannot bind DPG, so if a mother is living very high up, her fetus is going to have difficulty
Discuss the effect of partial pressure of CO2 on oxygen release, and the transmission mechanism
Partial pressure of CO2 rises with exercise. Affinity decreases, so this means that O2 is released more easily, b/c Co2 converts to carbonic acid, which dissociates to protons and bicarbonate ions, and more protons= lower pH = more acidic.
If a dissociation curve sifts right, affinity increases/decreases.
INCREASES (left)
DECREASES (right)
Name one molecule that can compete with oxygen to mind to hemoglobin. Does it have a higher or lower affinity for binding, and by how much? Which way does this sift the hemoglobin dissocation curve?
Carbon Monoxide
200x higher affinity!
Left, b/c many more hemoglobins are bound
Discuss the path of an oxygen molecule from air to cell
Enters alveoli, crosses capillary wall into blood, dissolves, then binds to red blood cell. Travels through blood stream, then dissolves back across capillary wall into interstitial fluid, then into cells.
Why does oxygen diffuse?
Because of a concentration gradient
Name three ways in which carbon dioxide is carried in the blood?
1) Dissolved in the plasma
2) Comgined with the globin part of the hemoglobin molecule to form CARBA-MINO-HEMOGLOBIN
3) In the form of a bicarbonate ion
Discuss the path of carbon dioxide from the cell
Dissolves across cell membrane into intersitial fluid, then across capilary wall into capillary. Travels Through blood to alveoli, where it diffuses back across the capillary wall and out!
How is CO2 transformed into bicarbonate in the blood stream?
CARBONIC ANHYDRASE in RED BLOOD CELLS catalyzes a reaction between CO2 and water to form carbonic acid, which can dissociate to form hydrogen ion and bicarbonate.
Name the three respiratory control centers and their locations
1) Pneumotaxic Area (pons)
2) Apneustic Area (pons)
3) Rhythmicity Area (medulla)
Describe the rhythmicity cells
They are AUTO-RHYTMIC CELLS, active for 2 sec, then inactive for 3 sec
Name two drugs that affect these areas of the brain, and what there effect is
1) Barbiturates (anesthesia)
2) Morphine
Decrease breathing rate!
What is one disorder that affects breathing? Discuss it
Ondines’ Curse a.k.a. CCHS
Body “forgets” to breathe, especially during sleep.
How do the lungs know when to stop stretching? (technical name and what detects it). This is most important in babies/adults. What nerve is associated with this?
Hering-Breuer Reflex
Stretch receptors detect lung stretch and terminate inspiration.
More important in babies!
PHRENIC NERVE
What detects O2 and CO2 levels in the blood? Where are they located? What two nerves transmit signals from them (each nerve hits both)
(Peripheral) Chemoreceptors
Carotid bodies and aortic arch bodies
Glossopharyngeal nerve and vagus nerve
Describe the mechanism by which the chemo-receptors work
Glomulus cells increase firing rate in response to low O2 or higher CO2, release more neurotransmitter to afferent axons
Name three factors that affect ventilation rate, and what that effect is
1) Oxygen levels (low o2=higher rate)
2) Carbon dioxide levels (high co2=higher rate)
3) Acidity levels (lower ph= higher proton concentration= more ventilation)
Do we witness a lot of change or a little change via partial pressure of o2 in the high range? How about partial pressure co2?
Little or no change over a wide range for o2. More variation in co2.
Does the body respond more strongly to changes in o2 or co2?
co2
How do chemorecepotrs respond to levels of co2?
They actually respond to higher proton levels as co2 is tranformed into bicarbonate ions and protons in the cerebrospinal fluid
Where are another set of chemoreceptors located, and what are they called?
Central chemoreceptors, in the medulla!
Describe the pathway for regulation of ventilation.
The cerebral cortex affects the apneustic center and the pneumotaxic center in the pons. These, along with the stretch receptors (Hering-Breuer), central chemoreceptors (medulla), and peripheral chemoreceptors (aortic and carotid bodies) all affect the rhythmicity area, which controls automatic breathing!
Name two drugs that affect these areas of the brain, and what there effect is
1) Barbiturates (anesthesia)
2) Morphine
Decrease breathing rate!
What is one disorder that affects breathing? Discuss it
Ondines’ Curse a.k.a. CCHS
Body “forgets” to breathe, especially during sleep.
How do the lungs know when to stop stretching? (technical name and what detects it). This is most important in babies/adults. What nerve is associated with this?
Hering-Breuer Reflex
Stretch receptors detect lung stretch and terminate inspiration.
More important in babies!
PHRENIC NERVE
What detects O2 and CO2 levels in the blood? Where are they located? What two nerves transmit signals from them (each nerve hits both)
(Peripheral) Chemoreceptors
Carotid bodies and aortic arch bodies
Glossopharyngeal nerve and vagus nerve
Describe the mechanism by which the chemo-receptors work
Glomulus cells increase firing rate in response to low O2 or higher CO2, release more neurotransmitter to afferent axons
Name three factors that affect ventilation rate, and what that effect is
1) Oxygen levels (low o2=higher rate)
2) Carbon dioxide levels (high co2=higher rate)
3) Acidity levels (lower ph= higher proton concentration= more ventilation)
Do we witness a lot of change or a little change via partial pressure of o2 in the high range? How about partial pressure co2?
Little or no change over a wide range for o2. More variation in co2.
Does the body respond more strongly to changes in o2 or co2?
co2
How do chemorecepotrs respond to levels of co2?
They actually respond to higher proton levels as co2 is tranformed into bicarbonate ions and protons in the cerebrospinal fluid
Where are another set of chemoreceptors located, and what are they called?
Central chemoreceptors, in the medulla!
Describe the pathway for regulation of ventilation.
The cerebral cortex affects the apneustic center and the pneumotaxic center in the pons. These, along with the stretch receptors (Hering-Breuer), central chemoreceptors (medulla), and peripheral chemoreceptors (aortic and carotid bodies) all affect the rhythmicity area, which controls automatic breathing!
