Question | Answer |
What is the main muscle of inspiration? | diaphragm |
What type of muscle is the diaphragm? | skeletal muscle |
The diaphragm (ascends or descends?) during inspiration. | descends |
What muscles (besides the diaphragm) are used during inspiration? | external intercostals (cause the ribs to flair apart) and scalene muscles (lift the upper part of the ribs during passive inspiration) |
When muscles of inspiration contract, the volume of the pleural cavity (increases or decreases?) | increases |
What is the primary muscle of passive expiration? | there isn't one-- just recoil (relaxation) of muscles of inspiration |
What are secondary muscles of expiration? | internal intercostals (pulls ribs together), and rectus abdominis muscle (pushes viscera up, forcing out more air) |
Lung volume (increases or decreases?) with inspiration. With expiration? | increases w/ inspiration; decreases w/ expiration |
True or False: At rest, alveolar pressure is at atmospheric pressure. | True |
At rest, the pleural cavity pressure is (higher or lower?) than atmospheric pressure. | lower (-5 or -6 cmH2O) |
What creates the pleural vacuum? | the thoracic walls have a tendency to be expanded outward, and the lungs have a tendency to want to collapse inward; this pull in opposite directions is responsible for creating the vacuum |
When we inhale, we are (increasing or decreasing?) the volume of the pleural cavity and (increasing or decreasing?) the pressure. | increasing the volume; decreasing the pressure (from -5 or -6 to -7 or -8) |
Due to the decreasing pressure in the pleural cavity, the lungs respond by (expanding or collapsing?) | expanding-- so air is pulled in from the upper airways (b/c atmospheric pressure > pressure in lungs) |
Define tidal volume. ______mL | the volume of air that goes and comes as we breathe normally (healthy lungs=500mL) |
Define inspiratory reserve volume. | the total amount inhaled forcefully as much as you can (the amount above tidal volume) |
Define expiratory reserve volume. | the total amount exhaled forcefully as much as you can (the amount below tidal volume) |
Define vital capacity. | tidal volume + inspiratory reserve volume + expiratory reserve volume |
Define residual volume. | the volume not at your exposal |
What are the 2 types of alveolar cells in the lungs? | 1) simple squamous cells 2) quboidal cells |
What is the purpose of simple squamous alveolar cells? | allow for gas exchange in and out of the alveoli |
What is the purpose of the quboidal alveolar cells? | produce surfactant |
True or False: Quboidal alveolar cells are too thick to allow gases to diffuse. | True |
Define surfactant. | chemical that can lower surface tension of water |
What is the purpose of surfactant? | allows alveoli to open successfully w/o surface tension of water |
The Type I (simple squamous) and Type II (quboidal) alveolar cells are glued to a ____________________ that meets right up with the capillary endothelium. | basement membrane |
The space between adjoining alveoli is called the _________________. | interstitial space |
What 3 things are found in the interstitial space between alveoli? | 1)collagen, 2)elastin, 3)capillaries |
What is the purpose of the collagen in the interstitial space between alveoli? | connective tissue that helps alveoli hold their shape |
What is the purpose of the elastin in the interstitial space between alveoli? | connective tissue that gives elasticity to interstitia (allows alveoli to inflate and deflate) |
What is the purpose of the capillaries found in the interstitial space between alveoli? | allows diffusion of O2 and CO2 |
What are 5 examples of obstructive disorders? | COPD, chronic bronchitis, emphysema, asthma, bronchiectasis |
Define "obstructive disorders". | the amount of air you breathe in and out is reduced |
Define "restrictive disorders." | something has injured the interstitial space, causing damage. Fibrocytes more in and lay down massive amounts of collagen (scarring/fibrosis) |
What is an example of a restrictive disorder? | pulmonary interstitial fibrosis |
Restrictive diseases cause what 2 problems? | 1)restricts alveoli (can't inflate properly), 2)prevents effective diffusion of gases |
What test can diagnose obstructive vs. restrictive disease? | FEV1/FVC Test |
What is FEV1? | forced expiratory volume in 1 sec |
What is FVC? | forced vital capacity (total) |
What is a normal FEV1/FVC ratio? | 0.8 or greater |
Describe the tracheobronchial tree from large to small. | large bronchi --> small bronchi --> bronchioles --> terminal bronchioles --> respiratory bronchioles --> alveolar ducts --> alveolar sacs |
What part of the tracheobronchial tree is the first place you see a few alveoli and gas exchange? | respiratory bronchioles |
What part of the tracheobronchial tree is where most gas exchange occurs? | alveolar sacs |
Where is the lower level respiratory defense system located? | cells in the alveoli |
What are the 2 cell types of the lower level respiratory defense system? | 1)neutrophils, 2)monocytes |
Which cell type (neutrophils or monocytes?) are the hallmark of chronic inflammation? | monocytes |
Which cell type (neutrophils or monocytes?) are the hallmark of acute inflammation? | neutrophils |
Which cell type (neutrophils or monocyes?) are only affective on living things? | both! (neither neutrophils or monocytes are able to destroy minerals like asbestos, coal dust, silica, etc) |
Define neutrophil. | highly phagocytic WBC (hallmark of acute inflammation) |
Where is the upper level respiratory defense system located? | lining of trachea/bronchi |
What 2 cells types are part of the upper level respiratory defense system? | 1)columnar cells, 2)goblet cells |
What is the function of goblet cells? | produce mucus |
How does the upper level respiratory defense system rid the airway of debris? | if you inhale dust, the goblet cells deposit a layer of mucus which catches the dust. The cilia of the columnar cells wave the dust up and out and it ends up being swallowed. |
What is the nickname for the way the upper level respiratory defense system? | mucu-ciliary escalator |
How does smoking disrupt the upper level respiratory defense system? | Smoking causes the tall columnar ciliary cells to be replaced with squamous cells. The goblet cells remain. Things that get trapped by the mucus can't get moved up d/t lack of cilia. Thus, smokers' cough. |
Which cells of the upper level respiratory defense system to we need to shut down to "dry" the airway during anesthesia? | goblet cells |
Define clara cells. | Special cells, only found in lower bronchioles, that provide protection against inhaled gases/vapors/chemicals |
Clara cells contain __________ enzymes. | CP450 |
Who are Clara cells named after? | doctor in Nazi concentration camp |
What part of the tracheobronchial tree is dead space? | from the terminal bronchioles and up (large and small bronchi, bronchioles, and terminal bronchioles) |
What part of the tracheobronchial tree is considered the gas exchange division? | from the respiratory bronchioles and down (respiratory bronchioles, alveolar ducts, and alveolar sacs) |
Where is the major respiratory center located? | medulla |
What are the names of the 2 respiratory neural groups contained in the medulla? | 1)dorsal respiratory group, 2)ventral respiratory group |
Describe the action of the dorsal respiratory group. | sends neurons down to spinal cord, that impinge on motor nerves that run out to the respiratory skeletal muscles (ex. phrenic nerve) |
What nerve controls the diaphragm? | phrenic nerve (part of the dorsal respiratory group) |
The signal sent by the dorsal respiratory group lasts _________. | 1-2 seconds |
What is the purpose of the short signal length sent by the dorsal respiratory group? | allows for muscle recoil; keeps a normal respiratory rate of ~12 breaths per min |
Describe the action of the dorsal respiratory group. | mostly inactive during normal, quiet breathing. Can activate the secondary expiratory muscles |
Where is the pons located in relation to the medulla? | above the medulla |
What 2 respiratory centers are located in the pons? | 1)apneustic center, 2)pneumotaxic center |
What happens if the apneustic center is stimulated? | stops breathing |
What happens if the pneumotaxic center is stimulated? | takes one big inhalation and holds it in |
What is the main common purpose of the apneustic and pneutaxic centers? | help evenly space the 12 breaths per minute initiated by the dorsal respiratory group in the medulla |
What are chemoreceptors? | receptors sensitive to chemicals in our blood |
Where are the central respiratory chemoreceptors located? | chemosensitive area in medulla |
Where are the peripheral respiratory chemoreceptors located? | arch of aorta and carotid bodies |
These respiratory chemoreceptors are sensitive to what 3 things? | 1)PO2, 2)PCO2, 3)pH |
Which of these (PO2, PCO2, or pH?) affects respiration the least? | PO2 |
Which of these (PO2, PCO2, or pH?) affects respiration the most? | PCO2 |
True or False: pH is functionally equivalent to PCO2? | True |
How do respiratory chemoreceptor alter our breathing? | tell us when we need to breathe faster and deeper |
What changes in PO2, PCO2, and pH would require faster, deeper breaths? | dec. in PO2, inc. in PCO2, dec. in pH |
What is the equation that represents gas exchange? | CO2 + H20 <--> H2CO3 --> H+ + HCO3- |
What enzyme causes CO2 and H2O to combine or break apart? | carbonic anhydrase |
What enzyme causes the breakdown of H2CO3 into H+ and HCO3- | no enzyme is required |
If CO2 rises, the equation swings to the (right or left?) and forms more __________. | swings to the right; more H+ |
If H+ rises, the equation swings to the (right or left?) and forms more __________. | swings to the left; more CO2 |
What is the concentration of O2 (PO2) in the blood when we go into the lungs (pulmonary arteries)? | 40mmHg |
What is the concentration of O2 in the alveoli? | 104 mmHg |
What is the concentration of O2 (PO2) in the blood when we leave the lungs (pulmonary veins)? | 104 mmHg |
What is the concentration of CO2 (PCO2) in the blood when we go into the lungs (pulmonary arteries)? | 45 mmHg |
What is the concentration of CO2 in the alveoli? | 40 mmHg |
What is the concentration of CO2 (PCO2) in the blood when we leave the lungs (pulmonary veins)? | 40 mmHg |
What does the "P" in PO2 or PCO2 stand for? | partial pressure |
What is the easiest way to determine the concentration of a gas? | by the pressure it exerts |
Explain the law of partial pressures. | In a mixture of gases in a container, each gas exerts its own partial pressure. The total pressure in the container is the sum of all of the partial pressures. |
How does O2 travel in the blood? | 97-98% is transported bound to hemoglobin; 2-3% is dissolved in the plasma |
Each hemoglobin molecule has ______ subunits. | 4 |
Each subunit of hemoglobin is made up of ... | 1 heme group bound to a globin |
Each heme group contains ______________. | an Fe2+ iron molecule |
What does the iron molecule on the heme group have to be Fe2+? | in order for O2 to bind |
What type of bond holds the O2 to the Fe2+? Why this type of bond? | a loose physiochemical bond; allows the O2 to come off readily when needed |
Each globin is made of... | 2 alpha chains and 2 beta chains |
How many O2 molecules can each hemoglobin carry? | 4 (1 per heme group) |
How much hemoglobin do you have in your body (per dL)? | 15 g/dL |
How much O2 (in mL) can each g of hemoglobin carry? | 1.34 mL |
Name the 5 possible forms of hemoglobin. | 1)oxyhemoglobin, 2)deoxyhemoglobin, 3)carb-aminohemoglobin, 4)met-hemoglobin, 5)carboxyhemoglobin |
Define oxyhemoglobin. | a hemoglobin molecule that has been oxygenated |
Define deoxyhemoglobin. | a hemoglobin molecule after the O2 has come off |
Define carb-aminohemoglobin. | CO2 is bound to an amino acid on the hemoglobin molecule |
Define met-hemoglobin. | hemoglobin in which the Fe has oxidized (3+), so O2 cannot bind |
Define carboxyhemoglobin. | hemoglobin in which the Fe carries carbon monoxide (CO) |
What causes met-hemoglobin? | certain chemicals (nitrates, nitrites, aniline), can happen spontaneously |
How can we reduce the Fe3+ in met-hemoglobin back to 2+? | met-hemoglobin reductase= enzyme in RBC |
Why is carboxyhemoglobin poisonous? | once CO binds to Fe2+, O2 can't bind |
Which has greater affinity for Fe2+? (O2 or CO?) | CO (carbon monoxide) |
What produces CO? | when organic coals, wood, gas is burned in low O2 levels |
What is a physical sign of CO poisoning? | cherry red appearance to skin d/t peripheral vasodilation |
What is 1 way to determine level of CO poisoning? | checking carbodyhemoglobin levels in blood |
How is CO2 transported in the blood? | 70% is carried in form of bicarbonate ion; 7% is dissolved in plasma; 23% forms carbaminohemoglobin |
As you increase O2 concentration, you (increase or decrease?) the amount of O2 bound to hemoglobin. | increase |
The oxygen hemoglobin dissociation curve is what shape? | sigmoid curve (starts out slow, then steep curve up, then slows down again at the top) |
What causes the flattening of the top of the oxygen hemoglobin dissociation curve? | once the hemoglobin is saturated with O2, it leaves the lungs to go to areas of low PO2, where the hemoglobin dumps the O2 into the tissues |
What 4 things cause the oxygen hemoglobin dissociation curve to shift to the RIGHT? | 1)increased H+ ions, 2)increased CO2, 3)increased temp, 4)increased BPG (byproduct of metabolism glycolysis |
What 4 things cause the oxygen hemoglobin dissociation curve to shift to the LEFT? | 1)decreased H+ ions, 2)decreased CO2, 3)decreased temp, 4)decreased BPG |
How do these things cause a shift to the RIGHT of the oxygen hemoglobin dissociation curve? | they cue the hemoglobin that this is a metabolically active tissue, so the hemoglobin is dumping more O2 in the tissues |
How do these things cause a shift to the LEFT of the oxygen hemoglobin dissociation curve? | they cue the hemoglobin that this is a metabolically inactive tissue, so the hemoglobin holds onto the O2 to give somewhere else |
Describe the Bohr effect. | If the blood flows through an area of increased H+ or increased CO2, the oxygen hemoglobin dissociation curve will shift to the RIGHT. |
Describe the Haldane effect. | hemoglobin does not like to have O2 and CO2 bound at the same time, so if CO2 starts to bind, O2 is released |
What is the respiratory minute ventilation equation? | RR X Tv |
Calculate a normal minute volume. | 12 bpm X 500mL per breath=6L/min |
True or False: The 6L/min of a normal minute ventilation is involved in gas exchange. | False: Some will stay in the dead space) |
What is the alveolar ventilation rate equation? | RR X (Tv-dead space) |
Calculate a normal alveolar ventilation rate. | 12 bpm X (500mL-150mL) per breath =4.2L/min |
What is a standard resting cardiac output? | 5L |
The pleural cavity is largest at the ___________. Why? | apex (d/t gravity pulling the lungs down to the base) |
Describe the intrapleural pressure at the apex, middle, and base of the lung. | apex=10cmH2O, middle=5cmH2O, base=2cmH2O |
True or False: As you go down the lung, volume decreases and pressure increases. | False: As you go down the lung, volume INCREASES, and pressure DECREASES |
Describe a normal ventilation/perfusion match. | alveolar ventilation=4.2L/min; normal resting CO=5L/min; normal match=0.8 or 80% |
Describe lung zone 1. (apex) | 1)alveoli are most inflated; 2)ventilation is closest to large bronchi, 3)alveoli are compressing pulmonary arteries, 4)PA>Pa>Pv; 5)lots of air, but almost no blood (V/P >0.8) |
Describe lung zone 2. (middle) | 1)alveoli are moderately inflated, 2)pulmonary arteries are less pinched off than zone 1, 3)Pa>PA>Pv, 4)equal amounts of air and blood (V/P=0.8); 4)most of the "action" takes place here |
Describe lung zone 3. (base) | 1)alveoli are least inflated, 2)pulmonary artieries are not pinched off, which allows for most perfusion, 3)Pa>Pv>PA, 4)lots of blood, but not so much air (V/P <<0.8) |
Which zone is located at the base of the lung? | zone 3 |
Which zone is located at the apex of the lung? | zone 1 |
Which zone is located in the middle of the lung? | zone 2 |
Which zone has moderately inflated alveoli? | zone 2 |
Which zone has alveoli that are least inflated? | zone 3 |
Which zone has alveoli that are most inflated? | zone 1 |
Which zone has the best V/P matching? | zone 2 |
Which zone has V/P < 0.8? | zone 3 |
Which zone has V/P > 0.8? | zone 1 |
Which zone has pressures: Pa>Pv>PA? | zone 3 |
Which zone has pressures: PA>Pa>Pv? | zone 1 |
Which zone has pressures: Pa>PA>Pv? | zone 2 |
Which zone is where most of the action takes place? | zone 2 |