Anatomy and Physiology II Test 1: Respiratory System
Normally, PCO2 is more important than PO2 at regulating ventilation; however, at high altitudes where barometric pressure is low, PO2 becomes the more important regulator. Explain.
*At high elevation PO2 becomes the only factor to stimulate an increase in depth and rate of breathing. *Normally, high PCO2 and low pH would be the primary cue to increase breathing, but in this case, PCO2 and pH would be unaffected by the altitude - the person would be able to exhale and blow CO2 off normally. So PCO2 and pH would never signal to the respiratory centers that breathing needed to increase. *PO2 would be the only signal for increased breathing.
What is the difference among external respiration, internal respiration, and cellular respiration?
*External respiration: gas exchange between air in the lungs and the blood *Internal respiration: gas exchange between the blood and the tissues of the body (somatic tissues) *Cellular respiration: a process within cells that breaks down glucose to produce ATP. Cellular respiration uses oxygen and produces carbon dioxide.
A patient with pulmonary edema is receiving concentrated oxygen. How would this affect the amount of carbon dioxide in the patient's blood?
*Giving the patient concentrated oxygen would not change the partial pressure gradient for carbon dioxide across the membrane - so movement of carbon dioxide across the respiratory membrane would be the same. Carbon dioxide would only be affected if the partial pressure of carbon dioxide changed. *Because more oxygen is getting into the blood, then more oxygen would get to the cells. As cells receive more oxygen, they would be able to do more cellular respiration, which would increase the amount of carbon dioxide in the cells, then tissues, then blood. With more carbon dioxide in the blood, there would be a steeper partial pressure gradient for carbon dioxide across the respiratory membrane and more carbon dioxide would move into the alveoli. *If the patient was give 100% oxygen - or air that contains only oxygen and no carbon dioxide, this would make a steeper partial pressure gradient for carbon dioxide (normally atmospheric air has a very low amount of carbon dioxide). With less (zero) carbon dioxide in the alveolus, more carbon dioxide would leave the blood.
What is the benefit of multiple lobes/lobules in the lungs?
*Lobules are anatomically distinct segments of a lobe. A lobe is an anatomically distinct portion of the lung. Each lobe and each lobule are intubated by their own bronchi. Because of this bronchial branching pattern, if debris blocks a portion of a secondary or tertiary bronchi, air could still be conducted to respiratory membrane in the remaining portions of the lung. *Additionally and arguably more significantly, compartmentalizing the lung like this could contain an infection within a single lobule.
In emphysema, the walls between alveoli are progressively destroyed, which creates larger alveoli. Why would patients with emphysema experience shortness of breath?
*The walls of the alveoli are the membranes over which gas exchange happens with the blood. More alveolar walls = more surface area for gas exchange. *In emphysema, the walls of the alveoli are lost and many small alveoli become one larger alveolus. Although the space inside the alveolus is larger and air can still fill the alveolus, only the gases that are contacting the walls of the alveolus can be exchanged with the gases in the blood vessels wrapping the alveolus. Therefore, a person with emphysema will not be achieving as much benefit (that is as much blood oxygenation) from each breath.
Describe which features of the nasal cavity enable it to cleanse, humidify, and warm the air.
*To humidify the air, the mucus within the air contains lots of water; the conchae bones form bumps in the lateral walls of the nasal cavity which causes turbulence in air flow which increases contact of the air and the mucus membranes. *To cleanse the air, large hairs in the vestibule trap large particles. The mucus membrane within the deeper nose will catch particles, and the cilia of these cells will push the trapped particles and mucus posteriorly to the pharynx where they will be swallowed to the stomach. *To warm the air, dense vascularization underlying the mucus membrane is warm. Heat is created by active tissues in the body (such as muscles), as blood moves through these hot tissues the blood picks up the heat and distributes it throughout the body. Because there are many blood vessels underlying the nasal epithelium, this blood will warm the air of the nasal cavity.
How is ventilation different from respiration?
*Ventilation is moving air into and out of lungs. *Respiration is gas exchange.
How would the pH, carbon dioxide levels, and temperature differ in the blood within the pulmonary capillaries compared to the blood within the capillaries of the tissues of the body? - in the pulmonary capillaries the pH would be - in the pulmonary capillaries the carbon dioxide levels would be -in the pulmonary capillaries the temperature would be
- in the pulmonary capillaries the pH would be higher - in the pulmonary capillaries the carbon dioxide levels would be lower -in the pulmonary capillaries the temperature would be lower
What is cellular respiration within the cells?
A series of reactions that break bonds in biomolecules (such as glucose) to release energy and produce ATP (energy currency of the cell). Aerobic respiration uses oxygen and produces carbon dioxide.
The partial pressures of N2, O2, CO2 and H2O are shown in mmHg. Which column corresponds to each: Air in the atmosphere: ______ Air in the alveolus: ______ Air expired: _____ Nitrogen: (A) 566 (B) 598 (C) 569 Oxygen: (A) 120 (B) 158 (C) 194 Carbon Dioxide: (A) 27 (B) 0.3 (C) 40 Water Vapor: (A) 47 (B) 0 (C) 47
Air in the atmosphere: ___B____ Air in the alveolus: ____C___ Air expired: __A____ *Once air moves through the respiratory tract it gains humidity, or water vapor. Air in the atmosphere would have the least amount of water vapor compared to air in the alveoli or exhaled air. Since column B has the lowest water vapor, it must be from the atmosphere (and have not been through the respiratory tract). So, B is atmospheric air. *Air in the alveoli is subjected to gas exchange. In the alveoli, oxygen leaves the air and moves into the blood, and carbon dioxide leaves the blood and enters the alveoli. So air in the alveoli will have a lower oxygen and higher carbon dioxide than atmospheric air. Both A and C fit this criteria: they both have lower oxygen and higher carbon dioxide than atmospheric. So how do we distinguish which is which? First consider the following. *Air that you exhale comes from both the alveoli and from the bronchioles, bronchi, and trachea - because when the alveoli are filled with air, the bronchi and trachea are also filled with air. However, air within the bronchi and trachea are never subjected to gas exchange, because this air stays in the conducting zone and does not reach the respiratory zone. The air exhaled then, would be mixed - it would be somewhere between the composition of air from the atmosphere and the composition of air in the alveoli. So, the amount of oxygen in exhaled air would be lower than the amount of oxygen in atmospheric air, but higher than the amount of air in the alveoli. Similarly, the amount of carbon dioxide in exhaled air would be higher than the amount of carbon dioxide in the atmosphere, but not as high as the amount of carbon dioxide in the alveoli. Suffice it to say that in the alveoli, the oxygen amount would be lowest and carbon dioxide amount would be the highest - So, C is the composition of air in the alveolus.
Which of these (pH, carbon dioxide levels, temperature) would facilitate oxygen binding to hemoglobin in the pulmonary capillaries?
All of these facilitate oxygen binding to hemoglobin: *Oxygen binds hemoglobin more easily when pH is higher. This is the Bohr effect. (most easily remembered as a caveat to "oxygen binds hemoglobin more easily when carbon dioxide is low" - since when carbon dioxide is low, pH is higher) *Oxygen binds hemoglobin more easily when carbon dioxide levels are low. (because normally carbon dioxide and oxygen compete for binding sites) *Oxygen binds hemoglobin more easily when temperature is low. (more movement of the molecules means more dissociation)
In the trachea, why would O-shaped cartilages instead of C-shaped cartilages be problematic?
C-shaped cartilages in the trachea allow the posterior wall of the trachea to be made of flexible tissues (smooth muscle and elastic connective tissue), which is important because the esophagus is posterior to the trachea. The esophagus is a muscular tube, which expands to accommodate a bolus of food. As food moves down the esophagus, the esophagus expands against the soft posterior wall of the trachea. If the trachea were made of O-shaped cartilages, then the esophagus would not be able to expand and swallowing would be difficult or impossible.
We exhale more carbon dioxide than we inhale. Where does the carbon dioxide come from?
Carbon dioxide is produced when cells break glucose down during cellular respiration. Carbon dioxide is then transported from the tissues to the blood and then carried in the bloodstream back to the lungs.
What is external respiration?
Gas exchange between the air within the lungs and the blood Respiratory zone
What is internal respiration?
Gas exchange between the blood and the tissues
What does blood transport?
Gases
What is ventilation?
Getting air in/out of lungs Conducting zone
Explain the effects of holding one's breath on blood pH.
Holding one's breath will decrease the pH of blood. The main factor affecting the pH of blood is CO2. When you prevent exhalation, you prevent the removal of CO2 from blood, which means that CO2 in blood increases. Increasing CO2 in blood makes the blood more acidic - that is, it lowers pH.
Explain the effects of hyperventilation on blood pH.
Hyperventilation increases the blood pH. The main factor affecting the pH of the blood is CO2. When you are hyperventilating, exhalation of CO2 increases. Increased exhalation of CO2 decreases the amount of CO2 in the blood. Less CO2 in blood, means the blood is less acidic - that is, it has a higher pH.
Which of the following best describes the lungs? a. Alveoli b. Bronchial tree c. "Air sacs" d. Both A and B e. All of the above
I argue that D is the best answer. The lungs are anatomically described as a bronchial tree with millions of alveoli. However, the lungs are commonly described as "air sacs". If you think of the alveoli as millions of tiny air sacs then this might be a decent descriptor. However, describing the lungs as 2 large air sacs would be analogous to describing a sponge as a box. All answers were counted correct on this item.
Which bronchi are objects more likely to become lodged in?
Objects are more likely to get lodged in the right bronchi because it has a wider diameter and is more vertical. Objects that have begun traveling down the trachea are more likely to continue their straight down path (instead of falling to the side and entering the more horizontal left bronchi). Also, because the right bronchi has a larger diameter, objects are more likely to enter this larger opening (instead of falling into the smaller opening of the left bronchi).
We inhale more oxygen than we exhale: What happens to the oxygen?
Oxygen enters the bloodstream and is carried to tissues throughout the body. At capillaries, oxygen diffuses into the tissues and into the cells. Oxygen is used by the cells in cellular respiration, which breaks down glucose and produces ATP.
A patient with pulmonary edema is receiving concentrated oxygen. How would this affect the amount of oxygen in the patient's blood?
Pulmonary edema would increase the thickness of the respiratory membrane which decreases gas exchange across the membrane. Giving the patient concentrated oxygen would not change the thickness of the membrane; however it would create a steeper partial pressure gradient across the respiratory membrane for oxygen. With a steeper oxygen partial pressure gradient, more oxygen would move into the blood.
When pH decreases, more oxygen is released from hemoglobin at the same PO2. Would you say this causes the curve to be "right-shifted" or "left-shifted"?
RIGHT SHIFTED. If more oxygen is released from hemoglobin at the same PO2, we would say the curve is right shifted. The Y-axis shows how saturated with oxygen hemoglobin is: from 0% (no oxygen on hemoglobin) to 100% saturated (maximum oxygen on hemoglobin). More oxygen is released from hemoglobin means that less oxygen is on hemoglobin, or hemoglobin is less saturated with oxygen. This means that at any PO2, lets say at PO2 = 40mmHg, the %O2 saturation would be less. So if we trace a line up for PO2 = 40mmHg, we would hit the curve at a lower %O2 saturation (at a lower Y-axis number) -- <see the red dashed line in figure above). In order to hit this point, the curve would have to be shifted to the right.
Put the following in the correct order to describe the path of blood flow from the external respiratory site to the internal respiratory site and back to the external respiratory site. Left-side of heart Pulmonary arteries Pulmonary capillaries Pulmonary veins Right-side of heart Systemic arteries Systemic capillaries Systemic veins
The pulmonary capillaries are the external respiration site, so they come first. Pulmonary capillaries pulmonary veins (veins = toward the heart) left-side of heart (Left-side= from lungs) systemic artery (artery = away from heart) systemic capillaries (site of internal respiration) systemic veins (veins = toward heart) right-side of heart (right-side is from-body-side) pulmonary arteries (arteries = away from heart) pulmonary capillaries
Is it easier to inhale when lying supine or when standing?
When standing gravity pulls down the abdominal contents (intestines etc). When lying down these abdominal contents press against the diaphragm to a greater extent. Therefore, when standing it is easier to inhale because the diaphragm can more easily flatten.
What happens when the phrenic nerve is stimulated? a. diaphragm contracts and air enters the lungs b. diaphragm relaxes and air enters the lung c. diaphragm contracts and air exits the lungs d. diaphragm relaxes and air exits the lungs
a. Diaphragm contracts and air enters the lungs When the diaphragm contracts it flattens which pulls down the parietal pleura and increasing the volume within the lungs. This increase in volume causes a decrease in pressure, which causes air to move into the lungs.
What type of biomolecule is hemoglobin? a. lipid b. protein c. carbohydrate d. nucleic acid
a. protein: hemoglobin is a protein
