MCAT Biology › Circulatory and Respiratory Systems
Which two muscles do humans use primarily for inhalation?
Diaphragm and external intercostal muscles
Internal and external intercostal muscles
Visceral and parietal pleurae
Diaphragm and teres minor
The two muscles that help with breathing are the diaphragm and the external intercostal muscles. The diaphragm pulls the thoracic cavity downward and the external intercostal muscles expand the cavity outward. This expansion of the thoracic cavity leads to a decrease in pressure and allows air to be drawn into the lungs.
Which of the following gases can bind to hemoglobin?
Hemoglobin can bind to all of these gases
Oxygen (O2)
Carbon dioxide (CO2)
Carbon monoxide (CO)
Hemoglobin can bind to all three of these gases, however, it binds to each of them with a different affinity. Hemoglobin's affinity for the three gases, from highest to lowest, is listed below.
carbon monoxide (CO) > oxygen (O2) > carbon dioxide (CO2).
Note that cabron monoxide has the highest affininty; this is why is can be dangerous to inhale too much carbon monoxide, as it will displace onxygen that would otherwise bind to hemoglobin.
Which factors contribute to the Bohr Effect?
Low pH, high CO2
High pH, low CO2
Low pH, high CO2, high temperature
Low pH, low CO2
Low pH, high CO2, low temperature
The Bohr Effect describes hemoglobin's affinty for oxygen as a function of blood pH and carbon dioxide content. An increase in CO2 concentration will lower the blood pH, causing the hemoglobin affinity for oxygen to reduce. High temperature also causes oxygen to be released from hemoglobin, but is not related to the Bohr Effect.
Think about when you're exercising. Your blood has a reduced O2 concentration and an elevated CO2 concentration. These factors allow hemoglobin to release more oxygen in the muscles to faciliate ATP production and maintain energy levels.
Which of the following gases can bind to hemoglobin?
Hemoglobin can bind to all of these gases
Oxygen (O2)
Carbon dioxide (CO2)
Carbon monoxide (CO)
Hemoglobin can bind to all three of these gases, however, it binds to each of them with a different affinity. Hemoglobin's affinity for the three gases, from highest to lowest, is listed below.
carbon monoxide (CO) > oxygen (O2) > carbon dioxide (CO2).
Note that cabron monoxide has the highest affininty; this is why is can be dangerous to inhale too much carbon monoxide, as it will displace onxygen that would otherwise bind to hemoglobin.
Which factors contribute to the Bohr Effect?
Low pH, high CO2
High pH, low CO2
Low pH, high CO2, high temperature
Low pH, low CO2
Low pH, high CO2, low temperature
The Bohr Effect describes hemoglobin's affinty for oxygen as a function of blood pH and carbon dioxide content. An increase in CO2 concentration will lower the blood pH, causing the hemoglobin affinity for oxygen to reduce. High temperature also causes oxygen to be released from hemoglobin, but is not related to the Bohr Effect.
Think about when you're exercising. Your blood has a reduced O2 concentration and an elevated CO2 concentration. These factors allow hemoglobin to release more oxygen in the muscles to faciliate ATP production and maintain energy levels.
Both the sympathetic and the parasympathetic nervous systems are essential for homeostasis and for survival. For example, when we are trying to run away from a threat, the sympathetic nervous system is in full effect to allow us to escape from danger. However, when there is no obvious threat, the parasympathetic nervous system tends to be more in control.
There are similarities and differences between the sympathetic and the parasympathetic nervous systems. In preganglionic nerve fibers, both the sympathetic and the parasympathetic nervous system utilize the neurotransmitter acetylcholine. Closer to the target organ, the parasympathetic nervous system remains dependent on acetylcholine whereas norepinephrine and epinephrine are the predominant neurotransmitters utilized by the sympathetic nervous system.
When norepinephrine and epinephrine bind to their receptors, different effects are carried out based on the type of receptor, affinity, and location of the receptor. For example, epinephrine has a higher affinity for the beta-2 receptor. When epinephrine binds to the beta-2 receptor, common effects include vasodilation and bronchodilation. Norepinephrine has a stronger affinity for the alpha-1, alpha-2 and beta-1 receptors. When norepinephrine binds to its receptor, common effects on the body include vasoconstriction (alpha-1), increased heart rate (beta-1) and uterine contraction (alpha-1).
When a patient has a severe allergic reaction, a common prescribed drug is epinephrine. Which of the follow best explains the effects of epinephrine on a patient experiencing a severe allergic reaction?
Epinephrine binds to the beta-2 receptor. Activating the beta-2 receptor causes vasodilation and bronchodilation. Bronchodilation allows the patient to breath easier by relaxing the smooth muscle that is constricting the airway.
Epinephrine binds to the beta-1 receptor. Activating the beta-1 receptor causes vasodilation and bronchodilation. Bronchodilation allows the patient to breath by relaxing the smooth muscle that is constricting the airway.
Epinephrine binds to the beta-2 receptor. Activating the beta-2 receptor causes vasodilation and bronchoconstriction. Bronchoconstriction allows the patient to breath by relaxing the smooth muscle that is constricting the airway.
Epinephrine binds to the beta-1 receptor. Activating the beta-1 receptor causes vasodilation and bronchoconstriction. Bronchoconstriction allows the patient to breath by relaxing the smooth muscle that is constricting the airway.
Epinephrine binds to the alpha-1 receptor. Activating the alpha-1 receptor causes vasodilation and bronchodilation. Bronchodilation allows the patient to breath by relaxing the smooth muscle that is constricting the airway.
Epinephrine binds to the beta-2 receptor. The binding of epinephrine to the beta-2 receptor causes bronchodilation by relaxing the smooth muscles surrounding the airway. The relaxation of the smooth muscles around the airway increases the airway diameter and therefore allows the patient to breathe easier.
Which two muscles do humans use primarily for inhalation?
Diaphragm and external intercostal muscles
Internal and external intercostal muscles
Visceral and parietal pleurae
Diaphragm and teres minor
The two muscles that help with breathing are the diaphragm and the external intercostal muscles. The diaphragm pulls the thoracic cavity downward and the external intercostal muscles expand the cavity outward. This expansion of the thoracic cavity leads to a decrease in pressure and allows air to be drawn into the lungs.
Which two muscles do humans use primarily for inhalation?
Diaphragm and external intercostal muscles
Internal and external intercostal muscles
Visceral and parietal pleurae
Diaphragm and teres minor
The two muscles that help with breathing are the diaphragm and the external intercostal muscles. The diaphragm pulls the thoracic cavity downward and the external intercostal muscles expand the cavity outward. This expansion of the thoracic cavity leads to a decrease in pressure and allows air to be drawn into the lungs.
Which of the following gases can bind to hemoglobin?
Hemoglobin can bind to all of these gases
Oxygen (O2)
Carbon dioxide (CO2)
Carbon monoxide (CO)
Hemoglobin can bind to all three of these gases, however, it binds to each of them with a different affinity. Hemoglobin's affinity for the three gases, from highest to lowest, is listed below.
carbon monoxide (CO) > oxygen (O2) > carbon dioxide (CO2).
Note that cabron monoxide has the highest affininty; this is why is can be dangerous to inhale too much carbon monoxide, as it will displace onxygen that would otherwise bind to hemoglobin.
Both the sympathetic and the parasympathetic nervous systems are essential for homeostasis and for survival. For example, when we are trying to run away from a threat, the sympathetic nervous system is in full effect to allow us to escape from danger. However, when there is no obvious threat, the parasympathetic nervous system tends to be more in control.
There are similarities and differences between the sympathetic and the parasympathetic nervous systems. In preganglionic nerve fibers, both the sympathetic and the parasympathetic nervous system utilize the neurotransmitter acetylcholine. Closer to the target organ, the parasympathetic nervous system remains dependent on acetylcholine whereas norepinephrine and epinephrine are the predominant neurotransmitters utilized by the sympathetic nervous system.
When norepinephrine and epinephrine bind to their receptors, different effects are carried out based on the type of receptor, affinity, and location of the receptor. For example, epinephrine has a higher affinity for the beta-2 receptor. When epinephrine binds to the beta-2 receptor, common effects include vasodilation and bronchodilation. Norepinephrine has a stronger affinity for the alpha-1, alpha-2 and beta-1 receptors. When norepinephrine binds to its receptor, common effects on the body include vasoconstriction (alpha-1), increased heart rate (beta-1) and uterine contraction (alpha-1).
When a patient has a severe allergic reaction, a common prescribed drug is epinephrine. Which of the follow best explains the effects of epinephrine on a patient experiencing a severe allergic reaction?
Epinephrine binds to the beta-2 receptor. Activating the beta-2 receptor causes vasodilation and bronchodilation. Bronchodilation allows the patient to breath easier by relaxing the smooth muscle that is constricting the airway.
Epinephrine binds to the beta-1 receptor. Activating the beta-1 receptor causes vasodilation and bronchodilation. Bronchodilation allows the patient to breath by relaxing the smooth muscle that is constricting the airway.
Epinephrine binds to the beta-2 receptor. Activating the beta-2 receptor causes vasodilation and bronchoconstriction. Bronchoconstriction allows the patient to breath by relaxing the smooth muscle that is constricting the airway.
Epinephrine binds to the beta-1 receptor. Activating the beta-1 receptor causes vasodilation and bronchoconstriction. Bronchoconstriction allows the patient to breath by relaxing the smooth muscle that is constricting the airway.
Epinephrine binds to the alpha-1 receptor. Activating the alpha-1 receptor causes vasodilation and bronchodilation. Bronchodilation allows the patient to breath by relaxing the smooth muscle that is constricting the airway.
Epinephrine binds to the beta-2 receptor. The binding of epinephrine to the beta-2 receptor causes bronchodilation by relaxing the smooth muscles surrounding the airway. The relaxation of the smooth muscles around the airway increases the airway diameter and therefore allows the patient to breathe easier.