Help with Inspiration and Expiration Physiology - Anatomy
Card 0 of 52
Which of the following muscles does NOT assist in forced inhalation?
Which of the following muscles does NOT assist in forced inhalation?
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Normal inspiration typically involves the flattening (contraction) of the diaphragm in order to increase the volume of the thoracic cavity, and can be done unconsciously. In order to increase the amount of inhaled air, other muscles such as the external intercostals and the sternocleidomastoids are included by conscious control. Both of these muscles aim to raise and expand the thoracic cavity in order to assist in inhalation.
The rectus abdominis is involved in the opposite action of forced exhalation. The rectus abdominis aims to decrease the volume of the thoracic cavity by contracting. This assists in forced exhalation.
Normal inspiration typically involves the flattening (contraction) of the diaphragm in order to increase the volume of the thoracic cavity, and can be done unconsciously. In order to increase the amount of inhaled air, other muscles such as the external intercostals and the sternocleidomastoids are included by conscious control. Both of these muscles aim to raise and expand the thoracic cavity in order to assist in inhalation.
The rectus abdominis is involved in the opposite action of forced exhalation. The rectus abdominis aims to decrease the volume of the thoracic cavity by contracting. This assists in forced exhalation.
Which section of the brain controls unconscious breathing?
Which section of the brain controls unconscious breathing?
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Unconscious breathing is controlled by the pons and the medulla oblongata, both of which are parts of the brain stem. This unconscious breathing can be consciously controlled by using the cerebral cortex, which manages most voluntary actions.
It helps to remember that the brain stem is responsible for unconscious control of the body: breathing, heart rate, blood pressure, etc. It is the addition of the cerebral cortex that allows humans to have conscious control over actions, such as breathing, and override the unconscious controls. For example, the cerebral cortex is used to consciously stop breathing when diving underwater.
Unconscious breathing is controlled by the pons and the medulla oblongata, both of which are parts of the brain stem. This unconscious breathing can be consciously controlled by using the cerebral cortex, which manages most voluntary actions.
It helps to remember that the brain stem is responsible for unconscious control of the body: breathing, heart rate, blood pressure, etc. It is the addition of the cerebral cortex that allows humans to have conscious control over actions, such as breathing, and override the unconscious controls. For example, the cerebral cortex is used to consciously stop breathing when diving underwater.
What happens during inspiration?
What happens during inspiration?
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At rest the diaphragm is slightly curved superiorly such that it makes this sort of shape: 
When it contracts, it flattens out, with the middle of the muscle being pulled down until the muscle is roughly horizontal. Remembering that the diaphragm separates the thoracic and abdominal cavities, if it contracts, it physically increases the volume of the thoracic cavity. Now, remembering your fluid physics, an increase in volume is accompanied with a decrease in pressure. We know that high pressure flows to low pressure spontaneously. The atmospheric pressure is now higher than the intrapleural (or thoracic cavity) pressure, causing air to flow into the lungs.
Note that the external intercostals aid in inspiration and the internal intercostals aid in expiration.
At rest the diaphragm is slightly curved superiorly such that it makes this sort of shape:
Note that the external intercostals aid in inspiration and the internal intercostals aid in expiration.
Which of the following describes tidal volume?
Which of the following describes tidal volume?
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Tidal volume is, by definition, the amount of air inspired/expired during normal breathing. The maximum volume of air that can be inspired after a normal expiration is the inspiratory capacity. The maximum volume of air that can be expired after a maximal inspiration is the vital capacity. The volume of air still in the lungs after a maximal expiration is the residual volume. The maximum volume of air that can be inspired after a normal inspiration is the inspiratory reserve volume.
Tidal volume is, by definition, the amount of air inspired/expired during normal breathing. The maximum volume of air that can be inspired after a normal expiration is the inspiratory capacity. The maximum volume of air that can be expired after a maximal inspiration is the vital capacity. The volume of air still in the lungs after a maximal expiration is the residual volume. The maximum volume of air that can be inspired after a normal inspiration is the inspiratory reserve volume.
When the diaphragm contracts (is pulled downward), occurs.
When the diaphragm contracts (is pulled downward), occurs.
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During a respiratory cycle, the diaphragm contracts and moves downward. When this occurs the pressure in the alveoli falls. This pulls air into the lungs. At the same time external intercostals muscles contract, raising ribs and sternum and enlarges the cavity even more. During exhalation the diaphragm relaxes (moves up) and air is foced out of the body. A hiccup is a muscular spasm of the respiratory muscles including the diaphragm. A pneumothorax is a "hole" in the lungs that causes air to accumulate in the pleural space.
During a respiratory cycle, the diaphragm contracts and moves downward. When this occurs the pressure in the alveoli falls. This pulls air into the lungs. At the same time external intercostals muscles contract, raising ribs and sternum and enlarges the cavity even more. During exhalation the diaphragm relaxes (moves up) and air is foced out of the body. A hiccup is a muscular spasm of the respiratory muscles including the diaphragm. A pneumothorax is a "hole" in the lungs that causes air to accumulate in the pleural space.
While breathing, the diaphragm alternately contracts and relaxes to change the pressure of the lungs. Which of the following is correct during expiration?
While breathing, the diaphragm alternately contracts and relaxes to change the pressure of the lungs. Which of the following is correct during expiration?
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When exhaling, the lungs elasticity compresses the walls increasing the pressure within so that it exceeds atmospheric pressure and forces air out. Humans, despite how it might feel, do not suck in air. Rather pressure differences allow air to rush in and out. During expiration, the diaphragm relaxes, bowing up into the thoracic cavity, thereby decreasing the volume of the thoracic cavity. This results in a corresponding increase in pressure (Boyle's law), and thus the movement of air from the lungs out of the body through the upper respiratory structures.
When exhaling, the lungs elasticity compresses the walls increasing the pressure within so that it exceeds atmospheric pressure and forces air out. Humans, despite how it might feel, do not suck in air. Rather pressure differences allow air to rush in and out. During expiration, the diaphragm relaxes, bowing up into the thoracic cavity, thereby decreasing the volume of the thoracic cavity. This results in a corresponding increase in pressure (Boyle's law), and thus the movement of air from the lungs out of the body through the upper respiratory structures.
Which nerve is responsible for innervating the diaphragm during respiration?
Which nerve is responsible for innervating the diaphragm during respiration?
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The phrenic nerve is the nerve responsible for innervation of the diaphragm. The term phrenic is often associated with descriptions of the diaphragm (i.e cardiophrenic ligament is a ligament associated with connecting the diaphragm to the pericardium of the heart)
The phrenic nerve is the nerve responsible for innervation of the diaphragm. The term phrenic is often associated with descriptions of the diaphragm (i.e cardiophrenic ligament is a ligament associated with connecting the diaphragm to the pericardium of the heart)
Which of the following best describes the physiological mechanism used by the human body during a normal inspiratory phase of breathing?
Which of the following best describes the physiological mechanism used by the human body during a normal inspiratory phase of breathing?
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During the normal inspiratory phase of breathing, in other words, when a human is "breathing in," the physiological mechanism used is called "negative-pressure" breathing. Negative-pressure refers to the pressure in the chest cavity as compared to the surrounding environment. The body generates negative-pressure in the chest cavity during breathing by the contraction of the diaphragm muscle (it pulls downward, expanding the thoracic cavity size and space for the lungs to fill), and the outward expansion of the ribcage (which also expands the thoracic cavity size and provides more space for the lungs to fill). With the increased volume of the thoracic cavity generated, this creates the negative pressure that is needed to draw air into the lungs down its gradient of higher pressure (outside the body/thorax) to lower pressure (into the lungs/thorax). Positive-pressure is an incorrect choice because it is the opposite of what occurs during normal human inspiration.
Positive-pressure is sometimes artificially used in the medical setting with machines in patients with obstructive sleep apnea, or in patients who cannot breathe on their own, but is not a part of standard physiological respiration. The Frank-Starling mechanism describes the mechanism by which the heart pumps blood, but does not describe respiration. Glomerular filtration describes the mechanism by which the glomeruli of the kidneys initially filter blood, but does not describe respiration. Idiopathic pulmonary fibrosis is a disease of the interstitium of lung tissue, but does not describe the physiological mechanism used during inspiration.
During the normal inspiratory phase of breathing, in other words, when a human is "breathing in," the physiological mechanism used is called "negative-pressure" breathing. Negative-pressure refers to the pressure in the chest cavity as compared to the surrounding environment. The body generates negative-pressure in the chest cavity during breathing by the contraction of the diaphragm muscle (it pulls downward, expanding the thoracic cavity size and space for the lungs to fill), and the outward expansion of the ribcage (which also expands the thoracic cavity size and provides more space for the lungs to fill). With the increased volume of the thoracic cavity generated, this creates the negative pressure that is needed to draw air into the lungs down its gradient of higher pressure (outside the body/thorax) to lower pressure (into the lungs/thorax). Positive-pressure is an incorrect choice because it is the opposite of what occurs during normal human inspiration.
Positive-pressure is sometimes artificially used in the medical setting with machines in patients with obstructive sleep apnea, or in patients who cannot breathe on their own, but is not a part of standard physiological respiration. The Frank-Starling mechanism describes the mechanism by which the heart pumps blood, but does not describe respiration. Glomerular filtration describes the mechanism by which the glomeruli of the kidneys initially filter blood, but does not describe respiration. Idiopathic pulmonary fibrosis is a disease of the interstitium of lung tissue, but does not describe the physiological mechanism used during inspiration.
You are a physician taking care of a patient with Chronic Obstructive Pulmonary Disease (COPD), a disease that results in difficulty expiring air from the lungs, but generally does not affect the ability to inspire air. You measure the amount of 
that the patient expires in a single breath. What do you expect the 
readings to be during this expired breath?
You are a physician taking care of a patient with Chronic Obstructive Pulmonary Disease (COPD), a disease that results in difficulty expiring air from the lungs, but generally does not affect the ability to inspire air. You measure the amount of
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In this patient with Chronic Obstructive Pulmonary Disease (COPD), which is a disease that results in difficulty expiring air (and generally does not affect one's ability to inspire air), we would expect to see an increased level of 
in the air that he/she expires, as compared to someone without COPD. Although this is a medically-oriented question, this does not require you to know anything about COPD that is not already supplied in the question. By stating that the ability to expire air is impacted but that the ability to inspire is generally not affected, this calls upon your knowledge of pulmonary physiology, telling you that if inspiration is not affected, 
levels are probably not significantly affected, and that if expiration is affected, 
levels are probably affected.
Once you identify that 
levels are affected in COPD, the question now is, how exactly are they affected? In a COPD patient, it is stated in the question stem, that they have a decreased ability to expire air. When a healthy person expires air, they remove 
from the body. In a COPD patient, who therefore has a decreased ability to remove 
from the lungs, if we measured the amount of a 
in a single breath, we would expect it to be elevated as compared to a healthy individual. At first glance, this may seem counter-intuitive, since we are stating that COPD patients have trouble removing 
from the body. However, the air that they expire is the same air that is coming from their lungs, which contains the elevated levels of 
. Thus, to answer the question, we expect the 
reading for the expired breath to be elevated as compared to that of a healthy person.
In this patient with Chronic Obstructive Pulmonary Disease (COPD), which is a disease that results in difficulty expiring air (and generally does not affect one's ability to inspire air), we would expect to see an increased level of
Once you identify that
The contraction of the abdominal muscles taking place is important in .
The contraction of the abdominal muscles taking place is important in .
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During forced maximum expiration, the lungs are trying their best to push air out of the lungs with the most force. This cannot be accomplished by the lungs alone, so the additional contraction of the abdominal muscles aid to help push air out of the lungs with maximum force.
This is different from normal (quiet) expiration, where only the elastic recoil of the lungs are needed with no additional muscle contractions. Normal expiration does not require pushing air out of the lungs with force.
During forced maximum expiration, the lungs are trying their best to push air out of the lungs with the most force. This cannot be accomplished by the lungs alone, so the additional contraction of the abdominal muscles aid to help push air out of the lungs with maximum force.
This is different from normal (quiet) expiration, where only the elastic recoil of the lungs are needed with no additional muscle contractions. Normal expiration does not require pushing air out of the lungs with force.
A man who suffers from complete paralysis of his intercostal muscles would still have a normal value for his .
A man who suffers from complete paralysis of his intercostal muscles would still have a normal value for his .
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None of the volumes listed would be normal. The internal intercostal muscles contribute to forced expiration and would affect ERV, TLC and VC. The external intercostal muscles contribute to inspiration and would affect the IRV, TLC and VC. Thus, none of the above volumes could be normal in a man who has non-functioning intercostal muscles.
None of the volumes listed would be normal. The internal intercostal muscles contribute to forced expiration and would affect ERV, TLC and VC. The external intercostal muscles contribute to inspiration and would affect the IRV, TLC and VC. Thus, none of the above volumes could be normal in a man who has non-functioning intercostal muscles.
When exercising, the muscles of inspiration include .
When exercising, the muscles of inspiration include .
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When exercising, the muscles of inspiration include: external intercostals, scalene muscles, sternocleidomastoids.
When exercising, the muscles of expiration include: rectus abdominis, internal and external obliques, transversus abdominis, internal intercostals.
When exercising, the muscles of inspiration include: external intercostals, scalene muscles, sternocleidomastoids.
When exercising, the muscles of expiration include: rectus abdominis, internal and external obliques, transversus abdominis, internal intercostals.
During quiet breathing, which of the following is the main inspiratory muscle operating?
During quiet breathing, which of the following is the main inspiratory muscle operating?
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The main inspiratory muscle involved in quiet breathing is the diaphragm, which is a dome shaped sheet of skeletal muscle that is attached to the ribs, sternum, and vertebral column. External intercostals are also involved in quiet breathing, but if these muscles were impaired, quiet breathing would still continue because the diaphragm is the main muscle involved. Accessory muscles are not involved in quiet breathing, but may become involved during exercise. The abdominal wall muscles and internal muscles are both involved in expiration.
The main inspiratory muscle involved in quiet breathing is the diaphragm, which is a dome shaped sheet of skeletal muscle that is attached to the ribs, sternum, and vertebral column. External intercostals are also involved in quiet breathing, but if these muscles were impaired, quiet breathing would still continue because the diaphragm is the main muscle involved. Accessory muscles are not involved in quiet breathing, but may become involved during exercise. The abdominal wall muscles and internal muscles are both involved in expiration.
Which nerve is responsible for innervating the diaphragm during respiration?
Which nerve is responsible for innervating the diaphragm during respiration?
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The phrenic nerve is the nerve responsible for innervation of the diaphragm. The term phrenic is often associated with descriptions of the diaphragm (i.e cardiophrenic ligament is a ligament associated with connecting the diaphragm to the pericardium of the heart)
The phrenic nerve is the nerve responsible for innervation of the diaphragm. The term phrenic is often associated with descriptions of the diaphragm (i.e cardiophrenic ligament is a ligament associated with connecting the diaphragm to the pericardium of the heart)
Which of the following muscles does NOT assist in forced inhalation?
Which of the following muscles does NOT assist in forced inhalation?
Tap to see back →
Normal inspiration typically involves the flattening (contraction) of the diaphragm in order to increase the volume of the thoracic cavity, and can be done unconsciously. In order to increase the amount of inhaled air, other muscles such as the external intercostals and the sternocleidomastoids are included by conscious control. Both of these muscles aim to raise and expand the thoracic cavity in order to assist in inhalation.
The rectus abdominis is involved in the opposite action of forced exhalation. The rectus abdominis aims to decrease the volume of the thoracic cavity by contracting. This assists in forced exhalation.
Normal inspiration typically involves the flattening (contraction) of the diaphragm in order to increase the volume of the thoracic cavity, and can be done unconsciously. In order to increase the amount of inhaled air, other muscles such as the external intercostals and the sternocleidomastoids are included by conscious control. Both of these muscles aim to raise and expand the thoracic cavity in order to assist in inhalation.
The rectus abdominis is involved in the opposite action of forced exhalation. The rectus abdominis aims to decrease the volume of the thoracic cavity by contracting. This assists in forced exhalation.
Which section of the brain controls unconscious breathing?
Which section of the brain controls unconscious breathing?
Tap to see back →
Unconscious breathing is controlled by the pons and the medulla oblongata, both of which are parts of the brain stem. This unconscious breathing can be consciously controlled by using the cerebral cortex, which manages most voluntary actions.
It helps to remember that the brain stem is responsible for unconscious control of the body: breathing, heart rate, blood pressure, etc. It is the addition of the cerebral cortex that allows humans to have conscious control over actions, such as breathing, and override the unconscious controls. For example, the cerebral cortex is used to consciously stop breathing when diving underwater.
Unconscious breathing is controlled by the pons and the medulla oblongata, both of which are parts of the brain stem. This unconscious breathing can be consciously controlled by using the cerebral cortex, which manages most voluntary actions.
It helps to remember that the brain stem is responsible for unconscious control of the body: breathing, heart rate, blood pressure, etc. It is the addition of the cerebral cortex that allows humans to have conscious control over actions, such as breathing, and override the unconscious controls. For example, the cerebral cortex is used to consciously stop breathing when diving underwater.
What happens during inspiration?
What happens during inspiration?
Tap to see back →
At rest the diaphragm is slightly curved superiorly such that it makes this sort of shape: When it contracts, it flattens out, with the middle of the muscle being pulled down until the muscle is roughly horizontal. Remembering that the diaphragm separates the thoracic and abdominal cavities, if it contracts, it physically increases the volume of the thoracic cavity. Now, remembering your fluid physics, an increase in volume is accompanied with a decrease in pressure. We know that high pressure flows to low pressure spontaneously. The atmospheric pressure is now higher than the intrapleural (or thoracic cavity) pressure, causing air to flow into the lungs.
Note that the external intercostals aid in inspiration and the internal intercostals aid in expiration.
At rest the diaphragm is slightly curved superiorly such that it makes this sort of shape:
Note that the external intercostals aid in inspiration and the internal intercostals aid in expiration.
Which of the following describes tidal volume?
Which of the following describes tidal volume?
Tap to see back →
Tidal volume is, by definition, the amount of air inspired/expired during normal breathing. The maximum volume of air that can be inspired after a normal expiration is the inspiratory capacity. The maximum volume of air that can be expired after a maximal inspiration is the vital capacity. The volume of air still in the lungs after a maximal expiration is the residual volume. The maximum volume of air that can be inspired after a normal inspiration is the inspiratory reserve volume.
Tidal volume is, by definition, the amount of air inspired/expired during normal breathing. The maximum volume of air that can be inspired after a normal expiration is the inspiratory capacity. The maximum volume of air that can be expired after a maximal inspiration is the vital capacity. The volume of air still in the lungs after a maximal expiration is the residual volume. The maximum volume of air that can be inspired after a normal inspiration is the inspiratory reserve volume.
When the diaphragm contracts (is pulled downward), occurs.
When the diaphragm contracts (is pulled downward), occurs.
Tap to see back →
During a respiratory cycle, the diaphragm contracts and moves downward. When this occurs the pressure in the alveoli falls. This pulls air into the lungs. At the same time external intercostals muscles contract, raising ribs and sternum and enlarges the cavity even more. During exhalation the diaphragm relaxes (moves up) and air is foced out of the body. A hiccup is a muscular spasm of the respiratory muscles including the diaphragm. A pneumothorax is a "hole" in the lungs that causes air to accumulate in the pleural space.
During a respiratory cycle, the diaphragm contracts and moves downward. When this occurs the pressure in the alveoli falls. This pulls air into the lungs. At the same time external intercostals muscles contract, raising ribs and sternum and enlarges the cavity even more. During exhalation the diaphragm relaxes (moves up) and air is foced out of the body. A hiccup is a muscular spasm of the respiratory muscles including the diaphragm. A pneumothorax is a "hole" in the lungs that causes air to accumulate in the pleural space.
While breathing, the diaphragm alternately contracts and relaxes to change the pressure of the lungs. Which of the following is correct during expiration?
While breathing, the diaphragm alternately contracts and relaxes to change the pressure of the lungs. Which of the following is correct during expiration?
Tap to see back →
When exhaling, the lungs elasticity compresses the walls increasing the pressure within so that it exceeds atmospheric pressure and forces air out. Humans, despite how it might feel, do not suck in air. Rather pressure differences allow air to rush in and out. During expiration, the diaphragm relaxes, bowing up into the thoracic cavity, thereby decreasing the volume of the thoracic cavity. This results in a corresponding increase in pressure (Boyle's law), and thus the movement of air from the lungs out of the body through the upper respiratory structures.
When exhaling, the lungs elasticity compresses the walls increasing the pressure within so that it exceeds atmospheric pressure and forces air out. Humans, despite how it might feel, do not suck in air. Rather pressure differences allow air to rush in and out. During expiration, the diaphragm relaxes, bowing up into the thoracic cavity, thereby decreasing the volume of the thoracic cavity. This results in a corresponding increase in pressure (Boyle's law), and thus the movement of air from the lungs out of the body through the upper respiratory structures.