Which muscles relax during a normal expiration?
Which TWO of the following choices are the primary inspiratory muscles involved in pulmonary ventilation? These are the ones you use during a normal inspiration.
We first breathe in oxygen (O2)
which makes it way to our alveoli
through the airways called bronchi
. This gas then enters the blood
and is picked up by red blood cells.
Red blood cells deliver the gas to the tissues.
The gas is used up in a process called cellular respiration which is necessary to make ATP (the usable energy of a cell).
In the process, carbon dioxide (CO2) is generated as a waste product.
This waste product is picked up by red blood cells from the tissues
and delivered to the alevoli
External respiration happens in the specifically the alveoli . Internal respiration happens in the . Both types of respiration involve the pulmonary or systemic capillaries, respectively.
Henry’s law describes the behavior of gases when they come into contact with a liquid, such as blood.
There are two types of sleep apnea: obstructive sleep apnea and central sleep apnea.
Obstructive sleep apnea is caused by an obstruction of the airway during sleep, which can occur at different points in the airway, depending on the underlying cause of the obstruction.
For example, the tongue and throat muscles of some individuals with obstructive sleep apnea may relax excessively, causing the muscles to push into the airway. Another example is obesity, which is a known risk factor for sleep apnea, as excess adipose tissue in the neck region can push the soft tissues towards the lumen of the airway, causing the trachea to narrow.
inspiration: the diaphragm and the external intercostal muscles. Additional muscles can be used if a bigger breath is required.
This increase in volume leads to a decrease in intra-alveolar pressure,
expiration- When the diaphragm contracts, it moves inferiorly toward the abdominal cavity, creating a larger thoracic cavity and more space for the lungs.
inspiration- Contraction of the external intercostal muscles moves the ribs upward and outward, causing the rib cage to expand, which increases the volume of the thoracic cavity.
This increase in volume leads to a decrease in intra-alveolar pressure, creating a pressure lower than atmospheric pressure. As a result, a pressure gradient is created that drives air into the lungs.
The process of normal expiration is passive, meaning that energy is not required to push air out of the lungs.
Instead, the elasticity of the lung tissue causes the lung to recoil, as the diaphragm and intercostal muscles relax following inspiration.
A deep breath, called diaphragmatic breathing, requires the diaphragm to contract. As the diaphragm relaxes, air passively leaves the lungs.
A shallow breath, called costal breathing, requires contraction of the intercostal muscles. As the intercostal muscles relax, air passively leaves the lungs.
There are four major types of respiratory volumes: tidal, residual, inspiratory reserve, and expiratory reserve.
Tidal volume (TV) is the amount of air that normally enters the lungs during quiet breathing, which is about 500 milliliters.
Expiratory reserve volume (ERV) is the amount of air you can forcefully exhale past a normal tidal expiration, up to 1200 milliliters for males.
Residual volume (RV) is the air left in the lungs if you exhale as much air as possible.
The residual volume makes breathing easier by preventing the alveoli from collapsing. Respiratory
The residual volume makes breathing easier by preventing the alveoli from collapsing.
Inspiratory reserve volume (IRV) is produced by a deep inhalation, past a tidal inspiration.
Aortic body Monitors blood PCO2, PO2, and pH
Carotid body Monitors blood PCO2, PO2, and pH
At a constant temperature, changing the volume occupied by the gas changes the pressure, as does changing the number of gas molecules. Boyle’s law describes the relationship between volume and pressure in a gas at a constant temperature.
inspiration: the diaphragm and the external intercostal muscles.
The major organs of the respiratory system function primarily to
The cough reflex is mediated by sensory fibres of the vagus nerve, a fundamental component of the autonomic nervous system.
The conducting zone of the respiratory system includes the organs and structures not directly involved in gas exchange.The epithelium contains goblet cells, one of the specialized, columnar epithelial cells that produce mucus to trap debris.
Interestingly, cold air slows the movement of the cilia, resulting in accumulation of mucus that may in turn lead to a runny nose during cold weather.
Serous and mucus-producing cells also secrete the lysozyme enzyme and proteins called defensins, which have antibacterial properties.
The cilia of the respiratory epithelium help remove the mucus and debris from the nasal cavity with a constant beating motion, sweeping materials towards the throat to be swallowed.
The epithelium of the nasal passages, for example, is essential to sensing odors, and the bronchial epithelium that lines the lungs can metabolize some airborne carcinogens.
zone, the respiratory zone includes structures that are directly involved in gas exchange. The respiratory zone begins where the terminal bronchioles join a respiratory bronchiole, the smallest type of bronchiole , which then leads to an alveolar duct, opening into a cluster of alveoli.
An alveolar duct is a tube composed of smooth muscle and connective tissue,
The alveolar wall consists of three major cell types:
The respiratory zone begins where the terminal bronchioles join a respiratory bronchiole, the smallest type of bronchiole (Figure 22.10), which then leads to an alveolar duct, opening into a cluster of alveoli.
The epithelium of the nasal passages, for example, is essential to sensing odors, and the bronchial epithelium that lines the lungs can metabolize some airborne carcinogens.
simple squamous epithelium that allows for the easy diffusion of oxygen and carbon dioxide.
1. Describe the movement of air through the airways. Be sure to use the following
terms: Primary and secondary bronchi, trachea, mouth, pharynx, larynx, nose,
bronchioles and alveoli, conducting zone, respiratory zone.
2. Describe the structure of an alveoli and how that structure facilitates gas exchange.
Be sure to use the following terms: Type I alveolar cells, type II alveolar cells,
capillaries, elastic fibers.
3. Where do you find the plural membranes? Specifically, where do you find the
parietal pleural membrane? Visceral pleural membrane?
a. What are the two functions of the plural fluid?
b. The pleural membranes anchor the lungs to the side of the thoracic cavity, but
the lungs are elastic. What happens during a pneumothorax that disrupts
these opposing forces?
4. Describe how pressure gradients direct airflow.
a. How does Boyle’s law apply to creating pressure gradients in the lungs?
5. What muscles contract during inspiration?
a. What happens to the volume of the thoracic cavity? What happens to
pressure in the thoracic cavity? What happens to airflow?
6. What muscles contract during passive expiration?
a. What happens to the
volume of the thoracic cavity? What happens to pressure in the thoracic
cavity? What happens to airflow?
7. What muscles contract during active expiration?
a. What happens to the volume of the thoracic cavity? What happens to
pressure in the thoracic cavity? What happens to airflow?
8. Define compliance and elasticity as they relate to the lungs.
a. How does surfactant act to increase compliance of the lung?
What happens to the lungs of premature babies before surfactant is
produced?
b. How does fibrotic lung disease affect
compliance?
c. Explain how emphysema affects the lung tissue. Why does a person with
emphysema have to engage active exhalation all the time?
9. Explain how airway diameter affects airflow to the alveoli.
a. How are diameter & resistance related?
b. How does asthma affect the airways?
10. How is alveolar ventilation affected when the rate of breathing changes?
a. How is alveolar ventilation affected when the depth of breathing changes?
b. How is alveolar ventilation affected when airway diameter changes?
11. How do bronchioles respond to altered CO2 and O2 levels?
12. Using Daltons Law, determine the partial pressure of O2 and CO2 in the atmosphere.
a. Define Henry’s law and describe how it explains how O2 and CO2 move
between the air and the aqueous fluids in the body.
13. Explain how and where O2 exchange occurs. Be sure to identify PO2 levels in the
following places: alveoli, pulmonary arteries, systemic arteries, systemic tissues,
systemic veins, and pulmonary veins.
a. Explain how and where CO2 exchange occurs. Be sure to identify PCO2 levels
in the following places: alveoli, pulmonary arteries, systemic arteries,
systemic tissues, systemic veins, and pulmonary veins.
14. Define hypoxia. Explain why and how high altitude impacts oxygen exchange.
15. How is oxygen is carried from the alveoli to the blood?
16. Describe the structure of hemoglobin.
a. What does it mean Hb is 100% saturated, 75% saturated, 50% saturated,
25% saturated or unsaturated? C. What determines when Hb is “loading” vs.
when it is “unloading”?
17. How is oxygen transported in the blood? (two ways)
18. Draw an oxygen disassociation curve. Identify where loading is taking place and
where unloading is taking place.
a. Using the information in the oxygen disassociation curve, follow one molecule
of Hb from an alveolar capillary through arterial circulation, to an exercising
muscle with a PO2 of 25mmHg, and back to the alveoli. Identify the PO2 levels,
when and where exchange is happening, where loading and unloading is
taking place, and saturation levels of the Hb.
b. Describe the effect of pH on how tightly Hb binds O2.
i. Does a reduction in pH shift the curve to the left or to the right?
c. Describe the effect of temperature on how tightly Hb binds O2.
i. Does an increase in temperature shift the curve to the left or to the
right?
d. Describe the effect of PCO2 on how tightly Hb binds O2.
i. Does it shift the curve to the left or to the right?
19. What are the three ways that CO2 is transported in the blood?
a. How is CO2 converted to bicarbonate?
b. Follow one molecule of CO2 from is source (for example, an exercising
muscle) as it is converted to bicarbonate and then exhaled (as CO2 ) from the
lungs.
20. Describe how the rate and depth of ventilation is controlled. Be sure to use the
following terms: central pattern generator, peripheral chemoreceptors, central
chemoreceptors, inspiratory muscles, and expiratory muscles.
a. Where are central chemoreceptors located and what parameters do they
monitor? How do they regulate the rate and depth of breathing?
b. Where are the peripheral chemoreceptors located and what parameters do
they monitor? How do they work to regulate the rate and depth
of breathing?
Score for this quiz: 12 out of 15 *
Eva made plans to visit her Grandpa one day, but when she rang the doorbell, he didn’t respond. Grandpa lives by himself these days and Eva likes to stop by regularly to make sure he’s doing okay. She decides to use the spare key to let herself into the house and when she walks into the kitchen, she’s shocked to find Grandpa lying on floor. Clutching at his chest, he was to respond weakly, and Eva called 911 and EMS arrived in just a few minutes.
At the hospital, Grandpa’s vital signs were recorded as follows:
| Grandpa | Normal |
Systolic BP (mm Hg) | 90 | 120 |
Diastolic BP (mm Hg) | 52 | 80 |
Oral temperature (F) | 98.9 | 97.8-99.1 |
Heart rate (bpm) | 120, irregular | 60-80 |
Respiratory rate (bpm) | 33, labored | 12-20 |
Oxygen saturation | 89% | 95-100 |
Which of Grandpa’s vitals signs and lab values were abnormal?
order ECG/EKG test and echo cardiogram
since oxygen saturation low to do blood test PH level
The cardiologist reviews one additional test, an echocardiogram. To help, I’ve labeled the 4 chambers to orient you to what you are looking at (note the heart is upside down!) Panel A shows an arrow pointing at the likely defect that’s causing Grandpa’s symptoms. Panel B shows blood flow (the warmer the color like yellow-red, the more blood). This image was taken during ventricular systole. The results are below.
Review your heart structure & function lab for some clues. You should also think about blood flow (direction and timing) through the heart (where should blood be during ventricular diastole?)
Based on the echocardiogram results, where do you think the defect is (left or right side of the heart)? Is the defect in the atria, ventricle, aorta, pulmonary vein, pulmonary artery, or valve?
The cardiologist sits down with Grandpa and Eva to discuss Grandpa's situation. "Your grandfather is 72 years old and has a history of heart disease. I'm very sorry, but it's clear that he has had another heart attack which has resulted in valve failure. A small muscle called a papillary muscles that regulates a valve in his heart has been severely damaged and is no longer working. Specifically, his mitral valve has prolapsed, or inverted, and is no longer working properly. We are going to get him on our schedule for a surgery to fix this issue as soon as we can get him into an OR."
The cardiologist further explained that Grandpa's cardiac output was slowly decreasing, blood pressure was also decreasing, and all of these signs are outcomes of left-sided heart failure.
In general, how is the direction of blood flow disrupted because of mitral valve prolapse?
Based on what you understand about cardiac output and blood pressure, why might Grandpa's blood pressure be low? In other words, what does low volume leaving the heart do to blood pressure?
Select the statements that are true!
Eva was so upset with the news of her grandpa's condition. As the day progressed with no news of when the surgery would be scheduled (it was a very booked OR day), she noticed Grandpa's breathing getting increasingly difficult. Now he could barely speak without losing his breath.
She called a nurse named Mariah into the room. "My grandpa can't breathe! What is wrong? You told me he had a heart attack not a problem with his lungs!!"
Mariah tried her best to comfort Eva and proceeded to ascultate Grandpa's chest while listening to his respirations. She noted that they were rapid and producing wet sounds. She turned to Eva and said, "I'm so sorry. Your grandfather's condition is worsening. The damage to his heart is causing these respiratory problems with his lungs."
If the bicuspid (mitral) valve is not fully closing, does pulmonary circulation increase, decrease, or not change?
Does pulmonary blood pressure increase or decrease with left-sided heart failure?
Does this change in pulmonary blood pressure increase or decrease capillary filtration in the lungs?
Take your best guess. How do these changes in pulmonary blood pressure and capillary filtration lead to wet breath sounds? And why is Grandpa breathing more rapidly?
(Be sure to answer both!)
Damage of mitral valve caused blood flows backwards from the left atria to left ventricle that leading decrease stroke volume decrease and decrease cardiac output.
Low cardiac output - caused in reduced oxygen delivery to tissues
Thus, the sympathetic nervous system response to pumps more blood that caused faster heart rate and increases respiration rate to improve oxygen uptake.
