1.
By a routine examination of respiratory functions a spirometer is used to measure lung volumes. Which lung volume or lung capacity can not be determined by this method?
Correct Answer
E. Total lung capacity (TLC)
Explanation
A spirometer is a device used to measure lung volumes, which are the different amounts of air that can be inhaled or exhaled. The inspiratory reserve volume (IRV), inspiratory capacity (IC), expiratory reserve volume (ERV), and vital capacity (VC) can all be determined using a spirometer. However, the total lung capacity (TLC) cannot be determined by this method because it includes the residual volume (RV), which is the amount of air that remains in the lungs after a maximal exhalation. The spirometer cannot measure the residual volume, so it cannot determine the total lung capacity.
2.
A patient exhales normally and then starts to breathe into a spirometer containing 2-L of 2% helium. After several minutes, the helium concentration in the spirometer falls to 1%. The patient's lung volume at FRC is approximately:
Correct Answer
B. 2L
Explanation
The patient's lung volume at FRC is approximately 2L. This can be inferred from the fact that the helium concentration in the spirometer falls from 2% to 1% after several minutes. This decrease in helium concentration indicates that the patient's lungs have taken in some of the helium from the spirometer. Since the spirometer initially contains 2L of helium, the fact that the concentration decreases by half suggests that the patient's lungs have taken in 1L of helium, which corresponds to an increase in lung volume of 1L. Therefore, the patient's lung volume at FRC is approximately 2L.
3.
You refer your patient with pulmonary fibrosis to the pulmonary function lab. Which of the following values can be measured using direct spirometry?
Correct Answer
C. Vital capacity
Explanation
Direct spirometry is a pulmonary function test that measures the volume and flow of air during forced breathing maneuvers. Vital capacity is the maximum amount of air a person can exhale after taking a deep breath. It is one of the values that can be measured using direct spirometry. Therefore, the correct answer is vital capacity.
4.
A patient inhales as much air as he can (maximal inspiratory level) and then you connect him with a spirometer containing a gas mixture of air and helium. After a homogeneous distribution of helium between spirometer gas and patients' lung volume, you are able to measure the patients' lung volume from helium dilution. Which of the following lung volumes or capacities do you have to know in add ition to above measured lung volume to be able to calculate residual volume of this patient?
Correct Answer
D. Vital capacity
Explanation
To calculate the residual volume of the patient, in addition to the measured lung volume from helium dilution, you need to know the vital capacity. The vital capacity is the maximum amount of air that can be exhaled after a maximal inhalation. By subtracting the vital capacity from the measured lung volume, you can calculate the residual volume, which is the volume of air remaining in the lungs after a maximal exhalation. The other lung volumes and capacities listed are not necessary for this calculation.
5.
Respiratorv histology
Which of the following statements is correct regarding trends observed In the respiratory airways as they progressively decrease in size?
Correct Answer
E. There is an Increase in the relative amount of smooth muscle
Explanation
As the respiratory airways decrease in size, there is an increase in the relative amount of smooth muscle. This is because the smooth muscle helps to regulate the diameter of the airways and control airflow. As the airways become smaller, the smooth muscle needs to increase in order to maintain proper control and function. This increase in smooth muscle allows for the airways to constrict or dilate as needed to facilitate efficient respiration.
6.
Which of the following structures in the respiratory tract is covered with stratified squamous epithelium?
Correct Answer
A. Laryngeal pHarynx
Explanation
The laryngeal pharynx is covered with stratified squamous epithelium. This type of epithelium is found in areas that are subject to mechanical stress and friction, such as the skin and the lining of the mouth and throat. The laryngeal pharynx, which is part of the respiratory tract, is responsible for conducting air from the nasal cavity to the larynx. Its location and function make it susceptible to mechanical stress, hence the presence of stratified squamous epithelium to provide protection.
7.
Oxygen diffuses from the alveolar cavity into the blood in the alveolar capillaries to become linked to red cell hemoglobin, and carbon dioxide diffuses from blood into the alveolar air. To cross the air-blood barrier the minimum number of plasma membranes would be:
Correct Answer
B. 5
Explanation
The question asks for the minimum number of plasma membranes required to cross the air-blood barrier. In the given passage, it is stated that oxygen diffuses from the alveolar cavity into the blood in the alveolar capillaries. This implies that oxygen needs to cross two plasma membranes - one in the alveolar cavity and one in the capillary. Similarly, carbon dioxide diffuses from blood into the alveolar air, requiring it to cross two plasma membranes as well. Therefore, the minimum number of plasma membranes required to cross the air-blood barrier is 5.
8.
Which of the following is a function characteristically associated with "respiratory epithelium"?
Correct Answer
A. Trapping of particles from passing air for elimination by swallowing
Explanation
The function characteristically associated with "respiratory epithelium" is the trapping of particles from passing air for elimination by swallowing. This is because the respiratory epithelium is lined with mucus-producing cells and cilia, which work together to trap and remove particles and foreign substances from the air before it reaches the lungs. This helps to protect the respiratory system from potential harm and maintains its proper functioning.
9.
Air inhaled through the nose is "conditioned" to protect the tissues of the deeper airways. For conditioning the air, nasal tissue possesses all of the following features EXCEPT:
Correct Answer
B. Generation of heat by mitochondria in the basal cells of the respiratory epithelium
Explanation
The nasal tissue possesses secretions supplied from goblet cells in the epithelium, secretions from seromucous glands in the subepithelial connective tissues, and venous plexuses at selected places in the subepithelial connective tissues. However, it does not generate heat by mitochondria in the basal cells of the respiratory epithelium.
10.
All of the following statements about the respiratory system are correct EXCEPT:
Correct Answer
D. Trachealis muscle contracts during inhalation
Explanation
only during coughing and forced expiration
11.
The large numbers of alveolar macrophages which migrate into lumens of alveoli are derived from
Correct Answer
D. Monocytes in circulating blood
Explanation
The correct answer is monocytes in circulating blood. Alveolar macrophages are immune cells that play a crucial role in the defense and clearance of pathogens and debris in the alveoli of the lungs. They are derived from monocytes, which are a type of white blood cell found in the circulating blood. Monocytes migrate from the bloodstream into the alveoli and differentiate into alveolar macrophages. These macrophages then reside within the alveoli, where they engulf and remove foreign particles and microorganisms to maintain lung health and function.
12.
Both goblet cells and ciliated epithelial cells occur in all of the following EXCEPT
Correct Answer
D. Alveoli
Explanation
Goblet cells and ciliated epithelial cells are both types of cells found in the respiratory system that help with the production and movement of mucus. Goblet cells secrete mucus, while ciliated epithelial cells have tiny hair-like structures called cilia that help move the mucus along. These cells are found in the nasal cavity, trachea, and bronchi, but not in the alveoli. The alveoli are small air sacs in the lungs where gas exchange occurs, and they do not contain goblet cells or ciliated epithelial cells.
13.
Pulmonary alveoli characteristically have
Correct Answer
C. Surfaces coated with a detergent-like material to facilitate alveolar inflation
Explanation
The correct answer is surfaces coated with a detergent-like material to facilitate alveolar inflation. This is because the surfactant, which is the detergent-like material, reduces surface tension in the alveoli, allowing them to expand and inflate more easily during inhalation. Without surfactant, the alveoli would collapse and make it difficult for gas exchange to occur in the lungs.
14.
Capillaries of pulmonary alveoli are
Correct Answer
B. Iarger in diameter than average systemic capilIanes
15.
"Respiratory" (i.e.. ciliated pseudostratified columnar) epithelium is found in all of the following structures EXCEPT
Correct Answer
E. Bronchioles
Explanation
The correct answer is bronchioles. Respiratory (ciliated pseudostratified columnar) epithelium is found in the nasal cavity, trachea, extrapulmonary bronchi, and intrapulmonary bronchi. However, bronchioles are lined with simple columnar or cuboidal epithelium, not respiratory epithelium.
16.
Which of the following is characterized by the presence of both skeletal muscle and cartilage?
Correct Answer
B. Larynx
Explanation
The larynx is characterized by the presence of both skeletal muscle and cartilage. The skeletal muscles in the larynx help in controlling the tension and position of the vocal cords, allowing for speech and sound production. The cartilage in the larynx, specifically the thyroid cartilage (Adam's apple) and the cricoid cartilage, provide structural support and protection for the vocal cords and other structures in the larynx. Therefore, the larynx is the correct answer as it exhibits the presence of both skeletal muscle and cartilage.
17.
Bronchioles differ from bronchi in all of the folloWing respects EXCEPT
Correct Answer
B. Presence of smooth muscle
Explanation
Bronchioles differ from bronchi in all of the listed respects except for the presence of smooth muscle. Bronchioles do not have cartilage, have a different type of epithelium, have Clara cells, and do not have sub-mucosal glands. However, both bronchioles and bronchi have smooth muscle.
18.
which of the following portions of the respiratory tract lack smooth muscle?
Correct Answer
E. Alveoli
Explanation
The alveoli are tiny air sacs located at the end of the bronchioles in the respiratory tract. They are responsible for the exchange of oxygen and carbon dioxide in the lungs. Unlike the trachea, bronchi, and bronchioles, the alveoli lack smooth muscle. This is because their main function is gas exchange rather than airway constriction or dilation. Smooth muscle is found in the trachea, bronchi, and bronchioles to help regulate the diameter of the airways and control airflow.
19.
All of the following are characteristics of capillaries found within the alveolar septa EXCEPT
Correct Answer
E. They lack a basement membrane
Explanation
Capillaries found within the alveolar septa have a smaller diameter than most capillaries, have lower pressure than most capillaries, are somatic, continuous capillaries, and have transport across the capillary wall using membranous vesicles. However, they do not lack a basement membrane.
20.
A unique feature of the olfactory epithelium is the presence of
Correct Answer
B. Neurons that are replaced throughout life
Explanation
The unique feature of the olfactory epithelium is the presence of neurons that are replaced throughout life. Unlike most neurons in the body, which cannot regenerate, the olfactory neurons have the ability to regenerate and replace themselves. This allows for the continuous detection and processing of smells throughout a person's lifetime.
21.
Respiratory epithelium and olfactory epithelium are alike in which of the following properties?
Correct Answer
B. Both are pseudostratified epithelia
Explanation
Both respiratory epithelium and olfactory epithelium are pseudostratified epithelia. This means that the cells appear to be layered or stratified, but in reality, all cells are in contact with the basement membrane. This arrangement allows for a larger surface area and increased absorption and secretion.
22.
All of the following are characteristics of Type II pneumocytes EXCEPT
Correct Answer
C. pHagocytose particulates reaching the aIveoli
Explanation
Type II pneumocytes are responsible for the secretion of surfactant, which helps to reduce surface tension in the alveoli. They also contain organelles called lamellar bodies, which store and release surfactant. Type II pneumocytes form tight junctions with Type I pneumocytes, which helps to maintain the integrity of the alveolar wall. They also have the ability to divide and produce both Type I and Type II cells. However, they do not phagocytose particulates reaching the alveoli. This function is primarily carried out by alveolar macrophages.
23.
In order for oxygen in the inspired air to reach hemoglobin, it must diffuse across all of the following structures EXCEPT
Correct Answer
D. One or more smooth muscle cells
Explanation
Oxygen in the inspired air reaches hemoglobin by diffusing across various structures. The layer of surfactant, endothelial cell, and Type I pneumocyte all play a role in this diffusion process. The plasma membrane of the erythrocyte also allows oxygen to diffuse into the red blood cells. However, smooth muscle cells do not directly participate in the diffusion of oxygen to hemoglobin. Therefore, the correct answer is "One or more smooth muscle cells."