PATH370 MIDTERM REVIEW WITH
CORRECT ANSWERS
Question 1: In which structures of the respiratory system does gas
exchange occur?
A) alveoli
B) terminal bronchioles
C) lungs
D) pulmonary vessels
E) pleurae
Answer: A) alveoli
Explanation: The alveoli are the primary sites of gas exchange. They are
thin-walled air sacs surrounded by capillaries. This close proximity
allows for efficient diffusion of oxygen into the bloodstream and carbon
dioxide out of the bloodstream. The alveolar membrane, only one cell
thick, facilitates this process. While the trachea and bronchi are
important for transporting gases to and from the alveoli, and the sinuses
are hollow spaces within the skull, they are not directly involved in gas
exchange. The pulmonary vessels are involved in blood flow to and from the
lungs.
Question 2: A patient with heart failure reports waking up frequently at
night with shortness of breath. Which term best describes this symptom?
A. Dyspnea
B. Cyanosis
C. Bradypnea
D. Paroxysmal nocturnal dyspnea
Answer: D. Paroxysmal nocturnal dyspnea
Explanation: Paroxysmal nocturnal dyspnea (PND) describes the sudden,
severe episodes of shortness of breath that occur at night and often
awaken the patient. Dyspnea is a general term for difficult or labored
breathing. Cyanosis refers to a bluish discoloration of the skin or mucous
membranes due to low oxygen levels. Bradypnea indicates an abnormally slow
breathing rate.
Question 3: What causes cyanosis in congenital heart disease?
A. Left-to-right shunting of blood
B. Right-to-left shunting of blood
C. Ventricular septal obstruction
D. Atrial septal defect
CORRECT ANSWERS
Question 1: In which structures of the respiratory system does gas
exchange occur?
A) alveoli
B) terminal bronchioles
C) lungs
D) pulmonary vessels
E) pleurae
Answer: A) alveoli
Explanation: The alveoli are the primary sites of gas exchange. They are
thin-walled air sacs surrounded by capillaries. This close proximity
allows for efficient diffusion of oxygen into the bloodstream and carbon
dioxide out of the bloodstream. The alveolar membrane, only one cell
thick, facilitates this process. While the trachea and bronchi are
important for transporting gases to and from the alveoli, and the sinuses
are hollow spaces within the skull, they are not directly involved in gas
exchange. The pulmonary vessels are involved in blood flow to and from the
lungs.
Question 2: A patient with heart failure reports waking up frequently at
night with shortness of breath. Which term best describes this symptom?
A. Dyspnea
B. Cyanosis
C. Bradypnea
D. Paroxysmal nocturnal dyspnea
Answer: D. Paroxysmal nocturnal dyspnea
Explanation: Paroxysmal nocturnal dyspnea (PND) describes the sudden,
severe episodes of shortness of breath that occur at night and often
awaken the patient. Dyspnea is a general term for difficult or labored
breathing. Cyanosis refers to a bluish discoloration of the skin or mucous
membranes due to low oxygen levels. Bradypnea indicates an abnormally slow
breathing rate.
Question 3: What causes cyanosis in congenital heart disease?
A. Left-to-right shunting of blood
B. Right-to-left shunting of blood
C. Ventricular septal obstruction
D. Atrial septal defect
