KMU Past Paper Practice

Question:

During thoracic examination, a physician explains that the lungs can move smoothly against the inner chest wall during breathing because a thin lubricating layer lies between two serous membranes. Where is this fluid normally located?

Options:

Correct Answer: Between visceral and parietal pleura

Explanation: A small amount of pleural fluid within the potential pleural space reduces friction and permits smooth movement of the lungs against the thoracic wall.

Question:

A radiologist identifies a lesion confined to the left lung below its major fissure. Which lobe is most likely involved?

Options:

Correct Answer: Left lower lobe

Explanation: The left lung has upper and lower lobes separated by the oblique fissure; lung below this fissure belongs to the lower lobe.

Question:

A patient is asked to breathe out normally and then exhale as much additional air as possible. Which lung volume is being measured during the additional effort?

Options:

Correct Answer: Expiratory reserve volume

Explanation: Expiratory reserve volume is the additional volume expelled after the completion of a normal tidal expiration.

Question:

At the end of a normal quiet expiration, a substantial amount of air remains within the lungs. Which capacity represents this remaining volume?

Options:

Correct Answer: Functional residual capacity

Explanation: Functional residual capacity is the volume remaining after normal expiration and consists of expiratory reserve volume plus residual volume.

Question:

A student completes a normal expiration and is then instructed to inspire maximally. Which capacity is represented by the volume inhaled from the end of normal expiration to maximal inspiration?

Options:

Correct Answer: Inspiratory capacity

Explanation: Inspiratory capacity is the maximum volume inspired after a normal expiration and combines tidal volume with inspiratory reserve volume.

Question:

A healthy adult stops contracting the diaphragm after a quiet inspiration. No forced expiratory muscles are recruited. Which change then drives air out of the lungs?

Options:

Correct Answer: Rise in alveolar pressure from recoil

Explanation: During quiet expiration, relaxation and elastic recoil reduce lung volume, raising alveolar pressure above atmospheric pressure and driving air outward.

Question:

Blood arriving in pulmonary capillaries has a lower oxygen partial pressure than alveolar gas. Which process is responsible for movement of oxygen into the blood?

Options:

Correct Answer: Passive diffusion down a partial-pressure gradient

Explanation: Respiratory gases cross the alveolar-capillary membrane by diffusion from higher to lower partial pressure without requiring active transport.

Question:

A localized lung region receives both fresh alveolar air and pulmonary capillary blood. Which additional feature is required for oxygen to pass efficiently between the two compartments?

Options:

Correct Answer: Thin alveolar-capillary barrier

Explanation: Effective gas transfer requires not only ventilation and perfusion but also a sufficiently thin alveolar-capillary interface for rapid diffusion.

Question:

A 24-year-old woman remains markedly hyperventilated for several hours. Her initial fall in PaCO₂ persists. Which biochemical change represents physiological compensation rather than the primary disturbance?

Options:

Correct Answer: Decrease in plasma bicarbonate

Explanation: Persistent respiratory alkalosis is compensated by renal loss of bicarbonate, which helps move the elevated pH back toward normal.

Question:

An arterial blood-gas sample from a patient with prolonged inadequate ventilation shows an elevated PaCO₂. Which additional finding would indicate that renal compensation has begun?

Options:

Correct Answer: Raised plasma bicarbonate

Explanation: Persistent respiratory acidosis stimulates renal conservation and generation of bicarbonate, partially buffering the increase in hydrogen ions.

Question:

A 50-year-old man presents with cough, fever and breathlessness. Before examining the chest, the physician determines how rapidly the symptoms developed and whether they are worsening. Which diagnostic purpose is primarily served by this step?

Options:

Correct Answer: Defining the temporal pattern of illness

Explanation: Onset, duration and progression establish whether the respiratory illness is acute, evolving or chronic and provide the framework for further diagnostic reasoning.

Question:

A 41-year-old worker with chronic cough reports daily exposure to airborne dust at work. Why is this information particularly important in the respiratory history?

Options:

Correct Answer: It identifies a relevant respiratory exposure

Explanation: Occupational exposure can provide an important etiological clue and should be interpreted alongside symptom duration, smoking history and examination findings.

Question:

A patient with respiratory symptoms has an area of increased density on chest radiography. Before naming the lesion, the clinician specifically looks for displacement of nearby structures. What is the main purpose of assessing this feature?

Options:

Correct Answer: To determine whether volume loss is present

Explanation: Displacement of adjacent structures toward an opacity suggests reduced lung volume and helps distinguish collapse from opacity without significant volume loss.

Question:

A chest X-ray shows increased lucency of both lungs with unusually large lung volumes. Which general radiographic principle best explains the increased lucency?

Options:

Correct Answer: Increase in the amount of intrapulmonary air

Explanation: Air attenuates X-rays less than fluid or tissue, so increased pulmonary air content makes the lungs appear more lucent on radiography.

Question:

A radiograph shows an abnormal basal shadow. The clinician notices that the normally sharp lateral recess between the diaphragm and chest wall is no longer clearly visible. Which anatomical region has been obscured?

Options:

Correct Answer: Costophrenic angle

Explanation: The costophrenic angle is formed where the diaphragm meets the lateral chest wall and is an important region to inspect on chest radiographs.

Question:

While reviewing a chest radiograph, a student focuses immediately on an obvious opacity and overlooks an abnormal tracheal position. Which interpretation strategy would most effectively prevent this error?

Options:

Correct Answer: Apply a fixed systematic review sequence

Explanation: A consistent review of airways, lungs, hila, pleura, diaphragms, heart and visible bones reduces satisfaction-of-search errors.

Question:

During fetal lung maturation, distal respiratory structures become progressively thinner and more closely associated with developing capillaries. What functional advantage results from this change?

Options:

Correct Answer: Improved potential for gas exchange

Explanation: Thinning of distal respiratory structures and closer capillary contact shorten the diffusion pathway and improve the structural basis for gas exchange.

Question:

A congenital disturbance affects repeated branching of the developing lower respiratory tract. Which mature structure would be most directly affected by abnormal development of this branching system?

Options:

Correct Answer: Tracheobronchial tree

Explanation: Repeated developmental branching forms the conducting bronchial system and progressively smaller airways of the tracheobronchial tree.

Question:

A patient with dyspnea has normal chest-wall movement and patent airways. However, oxygen uptake remains inefficient because the alveoli and pulmonary blood flow are poorly matched. Which physiological principle is most directly responsible for the impaired oxygenation?

Options:

Correct Answer: Ventilation-perfusion inequality

Explanation: Efficient oxygenation depends on appropriate matching between alveolar ventilation and pulmonary perfusion; disproportion between them reduces effective gas exchange.

Question:

A patient presents with cough, breathlessness and an abnormal chest radiograph. The history suggests recent onset, examination localizes findings to one region, and imaging shows a corresponding lesion. Which approach best reflects correct respiratory diagnostic reasoning?

Options:

Correct Answer: Correlate history, examination and imaging

Explanation: Respiratory assessment is strongest when symptoms, physical findings and radiographic abnormalities are interpreted together as one coherent clinical pattern.