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  • Question 1 - If O2 makes up 21% of air, then at one atmosphere (760mmHg) it...

    Incorrect

    • If O2 makes up 21% of air, then at one atmosphere (760mmHg) it would be expected that the PO2 of inspired air should be 0,21 x 760 = 160mmHg. In the alveoli the actual measure is 149mmHg because…

      Your Answer: Argon is an inert gas

      Correct Answer: Water is equilibrated with air

      Explanation:

      There are several factors that determine the value of alveolar partial oxygen pressure including: the pressure of outside air, the partial pressure of inspired oxygen and carbon dioxide, the rates of total body oxygen consumption and carbon dioxide production, the rates of alveolar ventilation and perfusion. The alveolar partial pressure is lower than the atmospheric oxygen partial pressure. One reason is, as the air enters the lungs, it is humidified by the upper airway and thus the partial pressure of water vapour reduces the oxygen partial pressure as water is equilibrated with air.

    • This question is part of the following fields:

      • Medicine
      • Respiratory
      38.4
      Seconds
  • Question 2 - Medullary chemoreceptors ...

    Correct

    • Medullary chemoreceptors

      Your Answer: Monitor H+ concentration of the CSF

      Explanation:

      Central chemoreceptors of the central nervous system, located on the ventrolateral medullary surface in the vicinity of the exit of the 9th and 10th cranial nerves, are sensitive to the pH of their environment. These act to detect the changes in pH of nearby cerebral spinal fluid (CSF) that are indicative of altered oxygen or carbon dioxide concentrations available to brain tissues.

    • This question is part of the following fields:

      • Medicine
      • Respiratory
      17.3
      Seconds
  • Question 3 - What is the most appropriate management of a DVT during pregnancy? ...

    Correct

    • What is the most appropriate management of a DVT during pregnancy?

      Your Answer: Heparin

      Explanation:

      Low molecular weight heparin (LMWH) is safe in pregnancy and is therefore the first line management. Warfarin is teratogenic and must be avoided whilst the other options have no role to play.

    • This question is part of the following fields:

      • Medicine
      • Respiratory
      15.5
      Seconds
  • Question 4 - Neurons that are inactive during quiet breathing, become active when the respiratory drive...

    Incorrect

    • Neurons that are inactive during quiet breathing, become active when the respiratory drive for increased ventilation becomes greater than normal. These are located in the:

      Your Answer: Nucleus of the tractus solitaries

      Correct Answer: Ventral respiratory group

      Explanation:

      The mechanism of control of ventilation is an interplay of multiple regions in the brain. Medullary respiratory centre sets the basic rhythm of breathing. The dorsal respiratory group integrates input from the stretch receptors and the chemoreceptors in the periphery and is composed mainly of inspiratory neurons which controls the basic rhythm of breathing. The ventral respiratory group generates breathing rhythm and integrates data coming in to the medulla. It contains both inspiratory and expiratory neurons. They are primarily active in exercise and stress.

    • This question is part of the following fields:

      • Medicine
      • Respiratory
      28.2
      Seconds
  • Question 5 - During quiet breathing the diaphragm’s part is: ...

    Incorrect

    • During quiet breathing the diaphragm’s part is:

      Your Answer: 10%

      Correct Answer: 0.75

      Explanation:

      The diaphragm is the major muscle of inspiration and intercostal muscles play a minor role in quiet breathing.

    • This question is part of the following fields:

      • Medicine
      • Respiratory
      15.5
      Seconds
  • Question 6 - Regarding bronchial innervation which of the following is correct: ...

    Incorrect

    • Regarding bronchial innervation which of the following is correct:

      Your Answer: None of the options are correct

      Correct Answer: Alpha 1 receptors increase bronchial constriction

      Explanation:

      Stimulation of β2 receptors results in smooth muscle relaxation and bronchodilation. α1 receptors cause smooth muscle contraction in the bronchioles although minor to the β2 effects.

    • This question is part of the following fields:

      • Medicine
      • Respiratory
      35.3
      Seconds
  • Question 7 - Carotid bodies... ...

    Correct

    • Carotid bodies...

      Your Answer: Are located near the bifurcation of the carotid arteries bilaterally

      Explanation:

      The carotid body is a small cluster of chemoreceptors and supporting cells located near the fork (bifurcation) of the carotid artery (which runs along both sides of the throat).The carotid body detects changes in the composition of arterial blood flowing through it, mainly the partial pressure of oxygen, but also of carbon dioxide. Furthermore, it is also sensitive to changes in pH and temperature. Carotid bodies trigger an action potential through the afferent fibers of the glossopharyngeal nerve,

    • This question is part of the following fields:

      • Medicine
      • Respiratory
      5.5
      Seconds
  • Question 8 - Which of the following limits the duration of inspiration and increases respiratory rate:...

    Incorrect

    • Which of the following limits the duration of inspiration and increases respiratory rate:

      Your Answer: Ventral respiratory group

      Correct Answer: Pneumotaxic centre

      Explanation:

      The mechanism of control of ventilation is an interplay of multiple regions in the brain. The medullary respiratory centre sets the basic rhythm of breathing and the pons modifies the output of the medullary centres. There are two pontine centres: apneustic and pneumotaxic. The pnuemotaxic centre controls inspiratory time. Increased signals to this area increases respiratory rate. The dorsal respiratory group (DRG) integrates input from the stretch receptors and the chemoreceptors in the periphery and is composed mainly of inspiratory neurons. The DRG controls the basic rhythm of breathing by triggering inspiratory impulses. The ventral respiratory group (VRG) generates breathing rhythm and integrates data coming into the medulla and contains both inspiratory and expiratory neurons. They are primarily active in exercise and stress.

    • This question is part of the following fields:

      • Medicine
      • Respiratory
      21
      Seconds
  • Question 9 - Mean intra pleural pressure at rest with inspiration can reach: ...

    Correct

    • Mean intra pleural pressure at rest with inspiration can reach:

      Your Answer: -6 mmHg

      Explanation:

      It is a negative pressure as it is lower than the atmospheric pressure. It can start from -2.5 and reach around -6 mmHg

    • This question is part of the following fields:

      • Medicine
      • Respiratory
      13
      Seconds
  • Question 10 - An obstruction in a pulmonary artery causes impaired perfusion to an area in...

    Incorrect

    • An obstruction in a pulmonary artery causes impaired perfusion to an area in the lung. The gas values in the unperfused alveoli at sea level will be:

      Your Answer: PO2 = 0 CO2 = 0

      Correct Answer: PO2 = 149 C02 =0

      Explanation:

      Partial pressure of oxygen at sea level is approximately 160 mmHg. Partial pressure of oxygen in alveoli is around 150 mmHg and in an arteriole is around 80-100 mmHg. Partial pressure of carbon dioxide is around 35 mmHg in alveolar air and around 40 mmHg in the arteriole.

    • This question is part of the following fields:

      • Medicine
      • Respiratory
      43
      Seconds
  • Question 11 - On a mountain the atmospheric pressure is 700 mmHg and the humidity close...

    Correct

    • On a mountain the atmospheric pressure is 700 mmHg and the humidity close to zero, the partial pressure of oxygen is:

      Your Answer: 147 mmHg

      Explanation:

      Natural air includes approximately 21% of oxygen. If humidity is zero, the partial pressure of oxygen is 700 × 21% = 147 mmHg

    • This question is part of the following fields:

      • Medicine
      • Respiratory
      15.7
      Seconds
  • Question 12 - Select the correct statement regarding terminal bronchioles: ...

    Incorrect

    • Select the correct statement regarding terminal bronchioles:

      Your Answer: Terminal bronchioles form part of the respiratory zone

      Correct Answer: Terminal bronchioles form part of the conducting zone

      Explanation:

      Bronchioles divide into even smaller bronchioles, called terminal, which are 0.5mm or less in diameter. Terminal bronchioles in turn divide into smaller respiratory bronchioles which divide into alveolar ducts. Terminal bronchioles mark the end of the conducting division of air flow in the respiratory system while respiratory bronchioles are the beginning of the respiratory division where actual gas exchange takes place. Terminal bronchioles are lined with simple cuboidal epithelium containing club cells. Terminal bronchioles contain a limited number of ciliated cells and no goblet cells. Club cells are non-ciliated, rounded protein secreting cells. Their secretions are a non-stick, proteinaceous compound (surfactant) to maintain the airway in the smallest bronchioles.

    • This question is part of the following fields:

      • Medicine
      • Respiratory
      29.6
      Seconds
  • Question 13 - After exercise, O2 debt repay may take up to: ...

    Incorrect

    • After exercise, O2 debt repay may take up to:

      Your Answer: 3 days

      Correct Answer: 90 min

      Explanation:

      Physical activity or exercise requires oxygen for production of ATP or energy via aerobic pathways of energy production. When the amount of oxygen that reaches muscles depletes, cells start producing energy anaerobically by partial breakdown of glucose resulting in lactic acid. Lactic acid should be removed from cells as it causes muscle fatigue. Oxygen is needed to oxidize lactic acid in to carbon dioxide and water and this need is known as oxygen debt. The existence of an oxygen debt explains why we continue to breathe deeply and quickly for a while after exercise. This may take up from 60 – 90 mins.

    • This question is part of the following fields:

      • Medicine
      • Respiratory
      9.1
      Seconds
  • Question 14 - Oxygen enters blood from the alveoli by: ...

    Correct

    • Oxygen enters blood from the alveoli by:

      Your Answer: Passive diffusion

      Explanation:

      Oxygen enters blood from the alveoli by simple diffusion along a concentration gradient. Concentration of oxygen and the partial pressure of oxygen in the alveoli are higher than the partial pressure of oxygen in the blood. So, oxygen moves from alveoli into blood via simple diffusion according to the concentration gradient.

    • This question is part of the following fields:

      • Medicine
      • Respiratory
      9.6
      Seconds
  • Question 15 - Which of the following statements with regards to regulation of pulmonary blood flow...

    Incorrect

    • Which of the following statements with regards to regulation of pulmonary blood flow is correct:

      Your Answer: Oxygen deficiency indirectly causes vasoconstriction

      Correct Answer: Decreased blood flow to a region causes constriction of bronchi that area

      Explanation:

      Oxygen deficiency or hypoxia has a direct effect on pulmonary vessels and results in vasoconstriction. Increased carbon dioxide levels causes pH levels to fall and results in pulmonary vasoconstriction. Decreased blood flow to a pulmonary region causes bronchoconstriction in that area to allow for flow of blood to an area where ventilation is high. Exercise increases demand of oxygen and causes increased pulmonary artery pressure.

    • This question is part of the following fields:

      • Medicine
      • Respiratory
      30.2
      Seconds
  • Question 16 - Regarding glomus cells, which of the following is true? ...

    Incorrect

    • Regarding glomus cells, which of the following is true?

      Your Answer: Are glial cells

      Correct Answer: Contain catecholamines

      Explanation:

      The carotid body detects changes in the composition of arterial blood flowing through it, mainly the partial pressure of oxygen, but also of carbon dioxide. Furthermore, it is also sensitive to changes in pH and temperature.The carotid body is made up of two types of cells, called glomus cells: Glomus type I/chief cells release a variety of neurotransmitters, including acetylcholine, ATP, and dopamine that trigger EPSPs in synapsed neurons leading to the respiratory centre.Glomus type II/sustentacular cells resemble glia, express the glial marker S100 and act as supporting cells.

    • This question is part of the following fields:

      • Medicine
      • Respiratory
      5.4
      Seconds
  • Question 17 - Bronchial smooth muscle: ...

    Incorrect

    • Bronchial smooth muscle:

      Your Answer: Is less in the terminal bronchioles

      Correct Answer: Tone is increased by cholinergic discharge

      Explanation:

      The lungs are supplied by both the sympathetic and parasympathetic divisions of the autonomic nervous system. The parasympathetic innervation is supplied by the vagus nerve. The parasympathetic nervous system is the dominant neuronal pathway in the control of airway smooth muscle tone. Stimulation of cholinergic nerves causes bronchoconstriction, mucus secretion, and bronchial vasodilation. Sympathetic innervation is supplied by the T1 to T5 of the spinal cord and act mainly via beta adrenergic receptors. Stimulation of the sympathetic nervous system causes vasoconstriction and bronchodilation.

    • This question is part of the following fields:

      • Medicine
      • Respiratory
      19.7
      Seconds
  • Question 18 - During strenuous exercise the following arterial change can take place in a fit...

    Incorrect

    • During strenuous exercise the following arterial change can take place in a fit athlete:

      Your Answer: Both oxygen and carbon dioxide will change

      Correct Answer: No change takes place

      Explanation:

      The changes which occur in arterial pH, PO2 and PCO2 values during exercise are usually small. Arterial PO2 often rises slightly because of hyperventilation although it may eventually fall at high work rates. During vigorous exercise, when sufficient oxygen for flux through the Krebs cycle is not available, the increased reliance on glycolysis results in increased accumulation of lactic acid, which initially leads to an increase in PaCO2 . However, this is counteracted by the stimulation of ventilation and as a result PaCO2 is decreased. This provides some respiratory compensation for further lactic acid production and prevents a decline in blood pH, which remains nearly constant during moderate exercise.

    • This question is part of the following fields:

      • Medicine
      • Respiratory
      33.4
      Seconds
  • Question 19 - Alveolar epithelial cells: ...

    Incorrect

    • Alveolar epithelial cells:

      Your Answer: Type 1 produces surfactant

      Correct Answer: Type 2 represent 60% of the cells

      Explanation:

      Type I alveolar cells are squamous (giving more surface area to each cell) and cover approximately 90–95% of the alveolar surface. Type I cells are involved in the process of gas exchange between the alveoli and blood. Type II alveolar cells cover a small fraction of the alveolar surface area. Their function is of major importance in the secretion of pulmonary surfactant, which decreases the surface tension within the alveoli. They are also capable of cellular division, giving rise to more type I alveolar cells when the lung tissue is damaged. These cells are granular and roughly cuboidal. Type II alveolar cells are typically found at the blood-air barrier. Although they only comprise <5% of the alveolar surface, they are relatively numerous (60% of alveolar epithelial cells).

    • This question is part of the following fields:

      • Medicine
      • Respiratory
      11
      Seconds
  • Question 20 - The chemosensitive area in the medulla responds to: ...

    Incorrect

    • The chemosensitive area in the medulla responds to:

      Your Answer: Low oxygen and high carbon dioxide

      Correct Answer: High hydrogen and high carbon dioxide

      Explanation:

      The chemosensitive area in the medulla responds mainly to high pH levels and carbon dioxide levels. Baroreceptors in the carotid and aortic body respond mainly to oxygen and carbon dioxide partial pressure in blood.

    • This question is part of the following fields:

      • Medicine
      • Respiratory
      20.3
      Seconds
  • Question 21 - During strenuous exercise the PO2 of mixed venous blood is: ...

    Incorrect

    • During strenuous exercise the PO2 of mixed venous blood is:

      Your Answer: 40 mmHg

      Correct Answer: 25 mmHg

      Explanation:

      During strenuous exercise the PO2 of mixed venous blood is less than 30 mmHg.

    • This question is part of the following fields:

      • Medicine
      • Respiratory
      20
      Seconds

SESSION STATS - PERFORMANCE PER SPECIALTY

Medicine (6/21) 29%
Respiratory (6/21) 29%
Passmed