Functions of medulla oblongata MCQs With Answer

Functions of medulla oblongata MCQs With Answer
The medulla oblongata is a critical brainstem structure controlling vital autonomic functions—respiration, cardiovascular regulation, reflexes like coughing, swallowing and vomiting—and housing key cranial nerve nuclei. This SEO-focused introduction highlights functions of medulla oblongata, medullary nuclei (nucleus ambiguus, dorsal motor nucleus of vagus, nucleus tractus solitarius), pyramidal decussation, chemoreceptor and baroreceptor integration, and pharmacological implications such as opioid-induced respiratory depression and antiemetic targets at the area postrema. Tailored for B. Pharm students, these points link anatomy, physiology and drug effects to clinical syndromes and medullary vascular lesions. Now let’s test your knowledge with 50 MCQs on this topic.

Q1. Which of the following is the primary role of the medulla oblongata in autonomic regulation?

• Motor coordination of limbs
• Higher cognitive processing
• Control of respiration and cardiovascular function
• Visual reflex integration

Correct Answer: Control of respiration and cardiovascular function

Q2. Where does the pyramidal (corticospinal) decussation occur?

• Midbrain
• Caudal medulla
• Pons
• Cervical spinal cord

Correct Answer: Caudal medulla

Q3. Which medullary nucleus is primarily responsible for integrating baroreceptor and chemoreceptor input?

• Vestibular nucleus
• Nucleus ambiguus
• Nucleus tractus solitarius (NTS)
• Dorsal raphe nucleus

Correct Answer: Nucleus tractus solitarius (NTS)

Q4. The respiratory rhythm generator located in the medulla is commonly associated with which of the following structures?

• Pre-Bötzinger complex
• Substantia nigra
• Red nucleus
• Inferior olivary nucleus

Correct Answer: Pre-Bötzinger complex

Q5. Which cranial nerve nucleus in the medulla provides parasympathetic output to thoracic and abdominal viscera?

• Dorsal motor nucleus of vagus
• Hypoglossal nucleus
• Trigeminal motor nucleus
• Superior salivatory nucleus

Correct Answer: Dorsal motor nucleus of vagus

Q6. The area postrema, located in the medulla, is clinically important because it:

• Contains the primary auditory cortex
• Lacks a normal blood–brain barrier and triggers vomiting
• Is the main center for voluntary movement
• Regulates circadian rhythm

Correct Answer: Lacks a normal blood–brain barrier and triggers vomiting

Q7. Which medullary lesion is typically associated with loss of ipsilateral facial pain and temperature and contralateral body pain and temperature sensation?

• Medial medullary syndrome
• Lateral medullary (Wallenberg) syndrome
• Midbrain lesion
• Anterior spinal artery infarct at cervical level

Correct Answer: Lateral medullary (Wallenberg) syndrome

Q8. Damage to the nucleus ambiguus in the medulla most likely causes which clinical sign?

• Loss of pupillary light reflex
• Dysphagia and dysphonia
• Ataxia without bulbar symptoms

Correct Answer: Dysphagia and dysphonia

Q9. Opioid-induced respiratory depression primarily affects which medullary function?

• Vasomotor tone regulation only
• Respiratory rhythm generation and chemoreceptor responsiveness
• Gag reflex but not respiration
• Somatic motor coordination

Correct Answer: Respiratory rhythm generation and chemoreceptor responsiveness

Q10. Which neurotransmitter receptor blockade in the area postrema is the main action of ondansetron as an antiemetic?

• Dopamine D2 receptor
• Serotonin 5-HT3 receptor
• GABA-A receptor
• Muscarinic M1 receptor

Correct Answer: Serotonin 5-HT3 receptor

Q11. The vasomotor center that controls sympathetic outflow to blood vessels is located in which part of the brainstem?

• Cerebellum
• Medulla oblongata
• Thalamus
• Hypothalamus only

Correct Answer: Medulla oblongata

Q12. Which artery is most commonly involved in lateral medullary (Wallenberg) syndrome?

• Anterior spinal artery
• Posterior inferior cerebellar artery (PICA)
• Anterior inferior cerebellar artery (AICA)
• Superior cerebellar artery

Correct Answer: Posterior inferior cerebellar artery (PICA)

Q13. The hypoglossal nucleus located in the medulla controls which muscle group?

• Extraocular muscles
• Tongue muscles
• Facial expression muscles
• Pharyngeal constrictors

Correct Answer: Tongue muscles

Q14. A lesion of the medial medulla (anterior spinal artery infarct) typically produces which triad?

• Contralateral loss of pain and temperature, ipsilateral facial numbness, ataxia
• Contralateral hemiparesis, contralateral loss of proprioception, ipsilateral hypoglossal dysfunction
• Ipsilateral facial paralysis, hearing loss, vertigo
• Memory loss, behavioral changes, aphasia

Correct Answer: Contralateral hemiparesis, contralateral loss of proprioception, ipsilateral hypoglossal dysfunction

Q15. Which medullary nucleus receives visceral sensory information from the carotid sinus and aortic arch?

• Inferior olivary nucleus
• Nucleus tractus solitarius (NTS)
• Hypoglossal nucleus
• Accessory nucleus

Correct Answer: Nucleus tractus solitarius (NTS)

Q16. Which reflex is mediated by medullary centers and involves afferents from glossopharyngeal nerve and efferents via vagus nerve?

• Pupillary light reflex
• Gag reflex
• Knee-jerk reflex
• Corneal blink reflex

Correct Answer: Gag reflex

Q17. The inferior olivary nucleus in the medulla is primarily involved in which function?

• Auditory processing
• Motor learning through connections with the cerebellum
• Visual association
• Olfactory relay

Correct Answer: Motor learning through connections with the cerebellum

Q18. Which of the following drugs acts centrally on medullary α2-adrenoceptors to reduce sympathetic outflow and lower blood pressure?

• Propranolol
• Clonidine
• Amlodipine
• Hydralazine

Correct Answer: Clonidine

Q19. Central chemoreceptors that respond primarily to CO2-induced pH changes are located near which medullary area?

• Ventral surface of the medulla
• Cerebellar vermis
• Posterior limb of internal capsule
• Medial geniculate body

Correct Answer: Ventral surface of the medulla

Q20. Which medullary lesion symptom would most likely impair swallowing and gag reflex on the same side?

• Lesion of vestibular nuclei
• Lesion of nucleus ambiguus
• Lesion of dorsal column
• Lesion of occipital lobe

Correct Answer: Lesion of nucleus ambiguus

Q21. The nucleus solitarius projects to which hypothalamic or brainstem center to coordinate autonomic responses?

• Superior colliculus
• Ventrolateral medulla and hypothalamus
• Primary motor cortex
• Basal ganglia

Correct Answer: Ventrolateral medulla and hypothalamus

Q22. Which of the following reflexes is NOT primarily mediated by medullary centers?

• Cough reflex
• Swallowing reflex
• Respiratory rhythm generation
• Patellar (knee-jerk) reflex

Correct Answer: Patellar (knee-jerk) reflex

Q23. A drug that suppresses the medullary vomiting center but spares the chemoreceptor trigger zone would likely act on which receptor class centrally?

• Peripheral H1 receptors only
• Central muscarinic and histaminergic receptors
• Cardiac beta-1 receptors
• Renal angiotensin receptors

Correct Answer: Central muscarinic and histaminergic receptors

Q24. Which medullary structure gives rise to the majority of preganglionic parasympathetic fibers in the vagus nerve?

• Nucleus ambiguus
• Dorsal motor nucleus of vagus
• Nucleus of the solitary tract
• Inferior olivary nucleus

Correct Answer: Dorsal motor nucleus of vagus

Q25. The ventrolateral medulla is most directly involved in which cardiovascular function?

• Integration of visual inputs
• Generation of voluntary movement
• Control of sympathetic vasomotor tone and blood pressure
• Sensory perception of touch

Correct Answer: Control of sympathetic vasomotor tone and blood pressure

Q26. Which clinical sign suggests involvement of the hypoglossal nerve in a medullary lesion?

• Tongue deviation toward the side of the lesion
• Loss of hearing
• Vertical gaze palsy
• Facial droop sparing the forehead

Correct Answer: Tongue deviation toward the side of the lesion

Q27. In the context of medullary function, the chemoreceptor trigger zone is particularly sensitive to which circulating stimuli?

• Glucose levels only
• Toxins, drugs, and metabolic disturbances in the blood
• Visual motion
• Sensory touch stimuli

Correct Answer: Toxins, drugs, and metabolic disturbances in the blood

Q28. Which nucleus in the medulla is a major relay for proprioceptive information to the cerebellum?

• Inferior olivary nucleus
• Medial geniculate nucleus
• Sensory trigeminal nucleus only
• Subthalamic nucleus

Correct Answer: Inferior olivary nucleus

Q29. Loss of the dorsal respiratory group in the medulla would most likely impair which function?

• Initiation and modulation of inspiration
• Conscious control of limb movement
• Coordination of eye movements
• Olfactory sensing

Correct Answer: Initiation and modulation of inspiration

Q30. Which of the following best describes nucleus ambiguus contributions to autonomic function?

• Provides sympathetic preganglionic fibers to the heart
• Provides motor and parasympathetic fibers to heart and larynx via cranial nerves IX and X
• Is a sensory nucleus for taste from the anterior tongue
• Relays visual information to cortex

Correct Answer: Provides motor and parasympathetic fibers to heart and larynx via cranial nerves IX and X

Q31. Which pharmacological agent is most likely to produce central apnea by acting at medullary opioid receptors?

• Haloperidol
• Morphine
• Lisinopril
• Metformin

Correct Answer: Morphine

Q32. Which medullary pathway carries ascending sensory information about fine touch and proprioception to the thalamus after decussation?

• Spinothalamic tract
• Dorsal column–medial lemniscus pathway
• Reticulospinal tract
• Corticospinal tract

Correct Answer: Dorsal column–medial lemniscus pathway

Q33. A patient with a medullary lesion presents with hoarseness and difficulty swallowing; which cranial nerve involvement is most consistent with these symptoms?

• Olfactory nerve (I)
• Vagus nerve (X) via nucleus ambiguus
• Optic nerve (II)
• Trochlear nerve (IV)

Correct Answer: Vagus nerve (X) via nucleus ambiguus

Q34. Which statement best characterizes the role of the medulla in emesis (vomiting)?

• Medulla initiates vomiting via coordinated activation of respiratory, gastrointestinal and oropharyngeal muscles
• Medulla only senses taste and has no role in vomiting
• Medulla inhibits vomiting centers located in cortex
• Medulla is solely responsible for bile secretion

Correct Answer: Medulla initiates vomiting via coordinated activation of respiratory, gastrointestinal and oropharyngeal muscles

Q35. The baroreceptor reflex lowering heart rate involves medullary output through which neural pathway?

• Sympathetic preganglionic fibers from the medulla to adrenal medulla
• Vagal efferent parasympathetic output via the dorsal motor nucleus and nucleus ambiguus
• Direct motor cortex inhibition of sinoatrial node
• Somatic efferents via spinal nerves

Correct Answer: Vagal efferent parasympathetic output via the dorsal motor nucleus and nucleus ambiguus

Q36. Which medullary structure is most directly implicated when a drug causes nausea by stimulating the chemoreceptor trigger zone?

• Area postrema
• Substantia nigra
• Primary somatosensory cortex
• Pineal gland

Correct Answer: Area postrema

Q37. Which of the following best explains why medullary strokes can be rapidly life-threatening?

• Medulla contains centers vital for respiration and cardiovascular regulation
• Medulla is responsible for long-term memory consolidation
• Medullary strokes exclusively affect only sensory perception
• Medulla controls limb growth and regeneration

Correct Answer: Medulla contains centers vital for respiration and cardiovascular regulation

Q38. Which reflex mediated in the medulla protects the airway by forcefully expelling irritants?

• Patellar reflex
• Cough reflex
• Pupillary light reflex
• Gag reflex only

Correct Answer: Cough reflex

Q39. The dorsal columns terminate in nuclei in the medulla before decussating as the medial lemniscus; which sensory modalities are transmitted by these pathways?

• Pain and temperature
• Fine touch and proprioception
• Auditory and visual
• Olfactory and gustatory

Correct Answer: Fine touch and proprioception

Q40. Which medullary lesion would most likely present with ipsilateral loss of facial pain and temperature, dysphagia, and contralateral loss of body pain and temperature?

• Medial medullary infarct due to ASA
• Lateral medullary (Wallenberg) infarct due to PICA
• Midbrain tectal lesion
• Superior cerebellar peduncle lesion

Correct Answer: Lateral medullary (Wallenberg) infarct due to PICA

Q41. The medulla contributes to which component of the autonomic nervous system during vomiting?

• Activation of sympathetic outflow exclusively
• Coordination of parasympathetic and motor outputs for retching and expulsion
• Inhibition of all digestive secretions only
• Exclusive control of gallbladder contraction

Correct Answer: Coordination of parasympathetic and motor outputs for retching and expulsion

Q42. Which cranial nerve motor nucleus located in the medulla innervates muscles of the larynx and pharynx important for speech and swallowing?

• Trigeminal motor nucleus
• Nucleus ambiguus
• Facial nucleus
• Oculomotor nucleus

Correct Answer: Nucleus ambiguus

Q43. Which clinical test assesses integrity of medullary-mediated gag reflex?

• Finger-to-nose test
• Oropharyngeal stimulation with observation of gag or swallow
• Pupillary light reflex
• Romberg test

Correct Answer: Oropharyngeal stimulation with observation of gag or swallow

Q44. In anesthesia practice, which central effect on the medulla is most concerning and must be monitored closely?

• Enhanced taste sensation
• Depression of respiratory center leading to hypoventilation
• Improved memory consolidation
• Increased skeletal muscle tone only

Correct Answer: Depression of respiratory center leading to hypoventilation

Q45. Which nucleus in the medulla processes visceral sensory information including taste from the epiglottis and posterior tongue?

• Nucleus ambiguus
• Nucleus tractus solitarius
• Hypoglossal nucleus
• Superior salivatory nucleus

Correct Answer: Nucleus tractus solitarius

Q46. The reticular formation in the medulla contributes to which of the following functions relevant to pharmacology?

• Modulation of arousal, pain, autonomic responses and drug-induced sedation
• Only local reflex arcs in the knee
• Production of cerebrospinal fluid
• Processing of visual images

Correct Answer: Modulation of arousal, pain, autonomic responses and drug-induced sedation

Q47. A lesion that damages the decussating corticospinal fibers at the caudal medulla would cause what deficit?

• Ipsilateral facial numbness only
• Bilateral loss of smell
• Contralateral weakness of the body due to interruption of fibers after decussation
• Loss of auditory reflexes

Correct Answer: Contralateral weakness of the body due to interruption of fibers after decussation

Q48. Which medullary nucleus is a major target for drugs that modulate vomiting by blocking dopamine receptors?

• Inferior olivary nucleus
• Area postrema / chemoreceptor trigger zone
• Vestibular nuclei only
• Hypothalamic suprachiasmatic nucleus

Correct Answer: Area postrema / chemoreceptor trigger zone

Q49. Which symptom would suggest involvement of medullary sympathetic pathways controlling pupil size?

• Miosis, ptosis and anhidrosis (Horner’s syndrome)
• Bilateral pupillary dilation only
• Loss of corneal reflex only
• Enhanced salivation without ocular signs

Correct Answer: Miosis, ptosis and anhidrosis (Horner’s syndrome)

Q50. In the context of drug development, why is understanding medullary nuclei important for B. Pharm students?

• Medullary nuclei are irrelevant to systemic drug effects
• They mediate vital autonomic, respiratory and emetic responses that influence drug safety and therapeutic targets
• They only affect hair growth and skin pigmentation
• They are exclusively involved in long-term potentiation and memory consolidation

Correct Answer: They mediate vital autonomic, respiratory and emetic responses that influence drug safety and therapeutic targets

G S Sachin

I am a Registered Pharmacist under the Pharmacy Act, 1948, and the founder of PharmacyFreak.com. I hold a Bachelor of Pharmacy degree from Rungta College of Pharmaceutical Science and Research. With a strong academic foundation and practical knowledge, I am committed to providing accurate, easy-to-understand content to support pharmacy students and professionals. My aim is to make complex pharmaceutical concepts accessible and useful for real-world application.

Mail- Sachin@pharmacyfreak.com