Physiology Important Questions For NEET PG/FMGE

Q1. A patient’s blood glucose level in a steady-state condition before a heavy lunch was 90 mg/dL. After lunch, the blood glucose level increased to 180 mg/dL. Insulin secretion from the pancreas reduced the blood glucose level to 120 mg/dL. Calculate the gain of the glucose regulatory mechanism.

1. +2
2. -2
3. +3
4. -3

Answer: 2) -2

Explanation:

Correction achieved by the insulin secretion is: (180 mg/dL - 120 mg/dL = 60 mg/dL)

Error compared to the initial state is: (120 mg/dL - 90 mg/dL = 30 mg/dL)

Gain  = Correction Achieved / Error Remaining

Substituting the values:
Gain  = 60 mg/dL / 30 mg/dL = 2

Since the gain is negative in the context of this glucose regulatory mechanism (because an increase in blood glucose results in a decrease in gain),

Gain  = -2

The degree to which a control system maintains constant conditions is determined by the gain of negative feedback.

Also read: Chemical Regulation of Respiration: Role of Chemoreceptors and Reflexes

Q2. Which of the following statements accurately describes the type, direction, and mediators of axonal transport?

1	Anterograde	Cell body to axon terminal	Dynein
2	Anterograde	Axon terminal to cell body	Kinesin
3	Retrograde	Axon terminal to cell body	Dynein
4	Retrograde	Cell body to axon terminal	Kinesin

1. 1
2. 2
3. 3
4. 4

Answer: 3) 3 

Explanation:

Axonal transport:

• It is a process in neurons which involves the transport of organelles, proteins and other cellular material along the axon
• It can be abolished by colchicine, dinitrophenol, azide, cyanide and prolonged anoxia

Type	Mediated by	Characteristics
Anterograde transport	Kinesin	- It involves the transport of cellular material from the soma to the axon terminal.  - It is responsible for the transport of proteins and synaptic vesicles necessary for synaptic transmission. Two types: - Fast axoplasmic transport at a rate of 400 mm/day, mediated by kinesin. - Slow axoplasmic transport at a rate of 0.5-2 mm/day, mediated by actin, neurofilaments, and microtubules. Supplies material required for regeneration following nerve injury.
Retrograde transport	Dynein	- It involves the transport from axon terminals to soma at a rate of about 200 mm/day. - It is important for the transport of viruses, toxins, nerve growth factors, and reuptake of synaptic neurotransmitters.

Q3. Which of the following combinations of features are characteristic of smooth muscle tissue?

1. Z-line and troponin present
2. Caveolae and T-Tubule present 
3. Calmodulin and titin present
4. Voltage-gated calcium channels and calmodulin present

Answer: 4) Voltage-gated calcium channels and calmodulin present

Explanation: Voltage-gated calcium channels and calmodulin are characteristics of smooth muscles, whereas  Z-line, troponin, and titin are features of skeletal muscle.

Also read: Cell Physiology: Overview of Membrane, Cytoskeleton 

Q4. Which of the following structures is repolarization?

1. Apical epicardial surface
2. Posterobasal portion of the left ventricle
3. Pulmonary conus
4. Endocardial surface

Answer: 4) Endocardial surface

Explanation:

Repolarization of ventricular muscle starts from the epicardial surface and ends in the endocardial surface.

Depolarization	Repolarization
Atrial depolarization starts at the SA node	Atrial repolarization starts near the SA node
Starts from the middle portion ofthe septum on the left side	Starts from the apex of the heart,
Ventricular depolarization:- Starts at the left side of the interventricular septum- Crosses to the right side through the interventricular septum- Spreads down to the apex of the heart	Ventricular repolarization occurs in the reverse direction
- The endocardial surface depolarizes first and the epicardial last	- The epicardial surface repolarizes first and the endocardial last.
Depolarized last:- Posterobasal portion of the left ventricle- Pulmonary conus- The uppermost portion of the septum	Repolarized last:- Septum- Endocardial surface

Q5. A patient undergoing PCI for myocardial infarction suddenly develops bradycardia, hypotension, and episodes of apnoea. Which of the following reflexes is most likely mediated by chemosensitive vagal C fibers in the cardiopulmonary region?

1. Cushing reflex
2. Bainbridge reflex
3. Bezold-Jarisch reflex
4. Baroreceptor reflex

Answer: 3) Bezold-Jarisch reflex

Explanation: 

Myocardial ischemia and reperfusion activate chemosensitive vagal C fibers in the cardiopulmonary region, causing the Bezold-Jarisch reflex, leading to profound bradycardia, hypotension, and a brief period of apnea followed by rapid, shallow breathing. 

Bezold-Jarisch reflex or coronary chemoreflex: 

• Activators: capsaicin, serotonin, phenylbiguanide, veratridine, and pathophysiologic conditions like reperfusion after myocardial ischemia ( increased production of oxygen radicals and agents used as radio contrast for coronary angiography).
• Mechanism: Activation of chemosensitive vagal C fibers (Option 3) in the cardiopulmonary region (juxtacapillary region of alveoli, ventricles, atria, great veins, and pulmonary artery). 
• Causing bradycardia, hypotension, and a brief apnea period followed by rapid shallow breathing. 

Q6. Which of the following statements best describes the Burst Forming Unit-Erythroid (BFU-E) in the process of erythropoiesis?

1. It is a mature red blood cell that participates in oxygen transport
2. It is a type of stem cell that can differentiate into any blood cell type
3. It is an early progenitor cell in erythropoiesis that gives rise to CFU-E
4. It is a precursor cell in erythropoiesis that directly produces reticulocytes

Answer: 3) It is an early progenitor cell in erythropoiesis that gives rise to CFU-E

Also read: Biostatistics Multiple-Choice Questions for Health Sciences 

Q7. A 40-year-old man presents with muscle weakness, bone pain, and polyuria. Lab tests show a normal anion gap metabolic acidosis, hypophosphatemia, hypokalemia, and glycosuria despite normal blood glucose levels. His urine pH is less than 5.5. Which of the following conditions is most likely responsible for his symptoms?

1. Distal Renal Tubular Acidosis (Type 1)
2. Proximal Renal Tubular Acidosis (Type 2)
3. Hyperkalemic Renal Tubular Acidosis (Type 4)
4. Chronic Kidney Disease (CKD)

Answer: 2) Proximal Renal Tubular Acidosis (Type 2)

Explanation:

Proximal RTA results from a defect in bicarbonate reabsorption in the proximal tubule. The patient’s symptoms and laboratory findings match those of proximal RTA, making it the most likely diagnosis.

Q8. A 58-year-old patient with chronic renal failure presents with symptoms of fatigue, fluid retention, and elevated serum potassium levels. On examination, the patient shows signs of hypertension and oedema. Which of the following types of cells being defective in the renal tubules is responsible for the following condition?

1. Principal Cells
2. Alpha Intercalated Cells
3. Beta-intercalated cells
4. Juxtaglomerular Cells

Answer: 1) Principal Cells

Explanation: 

Principal Cells

Functions

• Sodium reabsorption
• Potassium secretion
• Water reabsorption

Characteristics

• Responsive to aldosterone
• ADH receptors
• Columnar epithelium

Also read: Neural Regulation of Respiration: Control & Mechanisms

Q9. Which of the following is considered the primary pacemaker for respiration in the brainstem?

1. Rostral Ventral Respiratory Group (VRG)
2. Botzinger Complex
3. Pre-Bötzinger Complex
4. Caudal Ventral Respiratory Group (VRG)

Answer: 3) Pre-Bötzinger Complex

Explanation:

The ventricular respiratory group consists of 4 clear zones.

Zones	Location	Function
Pre-Bötzinger Complex	Ventrolateral medulla	A primary pacemaker for respiration generates the basic rhythmic pattern of breathing.
Bötzinger Complex	Medulla oblongata, dorsal	Modulates respiratory rhythm; involved in expiratory phase regulation and inhibition of inspiration.
Rostral Ventral Respiratory Group (VRG)	Medulla oblongata, rostral	It contributes to rhythm generation and integrates respiratory signals; it is involved in the inspiratory and expiratory phases.
Caudal Ventral Respiratory Group (VRG)	Medulla oblongata, caudal	Primarily involved in controlling the expiratory phase of respiration.

Q10. Which of the following statements is true?

1. Stagnant hypoxia is where tissues cannot utilize O2 despite a normal supply
2. Heart failure causes histotoxic hypoxia
3. Stagnant hypoxia is due to the inhibition of tissue oxidative processes
4. Arteriovenous oxygen difference increases in stagnant hypoxia

Answer: 4) Arteriovenous oxygen difference increases in stagnant hypoxia

Explanation: The arteriovenous oxygen difference will increase in stagnant hypoxia because the tissue will keep extracting more and more oxygen from the same blood, leading to a low oxygen level in the venous blood.

Also read: Hyponatremia: Classification, Signs & Symptoms

Q11. A biopsy from a segment of the respiratory tree reveals pseudostratified ciliated columnar epithelium with goblet cells. From which part of the respiratory tract was this sample most likely taken?

1. Alveoli
2. Terminal bronchioles
3. Trachea
4. Respiratory bronchioles

Answer: 3) Trachea
Explanation:
The epithelial lining of the trachea and large bronchi are composed of pseudostratified ciliated columnar epithelium.

Q12. A 52-year-old patient presents with symptoms of indigestion and steatorrhea. Laboratory tests suggest decreased bicarbonate secretion from the pancreas. Which gastrointestinal hormone is most likely deficient in this patient?

1. Cholecystokinin 
2. Gastrin 
3. Secretin 
4. Motilin 

Answer: 3) Secretin

Explanation: 

• Secretin is released from the S cells in response to acid and fat in the duodenum and is responsible for bicarbonate secretion in the GIT.
• Functions:
  • Pepsin secretion helps in protein digestion (patient is suffering from indigestion because of deficiency of this function)
  • Pancreatic and biliary bicarbonate secretion neutralizes the acid in the duodenum 
  • Stimulates hepatic ductal secretion 
  • Growth of exocrine pancreas 
  • Inhibition of gastrin release and direct gastric acid secretion 
  • It also inhibits gastric emptying and small intestinal motility.

Q13. A patient presents to the clinic with difficulty feeling the precise location of a stimulus on their skin and reports problems distinguishing between different textures and shapes. Additionally, they are having trouble detecting rapid changes in vibrations. Which of the following somatosensory pathways is most likely affected in this patient, given their symptoms?

1. Dorsal Column-Medial Lemniscal System
2. Lateral Spinothalamic Tract
3. Anterior Spinothalamic Tract
4. Corticospinal Tract

Answer: 1) Dorsal Column-Medial Lemniscal System

Explanation:

The Dorsal Column-Medial Lemniscal System handles precise touch localization, texture, vibration, and proprioception. The patient’s difficulty with these sensations suggests an issue with this system.

Somatosensory pathways:

• Two primary somatosensory pathways that transmit sensory signals from the body to the brain are the dorsal column-medial lemniscal system and the anterolateral system.

Also read: Hypernatremia: Causes, Pathophysiology

Q14. Match the following EEG wave types with their respective frequency ranges and associated activities.

Type of Wave	Frequency Range (Hz)	Activity During
1) Beta	A) 8-13	i) Deep sleep
2) Alpha	B) 14-30	ii) Relaxation, eyes closed
3) Theta	C) 2-4	iii) Alert and active thinking
4) Delta	D) 5-7	iv) Light sleep, emotional stress in adults

1. 1 - B - iii, 2 - A - ii, 3 - D - iv, 4 - C - i

1. 1 - C - i, 2 - B - iii, 3 - A - ii, 4 - D - iv
2. 1 - B - iii, 2 - D - iv, 3 - A - ii, 4 - C - i
3. 1 - A - ii, 2 - C - i, 3 - D - iv, 4 - B - iii

Answer: 1) 1 - B - iii, 2 - A - ii, 3 - D - iv, 4 - C - i

Explanation:

Type of Wave	Frequency Range (Hz)	Activity During
Beta	14-30	Alert and active thinking
Alpha	8-13	Relaxation, eyes closed
Theta	5-7	Light sleep, emotional stress in adults
Delta	2-4	Deep sleep

Q.15 A 63-year-old male presents with a neurodegenerative condition involving impaired glutamate regulation. Which type of glial cell is primarily involved in glutamate regulation?

1. Schwann cells
2. Astrocytes
3. Ependymal cells
4. Oligodendrocytes

Answer: 2) Astrocytes

Explanation: Astrocytes are glial cells that play an important role in regulating glutamate levels. They maintain glutamate levels by absorbing excess glutamate and preventing excitotoxicity.

Also read: NEET PG High Yield Questions for Physiology

Q.16 A 35-year-old woman presents with hypertension and hypokalemia. Genetic testing reveals a mutation in the genes coding for epithelial sodium channels (ENaCs). Which of the following conditions is most likely associated with her symptoms?

1. Conn syndrome
2. Liddle syndrome
3. Glucocorticoid-remediable aldosteronism (GRA)
4. Secondary hyperaldosteronism

Answer: 2) Liddle syndrome

Explanation:

The given clinical scenario is diagnosed as Liddle Syndrome.

Liddle Syndrome 

• Rare genetic disorder causing high blood pressure and low potassium levels.
• Caused by a mutation in genes coding for epithelial sodium channels (ENaCs) in kidneys.
• Leads to increased sodium reabsorption and potassium excretion.

Q.17 A 35-year-old male presents with symptoms of lethargy, hair loss, and cold intolerance. His lab results show elevated T4 levels but low T3 levels. Which of the following best explains the relationship between T4 and T3 in this patient?

1. T4 is the primary thyroid hormone and is converted to the more active T3 in peripheral tissues.
2. T3 has a longer half-life than T4, allowing it to maintain steady levels in the bloodstream.
3. Elevated T4 levels automatically indicate that T3 levels should also be elevated, due to their synchronous production.
4. T4 is biologically active, while T3 is inactive and serves primarily as a storage form of thyroid hormone.

Answer: 1) T4 is the primary thyroid hormone and is converted to the more active T3 in peripheral tissues.

Explanation:

T4 is the primary thyroid hormone secreted by the thyroid gland, and it is converted to the more active T3 in peripheral tissues.

Difference between T4 & T3
Aspect	T4	T3
Secretion	More (35% of total)	Less (7% of total)
Plasma conc.	8 mg/dL	0.15 mg/dL
Protein-bound	99.8%	99.8%
Free concentration in plasma	2 ng/dL	0.3 ng/dL
Half-life (t1/2) (Option B)	7 days	1 day
Action	Slower	Faster
Potency	Less	More (3-5 times)
Binding to thyroid hormone receptors	Low affinity	High affinity

Also read: Homeostasis: Definition, Mechanisms, and Importance

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