FMGE 2018 - Physiology PYQs Practice Questions

Q: From which part of the gastrointestinal tract is glucose absorbed?

Duodenum and jejunum. ***Duodenum and jejunum*** - The **duodenum** and **jejunum** are the primary sites for nutrient absorption in the small intestine, including the majority of **glucose**. - Their large surface area, due to **villi** and **microvilli**, and abundant transport mechanisms facilitate efficient glucose uptake. *Stomach* - The stomach's primary role is **digestion**, particularly of proteins, with very little absorption of nutrients. - While some small, lipid-soluble substances like alcohol can be absorbed, significant **glucose absorption does not occur** here. *Ileum* - The **ileum** is mainly responsible for the absorption of **vitamin B12** and **bile salts**. - Although some remaining nutrients might be absorbed, the bulk of **glucose absorption** is completed in the upstream **duodenum and jejunum**. *Colon* - The **colon's** main functions are **water and electrolyte absorption** and the formation of feces. - It does not play a significant role in the absorption of **glucose** or other macro-nutrients. [Practice more Physiology PYQs on OnCourse]

Q: Cardiac event at the end of isometric relaxation phase:

Atrioventricular valves open. ***Atrioventricular valves open*** - This event marks the end of isometric relaxation, where ventricular pressure has dropped below atrial pressure, allowing the **mitral and tricuspid valves** to open and ventricular filling to begin. - During **isometric relaxation**, the ventricles relax without changing volume, causing a rapid drop in intraventricular pressure until it is overcome by atrial pressure. *Corresponds to T wave in ECG* - The **T wave** on an ECG represents **ventricular repolarization**, which occurs during the early part of ventricular diastole, *before* the end of isometric relaxation when the AV valves open. - The opening of AV valves occurs a bit later, as ventricular filling phase commences. *Atrioventricular valves close* - The closing of the **atrioventricular valves** (mitral and tricuspid) occurs at the beginning of **isovolumetric contraction (systole)**, not at the end of isometric relaxation (diastole). - This event marks the start of ventricular systole and is associated with the **first heart sound (S1)**. *Corresponds to peak of C wave in JVP* - The **C wave** in the jugular venous pressure (JVP) tracing corresponds to the bulging of the **tricuspid valve** into the right atrium during early ventricular systole, immediately after the AV valves close. - This event is distinct from the end of isometric relaxation, which occurs later in diastole, *before* atrial filling. [Practice more Physiology PYQs on OnCourse]

Q: Which of the following receptors mediate stretch reflex?

Muscle spindle. ***Muscle spindle*** - Muscle spindles are **stretch-sensitive receptors** located within the muscle belly that detect changes in muscle length and the rate of change in length. - When a muscle is stretched, the muscle spindles are activated, sending signals via **afferent neurons** to the spinal cord, which then initiates a reflex contraction of the same muscle to counteract the stretch—this is the basis of the stretch reflex. *Golgi tendon organ* - **Golgi tendon organs** are located in the tendons and respond to changes in **muscle tension**, not muscle length. Its primary role is to prevent excessive muscle contraction. - When activated by high tension, Golgi tendon organs inhibit the muscle, leading to relaxation (inverse stretch reflex), which is opposite to the stretch reflex. *Meissner's corpuscles* - **Meissner's corpuscles** are **mechanoreceptors** located in the superficial layers of the skin, primarily responsible for detecting **light touch** and **vibrations**. - They are not involved in the regulation of muscle length or tension and therefore do not mediate the stretch reflex. *Merkel's disc* - **Merkel's discs** are **mechanoreceptors** found in the basal layer of the epidermis, specialized for detecting **sustained pressure** and **texture**. - These receptors contribute to fine tactile discrimination but are unrelated to the proprioceptive mechanisms of the stretch reflex. [Practice more Physiology PYQs on OnCourse]

Q: A child with diarrhea has deep & rapid respiration. Most likely diagnosis is:

Metabolic acidosis. ***Metabolic acidosis*** - Diarrhea leads to a loss of **bicarbonate** from the gastrointestinal tract, causing a decrease in blood pH [1]. - **Deep and rapid respirations** (Kussmaul breathing) are a compensatory mechanism to blow off CO2 and raise the blood pH [1], [2]. *Respiratory acidosis* - This condition results from **hypoventilation**, leading to CO2 retention and a reduced pH [2]. - Deep and rapid breathing would actually improve respiratory acidosis by expelling CO2. *Metabolic alkalosis* - Characterized by an **excess of bicarbonate** and an elevated blood pH [3]. - Compensatory mechanisms would involve decreased respiration to retain CO2, not increased [3]. *Respiratory alkalosis* - This is caused by **hyperventilation**, which leads to excessive CO2 expulsion and an elevated pH [2]. - While hyperventilation causes deep and rapid breathing, it leads to alkalosis, not acidosis (which is indicated by compensatory breathing in this scenario). [Practice more Physiology PYQs on OnCourse]

Q: Inhibin is secreted by:

Sertoli cells. ***Sertoli cells*** - **Sertoli cells** are located in the seminiferous tubules of the testes and play a crucial role in spermatogenesis. - They secrete **inhibin**, a hormone that selectively inhibits the secretion of follicle-stimulating hormone (FSH) from the anterior pituitary gland. *Peg cells* - **Peg cells** (non-ciliated secretory cells) are found in the lining of the fallopian tubes, not the testes. - They produce **tubal fluid** which nourishes the ovum and spermatozoa, and aids in sperm capacitation. *Leydig cells* - **Leydig cells** are found in the interstitial tissue between the seminiferous tubules of the testes. - Their primary function is to produce and secrete **androgens**, such as testosterone, in response to luteinizing hormone (LH). *Interstitial cells* - This term is a general descriptor for cells located in the spaces between functional tissues or organs. - In the context of the testes, **Leydig cells** are the primary interstitial cells responsible for hormone production, while **Sertoli cells** are part of the seminiferous tubules. [Practice more Physiology PYQs on OnCourse]

Question 1

From which part of the gastrointestinal tract is glucose absorbed?

Accepted Answer

Duodenum and jejunum

Answer

Stomach

Answer

Colon

Answer

Ileum

Question 2

Cardiac event at the end of isometric relaxation phase:

Accepted Answer

Atrioventricular valves open

Answer

Corresponds to T wave in ECG

Answer

Atrioventricular valves close

Answer

Corresponds to peak of C wave in JVP

Question 3

Which of the following receptors mediate stretch reflex?

Accepted Answer

Muscle spindle

Answer

Golgi tendon organ

Answer

Meissner's corpuscles

Answer

Merkel's disc

Question 4

A child with diarrhea has deep & rapid respiration. Most likely diagnosis is:

Accepted Answer

Metabolic acidosis

Answer

Respiratory acidosis

Answer

Metabolic alkalosis

Answer

Respiratory alkalosis

Question 5

Inhibin is secreted by:

Accepted Answer

Sertoli cells

Answer

Peg cells

Answer

Leydig cells

Answer

Interstitial cells

Question 6

In which of the following conditions there is an increase in lung diffusion capacity?

Accepted Answer

Alveolar haemorrhage

Answer

Pulmonary oedema

Answer

Idiopathic pulmonary fibrosis

Answer

Emphysema

Question 7

Enteropeptidase enzyme is secreted by:

Accepted Answer

Duodenum

Answer

Ileum

Answer

Stomach

Answer

Jejunum

Question 8

Resting membrane potential of nerve fibre is close to isoelectric potential of:

Accepted Answer

Potassium ions

Answer

Sodium ions

Answer

Chloride ions

Answer

Magnesium ions

Question 9

What is the best stimulus for release of vasopressin?

Accepted Answer

Hyperosmolality of extracellular fluid

Answer

Hypotension

Answer

Hypertension

Answer

Decreased plasma volume

Question 10

Which of the following hormones regulates blood levels of 1,25-OH-cholecalciferol positively?

Accepted Answer

Parathormone

Answer

Thyroxine

Answer

Calcitonin

Answer

Insulin

FMGE 2018 — Physiology