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: Cold water is not used for ear cleaning because

Caloric stimulation caused by cold water. ***Caloric stimulation caused by cold water*** - Irrigating the ear canal with **cold water** causes significant **caloric stimulation** of the vestibular system. - This can induce **vertigo**, **nausea**, and **vomiting** due to the temperature difference stimulating the semicircular canals. *Damage to tympanic membrane* - While excessive pressure from irrigation can potentially damage the **tympanic membrane**, the temperature of the water itself is not the primary factor for this risk. - Damage is more related to the **force of irrigation** and pre-existing membrane integrity, not cold temperature. *It will cause infection* - The temperature of the water used for irrigation does not directly determine the risk of infection. - **Infection risk** is primarily associated with using unsterile water or introducing bacteria into a compromised ear canal, regardless of water temperature. *It will make the wax hard* - Earwax, or **cerumen**, is softened by water irrigation, not hardened. - **Warm water** is typically preferred because it aids in softening the wax more effectively and comfortably than cold water. [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

Cold water is not used for ear cleaning because

Accepted Answer

Caloric stimulation caused by cold water

Answer

Damage to tympanic membrane

Answer

It will cause infection

Answer

It will make the wax hard

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

Cell that can form all cell types in the body is called?

Accepted Answer

Totipotent

Answer

Lineage stem cells

Answer

Multipotent

Answer

Pluripotent

Question 10

What is the best stimulus for release of vasopressin?

Accepted Answer

Hyperosmolality of extracellular fluid

Answer

Hypotension

Answer

Hypertension

Answer

Decreased plasma volume

FMGE 2018 — Physiology