UPSC-CMS 2016 - Physiology PYQs Practice Questions

Q: Regarding haemorrhagic shock, which one of the following statements is correct?

Loss of 40% of circulating volume is life threatening. ***Loss of 40% of circulating volume is life threatening*** - A loss of **40% or more** of circulating blood volume corresponds to **Class IV haemorrhagic shock**, which is a severe, life-threatening condition requiring immediate and aggressive resuscitation. - At this stage, the body's compensatory mechanisms are overwhelmed, leading to profound systemic hypoperfusion, **organ dysfunction**, and a high risk of mortality. *Tachycardia presents in 100% of hypovolemic patients* - While **tachycardia** is a common compensatory mechanism in hypovolemia, it is not present in 100% of patients due to factors such as **beta-blocker use** or **pacemaker rhythm**. - In some early stages of blood loss, especially in young, healthy individuals, sufficient compensatory mechanisms may delay the onset of significant tachycardia. *Clinically manifested when > 10% of loss of total blood volume occurs* - Haemorrhagic shock is typically **clinically manifest** when there is a blood loss greater than **15%** (Class I shock), which represents approximately 750 mL in an average adult. - A loss of **less than 10%** often does not produce overt clinical signs as the body's compensatory mechanisms can effectively maintain vital signs within normal ranges. *In acute stage of shock, systemic vasodilation becomes evident* - In the acute stage of hemorrhagic shock, the body's primary compensatory mechanism is **systemic vasoconstriction**, not vasodilation, to maintain central blood pressure and perfuse vital organs. - **Vasodilation** can occur in the later, decompensated stages of shock, particularly in instances of **septic or neurogenic shock**, leading to a further drop in blood pressure. [Practice more Physiology PYQs on OnCourse]

Q: The immunoglobulins that can be transported across the placenta include:

IgG only. ***IgG only*** - **IgG** is the only class of immunoglobulin that can actively be transported across the **placental barrier** from mother to fetus, providing passive immunity. - This transport is mediated by specialized receptors (FcRn) on placental cells, ensuring the fetus receives protection against pathogens. *IgA only* - **IgA** is primarily found in **mucosal secretions** (e.g., breast milk, tears, saliva) and plays a crucial role in mucosal immunity. - It does not significantly cross the placenta and therefore does not contribute to fetal immunity in utero. *Neither IgG nor IgA* - This statement is incorrect because **IgG** is well-established as being transported across the placenta. - Such an absence of maternal antibodies would leave the fetus highly vulnerable to infections during development and early life. *Both IgG and IgA* - While **IgG** readily crosses the placenta, **IgA** does not, making this option incorrect. - The primary route for IgA transfer to the infant is through **breast milk** after birth, providing crucial immunity for the newborn's gastrointestinal tract. [Practice more Physiology PYQs on OnCourse]

Question 1

Regarding haemorrhagic shock, which one of the following statements is correct?

Accepted Answer

Loss of 40% of circulating volume is life threatening

Answer

Tachycardia presents in 100% of hypovolemic patients

Answer

Clinically manifested when > 10% of loss of total blood volume occurs

Answer

In acute stage of shock, systemic vasodilation becomes evident

Question 2

The immunoglobulins that can be transported across the placenta include:

Accepted Answer

IgG only

Answer

IgA only

Answer

Neither IgG nor IgA

Answer

Both IgG and IgA

UPSC-CMS 2016 — Physiology