Q.Indicate whether the following statements are true or false:

Each statement judged against how the excretory system actually works:

• (a) True. Passing urine is brought about by the micturition reflex, a co-ordinated set of nerve signals triggered when the stretched bladder wall is detected.
• (b) False. Antidiuretic hormone promotes the reabsorption of water from the later parts of the tubule, so it prevents water loss and helps concentrate the urine rather than making it dilute.
• (c) True. During filtration almost the whole of the plasma passes into Bowman's capsule while the plasma proteins are held back, so the fluid entering is essentially protein-free.
• (d) True. Henle's loop helps build the high medullary osmolarity that lets the kidney concentrate the urine.
• (e) True. Glucose is one of the substances reabsorbed actively in the proximal convoluted tubule.

Working through each statement in turn shows why it is right or wrong.

1. Micturition is carried out by a reflex — True. The release of urine is not a purely willed act; it is set off by a reflex. When urine collects and stretches the bladder wall, stretch receptors send signals to the central nervous system, which sends motor messages back that make the bladder muscle contract and the urethral sphincter relax. This co-ordinated set of signals is the micturition reflex, so the act is indeed carried out by a reflex.
2. ADH helps in water elimination, making the urine hypotonic — False. This is the reverse of what antidiuretic hormone does. The hormone promotes the reabsorption of water from the later parts of the tubule, which prevents excessive loss of water as urine. By pulling water back into the body it conserves water and concentrates the urine, rather than eliminating water or making the urine dilute.
3. Protein-free fluid is filtered from blood plasma into Bowman's capsule — True. The glomerular membranes filter so finely that almost every component of the plasma passes into the lumen of Bowman's capsule, with the notable exception of the plasma proteins, which are held back. The fluid that enters is therefore effectively free of protein.
4. Henle's loop plays an important role in concentrating the urine — True. The loop is central to building and maintaining the high osmolarity of the medullary interstitial fluid. This steep concentration gradient is exactly what lets water leave the collecting duct later, so the loop is essential to producing concentrated urine.
5. Glucose is actively reabsorbed in the proximal convoluted tubule — True. Substances such as glucose, amino acids and sodium ions are reabsorbed actively, and the proximal convoluted tubule, with its brush border, is the chief site of this recovery.
   ✓Final answer

   In short, (a) True,

   (b) False,

   (c) True,

   (d) True and (e) True — only the claim that antidiuretic hormone dilutes the urine is wrong.

Method: Evaluating a Set of True/False Statements in Physiology

True/False questions with multiple independent statements test whether you can isolate a single factual claim inside each sentence and check it against what you actually know, rather than reacting to how confident the sentence sounds.

Steps

Step 1: Isolate the exact claim in each statement

Read each statement as a standalone factual claim — strip away connecting words and identify the one relationship being asserted (e.g. "ADH helps in water elimination, making urine hypotonic" is really asserting two linked things: what ADH does to water, and what that does to urine concentration).

Step 2: Recall the correct fact independently, before comparing

Before judging the statement, silently state what you know to be true about that structure, hormone or process. This stops you being misled by a statement that "sounds textbook-like" but reverses cause and effect.

Step 3: Check specifically for reversed direction or reversed terminology

A large share of False statements in this topic work by flipping a direction: a hormone said to do the opposite of what it does, a limb of Henle's loop assigned the wrong permeability, "hypotonic" swapped for "hypertonic." Always check whether the statement's DIRECTION matches the real physiology, not just whether the named structure or hormone is correct.

Step 4: Mark True or False and give the one-line correction for any False

For a True statement, a brief confirming reason is enough. For a False one, state the correct relationship in its place — this proves you didn't just guess, and it is what the mark scheme rewards for a "give reasons" variant of this question type.

Applying to this problem: four of the five statements align with known kidney physiology (the micturition reflex, protein-free filtrate, Henle's loop concentrating urine, active glucose reabsorption in the proximal tubule), while the ADH statement reverses ADH's real action — ADH promotes water reabsorption, producing a concentrated (hypertonic), not hypotonic, urine.