Question

Read the given statements regarding the human excretory system and select the correct ones.
(i) Presence of glucose in the urine is known as uremia.
(ii) Distal convoluted tubule (DCT) selectively secretes hydrogen ions, ammonia, and potassium ions into the filtrate.
(iii) Macula densa formed by cellular modifications in the distal convoluted tubule and the afferent arteriole at their contact location.
(iv) Atrial natriuretic factor (ANF) can cause vasoconstriction when blood flow is low to the atria of the heart.
(a) (i) and (ii)
(b) (i) and (iii)
(c) (ii) and (iii)
(d) (iii) and (iv)

Answer 1

Glycosuria occurs as blood sugar (blood glucose) flows through the urine. The atrial natriuretic factor (ANF) is a 28 amino acid hormone secreted primarily in response to atrial stretch by the atria of the heart. The final two components of the kidney nephron are the distal convoluted tubule (DCT) and the collecting duct (CD). They have a significant role in consuming several ions, and in reabsorbing water. The juxtaglomerular apparatus is composed of juxtaglomerular cells, macula densa, and lacis cells.

Complete answer:
The nephron portion that lies directly downstream of the macula densa is the distal convoluted tubule. It plays a critical role in sodium, potassium, and divalent cation homeostasis, even though it is short in length. Potassium, hydrogen, ammonia, and bicarbonate ions are secreted in the DCT by active transport to the filtrate. The juxtaglomerular apparatus is a sensitive area that is formed at its contact location by cellular modifications in the DCT and afferent arteriole. Atrial natriuretic peptide (ANP) works intensely by at least 3 pathways to minimize plasma volume: increased salt and water excretion in the renal system, vasodilatation, and increased vascular permeability.
The macula densa is a set of specialised epithelial cells which detect the sodium concentration of the fluid in the distal convoluted tubule. The main cells within the kidney are Macula densa (MD) cells, which play important sensory and regulatory roles in the maintenance of body fluid, electrolyte homeostasis, and blood pressure.

So, the correct answer is, '(ii) and (iii)'.

Note:
The excretory system is the structure of the body of an organism performing the purpose of excretion, the bodily mechanism of waste discharge. This process includes many parts of the body, such as sweat glands, liver, lungs, and kidney system. The nephron is considered as the kidney's basic structural and functional unit. By filtering the blood, reabsorbing what is needed, and excreting the rest as urine, the nephron controls water and soluble substances.
Glycosuria is the term used for glucose in the urine.
Atrial natriuretic factor (ANF) can cause vasodilation when the flow of blood to the heart atria is high.