Question

Which of the following represents the correct composition of sweat?
A) Water, salts, urea
B) Water, salt, calcium
C) Salt, calcium, phosphorous
D) Water, urea, calcium

Answer 1

Hint: Sweat is primarily composed of water. A microfluidic model of the eccrine sweat gland explains how solutes partition into a sweat, their partitioning mechanisms, and their fluidic transport to the skin surface. Sweat is a form of liquid containing mostly water. Sweating is also known as ‘Perspiration’, which is the production of fluids secreted by the sweat glands in the mammalian skin.

Complete answer:
Sweat is produced by the skin in the form of liquid to regulate body temperature. It is part of the excretory function of the skin and is important to maintain homeostasis. Sweat is primarily made up of water, but it also contains electrolytes that have an essential role in the body. Sodium and chloride are the most abundant electrolytes in sweat with potassium, magnesium, and calcium present in fewer amounts.

Sweat secretion by eccrine glands in the skin. Three genera of bacteria are key in producing scent- Staphylococcus, Corynebacterium and Propionibacterium. These bacteria metabolize sweat, a human byproduct, to produce a waste product, which has a distinct odour. Two types of glands-eccrine and apocrine which produce sweat.

As the evaporation of water makes the body cool. So, this is the main reason for perspiring and the main component of perspiration is water. Sweat is made up of several chemicals mainly consisting of water, minerals, urea, lactates.

Sweating allows the body to maintain a constant temperature. Sweating is controlled by a centre in the preoptic and anterior regions of the hypothalamus, which contains thermosensitive neurons. Inputs from temperature receptors in the skin also influence the hypothalamus's heat-regulation function. High skin temperature lowers the hypothalamic sweating and the gain of the hypothalamic feedback system in response to variations in core temperature.

Hence, the correct answer is Option (A) i.e, water, salts, urea.

Note: In humans, sweating is primarily a means of thermoregulation, which is achieved by the water-rich secretion of the eccrine glands. Sweat contributes to body odour when it is metabolized by bacteria on the skin.