Question

An athlete is running a marathon on a hot, dry day. Which of the following physiological responses would be most likely to occur in the athlete’s body by the end of the race?
A. The athlete would produce dilute urine
B. The athlete would have decreased blood osmolarity
C. The athlete would have increased levels of antidiuretic hormone
D. The athlete would secrete less epinephrine
E. The athlete would have an increase in the amount of urine produced

Answer 1

An athlete will experience loss of water on a hot day due to continuous sweating in a marathon in order to regulate the temperature of the body. This will make the athlete feel thirsty due to loss of water from the body through perspiration. A hormone released from the pituitary gland is very much important to maintain the osmolarity of the body.

Complete answer: The runner can suffer from dehydration if he is running a marathon on a hot dry day. Dehydration refers to a condition in which there is excessive water loss from the body. As a result of which, the pituitary gland neurohypophysis secretes ADH or antidiuretic hormone. This hormone released is generally seen when the hypothalamus osmoreceptors sense an increase in the blood osmolarity. Osmoreceptor cells also encourage thirst in this case. Water reabsorption in the distal convoluted tubule and collecting duct is also increased. The human kidney has a reddish-brown colour and is positioned on the right and left in the retroperitoneal space. Kidneys are made up of the kidney's smallest structural and functional unit, the nephron. The kidney consists of two parts, called the medulla, and the urine output in the human body is the responsibility of the nephron cortex.
Hence, option C is the correct answer.

Note: Water and wastes not reabsorbed by renal tubules are generated in the urine. The dysfunction of the renal tubule makes the body to not absorb glucose and is therefore present in the urine. This condition is known as diabetes mellitus.