Jacob is 45 years old and a keen cyclist. Every day he cycles to and from work about 25 km each way. For the past two weeks ambient temperature has exceeded 27°C, yet he kept cycling and one hot and sunny day he suddenly had an intense pain in his lower left side that radiated around his lower back. Upon arriving at the emergency room, the intensity of the pain was making him feel nauseous, and he was having problems sitting comfortably. Blood and urine samples were taken. His urine sample had a pinkish hue and upon analysis was found to have an osmolality of 1200 mOsm/l and contained small calcium oxalate crystals. Doctors suspected kidney stones as the source of the pain and ordered an abdominal CT. The diagnosis of kidney stones was confirmed as the CT scan showed a few stones of varying size in his left kidney. Jacob confirmed that he had a prolonged period of continuous exercise in very hot conditions and probably was not drinking enough water for proper hydration. He was given medication to help with the pain and instructed to drink lots of water to help pass the stones. Answer the following questions:
1. Explain the reason and mechanisms of increased osmolality of his urine.
2. What is the possible reason of his kidney stones formation?
3. How drinking the water would improve Jacob’s condition?

organ system-an organ system is a group of organs that work together to perform one or more functions. each does a particular job in the body, and is made up of certain tissues.

an individual’s sex (i.e., whether they are a male or female) is determined by the sex chromosomes. most people have two sex chromosomes, one that is inherited from their mother and one that is inherited from their father. typically, females have two x chromosomes (xx) and males have one x chromosome and one y chromosome (xy). conditions caused by changes (“mutations”) in genes located on the x chromosome are considered x-linked.

x-linked recessive inheritance

most x-linked conditions are recessive. this means that in a person with two x chromosomes (most females), both copies of a gene (i.e., one on each x chromosome) must have a change or mutation whereas in a person with one x chromosome (most males), only one copy of a gene must have a mutation. a female with a mutation in one copy of a gene on the x chromosome is said to be a “carrier” for an x-linked condition. a male with a mutation in a gene on the x chromosome is typically affected with the condition. because females have two copies of the x chromosome and males have only one x chromosome, x-linked recessive diseases are more common among males than females. however, x-linked recessive diseases can occur in both males and females.

for x-linked recessive disorders, an unaffected carrier mother who has a mutation in a gene on the x chromosome can transmit either the x chromosome with this mutation or a “normal” x chromosome to her children. if the father is unaffected, none of her daughters will be affected and all of her daughters will be unaffected—since they will inherit at least one normal x chromosome from their father. however, each daughter will have a 50% chance of being an unaffected carrier like her mother and a 50% chance of both x chromosomes being normal.

1. is geographic distribution

2 is increasing complexity

3 is transitional forms