Many body systems work together for proper functioning of the body and to maintain internal homeostasis. the (circulatory, digestive, excretory) works to break down food eaten before exercising. the (circulatory, digestive, excretory) takes in the nutrients obtained from the food. the body sweats as a mechanism to cool off, because the (circulatory, digestive, excretory) is working to flush out toxins.

The digestive works to break down food eaten before exercising. The digestive system is responsible for the process of digestion, which involves the breaking down of the consumed food into smaller parts which can be absorbed by the body. This system is comprised of the gastrointestinal tract and several organs participating in digestion, which are the tongue, salivary glands, pancreas, liver, and gallbladder. The circulatory takes in the nutrients obtained from the food. The circulatory system (also known as cardiovascular system) is responsible for circulating blood through the body and transporting nutrients and many other chemicals. The heart and the lungs are two critical components of this system since blood flows through the lungs and oxygenates. This oxygenated blood is pumped through the heart to the rest of the body. The body sweats as a mechanism to cool off, because the excretory is working to flush out toxins. The excretory system is responsible for removing excess and unnecessary materials from the body fluids of an organism. The main organ system involved in this system is urinary system, however, excretion is also achieved through breathing and sweating.

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.