1. Homeostasis. Functional systems of the body. Control systems of the body.
Negative and positive feedback.
Homeostasis. Functional systems of the body.
The term homeostasis is the maintenance of nearly constant conditions in the internal
environment.
● Extracellular fluid is transported throughout the body in two stages. The first
stage is movement of blood around the circulatory system, and the second stage
is movement of fluid between the blood capillaries and cells.
○ The circulatory system keeps the fluids of the internal environment
continuously mixed by pumping blood through the vascular system.
○ As blood passes through the capillaries, a large portion of its fluid diffuses
back and forth into the interstitial fluid that lies between the cells, allowing
continuous exchange of substances between the cells and the interstitial
fluid and between the interstitial fluid and the blood.
● The gastrointestinal system digests food and absorbs various nutrients, including
carbohydrates, fatty acids, and amino acids, into the extracellular fluid.
● The liver changes the chemical composition of many of the absorbed substances
to more usable forms, and other tissues of the body help modify the absorbed
substances or store them until they are needed. The liver eliminates certain
waste products produced in the body as well as toxic substances that are
ingested.
● The musculoskeletal system consists of skeletal muscles, bones, tendons, joints,
cartilage, and ligaments. This system also provides protection of internal organs
and support of the body.
● The respiratory system not only provides oxygen to the extracellular fluid but also
removes carbon dioxide, which is produced by the cells, released from the blood
into the alveoli, and then released to the external environment.
● The kidneys excrete most of the waste products other than carbon dioxide.
○ The kidneys play a major role in regulating the extracellular fluid
composition by controlling the excretion of salts, water, and waste
products of the chemical reactions of the cells. By controlling body fluid
volumes and compositions, the kidneys also regulate blood volume and
blood pressure.
Regulation of body functions.
Negative and positive feedback.
Homeostasis. Functional systems of the body.
The term homeostasis is the maintenance of nearly constant conditions in the internal
environment.
● Extracellular fluid is transported throughout the body in two stages. The first
stage is movement of blood around the circulatory system, and the second stage
is movement of fluid between the blood capillaries and cells.
○ The circulatory system keeps the fluids of the internal environment
continuously mixed by pumping blood through the vascular system.
○ As blood passes through the capillaries, a large portion of its fluid diffuses
back and forth into the interstitial fluid that lies between the cells, allowing
continuous exchange of substances between the cells and the interstitial
fluid and between the interstitial fluid and the blood.
● The gastrointestinal system digests food and absorbs various nutrients, including
carbohydrates, fatty acids, and amino acids, into the extracellular fluid.
● The liver changes the chemical composition of many of the absorbed substances
to more usable forms, and other tissues of the body help modify the absorbed
substances or store them until they are needed. The liver eliminates certain
waste products produced in the body as well as toxic substances that are
ingested.
● The musculoskeletal system consists of skeletal muscles, bones, tendons, joints,
cartilage, and ligaments. This system also provides protection of internal organs
and support of the body.
● The respiratory system not only provides oxygen to the extracellular fluid but also
removes carbon dioxide, which is produced by the cells, released from the blood
into the alveoli, and then released to the external environment.
● The kidneys excrete most of the waste products other than carbon dioxide.
○ The kidneys play a major role in regulating the extracellular fluid
composition by controlling the excretion of salts, water, and waste
products of the chemical reactions of the cells. By controlling body fluid
volumes and compositions, the kidneys also regulate blood volume and
blood pressure.
Regulation of body functions.
