Homeostasis Key Words

Hi, I was emailed this list by a teacher in the South Island. If you know who made this please email me and I will add credits as it would have taken a long time!!


Neurotransmitter produced by an enzyme in the body that stimulates muscle tissue.


hormone produced by the adrenal medulla that causes vasodilation of the small arteries in muscle and increases cardiac output.


substance that has an effect similar to that of adrenaline.


substance that cancels or counteracts the action of another.


the smallest vessels of the body.

Central nervous system (CNS)

one of two major divisions of the nervous system. The CNS consists of the brain, the cranial nerves and the spinal cord.


substance that has an effect similar to that of acetylcholine.


heat transfer by means of molecular agitation within a material without any motion of the material as a whole. If one end of a metal piece is at a higher temperature, then heat will be transferred down the piece toward the colder end.


heat transfer by motion of a fluid when the heated fluid is caused to move away from the source of heat, carrying energy with it.


layer of connective tissue underlying the skin. Contains smooth muscle tissue, nervous tissue and blood vessels.

Endocrine glands

glands that secrete substances which are released directly into the bloodstream and that regulate metabolism and other body functions.

Endocrine system

the system of glands in the body that secrete their hormones directly into the circulatory system.


type of protein produced by the body that speeds up chemical reactions. Some enzymes regulate certain functions due to their ability to change their activity by modifying their structure.

Extracellular fluid (ECF)

the fluid found outside of the cells and between the cells in body tissues.

Feedback system

feedback system uses as input the total or partial output of the system. Feedback systems are used to control and regulate processes. They use the consequences of the process (for example, too much or too little produced) to regulate the rate at which the process occurs (decrease or increase the rate of the process).


stability of the body's internal environment, achieved by a system of integrated control systems activated by feedback systems. Homeostasis is thus the maintenance of a constant internal environment (the immediate surroundings of cells) in response to changes occurring in the conditions of the external environment and the conditions of the internal body environment.


naturally occurring substance secreted by specialized cells that affects the metabolism or behavior of other cells possessing receptors for the hormone.


the hypothalamus is a tiny cluster of brain cells just above the pituitary gland, that is involved in the regulation of body temperature.

Metabolic effectors

substances, such as hormones, that can increase the metabolism of the body or of a target organ.


the sum of all the physical and biochemical processes occurring in the body to produce what is required to maintain life. This includes the transformation of nutrients into energy and the use of energy by the body.

Nervous system

the entire system of nerve tissue in the body. It includes the brain, the brainstem, the spinal cord, the nerves and the ganglia and is divided into the peripheral nervous system (PNS) and the central nervous system (CNS).

Peripheral nervous system (PNS)ne of the two major divisions of the nervous system. The PNS consists of the somatic nervous system (SNS), that controls voluntary activities and of the autonomic nervous system (ANS), that controls regulatory activities. The ANS is further divided into sympathetic and parasympathetic systems.


heat transfer that occurs by the emission of electromagnetic waves which carry energy away from the emitting object.


production of heat.


regulation of body temperature so as to maintain it nearly constant at 98.6°F (37°C).

Thyroid gland

butterfly-shaped endocrine gland located in the neck on both sides of the windpipe. It controls the rate at which the body produces energy from nutrients. It secretes the hormones triiodothyronine (T3) and thyroxine (T4) which increase the rate of metabolism and cardiac output.


the decrease in the internal diameter of a blood vessel resulting from tightening the smooth muscle located in the walls of the vessel. Vasoconstriction decreases the blood flow.


the increase in the internal diameter of a blood vessel resulting from relaxation of the smooth muscle located in the walls of the vessel. Vasodilation increases the blood flow.

Vasomotor system

the neural systems which act on vascular smooth muscle to control blood vessel diameter.