Anatomy and Related Anatomical Terms

(the structure of organisms from the smallest components of cells to the biggest organs and their relationships to other organs especially of the human body)

Diseases affect the anatomy and changes in the anatomical structure can cause diseases.

abdomen
The part of the body below the thorax, containing the digestive organs and female reproductive organs.

The abdomen is separated from the thorax by the diaphragm, a sheet of muscular tissue while the thorax is the part of the human body between the neck and abdomen, enclosed by the ribs and containing the heart and lungs.

accommodation
The ability of the eye to focus on near or far objects by changing the shape of the lens.
acetylcholine, ACh
A chemical that serves as a neurotransmitter, communicating nerve impulses between the cells of the nervous system.

Acetylcholine is largely associated with the transmission of impulses across the synapse (junction) between the nerve and muscle cells, causing the muscles to contract.

action potential
The change in the potential difference (voltage) across the membrane of a nerve cell when an impulse passes along it.

A change in potential (from about -60 to +45 millivolts) accompanies the passage of sodium and potassium ions across the membrane.

active transport
In cells, the use of energy to move substances, usually molecules or ions, across a membrane.
adenoids
Masses of lymphoid tissue, similar to tonsils, located in the upper part of the throat, behind the nose.

The adenoids are part of a child's natural defenses against the entry of germs but they usually shrink and disappear by the age of ten.

adipose tissue
1. A connective tissue having an abundance of fat-storing cells and blood vessels for transporting fats.
2. Connective tissue that serves as an energy reserve and also pads some organs.

It is normally called "fat tissue" and consists of large spherical cells filled with fat. Major layers are in the inner layer of the skin and around the kidneys and heart.

adrenal gland, suprarenal gland
A triangular gland situated on top of the kidney.
  1. The cortex (outer part) secretes various steroid hormones and other hormones that control salt and water metabolism and regulate the use of carbohydrates, proteins, and fats.
  2. The medulla (inner part) secretes the hormones adrenaline and noradrenaline which, during times of stress, prepare the body for "fight or flight".
adrenaline, epinephrine
The hormone that is secreted by the medulla of the adrenal glands.

Adrenaline is synthesized from a closely related substance, noradrenaline, and the two hormones are released into the bloodstream in situations of fear or stress.

adrenocorticotrophic hormone
A hormone secreted by the anterior lobe of the pituitary gland.
alimentary canal
1. The gut or digestive system in an insect.
2. A tube adapted for digestion, through which food passes.

It is a complex organ, consisting of the mouth cavity, pharynx, esophagus, stomach, and the small and large intestines.

alveolus (s), alveoli (pl)
One of the many thousands of tiny air sacs in the lungs in which an exchange of oxygen and carbon dioxide takes place between air and the bloodstream.
amylase
One of a group of enzymes that break down starches into their component molecules (sugars) for use in the body.

It is found in saliva (as ptyalin) and in pancreatic juices.

anatomic age
The estimated age of an individual based on the stage of development or deterioration of the body as compared to that of other people of the same chronological age.
anatomic pathology
The study of the effects of disease on the structures of the body.

Here is more information about Anatomy, Its Origins and Development.

Also see this Index or Menu for a variety of other topics.