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Abdominal Cavity

This lies below the diaphragm and consists of two parts in wide communication with each other: the abdominal cavity proper above and the pelvic cavity below. The boundaries of the abdominal cavity include the vertebral column behind, the muscular and fibrous walls of the abdomen at the back, sides and in front, the diaphragm above and the bony pelvis and its muscular floor below. The abdominal cavity contains many important organs of the digestive, urinary, and reproductive systems, as well as complex arrangements of blood vessels, nerve supplies, and lymphatic drainage.


Absorption

The process by which materials are taken into the body. The term is used mainly in relation to the take-up of the products of digestion from the lumen of the digestive tract into the blood stream (in the case of carbohydrates and amino acids) or lymphatic system (in the case of lipids).


Acute

A disease or process that has a sudden onset and progression.


Anatomy

The study of structure of the body. The term is derived from the Latin term for dissection - anatomia. Gross anatomy is the study of the body's structure as seen by the unaided eye, that is, without the use of a microscope. Traditionally, this is studied by medical students by dissection of a human cadaver.

Quotation from an exam answer:

"Overall anatomy is quite interesting even though there is a lot of it."


Apoptosis

Programmed cell death: the cell closes down its metabolic activities in an orderly way, either because it has been instructed to do so by signals from other cells, or because it has detected irreparable damage to its DNA or other vital systems. Apoptosis is a Greek word which means ‘the falling of leaves in autumn'.


Artery

A blood vessel carrying blood away from the heart.


Atom

A building block of matter. It was once believed that atoms were the smallest, most fundamental particles, but now we know that they are themselves built up of parts: electrons, neutrons, and protons. Even those parts are not fundamental, and are considered to be composed of different combinations of quarks. There is a suggestion from mathematics that quarks are built from superstrings, so it is best to keep an open mind about the possibility of truly fundamental 'particles'!


Atomic Number

The number of protons in an atom of a particular element. When the atom is in its neutral state, there will be an identical number of electrons. The atomic number of an element determines its position in the Periodic Table and also its chemical properties.


Autoimmune Disease

When the immune system turns against normal cells and tissues of the body.


Autonomic Nervous System

This is the part of the nervous system that looks after bodily functions that do not normally come to consciousness, for example control of the heart rate, blood pressure, digestive processes and so on. There are two main subdivisions of the autonomic nervous system: the sympathetic division which organizes arousal responses, and the parasympathetic division which is more to do with resting, repair, and the restoration of balances within the body.


Axon

The narrow process extending away from the cell body of a neuron: it carries nerve impulses towards the next cell with which the neuron communicates, either another neuron or a muscle or glandular cell.

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