ANATOMY is the study of the structure of the body and of the relationship of its constituent parts to each other.
In regional anatomy a geographical study is made and each region, e.g., arm, leg, head, chest, etc., is found to consist of a number of structures common to all regions such as bones, muscles, nerves, blood vessels and so on.
From this study it follows that a number of different systems exist.
These have been grouped together and described under the heading systematic anatomy .
A study of the position and relationship of one part of the body could not be separated from a consideration of the use of the terms functional anatomy , which is closely allied to the study of physiology.
Then again it was found that certain structures could be examined by the naked eye and the term macroscopic anatomy was introduced to describe this study, in distinction to microscopic anatomy, which necessitates the use of a microscope.
Closely allied to the study of anatomy are histology , the study of the fine structures of the body, and cytology , the study of the cells.
PHYSIOLOGY is the study of the functions of the normal human body.
It is closely linked with the study of all living things in the subject of biology ; as well as this three is the work of cytologist, interested in detail of the structure of cells, and that of the biochemist , dealing with the chemical changes and activities of cells and investigating the complex chemistry of life, and there is physics , the study of the physical reactions and movements taking place in the body.
The body is made up of many tissues and organs, each having its own particular function to perform.
In order to be able to produce energy, give rise to waste substances, and form new cells when needed, cells have tiny, specialized structures inside them, which can be observed with a very powerful microscope.
Eg., the internal carotid artery is within the cranial cavity and the external is outside the cavity.
The terms superficial and deep are used to denote relative distance from the surface of the body, and the terms superior and inferior denote positions relatively high or low, particularly in relation to the trunk, such as the superior and inferior surfaces of the clavicle.
The terms anterior and posterior are synonymous with ventral and dorsal .
The terms proximal or distal are employed to describe nearness to or distance from a given point.
This idea was disproved in 1828 by the German chemist Friedrich Wohler when he synthesized urea (H2NCONH2), an organic substance found in the urine of mammals, by heating ammonium cyanate (NH4OCN), an inorganic substance.
The notion that organic chemicals and living organisms are connected is certainly true in one sense: Life as we know it could not exist without a vast array of complex, biologically important organic molecules. The study of the chemistry of living species is called biological chemistry , or biochemistry .
Life is recognized by certain characteristics:
The sum of chemical processes in an organism
Anabolism = chemical reactions that build-up or synthesize
Catabolism = chemical reactions that break-down or fragment
Equilibrium exists when the organism is in "steady state",
i.e., amount of anabolism equals amount of catabolism. eg: healthy adult is in steady state; eg: growing healthy child is in anabolic state
eg: stimulus is scary situation, response is secretion of hormone adrenalin which sends blood and oxygen to heart, lungs, and muscles so you can escape, result is decrease in adrenalin due to escape from the original stimulus; blood and O2 transport return to resting state
eg: sensors in the tendons of your legs detect stretching when you are about to lose your balance, reflex neuron causes contraction of the muscle attached to the tendon, muscle pulls you upright & releases the stretch stimulus, result is restoration of balance