Cells

The smallest unit of the human body is the cell. Although there are a number of different types of cells, all of them share certain characteristics, one of them being metabolism. Metabolism is the act of converting energy by continually building up substances by anabolism and breaking down substances by catabolism for use by the body. Metabolism can be described as an equation:

< ?xml:namespace prefix = "mml" />Metabolism=Anabolism+Catabolism

See Fig. 2-1 for an illustration of a cell and the corresponding table below for a brief description of the pictured organelles and their functions.

Tissues

There are four major categories of tissues. Within each type, the tissue either supports (stromal tissue) or does the actual work (parenchymal tissue) of the organ. For example, parenchymal nerve cells are the neurons that conduct the nervous impulse. Neuroglia are stromal nerve cells that enhance and support the functions of the nervous system. The four types of tissue include the following:

When tissue is destroyed by disease or trauma, the possibility of tissue replacement may be an option. Autologous tissue is that which is taken from one part of an individual’s body and is transplanted to another location. Auto- means “self.” An example would be a vein that is used to bypass a blocked coronary artery. If nonautologous tissue is used, it would mean that it is not from one’s self, but from another human. A synonym for nonautologous is allogenic, this time referring to being produced by a different human being. Allo- means “different.” Zooplastic tissue is that which is derived from an animal, for example, a cow or pig heart valve that is used to temporarily replace a structure until human donor tissue is available. Zo/o means “animal.” If tissue is syngeneic, as in the case of identical twins, it refers to a genetically identical individual. Syn- means “together or joined,” as in the sharing of the same DNA. Synonyms for the term syngeneic are isoplastic, isogeneic, and isologous. The combining form is/o means “equal.” Note that the synonyms use all of the previous suffixes: -plastic, -geneic, and -logous.

Organs

Organs, also referred to as viscera (sing. viscus), are arrangements of various types of tissue that accomplish specific purposes. The heart, for example, is made up of muscle tissue, called myocardium, and it is lined with epithelial tissue known as endocardium. Organs are grouped within body systems but do have specific terms to describe their parts.

Parts of Organs

Organs can be divided into parts and have a set of terms that describe these various parts.

organ = viscer/o

myocardium

 myocardi/o = heart muscle

 -um = structure

endocardium

 endocardi/o = within the heart

 -um = structure

Parts of Organs

	Term	Combining Form	Definition
	apex	apic/o	The pointed extremity of a conical structure (pl. apices).
	body (corporis)	corpor/o, som/o, somat/o	The largest or most important part of an organ.
	fornix	fornic/o	Any vaultlike or arched structure (pl. fornices).
	fundus	fund/o	The base or deepest part of a hollow organ that is farthest from the mouth of the organ (pl. fundi).
	hilum	hil/o	Recess, exit, or entrance of a duct into a gland, or of a nerve and vessels into an organ (pl. hila).
	lumen	lumin/o	The space within an artery, vein, intestine, or tube (pl. lumina).
	sinus	sin/o, sinus/o	A cavity or channel in bone, a dilated channel for blood, or a cavity that permits the escape of purulent (pus-filled) material (pl. sinuses). Antrum (pl. antra) and sinus are synonyms.
	vestibule	vestibul/o	A small space or cavity at the beginning of a canal.

 Exercise 1:

Intracellular Functions

Match each cell part with its function.

____ 1. mitochondria ____ 2. ribosomes ____ 3. nucleus ____ 4. lysosomes ____ 5. cytoplasm

A control center of cell

B holds organelles of cell

C digestive function

D responsible for energy production

E formation of proteins