1. Cells are building blocks of all plants and animals 2. All cells come from the division of preexisting cells 3. Cells are the smallest units that perform all vital physiological functions 4. Each cell maintains homeostasis at the cellulr lvl
The human body contains two general classes of cells
Sex Cells and Somatic Cells
Sex Cells
AKA germ cells or reproductive cells are either the sprem of males or the oocytes of females
Somatic Cells
(soma means body) include all other (than sex) cells in the human body
Extracellular Fluid
Wattery medium surrounding most tissues (cell model is surrounded by on p 64)
Interstitial fluid
(interstitium - something standing between) the extracellular fluid in most tissues is called this.
Cell Membrane
Outter boundary of the cell. Separates the cytoplasm from the extracellular fluid.
Cytoplasm can be divided into
cytosol, a liquid and intracellular structures collectivelly known as organelles
Functions of the Cell Membrane (4)
1. Physical Isolation (conditions out and in very different, must be kept this way to preserve homeostatis). 2. Regulation of Exchange with the environment 3. Sensitivity to the environment (may receive chem. signals) 4. Structural support
Cell membrane is called a ....
phospholipid bilayer because the phosopholipid molecules in it form two layers. Phospholipid has both a hydrophilic (phosphate) end and a hydrophobic end (the lipid).
