Chapter 2- Overview of Cellular Physiology

homeostasis

the various physiologic arrangements which serve to restore the normal state, once it has been disturbed

plasma membrane

its permeability can also be varied because it contains numerous regulated ion channels and other transport proteins that can change the amounts of substances moving across it

hydrophilic

phospholipid head

hydrophobic

phospholipid tail

amphipatic

The possession of both hydrophilic and hydrophobic properties makes the lipid

lysosomes

interior of organelles is more acidic than the rest of the cytoplasm, and external material such as endocytosed bacteria, as well as worn-out cell components, are digested in them

mitochondria

providing the eukaryotic cells with the ability to form the energy-rich compound ATP by oxidative phosphorylation

cytoskeleton

a system of fibers that not only maintains the structure of the cell but also permits it to change shape and move

microfilament

protein subunit: actin

intermediate filament

protein subunit: several proteins

microtubule

protein subunit: tubulin

Filamentous (F actin)

refers to intact microfilaments

globular (G actin)

refers to the unpolymerized protein actin subunits

kinesin

a double-headed molecule that tends to move its cargo toward the plus (“+” ends of microtubules.

Dyneins

have two heads, with their neck pieces embedded in a complex of proteins

Cytoplasmic dyneins

have a function like that of conventional kinesin, except they tend to move particles and membranes to the minus (– end of the microtubules

centrosome

Near the nucleus in the cytoplasm of eukaryotic animal cells is a

centrioles and pericentriolar material

The centrosome is made up of

Cilia

specialized cellular projections that are used by unicellular organisms to propel themselves through liquid and by multicellular organisms to propel mucus and other substances over the surface of various epithelia.

axoneme

comprises a unique arrangement of nine outer microtubule doublets and two inner microtubules

neural communication

in which neurotransmitters are released at synaptic junctions from nerve cells and act across a narrow synaptic cleft on a postsynaptic cell

endocrine communication

in which hormones and growth factors reach cells via the circulating blood or the lymph

paracrine communication

in which the products of cells diffuse in the ECF to affect neighboring cells that may be some distance away