Unit 1 Cytology

cytology

study of cells

the cell

The basic unit of structure and function in living things

cell theory

"building blocks" of all plants and animals

produced by division of pre-existing cells

cells are the smallest units that preform all vital functions

sex cells

gametes sperm and egg

somatic cells

body cells

extracellular fluid

"cellular highway"

matrix of connective tissue provides medium for nutrients, gases and wastes

plasma membrane

A selectively-permeable phospholipid bilayer forming the boundary of the cells

plasma membranes functions

physical isolation, sensitivity, structural support, regulation of exchange of materials

physical isolation

barrier separates inside from outside of cell

sensitivity

to changes in extracellular fluid

phosphate head

polar, hydrophilic, align towards intra and extracellular fluid

lipid tails

hydrophobic, non-polar, align away from intra and extracellular fluid

phospholipid molecule

lipid-soluble solutes allowed to pass

proteins

water soluble solutes pass

intergral proteins

penetrate the hydrophobic interior of the lipid bilayer

peripheral proteins

bound to the surface of the membrane

cholesterol

adds fluidity and structure to the membrane

makes a bilayer

glycolipids and glycoproteins

carbohydrate attached to a lipid or protein. In cell membrane, help form fluid mosaic.

cell identification

passive process

no ATP required, substance moves down its concentration gradient

active process

ATP required

diffusion

Movement of molecules from an area of higher concentration to an area of lower concentration by way of kinetic energy

facilitated diffusion

Movement of specific molecules across cell membranes through protein channels

osmosis

Diffusion of water through a selectively permeable membrane

high concentration of H2O to low concentration H2O

filtration

dissolved solutes moved across a membrane by external mechanical forces

active transport

substances transported via membrane carrier protein usually against concentration gradient. ATP is used

endocytosis

A process in which a cell engulfs extracellular material through an inward folding of its plasma membrane.

exocytosis

release of substances out a cell by the fusion of a vesicle with the membrane.

microvili

increase surface area for absorption

microvili example

lining digestive tract

cilia

contain regularly arranged microtubules that beat regularly to move particle along cell's surface

cilia example

lining respiratory tract

flagella

similar to cilia only longer with single extension

flagella example

sperm

cytoskeleton

bones and muscles of the cells

ribosomes

site of protein synthesis

centrioles

cause movement of chromosomes in cell division

nucleus

Control center of the cell

contains genetic material

directs protein synthesis

directs cellular structures and functions

mitochondria

Powerhouse of the cell

generates ATP uses oxygen for cellular respiration

smooth endoplasmic reticulum

synthesis lipids and steroids

rough endoplasmic reticulum

synthesis proteins

ribosomes attached

Golgi apparatus

stacks of flattened membranous sacs, vesicle producing organelle, receives synthesized proteins and lipids from ER and forms secretory vesicles

lysosomes

An organelle containing digestive enzymes

cell suicide packages

perxisomes

enzyme packages used to detoxify molecules

provides protection and fixed environment for the cell

transports nutrients into the cell

transports toxic substances out of the cell

plasma membrane function

the bilayer is formed because the hydrophylic heads of the molecules have water on either surface and the hydrophoci tails are not near water in the bilayer

why does a bi layer form

gap junction

A type of intercellular junction that allows the passage of materials between cells.

tight junction

A type of intercellular junction that prevents the leakage of material between cells.

hemidesmosomes

attach epithelial cells to the basement membrane

spot desmosomes

tie cells together

allow bending and twisting

fixed cells

fibroblasts, fibrocytes, fixed macrophages, adipocytes, mesenchymal cells, melanocytes

wandering cells

free macrophages, mast cells, lymphocytes, neutrophils and eosinophils