anatomy module 2- cell anatomy

what separates the body compartments

membranes

plasma membrane

lipid bilayer separating intracellular and extracellular spaces

serous membrane

produce watery fluid (pleura, peritoneum, pericardium)

mucous membranes

produce a thick fluid, difficult to evaporate

cutaneous membrane

dry membrane on exterior surface

cells

• cell theory

-*smallest structural and functional unit of an organism

• basic structural and functional unit of living organisms

• activity of organisms depend on independent and combined activities

• cells are dictated by their shapes (form =function)

• cells can only arise from other cells

different cell tyoes (6)

• cells that connect body parts, form linings, or transport gases (epithelial cells, fibroblasts, erythrocytes)

• cells that move organs and body parts (skeletal muscle cell, smooth muscle cell)

• cells thar stores nutrients (fat cell)

• cell that fights disease (macrophage)

• cell that gathers information and controls body funcitons (nerve cell)

• cell of reproduction (sperm)

extracellular materials- types?

found outside of cells. substances that contribute to total body mass

• body fluids (ECF)- interstitial fluid, blood plasma, cerebromspinal fluid

• extracellular matrix- mix of proteins and polysaccharides that form a jelly-like substance

plasma membrane

fluid mosaic model- membrane is extremely thin, composed of a double layer of lipid molecules with protein molecules that are embedded or float that create a constantly changing landscape

membrane lipids

• phospholipids

• glycolipids

• cholesterol

phospholipids

polar head (HYDROPHILIC), 2 non-polar (HYDROPHOBIC) tails, and a phosphate groups

• orient to form double layer in which the nonpolar tails are sandwiched between the polar heads

glycolipids

lipids with sugars attached

cholesterol

large hydrocarbon ring embeds into the phospholipid bilayer which helps maintain fluidity and integrity

membrane proteins

• functions

• integral proteins

• peripheral proteins

  • transport

  • receptors

  • support

  • enxymes

  • cellular adhesions

  • cell communication

integral proteins

firmly inserted into the lipid bilayer, most are transmembrane (span the entire membrane)

peripheral proteins

not embedded in bilayer but attached loosley to integral proteins

glycocalyx

membrane carbohydrates that form a protective layer and play a key role in cell recognition and the immune system

cell junctions

provide attachment and communication points

nexus junctions

transmembrane integral proteins (connexons) span plasma membrane of adjacent cells

occulding (tight) junctions

proteins (claudins and occludins) fuse adjacent plasma membranes making a barrier

anchoring junctions

anchor cells to one another via caderins or integrins

• zonula aderens - cadherin

• macula adherens (desmosome)- cadherin

• focal adhesion (integrin)

• hemidesmosome-integrin

cytoplasm

• cytosol

• inclusion

• organelles

cellular material b/w plasma membrane and nucleus

• viscous, semi transpartent fluid

• inclusion- chemical substances

• organelles- metabolic machinery of the cell

mitochondria

• provide cell w ATP by oxidative phosphorylation

• double membrane

• inner membrane contains cristae

• inside matrix and on cristae is where aerobic respiration takes place

ribosomes

• small dark staining granules of proteins

• two globular subunites

• sit of protein synthesis

• free ribosomes- free in cytosol

  • membrane bound- attached to endoplasmic reticulum

endoplasmic reticulum

• interconnected membranous tubes enclosing fluid filled cavities (cisterns)

• continuous with outer nuclear membrane

• rough ER- studded with ribosomes and makes proteins for transport

• smooth ER- no ribosomes but has enzymes instead; lipid synthesis, steroid synthesis, fat transport, detox, glycogen breakdown

golgi apparatus

• stacked and flattened membranous sacs

• transport vesicles from rough ER fuse of cis surface

• proteins are modified

• proteins targeted for delivery

  • secretory vesicle bud off trans surface

peroxisomes

• spherical membranous sacs with powerful enzymes

• oxidases to detoxify harmful substances

• neutralizes free radicals (highly reactive chemicals with unpaired electrons) by converting to hydrogen peroxide

• numerous in liver and kidney

lysosomes

• spherical membranous organelles containaing digestive enzymes

• digest particles taken in via endocytosis

• degrade stressed or dead cells

• glycogen breakdown and release

• break down bone to calcium ions

• when lysosomes rupture, cell undergoes autolysis