HONORS ANATOMY & PHYSIOLOGY

Cytoplasm

 

Cytoplasm

material between plasma membrane& nucleus

site of most cellular activity3 elements1. Cytosol2. Organelles3. Inclusions

Cytosol

viscous, semitransparent fluid in which other elements in cytoplasm are suspended

complex mixture of:waterproteinssaltsSugarsother solutes

Organelles specialized cellular compartments or structures

each has specific function

Organelles

non-membranous:cytoskeletonribosome

Endomembrane System

membranes allow inside to differ from cytoplasm

membranous:mitochondria, Ers, Golgi, lysosomes,

peroxisomesintermembrane system: connections

between ERs, nucleus

structure Function

dbl membraneinner membrane

has enzymes used in e- transport chain

matrix w/in ↑ enzymes for citric acid cycle

aerobic cellular respiration ATP

Mitochondria

Mitochondria

Structure Function

proteins + rRNA2 subunits

large small

translation part of protein synthesis

Ribosomes

Ribosomes

Endoplasmic Reticulum

extensive system of interconnected tubes & parallel membranes enclosing fluid-filled cavities called cisterns

continuous with outer membrane of nuclear envelope

1. Smooth ER2. Rough ER

Structure Function

continuous with RER

enzymes (integral proteins)

metabolize lipidssynthesize cholesterol

& lipoproteinssynthesize steroid

hormonesabsorb, synthesize, &

transport fatsdetoxify drugs, cancer-

causing chemicalsglycogen free glucose

Smooth ER

SER

Structure Function

ribosomes stud surface of membrane

proteins made on these ribosomes thread way into cisterns

proteins then enclosed in vesicles Golgi

synthesize all proteins exported from cell

makes membranes

RER

RER

Structure Function

stacked & flattened membranous sacs

associated with numerous vesicles

modifies,, concentrates, & packages proteins &lipids destined for export

packages enzymes into vesicles lysosomes, peroxisomes

Golgi Apparatus

Structure Function

“peroxide bodies”membranous sacs

containing enzymes ex: oxidases,

catalasesmade in ER

detoxify harmful substances (many in liver& kidney)

breakdown & synthesize fatty acids

Peroxisomes

Structure Function

spherical, membranous organelles containing activated digestive enzymes in acid pH

many found in cells that phagocytize

plasma membrane has H+ pumps

enzymes digest all molecules

H+ pumps maintains normal pH in cytosol

degrade worn out organelles

glycogen glucosebreakdown

nonuseful tissues

Lysosome

Tay-Sachs

1 enzyme missing in lysosmes of nerve cells buildup of glycolipid lysosomes swell with undigested lipids interferes with normal nervous system functioning death in early childhood

Cytoskeleton

“cell skeleton”network of protein rods thru cytosolsupports cell structureallows cell movementTypes:1. Microfilaments2. Intermediate Filaments3. Microtubules

Structure Function

made of actin“web” just inside

plasma membrane of all cells

strengthens cell surface

transmit force during movement & shape changes

works with myosin muscle contractions & formation of cleavage furrow in cytokinesis

Microfilaments

Structure Function

tough, insoluble protein fibers

most stable & permanent of the 3

attach to desmosomes

resist pulling forces exerted on cell

Intermediate Filaments

Structure Function

hollow tubes made of protein tubulin

most radiate from centrosome

very dynamic: self-assemble/dissemble

have associated proteins that help organelles move in cytoplasm

determine overall shape of cell

distribute organelles

https://www.youtube.com/watch?v=4TGDPotbJV4

Microtubules

Structure Function

made of paired centrioles: barrel-shaped organelles oriented @ rt angles to each other

generates & organizes microtubules

organizes mitotic spindle

Centrosomes

Structure Function

whip-like, motile cellular extensions

found in large #s on surface of cell

9 paired microtubules runs length of cilium

as beat in unison mucus/particles swept over surface of cell

Cilia

http://www.zoology.ubc.ca/courses/bio332/Images/Cilia/Cil3/cilium.gif

Structure Function

cell projections formed by centrioles

longer than ciliaonly human cell

with flagella is the sperm

9 + 2 pattern of microtubules

propels entire cell

Flagella

http://worms.zoology.wisc.edu/dd2/echino/fert/sperm/sperm.html

Structure Function

minute projections of plasma membrane on cell surface

found on surface of absorptive cells

have core of microfilaments (actin)

↑ surface area

Microvilli

Structure Function

dbl membrane~5 µm in diametershape conforms to

cell shape3 regions:nuclear envelopenucleolichromatin

houses chromosomes (DNA) making it the control center of cell

Nucleus

Structure Function

selectively permeable dbl membrane with nuclear pores

outer membrane continuous with RER

inner membrane lined with rod-shaped proteins that give shape to nucleus

pores: complex of proteins

gives shape to nucleus

pores allow transport route for substance in/out of nucleus

encloses nucleoplasm (jelly-like similar to cytoplasm)

Nuclear Envelope

Structure Function

dark staining spherical bodies w/in nucleus

assemble ribosomal subunits combine rRNA with proteins

Nucleolus

Structure Function bumpy threads

weaving thru nucleoplasm

30% DNA60% histones

(proteins which package and regulate DNA

10% RNA

genomecodes for

proteins

Chromatin

Chromosomes

Structure

DNATelomeres : DNA at

either end of chromosome

Function

Codes for proteinsprotects

chromosome coding portion acting like “bumpers”

Other Roles of DNA

Iintrons (parts of pre-mRNA that stay in the nucleus) have role as other RNAsantisense RNAs: can block translationmicroRNAs: supress certain mRNAs made by

certain exonsriboswitches: folded RNAs that code for protein

that include an on or off switch responding to metabolic changes in their immediate environment (change in environment induces change in configuration stopping or starting protein translation)

Degradation of Organelles

autophagy: “self-eating”cell debris swept into vesicles (autophagosomes) lysosomes for digestion

rate increases in cell stressanoxia, high temp, lack of growth factors

can lead to apoptosis (programmed cell death)

Ubiquitins

proteins that mark other proteins no longer being used by cell for destruction

once marked hydrolyzed by proteosomes (giant waste disposal complexes) recycle a.a. and release ubiquitins

Extracellular Material (ECM)

any substance contributing to body mass found outside cells

1. Body Fluids2. Cellular Secretions

Body Fluids

1. interstitial fluid2. plasma3. cerebrospinal fluid

Cellular Secretions

gastric juicesbilemucussweatserous fluid

Extracellular Matrix

most abundant ECM = “cell glue”secreted by cells

jellylike substanceproteins + polysaccharides

Apoptosis

programmed cell deathcommon in developing embryo:

especially in nervous systemcarves out digits in developing hands,

feet

Hyperplasia

accelerated division of cells

Atrophy

decrease in size of an organ or body tissueloss of normal stimulation

muscles that lose their nerve supply atrophy & waste away

Cell Aging

still a mysterywear-and tear theorymitochondrial theoryprogressive disorders in immune system

genetic theory: telomere clock