الرحمن الله الرحمن بسم الله بسمالرحيمالرحيم

The cellThe cellByBy

Prof. Dr. Nahed ZohdyProf. Dr. Nahed Zohdy

Professor of Histology & Professor of Histology & Cell BiologyCell Biology

About this LectureAbout this Lecture

CytoplasmCytoplasm::

StructureStructure

OrganellesOrganelles

RibosomesRibosomes

ERER

Golgi apparatusGolgi apparatus

LysosomesLysosomes

MitochondriaMitochondria

Haematoxylin and Eosin Haematoxylin and Eosin (H&E)(H&E)

• HaematoxylinHaematoxylin is a basic violet stain. is a basic violet stain.

•EosinEosin is an acidic pink stain. is an acidic pink stain.

• Acidophilic structureAcidophilic structure= A structure = A structure that has affinity to stain with acidic that has affinity to stain with acidic dyes = basic in nature………So it stains dyes = basic in nature………So it stains pinkpink with eosin with eosin

•Basophilic structureBasophilic structure= A structure that = A structure that has affinity to stain with basic dyes = has affinity to stain with basic dyes = acidic in nature……… So it stains acidic in nature……… So it stains violetviolet with haematoxylinwith haematoxylin

Composed ofComposed of::

11-- CytosolCytosol:: jelly like fluid jelly like fluid

matrix, its matrix, its primary primary component is component is waterwater

22-- OrganellesOrganelles

33 - -InclusionInclusion

44 - -CytoskeletonCytoskeleton

The cytoplasmThe cytoplasm

Nucleus

cytoplasm

OrganellesOrganellesLittle organs:

-Living structures

-Metabolicaly active -Perform certain functions

-Permenant

-Present in all cell types Types:

- Memberanous organelles- Non-membranous organelles

RibosomesRibosomes - - Non-membranous organellesNon-membranous organelles

- - Chemical nature: Chemical nature: nucleoproteinsnucleoproteins consist consist of proteins of proteins conjugated with ribosomal RNA conjugated with ribosomal RNA (rRNA)(rRNA)-Structure:Structure:

LMLM:: By H&E stain: can not be seenBy H&E stain: can not be seen if large in number they impart if large in number they impart

Cytoplasmic basophiliaCytoplasmic basophilia..

Electron dense granulesElectron dense granules

22 subunitssubunits : :

Small subunit (RNA+30 P)Small subunit (RNA+30 P)

large subunit (2RNA+40 large subunit (2RNA+40 P)P)

EMEM::

Types of ribosomes

Free Attached

Solitary Polysomes

PolysomesPolysomes

- -Clusters of ribosomes connected Clusters of ribosomes connected by mRNA thread & producing by mRNA thread & producing identical proteinsidentical proteins

mRNA

ribosomes

Free protein in cytoplasm

Attachment of ribosmes to the Attachment of ribosmes to the rERrER

EM of attached ribosomesEM of attached ribosomes

Function of ribosomesFunction of ribosomes

Ribosomes are the sites of are the sites of protein protein synthesissynthesis::

SolitarySolitary: reserve: reserve

PolysomesPolysomes: proteins used by the cell: proteins used by the cell

AttachedAttached: proteins for secretion : proteins for secretion outside the celloutside the cell

Endoplasmic reticulumEndoplasmic reticulum - -Membranous organelleMembranous organelle

- -Network of interconnecting tubules and cisternae

Endoplasmic reticulum

Rough

(rER)

Smooth

(sER)

rERrER

Cyto. basophaliaCyto. basophalia

Cyto. acidophilia

sERsERLMLM

rERrER- - Interconnected Interconnected parallelparallel

cisternaecisternae- - Has attached ribosomesHas attached ribosomes- - Connected to nuclear mConnected to nuclear m..

--Interconnected Interconnected branching branching tubulestubules

--Lacks ribosomesLacks ribosomes----No connection with No connection with

nuclnucl..

sERsEREMEM

rERrER

Interconnected Interconnected cisternaecisternae

Has attached ribosomesHas attached ribosomes

Interconnected Interconnected tubulestubulesLacks ribosomesLacks ribosomes

sERsEREMEM

rERrER

Participates in Participates in protein synthesisprotein synthesis..

11-- Lipid synthesis Lipid synthesis (fatty acids ,cholestrol & (fatty acids ,cholestrol & steroid hormones)steroid hormones)

22 - -Detoxification of Detoxification of toxic substancetoxic substance

33 - -Muscle Muscle contractioncontraction

))control calcium ions -control calcium ions -sarcoplasmic reticulumsarcoplasmic reticulum((

44 - -Glycogen Glycogen synthesissynthesis

sERsERFunctionFunction

Role of rER in protein Role of rER in protein synthesissynthesis

1 -receiving of polypeptide chains in ER lumen2 -storage

3 -protein trasport

Golgi apparatusGolgi apparatus

-Membranous organelle-Membranous organelle

Structure:Structure:LM:LM: --H&E stain: not apparentH&E stain: not apparent

- -Special stain: Special stain: silver stainsilver stain

Golgi apparatus in Golgi apparatus in epididymisepididymis(Silver stain)(Silver stain)

Brown anastomosing network of threads at the secretory border of the cells

EM structure of Golgi EM structure of Golgi apparatusapparatus

3 components:

-macrovesicles

-flattened membranous saccules. (4-10)

-microvesicles

Flattened membranous cisternae:

Convex surface: immature face

Concave surface: Secretory face = mature face

Fate of protein transported Fate of protein transported by rERby rER

Fate of protein transported Fate of protein transported by rERby rER

Primary lysosomes

Functions of Golgi Functions of Golgi apparatusapparatus

1 -Chemical modification of proteins22 - -Formation of primary lysosomesFormation of primary lysosomes

33 - -Secretion of cell productsSecretion of cell products 44 - -Renewal of the cell membraneRenewal of the cell membrane

Cytoplasmic Organelles Cytoplasmic Organelles that participate in the that participate in the

process of process of protein protein synthesissynthesis

11 - -Ribosomes Ribosomes (factories)(factories)

22 - -Rough endoplasmic reticulum Rough endoplasmic reticulum (storage & transport)(storage & transport)

33 - -Golgi apparatus Golgi apparatus (chemical (chemical modification & secretion)modification & secretion)

LysosomesLysosomes

DefinitionDefinition:: -Membrane bound organelles containing

hydrolytic enzymes

)Digestive system of the cell(

StructureStructure::

LMLMHistochemical Histochemical methods methods staining staining their enzymestheir enzymes

LysosomesLysosomes -Membrane bound organelles containing

hydrolytic enzymes

EMEM22 typestypes

1ry lysosome

small, regular vesicle , contains homogenous dense content

2ry lysosome

Large, irregular vesicle, contains heterogenous dense and light contents

Function of lysosomesFunction of lysosomes

-The digestive system of the cell (contain hydrolytic enzymes that could digest the food vacuole's contents & destroy old cell organelles)

Formation of the 2 types of Formation of the 2 types of lysosomeslysosomes

Forms of secondary Forms of secondary lysosomeslysosomes

1ry lysosome + 1-pinocytotic vesicles = multivesicular body

2 -phagosomes =residual bodies

3 -autophagic vacuole = residual bodies

5 -Lipofuscin pigment

MitochondriaMitochondria

-Membranous organelles-Membranous organelles

Structure:Structure:LM:LM: --H&E stain: not apparentH&E stain: not apparent

- -Special stain: Special stain: silver stainsilver stain

Mitos= thread chondros= granule

LM picture of mitochondria LM picture of mitochondria (special stain: silver stain)(special stain: silver stain)

mitochondria appear as mitochondria appear as dark brown granules granules

EM of the Mitochondria

Double membranes:

-Outer smooth-Inner folded

forming cristae

Double spaces: -

intermembranous space

- intercristal space (matrix space)

intermembranous space

Inner membrane: -cristae to increase

surface area - contains protein

enzymes for respiratory chain

- contains ATP synthetase for ATP synthesis Matrix:

-oxidative enzymes - mitochondril DNA so mitochondria can replicate themselves

--Energy productionEnergy production & storage & storage (ATP synthesis)(ATP synthesis)

--Concerned with Concerned with cell cell respiration respiration (sites for Kreb’s (sites for Kreb’s and fatty acid cycles)and fatty acid cycles)

Function of a mitochondrion

LM:LM:can not be seencan not be seen

EM:EM:- - small, roundedsmall, rounded- similar to 1ry - similar to 1ry lysosomeslysosomes

- Contain 40 oxidative enzymes - Contain 40 oxidative enzymes (urate oxidase)(urate oxidase)

PeroxisomesPeroxisomes

Functions of Functions of peroxisomesperoxisomes::

1- Generate energy but can not store it 1- Generate energy but can not store it ((NO ATP formationNO ATP formation))

2- Maintenance of body temperature (The 2- Maintenance of body temperature (The energy is released as heat).energy is released as heat).

33 - -Cell protection : catalase enzymeCell protection : catalase enzyme

breaks down Hbreaks down H22OO22..

Thank youThank you