Тheme №2-n3 (author O.Mazuru) (1) (1).pdf

8/10/2019 heme 2-n3 (author O.Mazuru) (1) (1).pdf

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The State University of Medicine and

Pharmacy N. Testemitanu

Chief of Histology, Cytology and Embryology departament

Lilian Saptefrati

Vice Chief of Histology, Cytology and Embryology departament

Tatiana Globa


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Theme Nr.2

CYTOLOGY

CELL MEMBRANE, CELL MEMBRANESTRANSPORT. INTERCELLULARJUNCTIONS. NON-CELLULAR

STRUCTURES.


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The plasmalemma is composed of a

phospholipid bilayer and associatedintegral and peripheral proteins.

Types of lipids on plasmalemma are:-phospholipids,

-cholesterol and

-glycolipids.


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Elementary biological membraneIs composed of:

- phospholipids bilayer,- associated proteins.

Types of elementary biological membrane

- Plasmalemma- is the skeleton of the cellmembrane

- Endomembranes- are membranes of cellorganelles.

- Special membranesare membranes of nervefibres and photoreceptor cells.


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Cell membrane

glycocalyx

plasmalemma

elements ofcytoskeleton


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Glycicalix

Composed of carbohydrates chains linked tomembrane proteins and lipids.

Role:

- protects cell surface- interaction cell-cell

- interaction cell-extracellular matrix

- individuality to the cell

- provides the formation of the

cytoreceptors.


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Molecular structure of the cell

membrane.


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Ultrastructure of cell membrane


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Functions of cell membrane

Maintaining the structural integrity of the cell Controlling movements of substances in and out

of the cell (selective permeability)

Regulating cell-cell interactions

Recognizing, via receptors, antigens and foreigncells as well as altered cells

Acting as an interface between the cytoplasmand the external milieu

Establishing transport systems for specificmolecules

Transducing extracellular physical or chemical

signals into intracellular events.


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Structural classification of cell

membrane proteins


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Cryofracture ( frozen and fructered)


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Functional destination cell membranes

proteins can be classified:


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Receptors and their ligands.


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Each cell type in the body contains a set of

receptors proteins that enable it to respond to acomplementary set of signaling molecules in a

specific programmed way.

A molecule which binds (attaches) to a receptor is

called a ligand.

Receptors may be for

-self antigens -(endogenous) neurotransmitter, a

hormone, complement, Ig, etc.- non- selfantigens (exogenous) pharmaceutical

drug, viruses, bacteria or toxins.
http://en.wikipedia.org/wiki/Ligand_%28biochemistry%29http://en.wikipedia.org/wiki/Neurotransmitterhttp://en.wikipedia.org/wiki/Hormonehttp://en.wikipedia.org/wiki/Hormonehttp://en.wikipedia.org/wiki/Neurotransmitterhttp://en.wikipedia.org/wiki/Ligand_%28biochemistry%29


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Functions of protein receptors:

Control of selective permeability,

Regulating cell-cell interactions

Recognizing, via receptors, antigens and

foreign cells as well as altered cells


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Membrane transport

Large molecules

endocytosis

exocytosis

transcytosis


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Endocytosis :

-for solid

substance;

- with changing of

cells surface;

- pseudopodia.


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Endocytosis :

-for liquid

substance;

-without changincells surface ;


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Endocytosis :


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Intercellular junctions :

Simple

- linear-shaped

- denticular

- digital-shaped


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Compound junctions

Occludingtight junctions. Using

transmembrane proteins (occludins).Impermiable . They act as seals to prevent

the flow of the substance between the

cells.

Ex.: intestinal and bladder

Epithelium.


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Anchoring junctions

zonula adherens

(belt desmosome),

macula adherens

(spot desmosome),

hemidesmosome.


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desmoplakins

desmogleins

intermediate

filaments

Desmosome


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Desmosoma

desmoplakins

desmogleins

intermediate filaments


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Communicating junctions

GAP junction (nexus)

Smooth and cardiac muscle cells

connexin protein

connexon


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Non-cellular structures

Syncytium

Symplast


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Simplast

muscle fibres in

longitudinal section

nuclei of the muscle

fibre

isotrop (light) disk

anisotrop (dark)diskmuscle fibres in cross-

section

myofibrillae


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heme 3

CYTOPLASM: HYALOPLASM, CELLULAR

ORGANELLES, INCLUSIONS


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Cytoplasm

Is the cellular region between cellmembrane and the membranesurrounding the nucleus.

Main functions:

energy, storage and manufacturing.

Components of cytoplasm:

-cytosol,

-organelles,

-cytoskeleton,

-inclusions


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Cytosol(cytoplasmic matrix)

It is jelly-like material (80% water) and

usually incolor. The fluid of the cytosol is a

thick soup of proteins, carbhydrates, salts,

sugars, lipids, nucleotides and aminoacids.


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Structural classification of organells

membranous

Routh ER

Smooth ER

Golgi ap.

lysosome

peroxisome

mitochondria

nonmembranous

Ribosome

cytoskeleton

centrioles


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Functional

systems of the

cell

System of

synthesis of

cell

System of energy

System of intracellular

digestion

Cytoskeleton

System of synthesis


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System of synthesis

of cell


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Ribosome


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Types of ribosomes


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Rough and smooth endoplasmatic reticulum


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Golgi aparatus


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Inclusions


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Microtubules


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Lipid droplets in the hepatocytes

Glycogen inclusions in the hepatocytes


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Glycogen inclusions in the hepatocytes

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Тheme №2-n3 (author O.Mazuru) (1) (1).pdf

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