1-cell.pdf

Cytology DR\HEBA ABD ALRAZAK Lecturer of Histology October 6 university Objective -Define histology. - Know the common types of microscopes &their applications in medical researches. - Define magnification &resolution power of different microscopes. - Know the different types o...

Cytology DR\HEBA ABD ALRAZAK Lecturer of Histology October 6 university Objective -Define histology. - Know the common types of microscopes &their applications in medical researches. - Define magnification &resolution power of different microscopes. - Know the different types of stains - Know the mostly commonly used stain &their applications in medical field. Objective -Define the cell -Structure & function of cell membrane -Structure & function of mitochondria -Structure & function of endoplasmic reticulum -Structure & function of Golgi apparatus -Structure & function of lysosome - Histology: is the subject dealing with the microscopically structure of the normal tissue. - Types of microscopes are: - 1- Light microscope (L.M.). - 2- Electron microscope (E.M.). Light microscope & electron microscope differ in their optical resolution & magnification (enlargement). -Resolution power: - Means the least distance at which two points appear separate from one another, if the distance is less the two points will appear as one point. - Resolution power of the eye = 0.2 mm - Resolution power of the LM. = 0.2 um - Resolution power of the EM. = 0.2nm - Maximum magnification power in case of L.M. is about X 1000 while in case of EM. magnification power is about X 100.000 - Common stains used for Light microscopy: Cells are colourless and usually indistinguishable by LM unless stained. 1- Acidic stain: e.g. eosin, it can stain basic structures so these structures are acidophilic. 2- Basic stain: e.g. hematoxylin which stains acidic structures so these structures are basophilic. 3- Neutral stains: e.g. Leishman's stain. It is a combination of an acidic & a basic stain for staining of blood cells 4- Vital stain: It is used to stain a living structure inside a living animal such as staining of phagocytic cells using trypan blue or India ink. 5- Supravital stain: It can stain a living cell outside a living person e.g. Brilliant cresyl blue which stains reticulocytes (immature RBCs) 6- Metachromatic stain: It will give a new color after staining which is different from its original color. 7- Orcein stain for elastic fibers, they take brown color. 8- Silver stain: It can stain reticular fibers with brown or black color, it is also used to demonstrate Golgi apparatus in the cell. 9- Osmic acid: It stains myelin sheath with black colour. 10- Histochemical & cytochemical stains: These stains localize & demonstrate certain substance within a tissue or a cell depending on a biochemical reaction e.g. I- Glycogen can be stained red by Best's carmine. II- Lipids (fat) can be stained black with Sudan black & orange with Sudan III. III- Enzymes can also be stained using special methods e.g. acid & alkaline phosphatase enzymes - Cell The cell is the functional & structural unit of all living tissues. - The cell is the smallest living structure which has vital properties such as growth, secretion, excretion, digestion, contraction, respiration & reproduction. - The cells of the body are variable in shape, size& functions but they are similar in composition: I. Cytoplasm. II. Nucleus.  cell cytoplasm nucleus Inclusion Organelles They are permanent minute living They are non- living structures that are essential for the temporary structures, vital processesof all cells e.g. not essential for the respiration, secretion, digestion vitality of the cell.  organelles Membranous Non membranous 1-Cell membrane 1) Ribosomes 2-Mitochondria (2) Cytoskeleton 3-Endoplasmic reticulum A- microtubules 4-Lysosomes Centriole –cilia-flagella 5-Golgi apparatus B- Filamentous structure 6-Peroxisome Thin-intermediate-thick Cell membrane Definition: It is membranous organelles. L.M: Not seen under light L.M seen by special stain Ag, PAS stain very thin(8-10nm). E.M: Two dark thin layer separated by light one.(trilamellar membrane), outer covering rich with carbohydrates called cell coat  Structures of Cell Membrane (Microbiology) ♠Lipid 30%: Phospholipid 2 layers: Polar end (Hydrophilic) Directed out ward & toward cytoplasmic surface carry charge ,Lipid component of the cell membrane allows passage of fat soluble substances through it. Non polar end (Hydro phobic) to directed inward not charged Cholesterol Incorporated with non-polar end. ♠ Proteins 60%: Integral (intrinsic) Protein: Formed of large and small protein large one can trans membrane the cell membrane at both side act as path way for water soluble substance. Peripheral (extrinsic) protein: Small proteins present on extra or intra cellular (both) surface of cell membrane non continuous. ♠ Carbohydrates 10%: Short poly saccharides chain Present on lipid  Glyco lipid and Present on integral proteinGlyco proteins both forming (cell coat) or glycocalex. Functions of the cells membrane: I-Allow passage of substance: 1-Simple Transport: (1)Passive transport (water, salt)molecules cross according to concentration gradient. (2)Facilitated transport (need carrier intrinsic protein)eg: glucouse 2-Active Transport: Need energy cross against to concentration gradient e.g : Sodium pump at polarizing cell 4- Selective permeability: By presence of receptors 3-Bulk Transport (vesicular transport): macromolecule enter & leave cell by vesicular transport through cell membrane By exocytosis or endocytosis cytoplasmic extension: A-Endocyosis: In which substances enter the cell. (1) Phagocytosis: Cell engulf large particle Bacteria, virus to Protect cell. (2)Pinocytosis: Cell pass fluids and water in to cell B-Exocytosis: substance leave outside cell II-Surface Coat : it is glycolipid and glycoprotein Site Outer Surface of cell membrane ONLY Functions of Surface Coat: (1)Recognition. (2) Cell Immunity (3)adhesion III- Keep internal composition of cell.  Mitochondria Definition:Membranous organelles in cell. Responsible for respiration & energy production. Number and sits: It varying in number and function and development according to activity of cell not found at RBCs ,present in liver cells liver cells contain 1000- 2000/ cell. L.M:Seen after staining with iron haemolaxylin & janus green appear as rods, granules or filaments E.M: appear as vesicle rounded or oval in shape covered with double membrane E.M: appear as vesicle rounded or oval in shape covered with double membrane (1) Outer Smooth Layer (2)Inner Incomplete layer and alternating shelves (cristae) increase surface area for deposition of enzymes for oxidative phosphorylation. (3)Matrix: Contain: lipid protein carbohydrate, (A)Oxidative Enzymes. (B)Matrix granules is phosphor lipoprotein bind Ca, Mg (C)DNA,RNA for mitochondrial replication. Functions: (1)Production of energy. (2)Responsible for cell respiration. (3)Responsible for mitochondrial replication.  Endoplasmic Reticulum A) Smooth endoplasmic reticulum B) Rough endoplasmic reticulum  ( Granular Endoplasmic Reticulum) Rough Endoplasmic Reticulum Definition: It is membranous organelles protein forming cell.eg. Plasma cell, fibroblast. It is varying in number size development according to type of cell. L.M: It appears as basophilic area due to ribosomes. E.M: It appears as membrane bounded tubules vesicles or cisternae, sheets on it ribosomes.  Functions:- (1)Responsible for protein synthesis. (2)Condensation and packing of proteins. (3)Transfer of protein to Glogi apparatus. (4)Intra cellular pathway of protein to Golgi apparatus or cell. (5)Share in formation of lysosome by formation of hydrolytic enzyme  )A granular Endoplasmic Reticulum) Smooth Endoplasmic Reticulum Definition: It is membranous organelles of cell. L.M: Not seen ( not demonstrated) (no Ribosomes). E.M: Appears as membrane bounded tubules or vesicles surrounded with smooth membrane. Functions (1)Synthesis and storage of lipid and cholesterol. (2)Synthesis of steroid hormone (3)Storage and formation of glycogen in muscle and liver. (4)In liver it responsible for detoxification of drugs and hormones. (5)In muscle responsible for contraction (Ca pump). (6)Transfer lipid and cholesterol to Golgi apparatus. (7)Intra cellular pathway of lipid to Golgi apparatus.  Golgi apparatus Definition: It is membranous organelles considered as secretory system well developed in protein forming cells and secretory cells. L. M: Golgi apparatus networks of fibrils staining with silver stain. When cell stained with haematoxylin and eosine Golgi apparatus not stained Give Golgi negative image.  Golgi apparatus present between nucleus and secondary pole of cell in nerve cells it surrounds the nucleus(perinuclear).  E. M:  It appears as suecer shape flattened vesicles stacked over each other.  It has 2 faces. (1)Convex Face (Forming)( immature) (cis) facereceive transfer vesicles as protein from RER (2)Concave Face :(Mature face) secretory vesicles come out carrying condensed& modified protein Function: (1)Concentration of proteins and lipid from rough and smooth endoplasmic reticular. (2)Modification of proteins and lipid by coupling to carbohydrates. (3)Secretion of modified material may be hormones or enzymes (secretory vesicles). (4)Isolation and packing of hydrolytic enzymes in lysosomes, (5)Production and maintenance of cell membrane.  Lysosomes Definition: Membranous organelles rich in hydrolytic enzymes. considered as the digestive system of the cell. Number: They are numerous in phagocytic cells e.g. white blood cells. Origin: The hydrolytic enzymes are formed in rER &carried in transfer vesicles to Golgi apparatus &come out as primary lysosomes  Lysosomes E.M: Vesicles formed from and enzymes at Golgi apparatus formed of from RER Primary lysosomes: newly formed lysosomes homogenous vesicles surrounded single membrane.  Lysosomes Secondary lysosomes:It is Heterogeneous vesicles. It is primary lysosomes engulf macromolecules (1)Heterolysosomes:Fusion of primary lysosome with bacteria or virus (Phagosomes). (2) Multivesicular lysosome :It is primary fusion of lysosome with pinocytic vesicles. (3)Auto lysosome:fusion primary of lysosome with any old Organelles e.g dead mitochondria. (4)Residual bodies: It is secondary lysosome with undigested ruminants as lipofuscin granules in long lived cells as nerve and cardiac Function of Lysosomes: (1)Digestion of Nutrient materials absorbed by cell. (2)Defensive, destruction of Bacteria, virus (Phagocytosis). (3)Removal of any dreaded organelles. (4)Lysis of deeded cells and body after death (autolysis). (5)Change inactive hormone into active one as thyroid hormone (6)Help sperm to penetrate ovum