Cytology 1 & 2 PDF Notes

1.Enumerate the molecules constituting the cell membrane. Give short notes on the part that allow the passage of water-soluble molecules. Lipid component phospholipid bilayer, cholesterol Protein component peripheral proteins ,integral proteins Carbohydrate component Proteins allows passage of w...

1.Enumerate the molecules constituting the cell membrane. Give short notes on the part that allow the passage of water-soluble molecules. Lipid component phospholipid bilayer, cholesterol Protein component peripheral proteins ,integral proteins Carbohydrate component Proteins allows passage of water soluble molecules are present with in the lipid bilayer 2. Discuss the lipid part of the cell membrane. Phospholipid bilayer : It is basic structure, Act as barrier ,Heads: phosphate group and hydrophilic ,Tails: lipids (fatty acids) and hydrophopic Cholesterol molecules Present in lipid bilayer Fill the gaps between fatty acids tails. 3. Give short note on the cell coat "glycocalyx" with special reference to its importance. Oligosaccharide chans are conjugated to membrane proteins : glycoproteins membrane lipids : glycolipids cellrecognition , protection ,intercellular adhesion 4. Enumerate components of the nucleus. nuclear envelope ¸ nuclear sap ¸chromatin , nucleolus 5. Give short account on the structure of the nuclear envelope. two parallel unite membrane outer and inner nuclear are separated from each by perinclearspace Outer membrane : studded with ribosomes Inner membrane : have condensation of chromatin The nuclear envelope have nuclear pores covered by thin diagram 6. Give short notes on the type of chromatin. Composed mainly of stands of DNA in two forms Euchromatin Heterochromatin extended chromatin and active form condensed chromatin and inactive form ▪ Peripheral chromatin ▪The nucleus contains mainly euchromatin appears pale ▪ Islands of chromatin by LM ▪ Nucleolus associated chromatin ▪ It control protein synthesis in the cells ▪ The nucleus contains mainly heterochromatin appears dark basophilic by LM 7 Describe the structure of the nucleolus with special reference to its function ▪ It is composed of: DNA, rRNA, Basic Protein By LM: appear small rounded basophilic bodies. By EM: appears as electron dense (dark) network without surrounded membrane it is responsible for formation of ribosome and protein synthesis 1 Enumerate cytoplasmic membranous organelles & Give short account on ATP producing one Endoplasmicnreticlum , golgi apparatus , mitochondria, lysosomes , nucleus Mitochondria : Def: are membranous organelles responsible for energy production. Number: increase in cells with high metabolic activity e.g. liver & musclecell By L.M.: They appear as granules or rods by special stains as acid fuchsin or sliver. by E.M : Rounded or oval vesicle. Surrounded by two membranes: The outer membrane is smooth ,The inner membrane forms incomplete shelves called cristae. Fun power houses produce ATP Self replicating organelles by simple fission 2. Compare between RER &SER. Rough endoplasmic reticulum Smooth Endoplasmic Reticulum in cells for protein In steroid secreting secretion e.g. plasma cells, Cells (Adrenal cortex) pancreatic acinar cells LM It shows localized cytoplasmic Not been seen but gives acidophilic basophilia (due to ribosomes (r-RNA) EM Parallel interconnected flattened it consists of network of anastomosing tubuls. cisternae Their outer surfaces are Outer surface no ribosomes. covered with ribosomes Protein synthesis: By attached ribosomes Synthesis of membrane phospholipids and Secretory protein cholesterol. Cell membrane proteinLysosomal enzyme Steroid hormones. Transport vesicle buds off Ribosome Pump Calcium. Packing of formed protein in transfer Detoxification of drugs and toxins. vesicles Breakdown of glycogen to glucose in liver cells. 3. Give short note on EM picture of Golgi saccules. Flattened parallel curved saccules; interconnected & arranged one above the other forming a stack. Each stack has 2 surfaces: (Cis face) (Trans face) Immature face Mature face Convex concave Receive transfer vesicles originating From which secretory vesicles from RER and carry newly synthesized containing mature secretion arise proteins. 4. Discuss histological structure (LM &EM) of lysosomes. LM EM They can be seen by specific histochemical They are rounded small membranous vesicles reactions that show their enzymatic activity. which are classified into: a- Primary lysosomes: that contain hydrolytic digestive enzymes, which are synthesized in RER, then transferred to Golgi, where lysosomes bud from. They are homogenous. b- Secondary lysosomes: are formed when primary lysosomes interact with other substance. They are heterogenous