Delta University Level 1 Basic Science PDF

# Faculty of Medicine, Delta University for Science and Technology ## Level 1, Semester 1 - Module (Basic science) ### **Contact:** - Prof. Dr. Samar Asker - Department: Histology - Official email: [email protected] ### Academic hours: - ... day: 00:00-00:00 AM - ... day: 00:00-00:00 AM...

# Faculty of Medicine, Delta University for Science and Technology ## Level 1, Semester 1 - Module (Basic science) ### **Contact:** - Prof. Dr. Samar Asker - Department: Histology - Official email: [email protected] ### Academic hours: - ... day: 00:00-00:00 AM - ... day: 00:00-00:00 AM ## The Cell A diagram of an animal cell with labelled organelles. ### Learning Outcomes - Identify the histological structure of the cell. - Identify the histological structure of the membranous cell organelles at both light and electron microscope levels. - Recognize the functional significance of the membranous cell organelles. - Correlate the structure of the membranous cell organelles to their functions. ### Cell organelles: - **Membranous:** - Cell membrane - Mitochondria - Endoplasmic reticulum (smooth & rough) - Golgi apparatus - Lysosomes - **Non-membranous:** - Ribosomes - Cytoskeleton (microtubules as centriole, cilia & filaments as thin, intermediate & thick) ## Lysosomes - Membranous organelles - Contain a large variety of acid hydrolases for intra-cytoplasmic digestion. - **Stain:** - H&E: - Histochemically: for acid phosphatase activity. - **Site:** cytoplasm of all cells, but abundant in cells which have phagocytic activity like macrophages. ### EM (Electron Microscopy) - Two types: - **Primary lysosomes:** - Spherical membrane bounded vesicles - Contain many hydrolytic enzymes. - Homogenous moderate electron dense granular core. - Not yet engaged in intra-cellular digestion. - Smaller - **Secondary lysosomes:** - Heterogenous electron dense core. - Engaged in intra-cellular digestion. - Larger ### Secondary lysosomes - A diagram showing a primary and secondary lysosome fusing. - Secondary lysosomes form when a primary lysosome fuses with a phagosome, pinocytotic vesicles, or a dead organelle. - The contents of the phagosome, pinocytotic vesicles, or dead organelle are digested by the enzymes in the lysosome. - The remaining undigested portion is called a residual body. - The residual body is expelled outside the cell by exocytosis. - Types of secondary lysosomes includes: - **Heterolysosome:** Formed by the fusion of a primary lysosome with a phagosome. - **Multi-vesicular body:** Formed when the fusion of a primary lysosomes with pinocytotic vesicles. - **Autophagic vacuole:** Formed when the fusion of a primary lysosome with dead organelle. - Residual bodies can accumulate in cells such as liver, heart, and nerve cells as lipofuscin pigment (wear and tear pigment). ### Functions of Lysosomes: - Digestion of nutrient within cells. - Defensive. - Removal of old organelles. - Change of inactive hormone to an active one. - Help sperm to penetrate the ovum - Post mortem degeneration and autolysis. ## Peroxisomes - Tiny spherical membrane bounded organelles. - **Contains:** - Hydroxy acid oxidase - D-amino acid oxidase. - Uricase (in rodents only) - Catalase enzyme converts H2O2 → H2O + O2. ### LM and EM - **LM:** - H&E: Cannot be identified. - Hisochemically: for catalase enzyme - **EM:** - **In human:** membrane bounded vesicles containing a homogenous electron dense granular material. - **In rodents:** possess an electron dense semicrystalline core rich in uricase enzyme. ### Functions of Peroxisomes: - Segregate the developing H2O2 and protect the cell from its damaging effect. - Important for formation of bile acids. - B-oxidation of long chain fatty acids. - Play role in the metabolism of alcohol. ## It's MCQ Time! A diagram of a person holding their head, with a large question mark behind them. ### Lysosomes : - **a)** Contain catalase enzyme. - **b)** Are histochemically studied by acid phosphatase activity. - **c)** Measure 2 - 4 µm in diameter. - **d)** Contain D amino acid oxidase. - **e)** Are abundant in protein synthesizing cells. ## Practical! A diagram of a light microscope. ### Practical observations: - A diagram of a cell under a microscope, labelled with primary lysosomes, secondary lysosomes, and mitochondria. - Primary lysosomes: Smaller and round. - Secondary lysosomes: Larger and less round, contain a wide range of sizes, shapes, and contents. - mitochondria: rod-shaped, contain many folds within. - A diagram showing heterolysosomes. - A diagram of an autophagic vacuole. - A diagram of lipofuscin pigment in nerve cells. ## Thank you A diagram of a hand holding a pen.