Cytology Part 3 PDF

# CYTOLOGY - Part 3 ## **Part 1** * **SEEK YOUR DREAM** AND YOU WILL REACH IT * **BIOLOGY** * BIO * LIFE * **CYTOLOGY - Part 3** * MOHAMMED WALID ELĊANAI * **More information call us** * 0919072560 * **Online BIOLOGY** * FOR PRE-MEDICAL STUDENT * **المصدر / الكتاب الجامعي**...

# CYTOLOGY - Part 3 ## **Part 1** * **SEEK YOUR DREAM** AND YOU WILL REACH IT * **BIOLOGY** * BIO * LIFE * **CYTOLOGY - Part 3** * MOHAMMED WALID ELĊANAI * **More information call us** * 0919072560 * **Online BIOLOGY** * FOR PRE-MEDICAL STUDENT * **المصدر / الكتاب الجامعي** * **محمد الغناي** * **@Biology_2003** * **شرح بايو اعداد طب** ## **Part 2** ### **TRANSPORT MECHANISM** * **The way in which materials transferred cross the cell** * There are 2 basic types of transport: * **Passive**: which no energy * **Active**: that's generally employ ATP ### **ACTIVE transport** * **K NA PUMP** * **ENDOCYTOSIS** * **PHAGOCYTOSIS** * **PINOCYTOSIS** * **EXOCYTOSIS** ### **PASSIVE transport** * **SIMPLE DIFFUSION** * **OSMOSIS** * **FACILLITATED diffusion** ### **1 - PASSIVE TRANSPORT** * **SIMPLE DIFFUSION** * **IS** the movement of substance from **high** concentration to area **lower concentration**. * Play important role in spreading the **exchange** of materials between the cell and in the surrounding medium, and these materials are: * Oxygen * Carbon di oxide &substances that dissolve in lipids ### **2-OSMOSIS** * Is the net movement of water from a **high water concentrate** to **low water concentrate** through a partially permeable membrane. ## **Part 3** ### **TYPES OF SOLUTION** * **Hypertonic solution**: The solution surrounding the cell have higher solute concentration. * **Hypotonic solution**: the solution surrounding a cell have lower solute concentration. * **Isotonic solution**: The solution surrounding a cell have same solute concentration. | Solution | Solution concentration | Direction of osmosis | |---|---|---| | Hypotonic | Lower than cell | Into cell | | Hypertonic | Higher than cell | Out of cell | | Isotonic | Same as cell | No net movement| ### **3 - FACILITED DIFFUSION** * Molecules are carried from **high** to **low** concentration assisted by **protein carrier**. ### **2 - Active transport** * Its mechanism require the use of the **cell energy**, usually in form of ATP. * A substance must move into the cell against its concentration gradient. #### **A. sodium potassium pump**: (Na, K-ATPase) * Its function in the active transport of sodium & potassium across the cell membrane against concentration gradients. * **For each ATP** the pump break down, Two potassium ions are transported into the cell and 3 sodium ions out of the cell. ## **Part 4** ### **B -Bulk transport (Vesicle Mediated transport)** ### **1 - PHAGOCYTOSIS** * is the process by which a cell a engulfs a solid particles * Such as macromolecules, parts of cell or whole cell. * In phagocytosis a portion of membrane invaginates & flow around the particle, eventually pinching off & leaving the particle entirely enclosed by plasma membrane. ### **2 - Pinocytosis** * is the process by which a cell absorbs fluids outside the cell & brings them inside. * Its similar to phagocytosis but smaller scale. * The plasma membrane invaginates & pinches off, producing a small envelope of fluid from outside the cell. * Pincytosis imports substances that the cell needs from extracellular fluid. ### **3 - Exocytosis** * M1 a process by which materials transported out of the cell. ### **EXTRACELLULAR MATRIX OF ANIMAL CELL** * Most animals cells release materials into the extracellular matrix. * The primary components of these materials are proteins & most abundant protein is collagen. * Collagen fibers are interwoven with carbohydrate containing proteins called proteoglycans. * All these materials called extracellular matrix. * ECM hold cells together to form tissue & allow the cells to communicate with each others. ## **Part 5** ### **INTERCELLULAR JUNCTIONS** * Cells can communicate with each others via direct contact, reffered to as intercellular junctions. * The junctions between plant cells called plasmodesmata. * The junctions between animal cells include tight junctions, gap junction & desmosomes. ### **Gap junction** * Present in the animal cells, are channels between adjacent cells that allows for the transport of ions, nutrients & other substances. * Gap junction are particularly important in cardiac muscle (the electrical signals for the muscle to contract is passed through gap junction).