COURSE CODE: 102

COURSE CODE: 102. Dr. Muhammad Umair SEMESTER:1 (Fall 2021) REFERENCE TEXT BOOK: TEXTBOOK OF MEDICAL PHYSIOLOGY GYTON & HALL.

OVERVIEW. Environment Fluid and its compartments Homeostasis Factors that are homeostatically regulated Systems regulating homeostasis Feed back mechanisms.

Image result for human cell 3d. TODAY’S TOPIC. CELL ORGANIZATION,CELL MEMBRANE,CELL ADHESION MOLECULES,CELL OGRANELLES,PHAGOCYTOSIS ,ENDOCYTOSIS AND PINOCYTOSIS.

OUTLINE. Cell Organization Cell Membrane Cell adhesion molecules Cell Organelles Phagocytosis Endocytosis Pinocytosis.

CELL PHYSIOLOGY. Basic living unit of body Entire body contains almost 100 trillions cells.

ORGANIZATION OF CELL. 2 major components of cell. Nucelus Cytoplasm.

ORGANIZATION OF CELL. Different substances that makeup cell collectively called protoplasm Protoplasm is composed of: Water Electrolytes Proteins Lipids Carbohydrates.

CELL MEMBRANE. Outermost limit of a cell More than a simple boundary surrounding the cellular contents Many metabolic reactions take place on its surfaces.

Structure of the Cell Membrane Lipid Bilayer Transport Protein Outside of cell Carbohydrate chains Proteins Phospholipids Inside of cell (cytoplasm).

GENERAL CHARACTERISTICS. Extremely thin Flexibl e and elastic Complex surface features with Outpouchings and Infoldings Increase surface area.

GENERAL CHARACTERISTICS. If damaged Cell membrane quickly seals tiny breaks If damage is extensive Cell contents escape The cell dies.

CELL MEMBRANE STRUCTURE. Composed of lipids and proteins, with some carbohydrate Phospholipid bilayer Heads contain phosphate groups Form the surfaces of the membrane Water-soluble (hydrophilic or “water-loving”).

hydrophobic tail phospholipid polar nonpolar polar carbohydrate chain glycoprotein external membrane surface phospholipid bilayer internal membrane protein surface cholesterol cytoskeleton filaments.

CELL MEMBRANE STRUCTURE. Tails consisting of fatty acid chains, Make up the interior of the membrane Water insoluble (hydrophobic or “water-fearing”).

INTERIOR OF CELL MEMBRANE. Consists of the fatty acid portions Lipids soluble molecules can pass through this layer Oxygen Carbon dioxide Steroid hormones Impermeable to water-soluble molecules Amino acids Sugars Proteins Nucleic acids Various ions.

SPECIALIZED PROTEINS. Cell membrane includes many kinds of specialized proteins globular proteins fibrous proteins.

FIBROUS PROTEINS. Extend outward from its surface on one end They are water insoluble. They have supporting functions..

INTEGRAL PROTEINS. Form “ pores ” in the membrane Allow water molecules to pass through Other are highly selective Form channels that allow only particular ions to enter.

INTEGRAL PROTEINS. a Peripheral Protein Integral o y rates Channel Phosph Bilay Peripheral Protein.

PERIPHERAL PROTEINS. Function as enzymes Many are part of signal transduction Associated carbohydrate groups form glycoproteins Help cells to recognize and bind to each other Mark the cells of an individual as self.

PERIPHERAL PROTEINS. Peripheral Protein Phospholipid Bilayer Peripheral Protein Integral Protein Peripheral Protein.

CELLULAR ADHESION MOLECULES. Proteins located on the cell surface Involved in binding With other cells or With the extracellular matrix ( ECM ) Process called cell adhesion Selectin Integrin.

INTERCELLULAR JUNCTIONS. Cells are tightly packed by Structures called intercellular junctions Connecting their cell membranes.

TYPES OF JUNCTIONS. Tight junction Desmosome Gap junctions.

Interlocking junctional proteins Intercellular space (a) Tight Impermeable junctions prevent molecules from passing through the intercellular space. O 3 Pearson Educat*.n. Plasma membranes of adjacent cells Intermediate filament (keratin) Microvilli fltfii tl Intercellular space Basement membrane Intercellular space Plaque Linker proteins (cadherins) Intercellular space Channel between cells (formed by connexons) (b) Anchoring junctions bind adjacent cells together like a molecular "Velcro" and help form an internal tension- reducing network of fibers. (c) Gap junctions: Communicating junctions allow ions and small molecules to pass for intercellular communication..

TIGHT JUNCTIONS. The membranes of adjacent cells Converge and Fuse Junction closes the space between the cells Cells that form sheet like layers joined by tight junctions Digestive tract.

TIGHT JUNCTIONS.

Three-dimensional view of tight junctions Tight junction Plasma membranes of adjacent cells Membrane proteins that form tight junctions Figure 8-9b Biological Science, 2/e @ 2005 Pearson Prentice Hall, Inc..

DESMOSOME. Circular, dense body Attachment between certain epithelial cells Stratified epithelium of the epidermis “Spot welds” adjacent skin cells.

DESMOSOME.

Three-dimensional view of desmosome Plasma membranes of adjacent cells Anchoring proteins in each cell Membrane proteins that link cells Intermediate filaments Figure 8-10b Biological Science, 2/e @ 2005 Pearson Prentice Hall, Inc..

GAP JUNCTIONS. Link the cytoplasm of adjacent cells Form tubular channels Present in heart muscle and muscle of the digestive tract Allow movement of Ions Nutrients (such as sugars, amino acids, and nucleotides) Other small molecules.

Gap junctions create gaps that connect animal cells. 111 111 Gap junctions Figure 8-13b part2 Biological Science,2/e Membrane proteins from adjacent cells line up to form a channel @2005 Pearson Prentice Hall, Inc..

JUNCTIONS.

CYTOPLASM. Appears as clear jelly Contains networks of membranes and organelles suspended in a clear liquid called cytosol Activities of a cell mostly occur in cytoplasm.

Picture.

ENDOPLASMIC RETICULUM. Composed of membrane-bound Flattened sacs Elongated canals Fluid-filled vesicles These are interconnected.

ENDOPLASMIC RETICULUM. Also communicate with Cell membrane Nuclear envelope Certain cytoplasmic organelles.

FUNCTION OF ER. Widely distributed through the cytoplasm Provide a tubular transport system for molecules Participates in the synthesis of Proteins Lipid molecules.

TYPES OF ER. Rough ER Studded with many tiny, spherical organelles Called ribosomes The ribosomes of rough ER are Sites of protein synthesis.

TYPES OF ER. Smooth ER Lacks ribosomes Contains enzymes Important in lipid synthesis.

Nucleus Ribosomes.

RIBOSOMES. Scattered freely throughout the cytoplasm Composed of protein and RNA Provide a structural support to cell Serves as the primary site of biological protein synthesis.

FUNCTIONAL SYSTEMS OF CELL. Nutrients pass through cell membrane by Diffusion Active transport.

DIFFUSION. Simple movement through Cell membrane Lipid matrix of cell membrane.

Simple Diffusion: The movement of particles or molecules from a region of higher concentration to a region of a lower concentration is called diffusion..

FACILITATED DIFFUSION. Facilitated diffusion is the process of spontaneous passive transport of molecules or ions across a cell's membrane via specific transmembrane integral proteins..

OSMOSIS. Movement of a solvent (as water) through a semipermeable membrane (as of a living cell) into a solution of higher solute concentration that tends to equalize the concentrations of solute on the two sides of the membrane..