General Physiology PDF

Introduction to Physiology 1  Medical Physiology The practice of Medicine depends upon assessment bodily function, and medical students must learn how to determine to what extent a patient’s function differs from normal physiology....

Introduction to Physiology 1  Medical Physiology The practice of Medicine depends upon assessment bodily function, and medical students must learn how to determine to what extent a patient’s function differs from normal physiology. 2  General Physiology Cell physiology – cell structure and division, tissue organization. Transport across cell membrane. Body fluid compartment, measurements and homeostasis. 3 Organization of Cell 4  Organization Cell- The basic structural units of all living organisms Tissue- The cells having a common origin and performing a similar but specific function 5  Organization—contd. Organ. Several types of tissues may join collectively to form that carries out one or more specific functions System. several organs are interrelated to perform a specific function 6  Cell Physiology Cell membrane Cell organelles – endoplasmic reticulum, golgi apparatus, mitochondria, lysosomes, peroxisomes 7 Cell 8 9 10 11  Cell Membrane Boundary of the cell Made of a phospholipid bilayer 12 13  Cell - cytoplasm The cytoplasm is made up of 5 different substances : water, electrolytes, protein, lipids and carbohydrates 14  Cell cytoplasm Cell organelles – endoplasmic reticulum, golgi apparatus, mitochondria, lysosomes, peroxisomes 15  Endoplasmic reticulum It’s a network of tubular and flat vesicular structures. The space inside is filled with “endoplasmic matrix” It processes the molecules made by the cell It transports them to specific destination inside the cell Connected to nuclear membrane Rough ER: studded with ribosomes; it makes proteins Smooth ER: no ribosomes; it makes lipids 16 Types of ER 17 Endoplasmic reticulum 18  Golgi Apparatus Looks like a stack of plates Stores, modifies and packages proteins Molecules transported to and from the Golgi by means of vesicles 19 20  Lysosomes They form by breaking off from Golgi apparatus. They provide intracellular digestive system that allows cells to digest a) damaged cellular material b)unwanted matter such as bacteria. 40 different hydrolase enzymes seen. Protein is hydrolyzed to amino acids. 21 22  Peroxisomes They form by breaking off from endoplasmic reticulum. They provide intracellular digestive system. They contain oxidases rather than hydrolase enzyme. 23 Mitochondria 24 Mitochondria - ATP 25  Ribosome Site of protein synthesis Found attached to rough ER or floating free in cytosol Produced in a part of the nucleus called the nucleolus 26  Cytoskeleton The cytoskeleton is responsible for cell shape, motility (movement) of the cell as a whole, and motility of organelles within a cell. There are three types of filaments in the cytoplasm of most vertebrate cells: microfilaments, microtubules, and intermediate filaments. 27  Cytoskeleton Acts as skeleton and muscle Provides shape and structure Helps move organelles around the cell Made of three types of filaments 28 Nucleus 29  Nucleus 1. Control center of the cell 2. Contains DNA 3. Surrounded by a double membrane 4. Usually the easiest organelle to see under a microscope 5. Usually one per cell 30  Transport mechanisms 31  Learning objectives Passive Transport o Diffusion – simple and facilitated o Osmosis Active transport o Primary o secondary 32  Passive Transport cell uses no energy molecules move randomly Molecules spread out from an area of high concentration to an area of low concentration. (HighLow) Three types are seen 33 3 Types of Passive Transport 1. Simple Diffusion 2. Facilitative Diffusion – diffusion with the help of transport proteins 3. Osmosis – diffusion of water 34  Passive Transport: 1. Simple Diffusion Simple Diffusion Ani mation 1. Diffusion: random movement of particles from an area of high concentration to an area of low concentration. (High to Low) Diffusion continues until all molecules are evenly spaced (equilibrium is reached) 35 Simple diffusion Eg:- Oxygen 36  Passive Transport: 2. Facilitated Diffusion 2. Facilitated diffusion: diffusion of specific particles through transport proteins found in the membrane a.Transport Proteins are specific – they “select” only certain molecules to cross the membrane b.Transports larger or charged molecules c.Eg:- glucose and amino acid 37 Facilitated diffusion 38 Passive Transport: 3. Osmosis It is the diffusion of water through a selectively permeable membrane Water moves from high to low concentrations Water moves freely through pores. Solute (green) are too large to move across. 39 40  Isotonic Solution Isotonic: The concentration of solutes in the solution is equal to the concentration of solutes inside the cell. Result: Water moves equally in both directions and the cell remains same size! (Dynamic Equilibrium) 41  Hypotonic Solution Hypotonic: The solution has a lower concentration of solutes and a higher concentration of water than inside the cell. (Low solute; High water) Result: Water moves from the solution to inside the cell): Cell Swells and bursts open (cytolysis)! 42  Hypertonic Solution Hypertonic: The solution has a higher concentration of solutes and a lower concentration of water than inside the cell. (High solute; Low water) Result: Water moves from inside the cell into the solution: Cell shrinks (Plasmolysis)! 43  Active Transport Cell uses energy Actively moves molecules from an area of low concentration to an area of high concentration (Low  High) Uses a carrier protein. 44  Types of Active Transport 1.Primary active transport Eg:- sodium-potassium pump 2.Secondary active transport Co-transport(symport) Eg:- sodium-glucose pump Counter transport(antiport) Eg:- sodium- hydrogen pump 45 46 47 48  Other Types of Transport Endocytosis: takes bulky material into a cell - Uses energy - Cell membrane in- folds around food particle“cell eating”. - It forms food vacuole & digests food. This is how white blood cells eat bacteria! 49  Other Types of Transport Exocytosis: Forces material Endocytosis & E xocytosis out of cell in bulk animations membrane surrounding the material fuses with cell membrane Cell changes shape – requires energy EX: Hormones or wastes released from cell 50 Body fluid compartments 51  Learning Objective Distribution of body fluids Normal value Composition of different compartments Measurement of different compartments 52  The concept of homeostasis The term "homeostasis" refers to the maintenance of constancy of the internal environment such as temperature or pH etc. It was defined by Claude Bernard and later by Walter Bradford Cannon in 1926 An advantage of homeostatic regulation is that it allows an organism to function effectively in a broad range of environmental conditions 53  70 kg young adult male Total body water is 60% of the body weight 18% of body wt is proteins and related substance 15% of body wt is fat 7% of body wt is mineral 54  Body fluid Extracellular Intracellular fluid fluid Interstitial Transcellular fluid Plasma fluid Compartments of body fluids 55 56  Distribution of IONs between ICF and ECF ECF(meq/L H2O) ICF (meq/L H2O) Na+(meq/L H2O) 135-147 10-15 K+(meq/L H2O) 3.5-5 120-150 Cl-(meq/L H2O) 95-105 4 HCO3-(meq/L H2O) 24 10 Proteins(meq/L) 15 60 Phosphates(meq/L) 2 90 pH 7.4 7.3- 7.5 57 58  Positive Feedback Positive feedback is the body's mechanism to enhance a output needed to maintain homeostasis An example of positive feedback is the release of oxytocin to increase and keep the contractions of child birth happening as long as needed for the child's birth 59 Positive feed back mechanism 60  Negative Feedback With negative feedback, any change from the normal range of function, causes the negative feedback mechanisms to resist or oppose the change, bringing the function back to normal ranges. 61 Negative feed back mechanism 62 Thank you 63