MBBS 1st Lecture 2023 on Cell Physiology PDF

1st Lecture 2023 [email protected]  Physiology of the Cell, Nerve and Muscle References (Textbooks): ✓ The slides and contents in the class ✓ Guyton and Hall Textbook of Medical Physiology (latest version) ✓ Berne and Levy Physiology (7th edition)...

1st Lecture 2023 [email protected]  Physiology of the Cell, Nerve and Muscle References (Textbooks): ✓ The slides and contents in the class ✓ Guyton and Hall Textbook of Medical Physiology (latest version) ✓ Berne and Levy Physiology (7th edition) 2  Overview and review of cell organelles and their biological functions Principles of Homeostasis Structure and functions of a cell membrane Transport across biological membranes Fluid compartment of the body, its ionic composition & measurements Molecular basis of Resting Membrane Potential and Action Potential in excitable tissue Structure and functions of a neuron Synaptic transmission Skeletal and Smooth Muscle Physiology  The Cell Physiology The term physiology literally means After this lecture, you should be able to understand the structures and specific functions of the Cellular Organelles.  What is Physiology? The term physiology literally means ❖ Cells are tiny units of life that are like specialized factories, full of machinery designed to accomplish the business of life. ❖ There are two main types of cells, Prokaryotic and Eukaryotic. Prokaryotes are cells that do not have membrane bound nuclei, whereas eukaryotes do. What does Cell Physiology deal with?  Organelle Function Factory part Room where the blueprints are Nucleus DNA Storage kept Mitochondrion Energy production Powerplant Smooth Endoplasmic Lipid production; Accessory production - makes Reticulum (SER) Detoxification decorations for the toy, etc. Protein production; in Rough Endoplasmic Primary production line - particular for export out of Reticulum (RER) makes the toys the cell Protein modification and Golgi apparatus Shipping department export Lipid Destruction; contains Peroxisome Security and waste removal oxidative enzymes Lysosome Protein destruction Recycling and security Nucleus Endoplasmic Reticulum Ca2+ storage Protein synthesis Lipid metabolism Rough ER Smooth ER  Golgi apparatus Golgi identifies the molecule and sets it on one of 4 paths: Cytosol Cell membrane Secretion Lysosome Lysosome the breakdown/digestion Cell membrane repairs Responses against foreign substances such as bacteria, viruses and other antigens.  Approximately 60-150 known enzymes are present in the matrix of peroxisomes. They are responsible for carrying out oxidation reactions leading to the production of Hydrogen Peroxide. The main groups of enzymes include: 1.Urate oxidase 2.D-amino acid oxidase 3.Catalase  Functions of Peroxisomes Hydrogen Fatty Lipid Peroxide acid Metabolism oxidation biosynthesis H2O2  Some of the major regions of mitochondria include: Outer Membrane: This outer portion includes proteins called porins, which form channels that allow proteins to cross. Intermembrane Space: area between the inner and outer membranes. Inner Membrane: The inner membrane is where most ATP is created. Cristae: folds of the inner membrane, increase the surface area Matrix: space within the inner membrane Mitochondrial DNA is housed Some of the surprising truths about mitochondria: ▪ Different cell types have different numbers of mitochondria. ▪ Cells with a high demand for energy tend to have greater numbers of mitochondria. ▪ Although mitochondria are often drawn as oval-shaped organelles, they are constantly dividing (fission) and bonding together (fusion). So, in reality, these organelles are linked together in ever-changing networks. ▪ Also, in sperm cells, the mitochondria are spiraled in the midpiece and provide energy for tail motion. o Found in all Excitable Cells [Ca2+]i Three Best Studied Roles: o Shapes the Regenerative A.P. 1. Contraction of Muscle 2. Secretion 3. Gating Mitochondrial disease:  Symptoms of a mitochondrial disease Although symptoms of mitochondrial disease vary greatly, they might include: ❖ loss of muscle coordination and weakness ❖ problems with vision or hearing ❖ learning disabilities ❖ heart, liver, or kidney disease ❖ gastrointestinal problems ❖ neurological problems, including dementia Mitochondrial defects in central nervous system disorders Electrolyte Mitophagy imbalances Membrane Apoptotic pathway leakage activation Alzheimer’s disease Parkinson’s disease mechanisms implicated in the pathogenesis of Huntington’s disease neurodegenerative diseases as well as ischemic stroke Other conditions that are thought to involve some level of mitochondrial dysfunction, include: ❖ Parkinson’s disease ❖ Alzheimer’s disease ❖ bipolar disorder ❖ schizophrenia ❖ chronic fatigue syndrome ❖ Huntington’s disease ❖ diabetes ❖ autism [email protected]