PHYSIOLOGY.pdf

Physiology PHYSIOLOGY Physio- Functional logy- Study The science of life A branch of biology that aims to understand the mechanisms of living things  Cell Physiology NOTE: 60% OF MICROBIOTA- communities of microorganisms that inhabit the body THE BODY -...

Physiology PHYSIOLOGY Physio- Functional logy- Study The science of life A branch of biology that aims to understand the mechanisms of living things  Cell Physiology NOTE: 60% OF MICROBIOTA- communities of microorganisms that inhabit the body THE BODY - It can also cause diseases, but most of the time they live in harmony with their human hosts and provide vital functions that are essential CONSISTS for sur vival of their hosts. OF FLUIDS 7 Extracellular Fluid Intracellular Fluid 40%- ECF 20% ICF one-third of the spaces outside most of the fluid is inside the cell of the cell contains large amounts of: ECF contains large amount of: - Potassium (K+) Na+ - Sodium (Na+) - Magnesium (Mg+) Cl+ - Chloride (Cl+) - Phosphate Ions HC03 - Bicarbonate ions (HC03) - Sulfate Plus nutrients of the cells which - Organic Anion (Oa) ICF are: Contains large amount of K+ - Oxygen potassium but only small Mg+ - Glucose amount of sodium Phosphate - Fatty Acids Concentration of phosphates Sulfate - Amino Acids and proteins are greater than Also contains carbon dioxide extracellular fluids 11 Contains large amount of sodium but only small amount Most abundant positive ion is Potassium of potassium Most abundant negative ion is Most abundant positive ion is Organic Anion Chloride and negative ion is Sodium The Extracellular Fluid is also called the internal environment of the body, or the milieu intérieur. a term introduced by the great 19th-century French physiologist Claude Bernard (1813–1878). Pronunciation: Mili-u interiu Cell Basic unit of life or smallest unit of life A complex Society of Differentiated Cells Specialized cell — Tissue — Organ — System — Organism Tissues Four types Connective tissue- Tendons Epithelial tissue- Covers smooth organs Muscle tissue- Makes up your muscles Nervous tissue - spread through out your spinal cord and brain Cell It has t wo major parts: Nucleus - separated from the cytoplasm by a nuclear membrane - is the control center of the cell and sends messages to the cell to grow and mature, replicate, or die. - contains large quantities of DNA, which comprise the genes. - genes are determine the characteristics of the cell’s proteins Protoplasm Collective term for the substances that make up the cell: Water Ions Proteins Lipids Carbohydrate- Nutrition and energy Cell membrane Known as plasma membrane Envelops the cell and is a thin, pliable, elastic structure, composed almost entirely of proteins and lipids - Proteins- 55% (Abundant) - Cholesterol- 13% - Other Lipids- 4% - Phospholipids- 25% - Carbohydrates- 3%  Lipids are several types of substances that are grouped together because of their common property of being soluble in fat solvents. Water soluble Two most important lipids are: Phospholipids and Cholesterol substances (carrier protein) Ions Phospholipids and Cholesterol Glucose are mainly insoluble in water Urea used to form the cell membrane and intracellular membrane barriers some cells contain large quantities of triglycerides, also called Fat Solubles neutral fats. Substance Oxygen Lipid Bilayer Carbon which is a thin, double-layered film of lipids that is Dioxide continuous over the entire cell surface Alcohol Composed of 3 main types of lipids Phospholipids Hydrophilic - most abundant cell membrane lipids. - t wo ends of the Phospholipids is: - Hydrophobic: Soluble only in fats - Hydrophilic: Soluble in water / Hydrophobic Sphingolipids - amino alcohol sphingosine, also have hydrophobic and hydrophilic groups - are present in small amounts in the cell membranes, especially nerve cells. Cholesterol - their steroid nuclei are highly fat-soluble. - They mainly help determine the degree of permeability (or impermeability) of the bilayer to water- soluble constituents of body fluids. Main elements Permeability is the state, condition, 1. Bilayer lipid or property of a material to allow th 2. Ampiphatic passage of molecules through it. 3. Semi-permeable Cytoplasm - separated from the surrounding fluids by a plasma membrane. - The cytosol, the jelly-like fluid portion of the cytoplasm, contains mainly dissolved proteins, electrolytes and glucose. - Organelles: Endoplasmic reticulum Golgi apparatus Mitochondria Lysosomes Peroxisomes Endoplasmic Reticulum It helps process molecules made by the cell and transports them into their specific destinations inside or outside the cell It provides enzymes that help breakdown glycogen Endoplasmic matrix- watery medium inside thetubulesand vesicles Sub-classification: Granular Agranular Granular ER It contains Ribosomes(synthesizers of proteins) - Ribosomes are composed of a mixture of RNA and proteins It is also called as rough endoplasmic reticulum Agranular ER Produce lipids It is also called as smooth endoplasmic reticulum It does not contain ribosomes It synthesize lipids and other processes of the cell promoted by intra-reticular enzyme. Golgi Apparatus Composed of thin, flat, enclosed vesicles lying near one side of the nucleus Functions in association with endoplasmic reticulum Synthesizes certain carbohydrates that cannot be formed in the ER Provide fluid for smooth movements inside the body Hyaluronic acid Chondroitin sulfate Lysosomes formed by breaking off from the golgi apparatus Contains hydrolases that is used to split organic compounds Main function: digest damaged cellular structures, food particles that are ingested by the cell and unwanted matter (provides intracellular digestive enzymes) Peroxisomes Formed by self-replication Contains oxidase- forms hydrogen peroxide and used with catalase to oxidaze poisonous substances Main function: Catabolize long chain fatty acids Oxidase detoxifies alcohol Secretory Vesicles Strong vesicles for secretion of special chemical substances Made up of protein Mitochondria Powerhouse of the cell Composed of inner and outer membrane. Cytoskeleton A net work of fibrillary proteins organized into filaments or tubules Microtubules- strong tubular structure that provides a rigid structure for certain cell parts Nucleus Control center of the cell It contains the DNA which contains genes Nuclear Membrane Nuclear Envelope Can found nuclear pores Two separate bilayer membranes, one inside the other - Outer membrane- Continuous with ER Penetrated by thousands of nuclear pores - Where protein molecules are attached to the edges of its pores Nucleoli Does not have limiting membrane An accumulation of large amounts of RNA and proteins Functional Systems of the Cell Cell ingestion Cell digestion Synthesis of cellular structure Energy extraction Endocytosis Exocytosis process of cell ingestion Process of excreting of non- Classifies as either digestible substances - Pinocytosis (cell drinking) - Phagocytosis (cell eating) Pinocytosis( cell drinking) Phagocytosis(cell eating) Ingestion of small Ingestion of large particles in the ECF particles rather than and cytoplasm molecules Only way for Restricted to certain macromolecules to cells such as enter the cell macrophages and some Coated Pits— small WBC pits outside the cell Antibodies are involved membrane in bacterial cases  Exocytosis Process of excreting of non-digestible substances Autolysis vs. Autophagy Autolysis- Self digestion due to severe cell damage (eats its self) Autophagy- Worn out organelles are transferred to lysosomes, either autophagosomes or formation of lysosomal vesicles (no longer useful) ATP NOTE: Adenine, Ribose, and 3 Phosphate Radicals ADP can also Energy currency of the cell be When ATP releases energy, a phosphoric acid radical split away Adenosine and becomes ADP Diphosphate To reconstitute ATP, energy delivered from nutrient causes and ADP and phosphoric acid to recombine ATP is Adenosine Mitosis Apparatus Triphosphate Centrioles- small cylindrical body with tubular structures arranged in a cylinder that are replicated during interphase Shortly before mitosis is to take place, the t wo pairs of centrioles begin to move apart from each other Other microtubules also grow away from each of the centriole pairs, forming a spiny star (aster) in each cell end Spindle- complex of microtubules extending bet ween the t wo new centriole First phase- Prophase Second phase- Prometaphase Third phase- Metaphase Fourth phase- Anaphase Fifth phase- Telophase Cell Death Apoptosis- Natural or programmed cell death Necrosis- Death through swelling and bursting caused by an acute injury Neuromuscular Physiology Neuromuscular physiology - talks about the nerve and muscles of the human body. Two topics Neuro- Nerve Physiology Muscular- Muscle Physiology Membrane and Action Potential Membrane Potential It is a result of concentration difference of ions across a selectively permeable membrane that is caused by diffusion (difference of concentration on ions) Action Potential This are rapid changes in the membrane potential that spread rapidly along the nerve fiber membrane. It begins with a sudden change from the normal resting negative membrane potential to a positive potential and ends vice versa Resting membrane Potential RMP (Resting Membrane Potential) Small= -70mV Large= -90mV Phases of Action Potential Sodium comes inside Resting Stage (Polarization) the cell and then if it Before the action potential begins is too much Potassium leaves the Depolarization Rise of potential in the positive direction cell caused by SODIUM inflow Repolarization Re-establishment of the normal negative membrane potential (RMP) Hyperpolarization (cell becomes too positive) An overshoot of the RMP toward negativity Voltage Gated Na and K Channels Necessary actors in causing depolarization and repolarization NA Channels K Channels Activation: Activation: When the membrane Gate of the potassium potential becomes less channel is closed and negative, it activates the potassium ions are activation gate causing prevented from passing sodium ions to pour inward through Inactivation: Inactivation: The same stimuli for When the membrane activation also closes the potential becomes less inactivation gate. negative causing opening of However, closes a few the gate to allow potassium 10,000ths of a second diffusion. However, it after the activation gate happens with a delay - Initiation of AP Threshold: -65mV - Required sudden rise is 15-30mV Any initial rise in the membrane potential will lead to a positive feedback cycle that would open the sodium channel Ex. Rising voltage in MP causes more Na channels to open Propagation of AP An action potential elicited at any one point on an excitable membrane usually excites adjacent(neighboring) portions of the membrane Action potential propagates in all directions All-or-None Principle The depolarization process travels over the entire membrane if the conditions are right, but it does not travel at all if conditions are not right Allows the spread of depolarization (except if there is an abnormal condition) Plateau The potential remains near the peak of the potential for many milliseconds before repolarization Causes: - Calcium (slow) channels- slow opening allows for prolonged depolarization - Potassium channels- slow activation leads to delayed depolarization Nerve Neuron Dendrites Receives signals from other Dendrites Axon Propagates signals or Action Potential Myelin Sheath Facilitates a faster a conduction of Action Potential Axon Terminals Nerve Fibers # Myelinated Fibers Unmyelinated Fibers Has Myelin Sheath— Has no Myelin Sheath electric insulator Has no Node of Ranvier Has Node of Ranvier — Seen in small fibers uninsulated area Conduction velocity: bet ween sheaths 0.25m/sec Seen in large fibers Conduction velocity: 100 m/sec Myelinated Nerve Fiber: Unmyelinated Nerve Fiber Alpha Nerve Fibers Delta Nerve Fiber Beta Nerve Fibers Gama Nerve Fibers Simple Diffusion Facilitated Diffusion Active Transport Passive Transport Takes 4 forms: Simple diffusion Facilitated Osmosis