Pathophysiology: Chapters 1, 2, and 3
Pathophysiology: Chapters 1, 2, and 3 HLTHST 300
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This 17 page Class Notes was uploaded by firstname.lastname@example.org Notetaker on Friday September 2, 2016. The Class Notes belongs to HLTHST 300 at Boise State University taught by Jennifer Legget in Fall 2016. Since its upload, it has received 232 views. For similar materials see Pathophysiology in Biology at Boise State University.
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Date Created: 09/02/16
Pathophysiology: Chapter 2 – Cellular Responses to Stress, Injury, and Aging Cellular Adaptation o Allows the tissue to survive or maintain function in a stressed situation o If a cell does not adapt to stress, it will die Atrophy Cells shrink to a smaller size and become more efficient to focus on survival Seen when the patient is immobilized for prolonged periods of time Weakness, stiffness, and incoordination Hypertrophy An increase in cell size and amount of functioning tissue It is a response to an increased workload o The more weights you lift – the bigger your muscles get Seen in endocrine disorders o Ex: the thyroid becomes a huge goiter when over stimulated by a tumor in the pituitary gland Hyperplasia Increase in the number of cells in an organ or tissue Ex: Calluses on the feet build up in response to frequent shearing forces o More layers of cells = more protection Metaplasia Replacement of one type of tissue with the other A response to chronic irritation Changes are reversible Ex: Cells near the bottom of the esophagus are replaced with stronger, more durable stomach cells because of chronic acid reflux Dysplasia Disorderly cell reproduction and alterations to the cells because of chronic irritation and inflammation Dysplastic cells sometimes called precancerous Usually found in the respiratory tract or cervix Intracellular Accumulations The build-up of substances in cells that they cannot immediately use or eliminate Exogenous: from outside the body o Ex: mercury Endogenous: from inside the body o Ex: melanin Stressed cells may fill up with… o Unused lipids and glycogen from food o Abnormal proteins o Pigments o Calcium salts Over accumulation can injure or destroy the cell Pathogenic Calcifications Abnormal deposits of calcium and other minerals Dystrophic injured tissue Metastatic normal tissue Injurious Agents o Stresses damage cells by… Hypoxia Deprives the cell of oxygen and stops the production of ATP Aerobic metabolism stops, anaerobic takes over o Cell swells up with water o Lactic acid is produced o Acid damages cell membranes, intracellular structures, DNA Free Radicals Molecules with an unpaired electron in the outer shell Extremely unstable and highly reactive o Can react with normal cell components to damage them and turn them into free radicals Normally removed from the body by antioxidants o Like scavengers floating around trying to “disarm” and chemically stabilize free radicals Increased Intracellular Calcium Cell usually maintains low intracellular calcium When calcium is released into the cell it… o Acts as a “second messenger” o Turns on intracellular enzymes (some can cause damage) o Opens more calcium gates in the cell membrane Causes a “calcium cascade” flowing in Cell Death Apoptosis o Normal process to remove unwanted tissue o Removes cells that are being replaced or have worn out o Programmed death or “cell suicide” A cell turns on its own enzymes (caspases) The enzymes digest its own cell proteins and DNA Then destroyed by white blood cells The time leading up to self-destruction allows white blood cells to gather and immediately clean up the mess o If the self-destruction program is disabled (usually by mutation) the cell is immortal and probably cancerous Necrosis o Unregulated cell death caused by injury or a pathogen o Cells swell and rupture causing inflammation o Cells die by liquefaction, coagulation, infarction, caseous necrosis o Cell contents are released Can lead to injury or death of surrounding cells Waste products can get in the blood stream - cause fever o Inflammation o Gangrene A large area of necrotic tissue Treatment amputation, cleaning, antibiotics If not treated, it will spread and be fatal Dry Lack of arterial blood supply, but venous flow carries fluid out Tissue coagulates Wet Lack of venous flow, lets fluid accumulate Tissue liquefies and gets infective Gas Clostridium infection produces toxins and hydrogen sulfide bubbles WORST TYPE o 1. Physical Agents Extreme Temperature Heat o Vascular injury o Accelerates cell metabolism o Inactivates enzymes o Disrupts the cell membrane o Coagulation of blood and tissue proteins Cold o Increases blood viscosity o Vasoconstriction o Decreased blood flow Electricity Disrupts neural, cardiac, and muscular impulses o 2. Radiation Ionizing Radiation Frequencies above the UV range Ionizes molecules and atoms in the cell Produces free radicals Kills cells Interrupts cell replication Causes genetic mutations Can cause cancer over time Ultraviolet Radiation Disrupt intracellular bonds Cause sunburn Increase risk of skin cancer Nonionizing Radiation Frequencies below the UV range Vibration and rotation of atoms and molecules – converted to thermal energy o 3. Chemicals Lead Poisoning Lead is absorbed through the GI tract or lungs Children are more susceptible Inactivates enzymes Interferes with nerve transmission and brain development Anemia is a sign of toxicity o 4. Biologic Agents Viruses, bacteria, and parasites Can replicate and continue to cause injury o 5. Nutritional Imbalances Excesses and deficiencies both cause injury to cells Aging o Theories Programmed Aging is genetically programmed into the cells Telomeres become too short and the cell can no longer divide Error or Damage The result of accumulated damage Older cells have more DNA damage and free radicals Telomeres gradually become shorter and shorter with division o Older cells lose the ability to repair them o Cancerous cells reactivate their ability to maintain telomere length and become immortal Pathophysiology: Chapter 3 – Inflammation and Fever Inflammation o Automatic response to cell injury o Purpose: Increase the blood supply to the injured area to provide the cells and inflammatory mediators needed Neutralize harmful agents Removes dead tissue o White Blood Cells of Inflammation Granulocytes - Have granules Neutrophils o Most numerous o Nuclei with 3-5 lobes o First to appear in acute inflammation o Engulf and destroy bacteria using phagocytosis Eosinophils o Kill large parasitic worms that cannot be engulfed o Present in chronic inflammation o Present in allergic reactions Basophils o Least numerous o Present in allergic reactions o Trigger the release of histamine Mast Cells o Release their contents at the site of inflammation Triggers the release of histamine, cytokines, and growth factors Monocytes - Do not have granules Macrophages o Single nucleus o The largest leukocyte o Start as monocytes in the blood, but mature into macrophages at the site of inflammation o Produce prostaglandins, cytokines, and growth factors o Engulf and destroy bacteria using phagocytosis o Important in chronic inflammation o Acute Inflammation Triggered by infections, immune reactions, trauma, physical or chemical agents, and tissue necrosis Five Signs of Inflammation 1. Redness 2. Swelling 3. Heat 4. Pain 5. Loss of Function Vascular Stage First response Response starts immediately Vasodilation Capillaries dilate o Caused by histamine and nitric oxide o Increases blood flow to injured area o Causes redness and warmth Increased Permeability Capillaries become leaky o Exudate and white blood cells can escape into the tissues o Causes pain, swelling, and loss of function Cellular Stage Second Response Characterized by a migration of white blood cells to the injured area White blood cells slowdown in the blood stream and escape the capillary at the injured tissue site o Neutrophils, monocytes, and macrophages destroy pathogens by phagocytosis Margination: leukocytes accumulate in the blood stream Adhesion: leukocytes stick to the wall of the capillary Emigration: leukocytes squeeze out of the capillary Chemotaxis: chemokines are released that “direct traffic” and attract leukocytes to the injured area Phagocytosis: leukocytes engulf pathogens and destroy them o Inflammatory Mediators Stimulate inflammation Plasma Derived made in the liver Clotting Factors o Trap infectious agents and keep them from spreading Complement Proteins o Causes vasodilation o Helps chemotaxis and phagocytosis Kinins (bradykinin) o Stimulate pain receptors o Increase capillary permeability Cell Derived secreted from cells Histamine and Serotonin o Produced by mast cells, basophils, and platelets o Cause vasodilation and increased permeability o Inflammatory Exudates Protein rich fluid 1. Serous Clear, watery fluid that covers minor scrapes to protect the area as the layers underneath heal 2. Hemorrhagic Fluid accompanying severe tissue injury and damage to blood vessels (hemorrhages) 3. Fibrinous Thick and sticky meshwork of fluid (like a blood clot) Contains fibrinogen 4. Membranous Develops on mucus membrane surfaces 5. Purulent Especially with infections Many white blood cells are dye and produce a white discharge (pus) o Chronic Inflammation Macrophages, lymphocytes, and plasma cells accumulate in the damaged area and keep releasing inflammatory mediators Attempted connective tissue repair Causes Persistent infections and irritants Obesity Foreign agents Viruses, bacteria, fungi, and parasites Granulomatous Inflammation Macrophages mass together around foreign bodies Connective tissue surrounds and isolates the mass o Systemic Manifestations White Blood Cell Count Rises Inflammatory mediators cause white blood cell production Immature neutrophils are released into the blood stream Level of CRP (C-reactive protein) Rises Binds to the surface of invading microorganisms and flags them for destruction Tissue Repair o Growth factors stimulate local cells to divide o Tissue organization is controlled by the extracellular matrix o New cells are laid down on the extracellular matrix Tissue Regeneration: injured tissue is replaced by the same kind of cells Fibrous Tissue Repair: injured tissue is replaced by connective tissue Granulation Tissue: scar tissue Wound Healing o Inflammatory Phase o Proliferative Phase o Remodeling Phase Fever o An elevation in body temperature caused by an upward displacement of the set point of the thermoregulatory center o Physiology Core body temp is controlled by thermoregulatory center in the hypothalamus Core Temperature: temperature in the deep tissues of the body Uses negative feedback Heat is generated in the tissues and transferred to the skin surface by blood Thermostatic Set Point: level at which body temp is regulated so core temp stays in the normal range When temp rises above the set point, heat dissipating behaviors start When temp falls below the set point, heat production increases o Heat Production Metabolism switches from energy production to heat production Shivering Contraction of pilomotor muscles of the skin (goose bumps) o Heat Loss AV shunts allow hot arterial blood to directly enter veins close to the skin surface to release its heat Radiation: the transfer of heat through the air or a vacuum Environmental temp must be less than body temp 60% of heat loss Conduction: direct transfer of heat from one molecule to the other Inside the body or from the environment to the body (warming blanket) Convection: heat transfer through the circulation of air currents A layer of warm air around the body is continually replaced with cool air Evaporation: uses body heat to convert water on the skin to water vapor Sweating o Stages 1. Prodromal Headache, fatigue, aches and pains 2. Chill Cold and shaking even though the temp is rising Vasoconstriction and piloerection cause shivering Shivering causes the body temperature to reach the new set point 3. Flush Vasodilation causes the skin to be warm and red Once the new set point has been reached 4. Defervescence Sweating o Patterns Intermittent temp returns to normal once every 24 hours Sepsis, abscesses, acute bacterial endocarditis Remittent temp doesn’t return to normal, but varies a few degrees up/down Sustained temp stays above normal without variation Drug induced fevers Relapsing/Recurrent a few days between episodes of fever Tuberculosis, fungal infections, Lyme disease, malaria o Elderly People Have a lower baseline temperature Even slight increases in temperature can indicate a serious infection Thermoregulatory center may not be functioning properly Other signs of infection Changes in functional capacity Mental changes Weakness and fatigue Weight loss Pathophysiology: Chapter 1 – Cell and Tissue Function Organelles o Nucleus Enclosed in a nuclear envelope Contains chromatin: genetic material Control center Site of synthesis of the three types of RNA o Ribosomes Free or Bound (attached to ER) Translate mRNA into protein o Endoplasmic Reticulum Transports substances from one end of the cell to the other Smooth or Rough (has ribosomes) o Golgi Apparatus Modifies and packages substances from the ER o Lysosomes Break down excess, worn out, and foreign substances in the cell Digestive o Peroxisomes Oxidative reactions Use oxygen to produce peroxide and convert hydrogen peroxide to water o Mitochondria Power house of the cell Site of aerobic metabolism o Cytoskeleton Microtubules Develop and maintain the shape of the cell Microfilaments Cell Membrane o Functions Semipermeable Conducts electrical currents in nerve and muscle cells Regulates cell growth Controls transport between inside and outside Integral/Transmembrane Proteins o Function on both sides of the membrane o Transport materials across it o Form ion channels Hold and binds hormone receptors Peripheral Proteins o Bound to either the inside or outside of the membrane o Do not pass through the membrane o Serve as receptors or intracellular signaling systems o Structure Phospholipid Bilayer Hydrophilic heads pointing outward on either side of the membrane Hydrophobic tails in between the two outer layers of heads Impermeable to all but lipid-soluble substances Cell Metabolism o The process of converting carbs, fats, and proteins from food into energy o 3 Pathways o Adenosine Triphosphate (ATP) Adenosine + nitrogenous base + ribose + 3 phosphates When bonds between parts are broken, energy is released Breaking molecules involves removing electrons o Electrons given to electron carriers like NAD and FAD o H+ follows the electrons ATP ADP When one phosphate group is lost, energy is released, and ADP (Adenosine Diphosphate) is formed ATP AMP When two phosphate groups are lost, energy is released, and AMP (Adenosine Monophosphate) is formed The released energy is used for muscle contraction and active transport Energy from food converts AMP and ADP back to ATP o Anaerobic Without oxygen Occurs in the cytoplasm 1. Glycolytic Pathway Energy is released from glucose Important for cells without mitochondria and at times when oxygen is not available Requires 2 ATP to start A glucose molecule is broken o Produces 2 molecules of pyruvic acid o Produces 4 ATP o Produces 2 NAD+ When O2 is present, the pyruvic acid moves to the mitochondria and enters the Krebs Cycle When O2 is not present, pyruvic acid is converted to lactic acid o Aerobic With oxygen Occurs in the mitochondria Supplies 90% of the body’s energy needs Forms CO2 and H2O as energy is released 2. Krebs Cycle 2 molecules of Pyruvic acid (from glycolysis) enters the mitochondria o The molecules are broken into Acetyl coA Produces 2 ATP total Produces 8 NAD+ Produces 2 FAD Produces Citric Acid Carbon is lost as CO2 3. Electron Transport Chain Electrons from the hydrogen atoms in NAD+ and FAD are oxidized o Produces 34 ATP Membrane Transport o Proteins Channel Proteins Form water lined channels through the membrane Allow free movement of water Membrane Transport Proteins Bind molecules and ions to transport them across Uniporters Mediate the movement of a single solute from one side to the other Symporters and Antiporters Symporters move a solute in one direction to allow an Antiporter to move another solute in the opposite direction o Diffusion Passive Diffusion Molecules move into the cell through a random membrane opening Move from areas of high concentration to areas of low concentration Facilitated Movement across the membrane requires a carrier protein For molecules that are too big or are not lipid soluble Ion Channels Gates that open and close to allow ions in and out of the cell Highly selective for which ions they allow in and out Leak Channels always open Gated Channels open and close in response to specific stimuli o Voltage gated (charges) o Ligand-gated (lock (receptor) and key (ligand)) o Mechanically gated (vibrations, stretching, pressure) o Osmosis The movement of water across the cell membrane Regulated by concentration gradients Moves from the area of lower concentration of solutes to the area of higher concentration of solutes Aquaporins water channels in the membrane Types of Solutions Hypertonic cells shrink Isotonic not affected Hypotonic cells burst o Ex: Pure water o Active Transport Requires ATP Substances are pumped against the concentration gradient o Vesicular Transport Materials are transported in membrane-bound vesicles Endocytosis materials are moved into the cell Pinocytosis = small vesicle Phagocytosis = large vesicle Exocytosis materials are moved out of the cell Cell Communication o The surface of the cell is covered in receptor proteins When a messenger cell attaches to a receptor, it starts a response Opening ion channels Causing a second molecule to be released inside the cell Turning on enzymes inside the cell Stimulating the transcription of genes in the nucleus Electrical Potentials o Created by the diffusion of positively and negatively charged ions across the membrane o Action Potential Cells start with a negative charge (RESTING MEMBRANE POTENTIAL) A stimulus causes some Na+ channels to open Na+ diffuses in and makes the cell more positive At threshold potential, more Na+ channels open Na+ rushes in and makes the cell very positive (DEPOLARIZATION) Action Potential is reached (the cell responds) Ex: contracts a muscle fiber o Back to Normal K+ channels open K+ diffuses out and makes the cell negative again (REPOLARIZATION) Sodium Potassium pump removes the Na+ from the cell and pumps K+ back in Cell returns to resting membrane potential o Equilibrium Potential: there is no net movement of a particular ion across a membrane Types of Tissue o 1. Epithelial Sheets that cover body surfaces, line internal surfaces, and form glands Basement membrane underneath all types Characteristics 3 surfaces: Apical, Lateral, and Basal Formed by cell-to-cell adhesion molecules Basal surface is attached to basement membrane Simple Specialized for filtration Found in the lining of blood vessels, lymph nodes, and alveoli Simple Squamous one layer of flat cells Simple Cuboidal one layer of cube-shaped cells Simple Columnar one layer of tall, rectangular cells o One form is ciliated and has goblet cells Stratified Only the deepest layer rests on the basement membrane Designed to protect a body surface Stratified Squamous many layers of flat cells o Keratinized Makes the epidermis of the skin Keratin is a tough, fibrous protein Keratin is produced near the basement membrane When the cells on the top layer become filled with keratin, they die and fall off They are replaced by the younger cells below o Non-keratinized Found in the mouth and on the tongue Stratified Cuboidal many layers of cube-shaped cells o Found in salivary glands and mammary glands Stratified Columnar many layers of tall, rectangular cells o Found in salivary glands and mammary glands Pseudostratified o All cells have contact with the basement membrane, but not all reach the apical surface o Pseudostratified Ciliated Columnar with goblet cells lines the upper respiratory tract Transitional o Made of cells that can change shape and become thinner when the tissue is stretched o Found in the bladder Glandular Cells are specialized to produce a fluid Synthesize, store, and secrete proteins, lipids, and carbs Endocrine o Not connected to the surface tissue they originated from o Produce secretions that move directly into the bloodstream Exocrine o Connected with the surface tissue they originated from o Sweat glands and mammary glands o Secretions pass through ducts to reach the surface o 2. Connective Most abundant tissue type Connects, binds, and supports Builds the basement membrane under epithelial tissue Close to blood vessels – nutrients and wastes pass through it Connective Tissue Proper Loose/Areolar o Soft and pliable o Fills spaces between muscle sheaths, encases blood and lymphatic vessels, supports epithelial tissues, o Cell types Fibroblasts Mast cells Adipose cells Macrophages Leukocytes Adipose o Adipocyte cells store triglycerides and energy o Fills spaces between tissues and keep organs in place o Adipose under the skin shapes the body o Thermal insulation for the body (poor conductor of heat) Dense o Network of fibers with macrophages and fibroblasts that produce collagen fibers o Dense Regular Forms tendons and ligaments o Dense Irregular Found in the dermis of the skin, bone, fibrous capsules Reticular o Network of fibers with macrophages and fibroblasts that produce collagen fibers o Provide the framework for capillaries, nerves, and muscle cells Specialized Connective Bone Cartilage Hematopoietic (blood cells) o 3. Muscle Composed of thick actin and thin myosin filaments Muscle Contraction Calcium enters the Synaptic Knob which triggers release of acetylcholine Creates an End Plate Potential which triggers an Action Potential in the Sarcolemma The Action Potential causes the Sarcolemma to release calcium into the muscle fibers, triggering contraction Calcium binds to troponin so a cross-bridge can form o Troponin usually covers the tropomyosin Myosin Heads on the thick filaments attach to Myosin Binding Sites (TROPOMYOSIN) on the Thin Filament The Myosin Heads pull on the thin filaments, sliding them toward the midline (POWER STROKE) ATP causes the Myosin Head to release and reset to start the cycle over again Skeletal Striated and Multinucleated Most abundant type 45% of total body weight Responsible for moving the skeleton Structure o Muscle Fibers surrounded by the Endomysium o Fascicles surrounded by the Perimysium o Entire Muscle surrounded by the Epimysium Cardiac Striated Only found in the heart Smooth Found in the iris of the eye, blood vessel walls, and hollow organs Involuntary Contractions are slower and more sustained One nucleus o 4. Nervous Neurons Soma (cell body) Axon generates and conducts nerve impulses away from the soma Dendrites receive stimuli Afferent o Pick up sensory information o Carry info to the central nervous system o Signals are “arriving” Efferent o Send motor instructions to the body part o Carry information away from the central nervous system o Signals are “exiting” Supporting Cells (neuroglia) Support neurons Astrocytes blood-brain barrier o Most abundant Oligodendrocytes Provide myelination Microglia Phagocytic Ependymal Cells line cavities of the brain and spinal cord
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