Cellular Biology week 2 Nurs 207.pdf

Cellular Biology September 9, 2024 8:51 AM QUIZ questions will be based on what is talked about in-class (will not be on obscure facts from textbook) **Cellular Level of Organization EUKARYOTES (you-carry-oats) For intents and purposes- Cells of living organisms are Euk...

Cellular Biology September 9, 2024 8:51 AM QUIZ questions will be based on what is talked about in-class (will not be on obscure facts from textbook) **Cellular Level of Organization EUKARYOTES (you-carry-oats) For intents and purposes- Cells of living organisms are Eukaryotes or prokaryotes Eukaryotes are the cells that are in animals (us) and higher plants ○ These cells are complex- containing organelles and a distinct nucleus Prokaryotes are the cells which we see in *bacteria, rickettsiae, cyanobacteria ○ No organelles, NO distinct nucleus or nuclear membrane Differentiation --> cells start off similar and then they differentiate as development occurs Through differentiation, or maturation, cells will serve different purposes. They each have a role and, in normal circumstances, do an excellent job Just like people- cells have strengths and weaknesses. Cellular Functions (8 in total) --> All cells can either excel or bomb in the following (depending on their function) 1) Movement -- muscle cells, sperm cells 2) Conductivity -- nerve cells 3) Metabolic Absorption 4) Secretion 5) Excretion 6) Respiration 7) Reproductive 8) Communication Plasma Membrane control the movement, borders, shape, communication, and contents of the cell. Membranes allow some things in while rejecting others. This is controlled through gates, channels, & pumps. The structure/boarder of the cell Nucleus- motherboard. control cell division and genetic information. Right at the heart is the nucleolus where the DNA that define the organism are housed. Heart of each of the cells Cytoplasm -- describes all of the following Cytoplasmic Matrix ○ Fills space between nucleus and plasma membrane Cytosol ○ Storage for fat and carbohydrates (it’s the gel on the inside of the cell and its where the organelles hang out) Cytoplasmic organelles ○ Various functions including synthesis of proteins and hormones (they are like our own bodies organs) Mitochondria---site of ATP generation Cellular energy metabolism ATP generation Has role in: ○ Osmotic regulation ○ pH control -- acid base ○ Calcium homeostasis ○ Cell signalling Ribosomes RNA protein complexes Synthesized in nucleolus Sites for cellular protein synthesis within the cell Endoplasmic reticulum Network of tubular channels (cisternae) Synthesis and transport of protein and lipids Smooth and rough ER Golgi complex--processing and packaging building for protein Network of smooth membranes Processing and packaging of proteins Secretory vesicles Cytoskeleton Lysosomes Originate from the Golgi Contain enzymes for digestion (amino acids, fatty acids, carbs, etc.) Cellular injury causes enzyme release that leads to cellular self -destruction (the self-destruct button) Peroxisomes Contain oxidative enzymes ○ They break down things --- use hydrogen peroxide to eliminate waste within cells Break cellular waste down into harmless products Cytoskeleton “Bones and muscles” of cell shape -- a network of protein filaments Composed of protein filaments Forms cell extensions (microvilli, cilia, flagella) Caveolae Capture and transport material into cell They look like craters on a cells membrane Cave--accept things in Vaults Cytoplasmic ribonucleoproteins, shaped like octagonal barrels They are garbage trucks Cellular trucks moving molecules from nucleus to elsewhere in the cell PLASMA MEMBRANE: the skin of the cell (it’s a 2 layer fatty border that cells use to recognize eachother, provides shape, andhelps with movement) --> Controls the composition of a space or compartment it encloses Function: Cell-to-cell recognition Cellular mobility Cellular shape Movement of molecules Composition Lipid bilayer Solid-gel phase Fluid-liquid crystalline phase Liquid-ordered phase Lipids ---Phospholipid bilayer Amphipathic (hydrophobic and hydrophilic) **Hydrophobic tail and hydrophilic head ○ O2 and CO2 diffusion ○ Barrier to diffusion of water Molecular glue Membrane lipid rafts Proteins --workhorse of the cell Major workhorses of the cell Functions ○ Receptors ○ Transport channels/carriers ○ Enzymes ○ Surface markers ○ Cell adhesion molecules (CAMs) ○ Catalysts Protein homeostasis Main role is to minimize protein misfolding and protein aggregation ○ Regulated by: ▪ Ribosomes (makers) ▪ Chaperones (helpers) ▪ Proteolytic systems □ Lysosomes □ Ubiquitin-proteasome system (UPS) ○ Malfunction associated with human disease Carbohydrates ---usually bound to fats or proteins Protection Lubrication Recognition Adhesion Cellular Receptors Ligands ---will bind with things like hormones ○ Bind with cellular receptors to activate or inhibit the receptors associated signalling or biochemical pathway Plasma membrane receptors ○ Determine response to binding Cell-to-cell adhesions Formed on plasma membranes Held together by: ○ Cell adhesion molecules ○ Extracellular membrane ○ Specialized cell junctions Extracellular matrix—secreted by fibroblasts ***this chart is important to know Includes basement membrane Epithelium is connected to the basement membrane (provides Fibrous proteins in gel substance structure/foundation) in the extracellular space there is lots of protein -->this space is also called the interstitial space. You may hear that the IV went Diffusion of nutrients, wastes and water -soluble substances interstitial (or into the extracellular space) you will also hear health care workers Composed of: say that they have blown an IV When this happens the extracellular fluid will plump up and swell ○ Collagen and elastin The concentration of useful proteins/fibroblasts will be diluted and ○ Fibronectin 'watered-down' --> if the person is otherwise healthy they will be okay. However, if the patient is sickly or bedridden this can lead to necrosis of ○ Proteoglycans and hyaluronic acid tissues (because its impacting normal functioning of the extracellular fluids) ○ Regulates cell growth, movement, and differentiation With chronic inflammation in these areas we will see cancerous cells -- or arthritis Cell junctions Tight junctions ○ Barriers ○ Maintain polarity Desmosomes, hemidesmosomes ○ Unite cells Gap junctions ○ Communication Gating Enables uninjured cells to protect themselves from injured neighbours by controlling permeability Week 2 Sept 9 Page 1  ○ Maintain polarity Desmosomes, hemidesmosomes ○ Unite cells Gap junctions ○ Communication Gating Enables uninjured cells to protect themselves from injured neighbours by controlling permeability Cellular Communication Plasma membrane–bound receptors Intracellular receptors Gap junctions (contact signalling) Can bind to receptors on the outside of cells -- can send remote messages to the nucleus -- can Chemical signalling communicate via junctions in plasma membrane ○ Paracrine ○ Autocrine ○ Hormonal ○ Neurohormonal Neurotransmitters Signal Transduction Cells communicate via receptor proteins ○ Signals molecules to activate protein kinases ▪ Instructs cells to grow and reproduce, die, survive, or differentiate **Remember that death of a cell is APOPTOSIS Cellular Metabolism Metabolism Chemical tasks of maintaining essential cellular function Basal metabolic rate == energy requirement to keep body alive as is (resting rate) ○ Survival of the organism/cell Anabolism ○ Energy using: building (using of energy) Catabolism ○ Energy releasing: breaking down (molecules being broken down) ATP == units of energy Fuel for cell survival Oxygen is great if we don’t have adequate oxygenation cells will start to kill Created from the chemical energy contained within organic molecules --> breaking down macros releases ATP themselves down (apoptosis) Used in synthesis of organic molecules, muscle contraction, and active transport Stores and transfers energy May have role outside cells Cellular Energy Digestion (PHASE 1) Macros (Carbs/fats/proteins) come into the GI and enzymes start to break them down Extracellular breakdown of proteins, fats, polysaccharides into subunits Glycolysis (PHASE 2) Intracellular breakdown of subunits to pyruvate, then to acetyl CoA The caveoli accept macro nutrients into the cell Anaerobic Limited ATP produced Citric acid cycle (PHASE 3) --> occurs in the mitochondria Also called Krebs cycle or the tricarboxylic acid cycle (TCA) Much ATP produced via oxidative phosphorylation if oxygen present ○ Lots of ATP Waste products excreted (CO2 and water) Oxidative phosphorylation Occurs in the mitochondria Mechanism producing energy from fats, CHO, proteins Involves the removal or transfer of electrons from various intermediates via a coenzyme such as nicotinamide adenine dinucleo tide (NAD) thus called transfer reactions Anaerobic glycolysis: if oxygen is not available, CHO (glucose) is converted to pyruvic acid (pyruvate) in cytoplasm with production of two ATP molecules, which is insufficient for energy needs; pyruvate then converted to lactic acid ○ Aerobic exercise involves movement within the oxygen stores of the body ---> you are not out of oxygen when moving around ○ Anaerobic is a very hard work out ---> it's when you are out of breath Process reverses when oxygen becomes available and lactic acid is converted back to either pyruvic acid or glucose, which mov es into the mitochondria and enters the citric acid cycle If glycolysis is happening and we have no oxygen then lactic acid is forming ---> Lactic acid makes us sore/muscles burn/we have more waste products in the body If you are in really good shape, your body knows what to do with lactic acid --so it wont be as sore If we do have oxygen we go right into the kerbs cycle and we are producing more energy -- lactic acid is converted into pyruvate or glucose and the body will reuse it Membrane transport Cellular intake and output ○ Cells continually take in nutrients, fluids, and chemical messengers from the extracellular environment and expel metabolites, or the products of metabolism, and end products of lysosomal digestion. ○ Transporters allow movement of ions that fit the unique binding sites on the protein. ○ Channels allow ions and selective molecules to diffuse across the membrane. Passive transport---an easy transport Molecules move easily from region of high concentration to region of low concentration “downhill” Requires no energy Driven by osmosis, hydrostatic pressure, and diffusion ○ Osmosis == fluids shifting from place to place Active transport Flows “uphill” Requires energy Transporter pumps helps to transport ions Endocytosis = taking into cell Exocytosis = expelling from cell Electrolytes Account for ~95% of solutes in body fluids Electrically charged ○ Cations (positive charge) + ○ Anions (negative charge) - Measured in milliequivalents per litre (mEq/L) or millimoles per litre (mmol/L ○ Milliequivalent indicates the chemical-combining activity of an ion, which depends on the electrical charge, or valence (number of plus or minus signs) ○ Monovalent—1 charge (+) ○ Divalent—2 charges (++) Diffusion Movement of solutes from area of greater concentration to area of lesser concentration Rate of diffusion influenced by difference of electrical potential across the membrane ○ Also influenced by size of molecules and lipid solubility Filtration Movement of water and solutes through a membrane because of greater force on one side than on the other ○ Hydrostatic pressure ○ Blood pressure Osmosis Movement of water down a concentration gradient ○ Membrane must be more permeable to water than solutes ○ Concentration of solutes on one side greater than the other Controls the distribution of water between body compartments Osmotic pressure Related to hydrostatic pressure and solute concentration Oncotic pressure or colloid osmotic pressure Tonicity Osmolality Measures the number of milliosmoles per kilogram (mOsm/kg) of water ○ Concentration of molecules per weight of water Osmolarity Measures the number of milliosmoles per litre of solution ○ Concentration of molecules per volume of solution ACTIVE TRANSPORT Transport system for Na+ and K+ Uses direct energy of ATP Transporter protein: ATPase Process leads to electrical potential Transdport by vesicle formation Transport of macromolecules ○ Endocytosis ▪ Vesicle formed and moves into cell ▪ Pinocytosis—ingestion of fluids ▪ Phagocytosis—ingestion of large particles ○ Exocytosis ▪ Replaces plasma membrane removed by endocytosis ▪ Releases synthesized molecules into extracellular matrix Electrical impulses Resting membrane potential Action potential ○ Depolarization ○ Threshold potential Week 2 Sept 9 Page 2  ○ Threshold potential ○ Repolarization ○ Refectory period ▪ Absolute and relative Tissue formation Intercellular recognition and communication, adhesion, and memory Specialized patterns of gene expression Terminally differentiated cells--- this cells will be this speciality throughout its life Stem cells -- bone marrow, endothelial tissue, brain, teeth, etc. these cells cal turn into whatever they need to Nerve Highly specialized cells (neurons) Epithelial Covers most of internal and external body surfaces Connective Binds tissues and organs together Muscle Composed of myocytes, enables movement Mitosis versus cytokinesis Four phases S phase ○ DNA synthesized G2 phase ○ RNA and protein synthesis M phase (M=mitosis) ○ Nuclear and cytoplasmic division G1 phase ○ Period between M phase and start of DNA synthesis M Phase ○ Prophase ○ Metaphase ○ Anaphase ○ Telophase Influences on the cell cycle Cellular division rates depend on: ○ Protein growth factors ○ Genetic factors ○ Epigenetic factor Cells can adapt (change) for their environment in response to demands or threats Cells which have adapted are not normal, ALTERED CELLULAR AND TISSUE BIOLOGY neither are they injured Adaptions are reversible Cellular Adaption Adaptations have limitations Physiological (adaptive) versus pathogenic Physiological adaptation--is an internal body process to regulate ○ Atrophy and maintain homeostasis for an organism to survive in the ▪ Decrease in cellular size environment in which it exists (normal adaptations) ▪ Think about a decrease in the size of an arm after being in a cast. Pregnancy is a physiological change There has been atrophy in muscle cells due to lack of use ○ Hypertrophy Pathogenic adaptations are changes that result organs/tissues ▪ Increase in cellular size that are unable to functional normally (not -formal adaptations) ▪ Body builders -- increasing the size of their muscle cells Diabetic neuropathy -- numb and tingling feet ○ Hyperplasia ▪ Increase in number of cells ▪ Think about during the pandemic --- during lockdown phase (we all gained some weight) -- we were adding fat cells to our bodies ○ Physiological (adaptive) versus pathogenic ▪ Dysplasia □ Deranged cellular growth □ This is unusual cells in an area -- not cancer -- it can become cancer if it continues to develop atypically ▪ Metaplasia □ Replacement of one type of cell with another □ Think about acid reflux --> if you drink a lot of coffee and smoke a lot, your esophageal cells in your throat and stomach will change from a nice ciliated cell to a non-ciliated cell Cellular Injury ---> Occurs if cell unable to maintain homeostasis ○ Reversible ▪ Cells recover ○ Irreversible ▪ Cells die Electrolytes are going to impact contractions --alteration in muscular contraction Cellular Injury Mechanisms Hypoxic injury--->Single most common cause of cellular injury ○ Results from: ▪ Reduced amount of oxygen in the air ▪ Loss of hemoglobin or decreased efficacy of hemoglobin ▪ Decreased production of red blood cells ▪ Diseases of the respiratory and cardiovascular systems ▪ Poisoning of the oxidative enzymes (cytochromes) within the cells ○ Ischemia ----LACK OF O2 AND BLOOD TO A REGION ▪ Castration of bull calves --- tissue dies after blood flow and O2 is cut Chemical injury off with a thick rubber band ▪ Most common case of hypoxia □ Ischemia-reperfusion injury Additional injury that can be caused by restoration of blood flow and oxygen Mechanisms: ◊ Oxidative stress ◊ Increased intracellular calcium ◊ Inflammation ◊ Complement activation Anoxia---> ABSENCE OF OXYGEN Cellular responses: ○ Decrease in ATP, causing failure of sodium –potassium pump and sodium– calcium exchange ○ Cellular swelling---> it will hurt the organelles and the plasma membrane of the cells ○ Vacuolation Reperfusion injury Free Radicals Free radicals and reactive oxygen species (ROS) ○ Electrically uncharged atom or group of atoms having an unpaired electron that damage: ▪ Lipid peroxidation ▪ Alteration of proteins Reactive Oxygen Species ▪ Alteration of DNA ▪ Mitochondria Chemical injury Xenobiotics---> substances that are foreign to our body or the ecosystem ○ Carbon tetrachloride ○ Lead ○ Carbon monoxide ○ Ethanol ○ Mercury ○ Social or street drugs (see Table 4.5) Chemical agents including medications ○ Over-the-counter and prescribed medications---->leading cause of child poisoning ▪ Direct damage □ Chemicals and medications injure cells by combining directly with critical molecular substances □ Chemotherapeutic medications □ Drugs of abuse ▪ Hypersensitivity reactions □ Range from mild skin rashes to immune-mediated organ failure Week 2 Sept 9 Page 3  □ Range from mild skin rashes to immune-mediated organ failure Unintentional and intentional injuries Significant cause of morbidity and disability Blunt-force injuries ○ Result of application of mechanical force to body ▪ Results in tearing, shearing, or crushing of tissues ▪ Motor vehicle accidents and falls ○ Contusions -- bruising ○ Lacerations -- deep cuts ○ Fractures -- partial or complete breaks in bone ○ Any force that is applied to the body will have some sort of affect Sharp-force injuries ○ Incised wound -- cut that doesn’t affect underlying tissues around (clean cut) ○ Stab wound--generally caused by others ○ Puncture wound -- its an in-and-out wound ○ Chopping wound -- auger accidents/ different directional forces causing a lot of regional damage (swelling, bruising, etc.) the injury will take longer to heal Gunshot wounds ○ Entrance ○ Exit ○ Range of fire --- was it a distant shot or a close -up shot…will determine tissue damage Asphyxial injuries: Caused by a failure of cells to receive or use oxygen ○ Suffocation ▪ Choking asphyxiation ○ Strangulation ▪ Hanging, ligature, and manual strangulation ○ Chemical asphyxiants ▪ Cyanide and hydrogen sulphide ▪ Can occur accidently like with CO2 or when mixing cleaning chemicals ○ Drowning Infectious Injury Pathogenicity of a microorganism ---body aches, exhaustion, swelling, etc. the response to the pathogen (body fighting back) can lead to multi -system body failure-->the cells in multiple parts of the body are not receiving enough oxygen -- it was a huge immune response that was causing the damage Calcium infiltration Disease-producing potential ○ Invasion and destruction ○ Toxin production ○ Production of hypersensitivity reactions Immunological and Inflammatory Injury Phagocytic cells--cells that will consume other cells Immune and inflammatory substances ○ Histamine, antibodies, lymphokines, complement, and proteases Membrane alterations Manifestations of Cellular injury Cellular accumulations (infiltrations): ○ Water ○ Lipids and carbohydrates ○ Glycogen ○ Proteins Cellular accumulations (infiltrations) (cont.): Pigments ○ Melanin, hemoproteins, bilirubin Calcium ○ Dystrophic ○ Metastatic Urate Systemic manifestations (see Table 4.10) Process of Oncosis (Degeneration) SYSTEMATIC MANIFESTATIONS OF CELLULAR INJURY Manifestation Cause Fever Release of endogenous pyrogens (interleukin-1, tumour necrosis factor-alpha, prostaglandins) from bacteria or macrophages; acute inflammatory response Increased heart rate Increase in oxidative metabolic processes resulting from fever Increase in leukocytes Increase in total number of white blood cells because of infection; normal is 5 000–9 000/mm3 (increase is (leukocytosis) directly related to severity of infection) Pain Various mechanisms, such as release of bradykinins, obstruction, pressure Presence of cellular enzymes Release of enzymes from cells of tissue* in extracellular fluid Lactate dehydrogenase (LDH) (LDH Release from red blood cells, liver, kidney, skeletal muscle isoenzymes) Manifestation Cause Creatinine kinase (CK) (CK isoenzymes) Release from skeletal muscle, brain, heart Aspartate aminotransferase (AST/SGOT) Release from heart, liver, skeletal muscle, kidney, pancreas Alanine aminotransferase (ALT/SGPT) Release from liver, kidney, heart Alklaline phosphatase (ALP) Release from liver, bone Amylase Release from pancreas Aldolase Release from skeletal muscle, heart Cellular death Necrosis Sum of cellular changes after local cell death and the process of cellular autodigestion (autolysis)--> eating or killing themselves ○ Coagulative ○ Liquefactive ○ Caseous ○ Fat Dead tissue Dead tissue ○ Gangrenous ○ Gas gangrene Coagulative Necrosis --> Kidneys, heart, and adrenal glands Protein denaturation Liquefaction Necrosis Neurons and gual cells of the brain Hydrolytic enzymes Bacterial infection ○ Staphylococci, streptococci, and Escherichia coli Dead tissue from TB on the Lungs Caseous necrosis Tuberculous pulmonary infection ○ Combination of coagulation and liquefactive necrosis Fat necrosis Breast, pancreas, and other abdominal organs Action of lipases Gangrenous necrosis Death of tissue from severe hypoxic injury ○ Dry versus wet gangrene Gas gangrene ○ Clostridium Apoptosis Programmed cellular death Physiological versus pathological Tissue is dead--lack of oxygen Autophagy Self-destructive and a survival mechanism Week 2 Sept 9 Page 4 Apoptosis Programmed cellular death Physiological versus pathological Tissue is dead--lack of oxygen Autophagy Self-destructive and a survival mechanism Cytoplasmic contents delivered to lysosomes for degradation Contributes to the aging process Aging and altered cellular and tissue biology Aging versus disease versus life span Normal life span and life expectancy Degenerative extracellular changes Aging Cellular aging ○ Atrophy, decreased function, and loss of cells Tissue and systemic aging ○ Progressive stiffness and rigidity ○ Sarcopenia Frailty ○ Mobility, balance, muscle strength, motor activity, cognition, nutrition, endurance, falls, fractures, and bone density Somatic death Death of an entire person ○ Postmortem changes ▪ Algor mortis -- change in temp ▪ Livor mortis--when we see pooling the liquids pool ▪ Rigor mortis-- we stiffen and then become lax again ▪ Postmortem autolysis -- the cells start to eat themselves □ Petrification of the body Week 2 Sept 9 Page 5