Advanced Pathophysiology Advanced Pathophysiology, Exams of Pathophysiology

Download Advanced Pathophysiology Advanced Pathophysiology and more Exams Pathophysiology in PDF only on Docsity! Advanced Pathophysiology Basic Cellular Functions - 1. Movement 2. Conductivity 3. Excretion 4. Metabolic Absoption 5. Creation of ATP 6. Tissue Growth 7. Communication 8. Secretion Functions of Plasma Membrane - 1. Structure 2. Protection 3. Activation of Cell 4. Transport 5. Cell to Cell Interaction Nucleus Function - Membrane bound structure, controls cell division and contains genetic information/material Cytoplasm - Cytoplasmic matrix that surrounds organelles Mitochondria - Primary energy maker, responsible for cellular respiration & energy production, makes ATP Smooth Endoplasmic Reticulum - An endomembrane system where lipids are synthesized, calcium levels are regulated, and toxic substances are broken down. Rough Endoplasmic Reticulum - An endomembrane system covered with ribosomes where many proteins for transport are assembled. Golgi apparatus - A system of membranes that modifies and packages proteins for export by the cell Lysosomes - originate in Golgi, 40 digestive/degradative enzymes that catalyze proteins, lipids, nucleic acids, carbs Peroxisomes - Contain oxidative enzymes that detoxify compounds and fatty acids and breakdown substances into harmless products Cytoskeleton - A network of fibers that holds the cell together, helps the cell to keep its shape, and aids in movement Vesicles - small membrane sacs that specialize in moving products into, out of, and within a cell Vacuole - Cell organelle that stores materials such as water, salts, proteins, and carbohydrates Ribosomes - RNA protein complex that is responsible for protein synthesis (free & attached) Cell membrane (plasma membrane) - phospholipid bilayer that surrounds all cells and regulates what enters and leaves the cell Muscle Cells Function - • Movement 1. Can be striated (skeletal) or smooth (bowels, bronchi) 2. Can generate forces that produce motion 3. Can be smooth AND striated (diaphragm or intercostals) Cardiac & Neuro Cells Function - • Conductivity 1. Stimulus causes excitation & electrical potential that passes along surface of cell to reach destination 2. Cardiac muscle cells have automaticity GI & Kidney Cells - 1. All cells take in nutrients but cells of intestines & kidneys specialize in absorption 2. Kidney tubules reabsorb fluids and synthesize proteins 3. Intestinal epithelial cells reabsorb fluid & synthesize protein enzymes Endocrine & Neuro Cells - Depolarization is a change within a cell, during which the cell undergoes a shift in electric charge distribution, resulting in less negative charge inside the cell. Repolarization - Period during which potassium ions diffuse out of the neuron. Repolarization refers to the change in membrane potential that returns it to a negative value just after the depolarization phase of an action potential has changed the membrane potential to a positive value. Hyperpolarization - It inhibits action potentials by increasing the stimulus required to move the membrane potential to the action potential threshold. •Less Excitable Hypopolorization - Smaller than normal stimulus could reach threshold potential and depolarize the cell. •More Excitable Does Low Potassium Cause Cell to be MORE or LESS Excitable? Why? - Causes cell to be less Excitable, potassium (K+) is positivity charged. Having less potassium makes cell more negative or Hyperpolarized, requiring more stimulus to generate an action potential. Does high potassium cause cell to be MORE or LESS excitable? Why? - Causes cell to be more excitable, potassium (K+) is positively charged and causes testing membrane potential to become less negatively charged requiring less than normal stimulus to generate an action potential. 5 Ways Cells Communicate - 1. Contact Dependent 2. Autocrine 3. Paracrine 4. Synaptic 5. Endocrine Tight Junctions - Tight junctions, also known as occluding junctions or zonulae occludentes (singular, zonula occludens) are multiprotein junctional complexes whose general function is to prevent leakage of transported solutes and water and seals the paracellular pathway. Gap Junctions - Gap junctions are a specialized intercellular connection between a multitude of animal cell- types. They directly connect the cytoplasm of two cells, which allows various molecules, ions and electrical impulses to directly pass through a regulated gate between cells. Desmosomes - Desmosomes are intercellular junctions that provide strong adhesion between cells. Because they also link intracellularly to the intermediate filament cytoskeleton they form the adhesive bonds in a network that gives mechanical strength to tissues. Paracrine Cell Communication - Paracrine signaling is a form of cell signaling or cell-to-cell communication in which a cell produces a signal to induce changes in nearby cells, altering the behavior of those cells. Autocrine Cell Communication - Autocrine signaling is a form of cell signaling in which a cell secretes a hormone or chemical messenger that binds to autocrine receptors on that same cell, leading to changes in the cell. 4 Basic Types of Tissue - 1. Epithelial 2. Connective 3. Muscle 4. Neural 5 Types of Cellular Adaptation - 1. Atrophy 2. Hypertrophy 3. Hyperplasia 4. Dysplasia 5. Metaplasia Atrophy - 1. Shrinking in size such as skeletal muscle atrophy. Disuse atrophy, withdrawal of growth factors or hormones 2. Physiologic atrophy—thymus gland atrophies in childhood Hypertrophy - 1. Enlarging of cells and thus the organ usually due to increased workload 2. Ex. Left ventricular hypertrophy, cells enlarge not multiply 3. Physiologic hypertrophy turns into pathologic. Hyperplasia - 1. Multiplication of cells (increased number of normal appearing cells in response to physiologic or excessive hormonal stimulation 2. Increased rate of cell division 3. After ovulation, estrogen stimulates endometrium to grow & thicken for implantation. Dysplasia - 1. Change in size, shape or organization, abnormal development of cells. 2. May be reversible, may lead to malignancy 3. IT IS NEVER NORMAL 4. Ex. Epithelial, cervical Metaplasia - 1. Reversible replacement of one mature cell by another differentiated cell type 2. Bronchial columnar cells by squamous cells (recurrent injury) 3. Squamous cells do not secrete mucus or have cilia thus loosing vital protective mechanism Aquaporins - Aquaporins, also called water channels, are integral membrane proteins from a larger family of major intrinsic proteins that form pores in the membrane of biological cells, mainly facilitating transport of water between cells. Net Filtration - 1. Is a calculation of the forces that favor filtration vs the forces that oppose filtration Fluid distribution between the permeable capillaries of the vascular and interstitial bed is going to be the net result of oncotic pressure and hydrostatic pressure—measurements of these forces pulling and pushing against each other 2. Pushing and pulling of fluid will determine if fluid moves out of capillary and into interstitial space=filtration. Or if fluid moves into the venous end of the capillary=reabsorption Examples That Cause Edema - 1. Liver failure resulting in portal hypertension causing fluid to leak out of capillaries. Also decreases the production of blood proteins such as albumin, decreasing osmotic pressure in vessels. 2. Hypertension leading to increased hydrostatic pressure filtering more fluid into interstitial space. 3. Increase in blood vessel permeability due infection or injury or burn causing increased fluid to accumulate in interstitial space. 4. Increased venous pressure and decreased reabsorption and thus increased hydrostatic pressure due to heart failure. 5. Lymphatic obstruction decreasing absorption of fluid into lymphatic system. Oncotic Pressure (Colloid Osmotic Pressure) - Pressure exerted by plasma proteins that pull fluid back into blood vessel. Or into interstitial space. Remember RAAS System and Function - E-xcessive Urination Hypercalcemia Causes - 90% attributed to Hyperparathyroidism and Cancers. Other causes - Vitamin D and dietary calcium excess, hyperthyroidism, paget's disease, thiazide use. Hypophoshphatemia Causes - Intestinal malabsorption Increased renal excretion Hyperparathyroidism malnutrion, Vit D, deficiency, alcoholism, severe burns, DKA, Fanconi Syndrome, X-linked familial hypophosphatemia Hypophosphatemia S/S - Paresthesias, Muscle weakness, Muscle pain, Mental changes, Cardiomyopathy, Respiratory failure, increased serum calcium. Hyperphosphatemia Causes - Hypoparathyroidism, High Vit D, DKA, muscle damage, infections, acute and chronic renal failure, treatment with chemotherapy (releases large amounts of phosphate into serum), laxative and enema use containing phosphates. Hyperphosphatemia S/S - *Neuromuscular irritability* Muscle weakness Hyperactive reflexes Tetany Positive Chvostek's or Trousseau's sign Hypermagnesemia Causes - Most commonly caused by Renal or Kidney failure. Lithium therapy Hypothyroidism Addison's Disease Milk-Alkali Syndrome (high calcium and metabolic acidosis from excess calcium and alkali supplements for osteoporosis and antacids) Drugs containing magnesium Hypermagnesemia S/S - Weakness and Nausea Impaired Breathing Hypoventilation Hypotension Low Serum Calcium Arrhythmias and asystole Decreased or absent deep tendon reflexes Dizziness Sleepiness Hypomagnesemia Causes - Most common are decreased GI absorption and increased renal loss. Alcoholism, CHF, DM, chronic diarrhea, Hypokalemia, Hypocalcemia, Malnutrition, celiac disease. Hypomagnesemia S/S - Nerumuscular and neuropsychiatric disturbances, hyperexcitability, tremor, tetany, convulsions, muscle cramps, weakness, vomiting. Causes for Acidosis - Lung Impairment - COPD, Pneumonia, lung diseases or traumas. Diarrhea, DKA, Renal failure, Drug Overdose. Protein Buffer System - Hemoglobin serves as buffer. Hemoglobin = Amino Acid which has NH3+ _C_COO-, H+ can bind to COO- if blood is acidic, or release the H+ if blood is alkalinic. NH3+ can drop a H+ if blood is alkalinic or bind a H+ if blood is acidic. Approx 250 million Hemoglobin in every RBC. Causes of Alkolosis - Hyperventilation, vomiting, increased H+ loss from diuretics, high altitudes, hyper-metabolic states such as fever. Bicarbonate Buffer System - a solution of carbonic acid and bicarbonate ions, regulated by lungs by blowing off CO2 and Kidneys by releasing Bicarbonate and/or excreting H+ Phosphate Buffer System - Buffers ICF and Urine. Consists of Dihydrogen phosphate ions and Hydrogen Phosphate ions. Dihydrogen Phosphate can release an H+ increasing acidity and Hydrogen Phosphate ions can bind H+ to increase alkalinity. Ammonia Buffer System - Ammonium is generated in tubular cells through glutamine metabolism. Ammonia binds to protons and helps kidneys when maximum proton absorption by tubules are reached. DNA Structure - DNA consists of two long chains of nucleotides twisted into a double helix and joined by hydrogen bonds between the complementary bases adenine and thymine or cytosine and guanine DNA Function - Deoxyribonucleic acid (DNA) is a nucleic acid that contains the genetic instructions for the development and function of living things. All known cellular life and some viruses contain DNA. The main role of DNA in the cell is the long-term storage of information. What is considered the backbone of DNA - Deoxyribose - Deoxyribose is the five-carbon sugar molecule that helps form the phosphate backbone of DNA molecules. What are the Nitrogenous bases in DNA? - The four nitrogenous bases present in DNA are adenine (A), guanine (G), cytosine (C) and thymine (T). In RNA, the only differing nitrogenous base is uracil (U) (which replaces thymine in DNA and differs thymine only by the missing methyl group at carbon 5 of the pyrimidine ring). What is a codon? Anticodon? - A codon is a sequence of three nucleotides that together form a unit of genetic code in a DNA or RNA molecule. Such as UAG, AGA, GAC. An anticodon is a series of 3 unpaired bases that is complementary to to a codon. For example the codon UAC‛s anticodon is AUG. The Codon directs ribosomes to create an amino acid. Summarize steps of DNA Replication - Helicase unwinds & Unzips DNA by breaking the hydrogen bonds between neucleotides and bad pairs, DNA primase synthesisez a small set of primer neucleotides so DNA Polymerase can synthesize continuously the rest from 5' to 3' direction in leading strand. The lagging strand is synthesizes discontinuously due to the 3' to 5' synthesis. DNA primase synthesizes a short RNA primer so they DNA Polymerase can synthesize short fragments at a time (Okazaki Fragments). DNA Ligase then joins fragments together. Replication occurs in preparation for mitosis (Cell division) Summarize steps of DNA Transcription - Initiation - Basal transcription factors (helper proteins) bind to promotor site (TATA Box) on DNA so that RNA polymerase can attach. Elongation - RNA polymerase unwinds and transcribes one strand of DNA (template strand) adding new nucleotides for each complementary base pair, using Uracil instead of Thymine. Termination - Transcription stops when it gets to a terminator sequence signaling termination of transcription. 5' and 3' cap are attached to the pre-RNA strand. Spliceosome removes introns (non gene coding sections) and remaining sections are attached creating the Messenger RNA (mRNA) that can then be translated. Summarize steps of mRNA Translation - mRNA is moved out of nucleus to ribosome where translation takes place. Initiation - Ribosome reads and translates the mRNA when it sees the start codon and continues to translate one codon at a time. Elongation - tRNA makes the specific amino acid for each codon translated eventually making a long chain of different amino acids based on the codons translated Termination- ribosome and and tRNA stop translating when a stop codon is read and the amino acid chain is released.