Pathophysiology Unit 2 | Chapter 2 (Porth 5th Edition) Flashcards
Protoplasm
Intracellular fluid composed of water, proteins, lipids, carbohydrates, and electrolytes; divided into karyoplasm (nucleus) and cytoplasm.
Nucleus
Control center of the cell containing DNA and RNA; site of transcription and synthesis of mRNA, rRNA, and tRNA.
Ribosomes
Cellular structures responsible for protein synthesis; composed of rRNA and proteins; found free in cytoplasm or attached to rough ER.
Rough Endoplasmic Reticulum
ER studded with ribosomes; synthesizes proteins for organelles, membranes, or secretion (e.g., insulin, lysosomal enzymes).
Smooth Endoplasmic Reticulum
ER without ribosomes; synthesizes lipids, metabolizes hormones, and stores glucose as glycogen in the liver.
Golgi Complex
Modifies and packages proteins from the ER into vesicles for secretion, membrane incorporation, or lysosomal storage.
Lysosomes
Digestive organelles containing acidic enzymes; break down cellular debris, pathogens, and worn-out organelles via autophagy or heterophagy.
Peroxisomes
Organelles containing enzymes to degrade peroxides (e.g., hydrogen peroxide) and synthesize bile acids in liver cells.
Proteasomes
Cytoplasmic and nuclear complexes that degrade misfolded or damaged proteins tagged with ubiquitin.
Mitochondria
Powerhouse of the cell; site of aerobic respiration (citric acid cycle, electron transport chain) producing ATP; contains mtDNA.
Cytoskeleton
Network of microtubules, microfilaments, and intermediate filaments maintaining cell shape, motility, and organelle transport.
Microtubules
Hollow tubes of tubulin; involved in cell structure, intracellular transport, and formation of cilia/flagella; targeted by cancer drugs (e.g., vincristine).
Microfilaments
Thin actin filaments involved in cell movement (e.g., muscle contraction, microvilli structure).
Cell Membrane
Lipid bilayer with embedded proteins; regulates transport, contains receptors, and maintains electrochemical gradients.
Autocrine Signaling
Cell releases chemical messengers that act on its own receptors (e.g., immune cells).
Paracrine Signaling
Local signaling where chemicals act on nearby cells (e.g., neurotransmitters).
Endocrine Signaling
Hormones released into bloodstream to act on distant target cells (e.g., insulin).
G-Protein-Linked Receptors
Largest receptor family; use G-proteins to activate second messengers (e.g., cAMP) upon ligand binding.
Ion Channel-Linked Receptors
Receptors that open ion channels upon ligand binding (e.g., acetylcholine in neuromuscular junctions).
Enzyme-Linked Receptors
Receptors with intrinsic enzymatic activity (e.g., tyrosine kinases activated by growth factors).
Cell Cycle Phases (G0
G1
ATP
Adenosine triphosphate; energy currency of the cell with high-energy phosphate bonds; produced via glycolysis and oxidative phosphorylation.
Glycolysis
Anaerobic breakdown of glucose into pyruvate in the cytoplasm; yields 2 ATP and NADH.
Citric Acid Cycle (Krebs Cycle)
Mitochondrial pathway oxidizing acetyl-CoA to CO2; generates NADH, FADH2, and 2 ATP per glucose.
Electron Transport Chain
Mitochondrial process using NADH/FADH2 to create proton gradient; produces 32-34 ATP via oxidative phosphorylation.
Diffusion
Passive movement of substances down a concentration gradient (e.g., O2, CO2).
Osmosis
Passive movement of water through aquaporins from low to high solute concentration.
Facilitated Diffusion
Carrier-mediated transport of molecules (e.g., glucose) down a concentration gradient without energy.
Active Transport
Energy-dependent movement against a gradient (e.g., Na+/K+ ATPase pump).
Na+/K+ ATPase Pump
Primary active transporter moving 3 Na+ out and 2 K+ into the cell; maintains resting membrane potential.
Endocytosis
Cellular uptake of materials via vesicles (phagocytosis for solids, pinocytosis for liquids, receptor-mediated for specific molecules).
Exocytosis
Release of intracellular substances (e.g., hormones, neurotransmitters) via vesicle fusion with the cell membrane.
Resting Membrane Potential (RMP)
-70 to -90 mV in neurons; maintained by K+ leakage and Na+/K+ pump; critical for electrical excitability.
Depolarization
Reduction in membrane potential (inside becomes less negative) due to Na+ or Ca2+ influx.
Hyperpolarization
Increase in membrane potential (inside becomes more negative) due to K+ efflux or Cl- influx.
Action Potential
Rapid depolarization and repolarization in excitable cells (neurons, muscle) for signal transmission.
Epithelial Tissue
Avascular tissue lining surfaces (e.g., skin, gut); classified by shape (squamous, cuboidal, columnar) and layers (simple, stratified).
Basement Membrane
Extracellular matrix layer anchoring epithelial cells; composed of basal lamina and reticular fibers.
Tight Junctions
Zonula occludens; seal adjacent epithelial cells to prevent leakage (e.g., intestinal barrier).
Gap Junctions
Channels connecting cytoplasm of adjacent cells; allow ion/molecule exchange (e.g., cardiac muscle).
Connective Tissue
Supports and connects structures; includes loose, dense, adipose, bone, cartilage, and blood.
Skeletal Muscle
Striated, voluntary muscle attached to bones; contains sarcomeres, T-tubules, and sarcoplasmic reticulum for Ca2+ storage.
Cardiac Muscle
Striated, involuntary heart muscle with intercalated discs and gap junctions for synchronized contraction.
Smooth Muscle
Non-striated, involuntary muscle in hollow organs; uses calmodulin (not troponin) for Ca2+-mediated contraction.
Neurons
Nerve cells with soma, dendrites, and axon; transmit signals via action potentials and synapses.
Neuroglia
Supporting cells in nervous system (e.g., astrocytes, oligodendrocytes, Schwann cells for myelination).
Collagen
Most abundant extracellular protein; provides tensile strength in tendons, skin, and bones.
Elastin
Extracellular protein allowing tissue elasticity (e.g., aorta, lungs).
Lysosomal Storage Disorders
Diseases caused by deficient lysosomal enzymes (e.g., Tay-Sachs due to hexosaminidase A deficiency).
Cystic Fibrosis
Genetic defect in CFTR chloride channel; causes thick mucus in lungs and pancreas.
Primary Ciliary Dyskinesia
Immotile cilia syndrome; leads to chronic respiratory infections and infertility.
