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NURS6501 Pathophysiology chapter 1
Prokaryocytes lack histones, no organelles, nuclear material not encased by nuclear membrane, cyanobacteria, bacteria, and rickettsiae. Eukaryocyte cell with a nucleus, large, more extensive intracellular anatomy. have organelles Differentiation process in which cells become specialized in structure and function cellular functions movement, conductivity, metabolic absorption, secretion, excretion, respiration, reproduction, communication Nucleus A part of the cell containing DNA and RNA and responsible for growth and reproduction. Primary function is cell division and control of genetic information Nuclear membrane/envelope Surrounds the nucleolus and DNA. Controls what enters and leaves the nucleus. Nuclear pore complexes (NPC) allow molecules to move between nucleus and cytosol cytoplasmic matrix the space between the nuclear envelope and the plasma membrane. Filled with cytosol, takes up half the volume of the cell. Cytosol is the main site for protein synthesis. Ribosomes
Chief function is providing sites for protein synthesis. Secreted into the cytoplasm through nuclear pore complexes (NPCs). Ribosomes have signal recognition particles that bind to it. the ribophorins are receiver proteins on the ER. The protein then threads through the ER into the lumen and a new protein chain is formed. Endoplasmic Reticulum (ER) A cell structure that forms a maze of passageways in which proteins and other materials are carried from one part of the cell to another. (endo=within, plasma= cytoplasm, reticulum= network). Tubular or sac-like channels responsible for much of the cell's protein synthesis and folding- senses cellular stress. Golgi complex organelle that modifies, packages, and transports material out of the cell. Lysosomes cell organelle filled with enzymes needed to break down certain materials in the cell. (lyso= dissolution, soma=body). contain digestive enzymes called hydrolases. Autophagy A process in which lysosomes decompose damaged organelles to reuse their organic monomers Peroxisomes Break down fatty acids and produce hydrogen peroxide. contain enzymes that use oxygen to remove hydrogen atoms. mitochonddria power house of the cell since provide most of ATP; enclosed by two membranes; dna and rna and celf-replicating. responsible for cellular respiration and energy production. Cytosol
proteins found on the surface of most cells that aid in the binding of the cell to the extracellular matrix or other cells; integral membrane proteins; three major families: cadherins, integrins, selectins Proteostasis The maintenance of a cellular steady-state collection of proteins that are required for cell functions under a given set of conditions. Cell homeostasis Proteases enzymes that break down proteins cellular receptors proteins that have a binding site ("docking site") complementary in shape to a specific hormone. also called ligands. Hormones are ligands- fit together like jigsaw puzzle. cell-cell adhesion holds tissues together. forms organs extracellular matrix (ECM) intricate meshwork of interstitial fibrous proteins embedded in a watery, gel-like substance composed of complex carbohydrates. basement membrane Layer between epithelium and underlying connective tissue cell junctions connections between cells that hold the cells together as a unit cellular communication
Cells in a large organism communicate by means of chemical signals that are passed from one cell to another. communicate to maintain homeostasis, regulate growth and division, and organization into tissues. paracrine signaling secreted molecules diffuse locally and trigger a response in neighboring cells autocrine signaling cells respond to signaling substances that they themselves secrete neurohormonal signaling hormones are released into the blood by neurosecretory neurons membrane channels involved with the movement of substances through the cell membrane cellular metabolism anabolism is the use of energy, catabolism is the release of energy. ATP (adenosine triphosphate) main energy source that cells use for most of their work oxidative phosphorylation The production of ATP using energy derived from the redox reactions of an electron transport chain; the third major stage of cellular respiration. membrane transport proteins Proteins embedded in the membrane of a cell that assist in the transport of large molecules.
charge difference across the plasma membrane action potential a neural impulse; a brief electrical charge that travels down an axon. A rapid change in the RMP Depolarization The process during the action potential when sodium is rushing into the cell causing the interior to become more positive. cell cycle The regular sequence of growth and division that cells undergo DNA damage response A group of reactions that enable a cell to repair certain types of DNA changes that occur during replication. Tissue Formation differentiation and movement/shape change of cells to form specific functional structures cell signals autocrine- from cell to it's own, paracrine- from cell to target cells nearby, endocrine- from cell to far away cells (hormones or cytokines). signaling molecules ligands- most are hydrophilic so they can float in extracellular pace but can't pass through the membrane- have to bind to receptors transmembrane receptors
three major classes- g protein coupled receptors, enzyme coupled receptors (single pass- enzyme<-->receptor), ion channel receptors (open only to specific ligands- change the electrical charge) osmosis how water molecules move across a semi permeable membrane, equalizes. passive diffusion. hypertonic- more concentrated, hypotonic- less concentrated. entropy- movement is random- ions interfere with water molecules from crossing the membrane by bouncing off other membranes. Resting Membrane Potential (RMP) permeability and electrical charges on inside and outside of cell establish RMP. the more negatively charged ions inside of the cell attracts positively charged molecules (K+) back in cell- called electrostatic gradient. concentration gradient difference in the concentration of a substance from one location to another. low amount of K+ on outside of cell, Ca2+, Na+, Cl- all high concentration outside of cell free radicals naturally occurring, highly reactive chemicals that form in the presence of oxygen( when oxygen doesn't get the 4 electrons from this process). formed when any molecule gains or loses an electron. Oncogenes cancer causing genes ( gas pedal- stimulates growth and division) tumor suppressor genes make proteins that stop cell division and kill cells (brake pedal- negative regulation of cell cycle).
