NURS 3093 Study Guide for Pathophysiology Test 1_2020 - Lipscomb University

NURS 3093 Study Guide for Pathophysiology Test 1_2020 - Lipscomb University Study guide for pathophysiology Chapter 1: Prokaryotes include cyanobacteria (blue-green algae), bacteria, and rickettsiae. Simple organization, no organelles, no nuclear membrane, lack of distinct nucleus, single, circular chromosome. Eukaryotic cells Animals, plants, protozoa, fungi, most algae, Membrane bound organelles multiple, structured chromosomes with supercoiled DNA, Well-defined nucleus, Ability to transport across outer membrane. *Cellular functions: Cells become specialized through cellular differentiation, or maturation, to perform a specific kind of function. Cells with a highly developed function, such as movement, often lack some other property, such as hormone production, which is more highly developed in other cells. *Plasma membrane proteins and their functions *The nucleus* This is involved in cell division and contains our genetic information. Within the nucleus we find: ---Nucleolus- Dense RNA protein –and ---Histones – DNA- binding proteins, cause coiling. The Nucleus contains loosely arranged chromatin. In the chromatin we have the DNA. The primary functions of the nucleus are cell division and control of genetic information The chromatin aggregates into discrete bands (Chromosomes) during cell division (Mitosis). Genetic information is transcribed into ribonucleic acid (RNA), which can be processed into messenger, transport, and ribosomal RNAs and introduced into the cytoplasm, where it directs cellular activities. Most of the processing of RNA occurs in the nucleolus. Ribosomes *Cytoplasmic organelles* • Synthesized in nucleus • RNA protein complexes • Functions for cellular protein synthesis Rough ER • Set of membranes lined with ribosomes • Produce proteins • Sends proteins to Golgi apparatus Smooth ER • Set of membranes without ribosomes • Produces biochemicals other than proteins • Can transport materials through the cell. Mitochondria 1. Generates energy (ATP) • Electron transport chain • Oxidative phosphorylation • Krebs cycle (Citric Acid Cycle) 2. Cellular energy metabolism (Contain metabolic machinery needed for cellular energy metabolism) • Homeostasis • pH control • Osmotic regulation Golgi complex • Modifies, sorts and stores proteins for secretion • Emits secretory vesicles • Network of smooth membranes and vesicles • This is like the shipping and processing department Lysosome • Membrane bound packet of digestive enzymes • Phagocytosis of foreign substances • Autophagocytosis of worn out cytoplasm or organelles • Peroxisomes- similar function but contains oxidative enzymes. Mitochondrial dysfunction *Cell-to-cell interactions* • Cellular receptors are located on the cell membrane. • Ligands- smaller proteins that bind to receptors. Ligand is just an ion. Binding site – region of protein that interacts with ligand • Depends on bonds/attractions • Binding leads to activation or inhibition signaling or pathway Plasma membrane receptors: • Protrude from external membrane for binding of ligands • Cellular uptake of ligands • Drug, bacterial, viruses, antibody, hormone or other type of receptor. The ligands that bind with membrane receptors include hormones, neurotransmitters, antigens, complement components, lipoproteins, infectious agents, drugs, and metabolites. *Cell to cell Adhesions: Specialized cell junction which are classified by whether they are symmetrical, Asymmetrical, by their function, and they allow for communication. *Symmetrical* Desmosomes: • Unite/bind cells • Strong mechanical attachments Tight junctions • Tight seal • Barrier to ion loss and diffusion Gap junctions • Communication • Electrical or chemical wave; molecule propagation *Asymmetrical* • hemidesmosomes (adhering junction) *Cellular communication Plasma membranes not only serve as the outer boundaries of all cells but also allow groups of cells to be held together robustly, in cell-to-cell adhesions, to form tissues and organs. Once arranged, cells are linked by three different means: (1) cell adhesion molecules in the cell's plasma membrane (see p. 8), (2) the extracellular matrix, and (3) specialized cell junctions. • Extracellular matrix: Cells can be united by attachment to one another or through the extracellular matrix, which the cells secrete around themselves. The extracellular matrix is an intricate meshwork of fibrous proteins embedded in a watery, gel-like substance. The matrix is similar to glue and provides a pathway for diffusion of nutrients, wastes, and other water-soluble substances between the blood and tissue cells. What this is in the cell is called: Collagen, elastin, fibronectin. • Specialized cell junctions: Classified as: Symmetric, asymmetric Classified by Function: Cell junctions classified by their function: (1) some hold cells together and form a tight seal (tight junctions); (2) some provide strong mechanical attachments (desmosomes, hemidesmosomes); (3) some provide a special type of chemical communication, such as those causing an electrical wave and fast communication (gap junctions); and, allow communication, Maintains cell polarity, and provides leak-proof and attachments. Symmetric junctions include: tight junctions, desmosomes, and gap junctions which is also called communication junction. Desmosomes: are used for structural stability. Tight junctions: are barriors to diffusion and prevent the movement of substances through transport proteins in the plasma membrane, and prevent the leakage of small molecules between the plasma membranes of adjacent cells. Gap junctions are clusters of communicating tunnels, allowing ions to pass. These can be chemical or electrical. Chemical signaling for cellular communication. Alterations in cellular communication affect disease onset and progression. In fact, if a cell cannot perform gap junctional intercellular communication, normal growth control and cell differentiation is compromised, thereby favoring cancerous tumor development. Secreted chemical signals involve communication locally and at a distance. Primary modes of intercellular signaling are contact-dependent, paracrine, hormonal, neurohormonal, and neurotransmitter. Autocrine stimulation occurs when the secreting cell targets itself. Picture example on next page In paracrine signaling, cells secrete local chemical mediators that are quickly taken up, destroyed, or immobilized. Paracrine signaling usually involves different cell types. cells also can produce signals to which they alone respond, called autocrine signaling (see picture above). For example, cancer cells use this form of signaling to stimulate their survival and proliferation. The mediators act only on nearby cells. Hormonal signaling involves specialized endocrine cells that secrete chemicals called hormones; hormones are released by one set of cells and travel through the bloodstream to produce a response in other sets of cells. In neurohormonal signaling hormones are released into the blood by neurosecretory neurons. Like endocrine cells, neurosecretory neurons release blood-borne chemical messengers, whereas ordinary neurons secrete short-range neurotransmitters into a small discrete space. Neurons communicate directly with the cells they innervate by releasing chemicals or neurotransmitters at specialized junctions called chemical synapses; the neurotransmitter diffuses across the synaptic cleft and acts on the postsynaptic target cell. Cells respond to external stimuli by activating a variety of signal transduction pathways, which are communication pathways, or signaling cascades. These are examples of that concept