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2011-11-11 21:20:29
vet tech anatomy physiology chapter cell set

vet tech anatomy physiology 1 chapter 3 cell physiology set
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  1. Cell anatomy
    • looks at parts
    • like looking at a car engine that's not working
  2. Cell physiology
    • looks at function
    • like looking at how the car runs
  3. Body fluids
    • intracellular
    • extracellular
  4. Intracellular body fluids
    • 90-94% water
    • majority of fluid is contained within cell membranes
  5. Extracellular body fluids
    • interstitial fluid
    • plasma
  6. Interstitial fluid
    • within tissues
    • fluid/serum that leaks out when you skin your knee
    • think of this as the humidity in the air in your house
    • in order to move stuff from blood into cell, must travel through interstitial fluid
  7. Plasma
    • within the blood vessels
    • think of this as water in the pipes of your house
  8. Body fluid compartments
    • extracellular fluid
    • intracellular fluid
    • solid matter
  9. Extracellular body fluid compartment
    • 20% of body weight
    • joint fluid
    • fluid in stomach and intestines
    • plasma
    • fluid surrounding brain
    • lymph fluid
    • interstitial fluid
  10. Intracellular body fluid compartment
    • 40% of body weight
    • cells
  11. Solid matter body fluid compartment
    • 40% of body weight
    • tissue matter
    • bone
  12. Fluid regulation
    • plasma membranes
    • semi-permeable barrier
    • - some things can get in, some can't
    • ions
    • - tend to be things that can get in
    • - cations
    • - anions
    • - electrolytes
    • -- salts
    • -- acids
    • -- bases
  13. Passive membrane processes
    • require no cellular energy (ATP)
    • 4 types:
    • - diffusion
    • - facilitated diffusion
    • - osmosis
    • - filtration
  14. Diffusion
    • inherent molecular motion
    • concentration gradient
    • diffusion in biological systems
    • selectively permeable membranes (plasmalemma)
  15. Inherent molecular motion
    • - aka Brownian motion
    • - kinetic energy
  16. Concentration gradient
    • movement of molecules from areas of high concentration to areas of low concentration
    • because of inherent molecular energy and reach equilibrium
  17. Diffusion in living systems
    • think of this as huge open archway
    • governed by
    • - molecular size
    • - lipid solubility
    • - molecular charge
    • rate
    • facilitated diffusion
  18. Molecular size
    small molecules diffuse readily across plasma membrane
  19. Lipid solubility
    • phospholipid bilayer
    • alchols, steroids, and gases are highly lipid soluble and readily diffuse
  20. Molecular charge
    • charged particles require channels to pass through membranes
    • eg sodium, potassium, chloride ions
  21. Rate
    • limited by number of carriers or channels present
    • fever increases rate of reactions
    • cold (hypothermia) slows everything down
    • anesthesia is all about delivering chemicals across the plasma membrane in one direction or the other
  22. Facilitated diffusion
    • utilites integral proteins to provide a means of passage for large or charged particles to pass freely through the membrane
    • think of this as a small door
    • each cell has its own varieties of integral proteins to determine that can go in and out
    • large molecules require action of integral proteins to permit diffusion
    • channel proteins are like a door
    • carrier proteins are like a turnstyle
  23. Osmosis
    • special form of diffusion of water across a semi-permeable membrane
    • specifically the movement of water molecules from areas of high concentration to areas of low concentration
    • water moves readily across membranes until equilibrium is reached
    • water and solutes tend to move in opposite directions
    • in homeostasis, the concentration of water molecules inside of cells is equal to the concentration outside the cells
    • solutes can be different, but water molecules are the same
    • don't give pure water IV as water would rush in and cell would burst
  24. Osmotic flow
    movement of water molecules from areas of high concentration to areas of lower concentration
  25. Osmotic pressure
    the force of the movement of water molecules
  26. Tonicity
    • isotonic
    • hypertonic
    • hypotonic
  27. Isotonic medium
    • cells structure will remain the same
    • picture a normal RBC
    • give isotonic fluids IV (isotonic to what is normally in cell), eg 0.9% NaCl
  28. Hypertonic medium
    • cells will collapse in on themselves
    • picture a crenallated (spiky) RBC
    • crenallated => dehydrated
    • need water for Kreb's cycle, so as you get dehydrated, cells will not function
  29. Hypotonic medium
    • cell will expand and, possibly, burst
    • picture RBC as a ball
    • sometimes will give this initially in severe dehydration to speed recovery, eg 0.45% NaCl
  30. Oncotic pressure
    • difference between the osmotic pressure of bloos and the osmotic pressure of the interstitial fluids
    • - big molecules pulling stuff in
  31. Hydrostatic pressure
    • liquids (interstitial fluid) pulling stuff out
    • the force that pushes liquid through membranes
    • generated by beating heart
    • the rest is from
    • - the pressure in the circulatory system exerted by the volume of blood when it is confined in a blood vessel.
    • - The hydrostatic pressure, coupled with the osmotic pressure within a capillary is opposed by the hydrostatic and osmotic pressure of the surrounding tissues.
    • - Fluids flow from the higher pressure areas to the lower pressure areas.
  32. Filtraton
    • requires a pressure gradient, eg heart beat (BP)
    • molecules are pushed through the membrane due to differences in pressure on either side
    • molecules that would not normally pass, may
    • really important in kidneys
    • by the time you can diagnose kidney disease, 75% of nephrons are not functioning correctly
  33. Active membrane processes
    • requires ATP to assist movement of molecules across cell membranes
    • relies on carrier proteins
    • works against the concentration gradient
    • Na+, K+, Mg+, Ca+ actively transport across cell membranes
    • - eg more potassium needed in cell for electrical activity
    • Cl-, I-, Fe2+ trasport across specialized cells, eg thyroid
  34. Active Transport
    • uniport
    • symport
    • antiport
  35. Uniport
    one substance moves in one direction
  36. Symport
    • more than one substance moves in one direction
    • sometimes, must be together
    • eg proton pump and sucrose-H+ cotransporter work together to form a symport
  37. Antiport
    • some substances move in and some move out
    • - eg sodium potassium pump - 3 NA, 2 K
    • - need more K in cells than out for muscle contraction, nerve impulses
    • - sodium diffuses in to cell down concentration gradient, usually drags in water
    • - that's why BP goes up when eat salt
  38. Cytosis
    active transport requiring ATP
  39. Endocytosis
    • moves material into the cell
    • non-specific - takes everything
    • - phagocytosis - cell eating
    • - pinocytosis - cell drinking
    • -- when drink orally, osmosis not enough to move water, so large int?? cells take chunks of water to move in
    • -- macrophages will drink harmful fluids like botulin toxin
  40. Phagocytosis
    • phagosomes
    • - ameboid motion of pseudopodia
  41. Pinocytosis
    • - tiny infolding of the plasma membrane
    • - fluid released into the cytoplasm
  42. Receptor mediated endocytosis
    • specific proteins act as specialized receptors
    • ligands bind to these receptors
    • coated pit forms
    • receptor molecule is recycled
  43. Exocytosis
    • moves material out of cell
    • - excretion
    • - secretion
    • - both processes very similar
  44. Excretion
    • removal of waste products
    • - eg urine
  45. Secretion
    • export of cell manufactured molecules
    • - eg ear wax
  46. Resting membrane potential
    • there is a charge inside and outside each cell
    • membrane potential = Voltage
    • all cells maintain a membrane potential, -20 to -200 millivolts
    • EKG measures this in the heart
    • negative charge
    • - is on the inside of the plasma membrane
    • - is negative relative to the extracellular fluid
    • electrons move toward positive pole
    • cells are like little batteries
    • sodium potassium pump maintains negative charge bu releasing 3 Na for each 2K that come back in
    • irritable cells - conductive - muscle and nerve
    • change polarity to allow flow of information
    • epithelial and connective tissues not conductive
    • electricity runs through a cell
    • to bridge the gap between cells, chemicals are released which bond to the next cell and change its electrical gradient
    • neurotransmitters are chemical switches to turn on/off electrical gradient
    • - eg dopamine, nicotine, caffeine, morphine, acetylcholine
  47. Voltage
    the potential electrical energy created by the separation of opposite charges
  48. Life cycle of the cell
    • somatic cells divide by mitosis
    • produce 2 genetically identical daughter cells
    • in juveniles, all cells are mitotically active
    • cells reproduce to maintain body tissues, heal wounds and enable growth
  49. Somatic cell
    all cells in the body exclusive of the reproductive cells (sperm and eggs)
  50. Interphase
    • the period between cell divisions
    • historically called the resting phase
    • now referred to as the metabolic phase - when cell is doing most of its regular work
    • nucleus and nuceoli visible
    • DNA arranged as loose chromatin strands
    • divided into 3 phases:
    • - Growth 1
    • - Synthesis
    • - Growth 2
  51. Growth 1 phase
    • most active phase
    • lasts for variable periods depending on the nature of the cell
    • - minutes to years
    • - muscle & nerve cells in adult are long term
    • - cells in mouth are replaced every 24-36 hours
    • intensive metabolic activity
    • cell growth - small amount
  52. Synthesis phase
    • DNA replication occurs
    • new histones are produced
    • - cell is working for itself now
    • chromatin is assembled
  53. Growth 2 phase
    • very brief
    • enzymes and proteins required for cell division are produced
  54. DNA replication
    • must occur before cell division can proceed
    • intricate multistep process that is not fully understood
    • helicase breaks the hydrogen bonds between bases (unzips)
    • primase forms DNA on the leading strand
    • polymerase forms DNA on lagging strand
    • ligase joins fragments (replaces RNA) on lagging strand
    • only does this during synthesis phase
    • rest of the time DNA is active in protein synthesis
    • estrogen is trigger for bone cells to reproduce
  55. Protein synthesis
    • during G1 phase - normal maintenace
    • during G2 phase - stuff for new cell
    • doesn't require entire DNA strand to unravel to make a protein
    • RNA polymerase causes DNA to open at the specific gene needed
    • creates messenger RNA (mRNA) from gene
    • mRNA exits nucleus
    • nucleoli also forms tRNA, rRNA & ribosome exits nucleus
    • ribosome attaches to mRNA
    • tRNA brings amino acids to ribosome
    • attach to each other to form polypeptide which forms protein (goes to ER, folds it, then Golgi apparatus to be packaged)
  56. Anticodon
    3 base code for one amino acid
  57. Transcription
    • DNA -> mRNA
    • inside nucleus
    • genes - sections of DNA that code for a specific protein (only 10% codes for protein)
    • replicaton begins at the start signal or promoter
    • RNA polymerase encourages binding of mRNA to DNA
    • 3 RNA nucleotides form a codon
    • each codon represents a different amino acid
    • ends when reach the terminator code
    • spliceosomes remove introns
    • small ribonucleic proteins splice the exons back together
  58. Introns
    non-informational triplets of DNA
  59. Extrons
    informational triplets of DNA
  60. Translation
    • nucleic acid (mRNA) -> amino acid
    • outide nucleus
    • mRNA binds to a ribosome and protein synthesis begins
    • tRNA docks to the larger ribosomal unit's active site
    • tRNA contains an anti-codon and an amino acid binding site
  61. Mutation
    • a genetic error
    • sometimes neutral
    • DNA wears out and breaks
    • minimum number of mutations needed to make cancer is 4
    • - some cancers needs up to 20
    • cancer usually occurs in:
    • - young - rapidly dividing cells
    • - old - cells have divided many times, possibly many mutations
    • - BRCA1 & BRCA2 genes don't guarantee cancer, just means you need fewer mutations
  62. Mutagen
    • factors that cause mutations
    • - wear & tear
    • - viruses
    • - ionizing radiation
    • - certain chemicals
  63. Development
    complex multicellular organism from one cell
  64. Cell differentiation and development
    • each division results in increased specialization of the cells
    • controlled by the genes within the DNA
    • genes can be turned on or off based upone the geometry of the DNA molecule
  65. Differentiation
    • involves temporary or permanent inhibition of genes within a given cell that may be active in another cell
    • eg nerve cells make neurotransmitters, epithelial cells do not
    • eg epithelial cells make keratin, nerve cells do not
    • juvenile cells are more active than adult cells
  66. Specialization
    • what type of cell within the tissue type
    • occurs as a result of differentiation
    • leads to morphologic changes involving the number and types of organelles within a cell