Physio midterm

• Physiology


  Study of normal functioning in chemical and physical processes in organism
• Homeostasis


  Regulation of body's internal environment in response to external changes
• Teleological approach


  Focuses on why
• Mechanistic approach


  Focuses on how
• Placebo


  Fake drug used to test effectiveness of medication
• Hypothesis


  Logical guess based on observation
• Cation


  Positively charged ion
• Electrons


  Negatively charged particle orbiting nucleus of an atom
• Amino acids


  • Essential (cannot be made by body)
  • Nonessential (can be made by body)
• pH scale


  <7 acidic; 7 neutral; >7 basic
• pH


  Dependent on free floating H+ ions
• Body Compartments


  • Intracellular (⅔ of fluid; inside cells)
  • Extracellular (⅓ of fluid; outside cells)
  • Interstitial (between cells)
  • Plasma (in blood vessels)
• Intracellular, extracellular, and plasma ion and protein concentrations

  • Intracellular: protein and K+
  • Interstitial: Na+ and Cl-
  • Plasma: Na+, Cl-, and proteins
• Diffusion


  Solutes move from areas of high to low concentrations
• Tay-Sachs disease effects the lysosome cell organelle
• Rough ER


  Protein synthesis
• Golgi Body/Golgi Apparatus


  Packages proteins and lipids
• Cell membrane


  Barrier and gateway between intra and extra cellular fluid
• Cell membrane proteins


  • Integral (embedded in membrane for structure)
  • Peripheral (on either surface of membrane for binding)
  • Transmembrane (through membrane for transport)
• Cholesterol


  • Main source of steroids
  • Embedded in membrane for fluidity
• Protein synthesis


  1. Transcription: DNA → mRNA in nucleus

  2. Translation: mRNA → protein in ribosome
• Exocrine Glands


  Use ducts to secrete substance that will leave body
• Examples of exocrine glands

  • Liver
  • Pancreas
  • Salivary
  • Mammary
• Levels of organization


  • Atom
  • Molecule
  • Organelle
  • Cell
  • Tissue
  • Organ
  • Organ system
  • Organism
• Energy


  Capacity to do work
• Activation energy


  Energy required to initiate reaction
• Enzymes


  Proteins that speed up reactions by lowering activation energy
• Enzyme specificity


  Each enzyme catalyzes specific reaction since it is shaped for certain substrates
• Exocytosis


  Active transport that uses vesicles to export materials
• Resting membrane potential


  • (-70mV), created by K+ leak channels; majority K+ concentration inside cell
• Nervous system divisions


  • Central Nervous System (brain and spinal cord)
  • Peripheral Nervous System (everything else)
• Ganglia


  Cell body clusters in PNS
• Nuclei


  Cell body clusters in CNS
• Neuron types


  • Sensory/Afferent (in dorsal root)
  • Motor/Efferent (in ventral root)
• Neuron anatomy


  • Dendrites (receivers on cell body)
  • Cell body (control center with nucleus)
  • Axon hillock (action potential generator)
  • Axon (shaft where action potential travels)
  • Myelin sheath (lipid structures that speed up signal)
  • Nodes of Ranvier (bare axon between myelin)
  • Axon terminal (sends signals into synapse)
• Neuronal action potential


  1. Membrane begins at -70mV

  2. Positive graded potentials trigger voltage threshold

  3. Axon hillock fires action potential causing Na+ channels to open

  4. Influx of Na+ causes depolarization

  5. Overshoot point where Na+ channels close and K+ channels open

  6. Hyperpolarization from excess K+ efflux
• Overshoot point


  Na+ channels close and K+ channels open at peak of potential
• All-or-none principle


  If voltage-threshold is reached, action potential is generated
• Refractory periods


  • Absolute (action potential will not fire)
  • Relative (action potential will only fire if stimulus is strong)
• Excitatory Postsynaptic Potential (EPSP)

  If a stimulus depolarizes cell, it is an excitatory