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• Voltage gated sodium channels

  Provide rapid repolarization phase in neurons
• Blood pressure


  Usually expressed as systolic pressure over diastolic pressure
• Synaptic transmission


  1. Entry of extracellular calcium

  2. Triggers release of transmitter
• Neuromuscular transmission


  Also known as cholinergic transmission
• Channels required for depolarization phase and action potential generation

  Sodium channels
• Order blood flows through blood vessels

  • Arteries
  • Arterioles
  • Capillaries
  • Venules
  • Veins
• Largest action potential duration

  • Seen in cardiac muscle
• Membrane transport against concentration gradient


  Active transport
• Termination of acetylcholine action


  Mainly by enzymatic destruction
• Where neurotransmitters are synthesized

  • Peptide transmitters - Neuron cell body
  • Nonpeptide transmitters - Nerve terminal
• Myelination in central nervous system

  Done by oligodendrocytes
• Catecholamines


  Formed by hydroxylation and decarboxylation of the amino acid tyrosine
• Medications that work on chloride channels

  Sedatives, hypnotics, tranquilizers, anti-convulsants
• Rate-limiting step in adrenergic transmitter synthesis

  Conversion of dopa to dopamine
• Neurotransmitter associated with organophosphate poisoning

  Acetylcholine
• Na/K-ATPase pump and calcium pump


  Examples of primary active transport
• Sections of gastrointestinal tract


  • Esophagus
  • Stomach
  • Small intestine
  • Large intestine
• Blood flows out of ventricles


  When semi-lunar valves are open
• Normal cardiac cycle duration

  0.8 seconds
• Norepinephrine acts on alpha 2 receptors


  To inhibit further transmitter release
• Heart block


  Occurs when impulse formation is impaired or conduction is prevented, and the delay between atrial and ventricular contraction is increased
• Absolute refractory period


  Due to voltage inactivation of sodium channels
• Structural protein of thin filament with cross-bridge attachment sites


  Actin
• Filament that binds to calcium

  Troponin
• Main supporting tissue of central nervous system

  Astrocytes
• Mechanism to terminate adrenergic transmission

  Reuptake by presynaptic nerve
• Primary transmitter for postganglionic sympathetic neurons

  Norepinephrine
• Epinephrine release


  By adrenal medulla
• Substances that can alter synaptic membrane sensitivity

  Norepinephrine
• Presynaptic inhibition decreases entry of

  Calcium
• Symptoms of cerebellar lesion

  Tremor while reaching, inability to perform rapid alternating movements
• Acetylcholine is not a dominant neurotransmitter at


  Sympathetic postganglionic neurons
• Normal blood pressure


  120/80 mm Hg
• Types of spinal nerves

  • Mixed nerves
• Nitric oxide


  A neurotransmitter that is a gas that readily diffuses across cell membranes
• Neurotransmitters that generate IPSPs via ligand gated chloride channels

  Glycine and GABA
• Ligand-gated channels on postsynaptic membranes

  Allow influx of sodium and efflux of chloride
• No extracellular calcium utilized in

  Voluntary muscle
• Positive feedback in


  Oxytocin secretion
• Why CO2 diffuses faster across membranes than O2

  CO2 is more soluble