physio prelim exam

• Egyptian, Indian, Chinese, and Greek considered the heart the center of thought and emotions.
• Rene Descartes viewed humans and animals as mechanical devices, behaviors are controlled by environmental stimuli
• Rene Descartes, a dualist, believed in a non-physical mind linked to the physical brain
• Luigi Galvani - discovered that dead frog muscles could be made to twitch by touching them with a metal wire
• Luigi Galvani - electrical stimulation of frog nerves caused muscle contractions independent of the body.
• pierre flourens - pioneered experimental ablation, removing parts of animals' brains to observe behavior.
• Broca's Area and Experimental Ablation

  • applied experimental ablation to humans, linking brain regions to specific functions
  • identified Broca's area in the left frontal cortex, associated with speech
• electrical stimulation and Helmholtz

  • used electrical stimulation to map the primary motor cortex
  • Hermann vo Helmholtz measured nerve conduction speed, challenging the notion of rapid neural conduction
• Jan Purkinje - studied cardiac neurons and visual system, identified Purkinje fibers
• Ramon Santiago y Cajal

  • used Golgi staining to depict individual neurons' structures
• consciousness - encompasses various meanings, from basic wakefulness to self-awareness
• cells in the nervous system fall into 2 parts; glia and neurons
• glia

  • means "glue"
  • support system of the NS
• glia

  astroglia or astrocytes

  - caretakers

  regulate the blood brain barrier, allowing nutrient and molecules to interact with neurons.

  • control homeostasis, neuronal defense and repair, scar formation, and also affect electrical impulses
• glia


  Oligodendroglia

  • create a fatty substance called myelin that insulates axons- allowing electrical massages to travel faster.
  • located in the CNS
• glia


  Ependymal

  • cells line the ventricles and secrete cerebrospinal fluid
• glia


  Microglia

  • the brain's immune cells, protecting it from invaders and cleaning up debris.
  • they also prune synapses
• glia


  Schwann cells

  • similar function with oligodendrocytes but located in the PNS
• STIMULATION OF THE NEURON

  • when a neuron is stimulated, there will be a change in the membrane potential of a neuron

  Membrane potential - the electrical charge across a cell membrane.
• Membrane Potential


  is the result of the balance between two opposing forces; diffusion and electrostatic pressure
• Diffusion - molecules move from regions of higher concentration to regions of lower concentration
• Electrostatic Pressure - positively charged ion molecules are repelled by same positively charged ions while attracted to negatively charged ions, vice versa
• Sodium-Potassium Pump

  • acts like a cellular bouncer, moving three sodium ions out and welcoming two potassium ions in
  • maintain the concentration of sodium ions to be always higher outside than inside the cell, vice versa with potassium
• CONDUCTION OF ACTION POTENTIAL

  • depolarization - inside of the cell becomes more positive/less negative
  • repolarization - inside the cell becomes more negative
• rate law - strong stimulus fires more frequent action potentials compared to weak stimuli
• Five processes of neuronal communication:

  1. Synthesis and Storage:

  • Neurotransmitters are made in the presynaptic terminal and stored in small vesicles

  2. Release:

  • Calcium ions in the presynaptic membrane trigger the release of neurotransmitters from vesicles
  • Two types of release: "kiss and run" where the vesicle reseals and "merge and recycle" where the vesicle fuses with the membrane and then reforms

  3. Binding:

  • Neurotransmitters attach to receptors on the postsynaptic membrane
  • Two methods: direct (ion channels open directly) and indirect (chemical cascade initiates via metabotropic receptors)

  4. Inactivation:

  • Enzymes alter the neurotransmitter's structure so it can't bind to receptors

  5. Reuptake:

  • Neurotransmitter molecules are taken back into the axon terminal for recycling