physio exam

• Ancient cultures like Egyptian, Indian, Chinese, and Greek initially considered the heart the center of thought and emotions before transitioning to brain-centric views, laying the groundwork for the study of behavior physiology
• René Descartes, a 17th-century French philosopher, viewed animals and humans as mechanical devices controlled by environmental stimuli, introducing the concept of reflexes for automatic, involuntary actions and believed in a non-physical mind linked to the physical brain
• Luigi Galvani's 17th-century experiments challenged Descartes' ideas by disproving the notion of pressurized fluid in the brain through electrical stimulation of frog nerves causing muscle contractions independent of the body
• Pierre Flourens, a 19th-century French physiologist, pioneered experimental ablation by removing parts of animals' brains to observe behavior, while Broca's area in the left frontal cortex was identified as associated with speech
• Hermann von Helmholtz measured nerve conduction speed, challenging the notion of rapid neural conduction, while Ramon Santiago y Cajal used Golgi staining to depict individual neurons' structures and was awarded the Nobel Prize in 1906 for contributions to understanding the nervous system's structure
• In the 20th century, vital inventions like sensitive amplifiers and neurochemical techniques emerged, leading to advancements in spatial positioning systems recognized by a Nobel Prize in 2014 and enabling treatments for depression and Parkinson’s using deep brain stimulation
• Consciousness encompasses various meanings, from basic wakefulness to self-awareness, while blindsight refers to the ability to accurately reach for objects in the blind field without conscious perception, caused by damage to the "mammalian" visual system of the brain
• Physiological psychology challenges the belief that perceptions must enter consciousness to influence behavior, showing that behavior can be guided by sensory information of which a person is unaware
• Split-brain surgery involves cutting the corpus callosum to reduce uncontrollable overactivity of nerve cells, leading to hemispheres operating independently after disconnection, with effects like conflict between hemispheres and unintentional gestures demonstrating challenges in hemisphere coordination
• Unilateral neglect, caused by damage to the right side of the brain's parietal lobe, leads individuals to ignore stimuli on the left side, acting as if the left side of the world and their bodies don't exist, showcasing characteristics like inattention and lack of consciousness regarding left-side stimuli
• The rubber hand illusion study confirmed the role of the parietal lobe and another brain region in body ownership feelings, showing that subjects perceived a lifelike rubber hand as their own when strokes were synchronous and in the same direction
• Experimental ablation involves destroying part of the brain to observe subsequent behavioral changes, constituting one of the oldest neuroscience research methods, with a lesion being a wound or injury referred to as a brain lesion by researchers
• Histological methods like fixation and sectioning, staining, electron microscopy, and confocal laser scanning microscopy are essential for studying tissues and structures in neuroscience research
• Stimulations in neuroscience research include electric stimulation passing an electric current through a wire inserted and chemical stimulation accomplished by injecting small amounts of excitatory acids into the brain
• Recording of neural activity involves techniques like microelectrodes recording electrical activity of single neurons, macroelectrodes recording electrical activity of brain regions, magnetoencephalography recording magnetic fields induced by neural activity, and autoradiography using radioactive material to develop pictures
• Stimulating neural activity methods include transcranial magnetic stimulation to stimulate neurons in the human cerebral cortex with an electromagnet placed on the head
• Cells in the nervous system fall into 2 types: glia and neurons
• Transcranial Magnetic Stimulation stimulates neurons in the human cerebral cortex with an electromagnet placed on the head
• Glia:

  • Literally means “glue”
  • Astroglia or astrocytes regulate the blood-brain barrier, control homeostasis, neuronal defense and repair, scar formation, and affect electrical impulses
  • Oligodendroglia cells create myelin that insulates axons, located in the CNS
  • Ependymal cells line the ventricles and secrete cerebrospinal fluid
  • Microglia are the brain’s immune cells, protecting it from invaders and cleaning up debris, they also prune synapses
  • Schwann cells have a similar function to oligodendrocytes but are located in the PNS
• When a neuron is stimulated, there will be a change in the membrane potential, which is the electrical charge across a cell membrane
• 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 to maintain the concentration of sodium ions higher outside than inside the cell, and vice versa with potassium
• Conduction of Action Potential:

  • Depolarization: inside of the cell becomes more positive/less negative
  • Repolarization: inside of the cell becomes more negative
• Five processes of neuronal communication:

  1. Synthesis and storage of neurotransmitter

  2. Release of neurotransmitter into synaptic cleft

  3. Binding of neurotransmitters at receptor sites on post-synaptic membrane

  4. Inactivation of neurotransmitter

  5. Reuptake of Neurotransmitter