MODULE 2: NEURONS AND NERVES

• Types of cells


  • Neurons
  • Glial Cells
• Parts of a neuron


  • Dendrite
  • Soma/ Cell Body
  • Axon
  • Nerves
  • Myelin Sheath
• Dendrite


  Receives messages from neighboring neurons
• Soma/ Cell Body


  Cell body that contain the nucleus, keeps the neurons alive
• Axon


  Carries messages to other cells, carries and transmits the information to other parts of the cell, axon terminals can be found at its ends
• Nerves


  Bundles of axons in the body coated with
• Myelin Sheath


  Protective sheath made up of glial cells called Schwann cells, serves to protect the neurons as they heal and reconnect
• Glial Cells


  Looks like an arm nursing pillow
• Functions of glial cells


  • Holds neurons in place while developing
  • Gets nutrients to neurons
  • Cleaning up dead neurons
  • Insulating the axons of neurons
• Types of glial cells


  • OLIGODENDROCYTES
  • SCHWANN CELLS
• OLIGODENDROCYTES


  Generates Myelin sheath for brain and spinal cord
• SCHWANN CELLS


  Generates myelin sheath for the body
• Action potential


  Neurons communicate with
• Synaptic Transmission


  Signal reaches axon terminals, synaptic vesicles (pockets) open up and release neurotransmitters into the synapse (space bet axon terminal and the dendrite of next neuron)
• Neurotransmitters


  Once released into the synapse, they float and attach themselves to their own specific receptor sites, either stimulating the neuron to fire another message (excitatory neurotransmitters) or stopping the neuron from doing so (inhibitory neurotransmitters)
• What happens to neurotransmitters after synaptic transmission


  • Diffusion
  • Enzymatic breakdown
  • Glial cells clean up
  • Reuptake
• Excitatory neurotransmitters


  Initiates action potential
• Inhibitory neurotransmitters


  Prevents action potential
• Agonist


  Magnifies neurotransmitter effect
• Antagonist


  Blocks neurotransmitter effect
• Neurotransmitters and their functions


  • Acetylcholine - Excitatory/Inhibitory, arousal, attention, memory, muscle contraction
  • Norepinephrine - Excitatory, arousal and mood
  • Dopamine - Excitatory/Inhibitory, movement and pleasure
  • Serotonin - Excitatory/Inhibitory, sleep and limits movement
  • GABA - Inhibitory, sleep and limits movement
  • Glutamate - Excitatory, learning, memory formation, synaptic plasticity, nervous system development
• Parts of the central nervous system


  • Brain
  • Spinal Cord
• Two cells in the nervous system


  • White matter
  • Gray matter
• 3 main parts of the brain


  • Forebrain
  • Midbrain
  • Hindbrain
• Forebrain


  Limbic system - emotions, motivation, memory and learning, cortex
• Midbrain


  Top of the hindbrain, parts include colliculi (processing of visual and auditory), tegmentum (coordination of movement and suppression of pain), cerebral peduncles (connection between the brain stem and the forebrain)
• Hindbrain


  Lowest part of the brain near the base of the skull, for breathing, heartbeat, composed of: medulla, pons, reticular, formation, cerebellum
• Parts of the peripheral nervous system


  • Somatic Nervous System - Afferent/Sensory Pathway, Efferent/Motor Pathway
  • Autonomic Nervous System - Sympathetic Nervous System, Parasympathetic Nervous System
• Somatic Nervous System


  Senses to CNS, CNS to muscles and glands
• Sympathetic Nervous System


  Stress (positive and negative) response
• Parasympathetic Nervous System


  Returns body to normal functioning after stress, manages day-to-day physiological functioning
• Endocrine system glands


  • Pituitary gland
  • Pineal gland
  • Thyroid
  • Parathyroid
  • Adrenal gland
  • Ovaries
  • Testes
  • Pancreas
• Endocrine system


  Produces hormones which flows through the bloodstream, affects muscles, organs, glands, has excitatory or inhibitory effects on the brain
• Hypothalamus


  Connected to the endocrine system
• Oxytocin


  Encourages uterine contraction and milk production, social cognition and behaviors, inferring mental state via facial expressions, trust
• Major lobes of the cortex


  • Occipital - processes visual information; visual association cortex
  • Parietal - somatosensory cortex; info from skin and body position
  • Temporal - primary auditory cortex; language
  • Frontal - planning, personality, memory, storage, regulating emotions
• Cortical


  Planning, decision-making
• Subcortical


  Emotion, motivation
• Broca's Area


  Interaction between frontal, temporal, and motor areas responsible for speech production, Broca's Aphasia - loss of the ability to form speaking sentences with proper grammar
• Wernicke's Area


  Understanding the meaning of words, Wernicke's Aphasia - difficulty in understanding language