HUBS191 k8

• what are the basic (anatomical) organisations of the nervous system

  central nervous system (CNS) , peripheral nervous system (PNS)
• Cells of the nervous system?

  neurons and glia
• what are the four structural components of a neuron?

  dendrites, cell body, axon, axon terminals
• group of cell bodies in the CNS

  nucleus / nuclei
• bundle of axons


  tract
• group of cell bodies in cerebral cortex or spinal cord

  gray matter
• bundle of axons in cerebral cortex or spinal cord

  white matter
• group of cell bodies in the PNS?

  ganglion / ganglia
• bundle of axons in the PNS

  nerves
• where is the neuron input zone? and what do they do?

  dendrites

  they recieve chemical signals from other neurons
• neuron summation zone structure? and what do these do?

  axon hillock - summation of inputs
• what is the summation zone of neurons? and what does this do?

  axon (can be quite long)

  they carry electrical signals between brain areas, to and from spinal cord, or from Peripheral sensory receptors and to the effector cells
• where is the neuron output zone? and what does it do?


  axon terminals - contact with input zone of other neurons or effectors, these release a neurotransmitter (chemical signal)
• what occurs before action potential?

  axon hillock summates inputs
• the four types of neurons?

  multipolar, bipolar, unipolar, anaxonix (axonless)
• multipolar neuron

  multiple processes emanate (spread out) from the cell body
• bipolar

  two processes (axons & dendrites) emanate (spread out) from the cell body
• unipolar neuron


  one process emanates (spreads out) from the cell body, it then branches into dendrites and axons
• anxonic (axonless)


  no distinct axon and all processes look alike
• 4 CNS glia types

  astrocytes, microglia, ependymal cells, oligodendrocytes
• astrocytes features:


  astrocytes supply nutrients to neurons, they ensheath blood capillaries, injury response
• micro glia features:


  they are the immune cells of the CNS, they engulf microorganisms and debris
• ependymal cells features:


  these cells line fluid-filled spaces of the brain and spinal cord, they have cilia (hair-like processes) to circulate cerebrospinal fluid (CSF)
• CSF?


  Cerebrospinal fluid
• oligodendrocytes features:


  they support nerve fibres, they ensheath axons with myelin
• the one type of PNS glia

  shwann cells
• shwann cells features:


  support peripheral nerve fibres, ensheath axons in myelin, similar to oligodendrocytes (type of CNS glia)
• what is myelin sheath and what is its purpose?

  myelin sheath is lipid (fat) that is wrapped around an axon to increase conduction velocity
• myelin sheath in CNS

  oligodendrocytes
• myelin sheath in PNS

  Shwann cells
• nodes of ranvier


  gaps between myelin, also increase conduction velocity
• what does a SYNAPSE do

  allows for communication between neurons through a junction
• SYNAPSE process


  At a synapse, one neuron sends a message to a target neuron—another cell.
• information INTO the brain is:

  afferent
• information OUT OF the brain is:

  efferent
• information goes into the brain through receptors
• effectors respond to motor command and create an action
• somatic


  stuff we are aware of and have control of
• voluntary muscle control

  somatic efferent (motor)
• sensory information we are aware of (can see)

  somatic afferent (sensory)