Nervous system

• the collagenous tissue on the outer surface of the nerve

  epineurium
• what covers the axon and myelin sheath?

  endoneurium
• Receives information from body stimuli - Sends information for stimuli response

  central nervous system
• detecting stimuli in and around the body and sending that information to the CNS and then communicating messages from the CNS to the body
• carry sensory info from receptors to cns

  afferent neurons
• carry motor info from brain to pns

  efferent neurons
• voluntary movement of skeletal muscle

  somatic
• stimulate body's flight-or-flight response

  sympathetic
• rest-and-digest, feed and breed

  parasympathetic
• what is plexus composed of?
• it is the collections of neurons


  ganglia
• it is found within walls of entire GI tract

  enteric nervous system
• has many dendrites and an axon

  multipolar neuron
• found within retina of eyes and in the nasal cavity

  bipolar neurons
• dendrite is often specialized to receive the stimulus and the axon conducts action potential to the cns

  bipolar neurons
• one extends to the periphery while the other extends to the cns

  pseudo-unipolar neurons
• found within the brain and the retina, only communicate with graded potentials not action potentials

  anaxonic neurons
• phagocytic cells within the cns

  microglia
• form part of myelin sheaths

  oligodendrocytes
• lining the ventricles of the brain and the central canal of the spinal cord help move cerebrospinal fluid.

  ependymal cells
• secrete cerebrospinal fluids

  ependymal cells
• provide structural support and play a role in regulating what substances from the blood reach the neurons.

  astrocytes
• surround neuron cell bodies in sensory and autonomic ganglia.

  satellite cells
• protects neurons from heavy metal poisoning

  satellite cells
• forms the myelin sheaths

  schwann cells
• the outermost layer of this cell is called neurillema

  schwann cells
• used for short distance communications

  graded potential
• allow communication over short or long distance within the body

  action potentials
• is a measure of the electrical properties of the cell membrane

  membrane potential
• always open and are responsible for the permeability of the plasma membrane to ions when the plasma membrane is unstimulated, or at rest.

  leak-ion channels
• are closed until opened by specific signals.

  gated-ion channels
• stimulated to open by the binding of a specific molecule to the receptor site of the ion channel

  ligand-gated ion channels
• open and close in response to a specific, small voltage change across the plasma membrane

  voltage-gated ion channels
• this channel is physically disrupted and opens

  mechanically-gated ion channels
• Occurs when the inside of the cell becomes more positive

  depolarization
• Occurs when the inside of the cell becomes even more negative compared to the outside

  hyperpolarization
• occur between cells connected by gap junctions, which is a 2 nm gap between adjacent cell membranes where cytoplasm is shared through tunnel-like protein structures called connexons

  electrical synapse
• occurs where a chemical messenger, called a neurotransmitter, is used to communicate a message to an effector

  chemical synapse
• They carry chemical signals (“messages”) from one neuron to the next target cell

  neurotransmitters
• This is the most common excitatory neurotransmitter of your nervous system. It’s the most abundant neurotransmitter in your brain

  glutamate