Chapter 2- Nerve Cells and Behavior Flashcards
where is the first place the action potential is seen
axon hillock
types of neurons (cells)
- unipolar
- bipolar
- pseudo-unipolar
- 3 types of multipolar cells
a. motor neuron of spinal cord
b. pyrimidal cell of hippocampus
c. purkinje cell of cerebellum
types of neurons (Categories)
sensory neurons
inter neurons
motor neurons
glia
neural support system -astrocytes microglia oligodendrocytes schwann cells radial glia
astrocytes
- wrap around presynaptic termincals of several axons
- help regulate neurochemicals in the synapse
- end feet on capillaries
microglia
- remove waste material
- eat viruses, fungi, and microorganisms
- eat waste from damage
oligodendrocytes
- CNS only
- make the myelin sheath in the NCNS
- one oligo makes multiple myelin sheaths, wont allow for regrowth
schwann cell
-PNS myelin sheath
-allow for regrowth
1 schwann cell to 1 bead myelin
radial glia
- especially important during development
- help guide the migrating neurons from where they are born to where they end up
knee jerk reflex
- sensory input (hammer)
- sensory detection (sensory neuron)
- motor command (motor neuron)
- behavior (contraction of mm)
knee jerk reflex (simple behavior)
- mm spindle detects stretch
- dendritic end in mm spindle
- cell body in DRG
- terminal is in spinal cord
- excitatory synapse with MN
- mm stretch
- secondary connection with inhibitory interneuron, synapse with motor neuron that will inhibit antagonist mm
divergence
one sensory neuron sends information to lots of downstream neurons
convergence
-many neurons converge on one neuron, many needed to activate AP
feed forward inhibition
enhances pathway
inhibits opposing actions (patellar reflex)
feedback inhibition
- self regulating
- prevents excessive activation (damage occuring)
4 functional regions of neurons
- input (dendrites)
- integrative (axon hillock)
- conductive (axon)
- output (terminal bouton)
resting membrane potential
more (-) inside the cell
- more K+ inside the cell along with impermeable anions (-)
- K+ ions diffuse out of cell, impermeable anions left behind which creates a membrane potential
- permeability of neuron determines resting potential, and permeability can change
how the MP changes in diff parts of neuron
-hammer hits knee
Na+ diffuses into dendrite (graded potential)
-action potential occurs (all or none, same in all neurons)
-# of Ap
-Time interval
-neurotransmitter release
-Na+ diffuses into cell, diffuses around area, depolarizes area of cell, which opens next gate for Na+ to diffuse in
graded potential vs action potential
graded potential is not enough of a stimulus to create the needed action potential to further the communication down the chain of axons
