Chapter 4- Nervous System Flashcards
(33 cards)
What cells support and help myelinated neurons?
Glial/Neuroglia
Four types of Glial Cells/Neuroglia
Astrocytes: nourish neurons and form blood brain barrier (controls transmission of solutes from the bloodstream into nervous tissue)
Ependymal Cells: line ventricles of the brain and produce cerebrospinal fluid
Microglia: phagocytic cells break form waste product
Oligodendrocytes/Schwann cells produce myelin in the CNS and PNS respectively
Oligodendrocytes:
What is the resting membrane potential of a neuron?
-70mV
What is the threshold range for excitatory input?
- 55 to - 40
What are the two types of summation?
Temporal- multiple signals in a relatively short period of time
Spatial- large number of signals in the same location
What are the two types of refractory periods?
Relative: requires greater than normal stimulation to cause an action potential
Absolute: no amount of stimulation will cause another action potential to occur.
Where are neuro transmitters stored?
In membrane bound vesicles in the cellular membrane near the nerve terminal
What ion is released at the nerve terminal to signal the release of neurotransmitters?
Calcium
What are the three main ways neurotransmitters are removed from the synaptic cleft?
Enzymatic breakdown, reuptake carriers bring the neurotransmitters back to the presynaptic neuron, simple diffusion
Which cranial nerves are part of the peripheral nervous system?
10/12 of the cranial nerves (all except the optic and olfactory nerves)
What are the two types of reflex arcs?
Monosynaptic: single synapse between the sensory neuron that receives the stimulus and the motor neuron the responds to it.
Polysynaptic: at least one interneuron in between the sensory and motor neurons.
Which cells produce myelin in the CNS and PNS?
Oligodendrocytes: CNS
Schwann Cells: PNS
Bundle of nerves in the CNS vs PNS are called what?
Tracts- CNS
Nuclei- CNS (cell bodies of individual neurons within a tract cluster together in nuclei
Ganglia- PNS (cell bodies of neurons of the same type within a nerve)
What maintains the resting potential of a cell?
Na/K ATPase’s
How many Na/K’s are pumped in/out of the cell by Na/K ATPase’s?
2 K in
3 Na out
During depolarization what flows in/out of the cell?
Voltage gated Na channels are open and Na flows into neuron
During repolarization what flows in/out of the cell?
Na channels close. Voltage gated K channels open and K flows out of the cell
Depolarization vs Repolarization
Depolarization makes potential more positive
Depolarization makes potential more negative
What is the peak of the action potential (number)?
+35 mV
Hyperpolarization value
Below resting membrane potential (less than -70)
Where does Na/K naturally want to flow?
Down their concentration gradient
Na naturally wants to flow into the cell
K naturally wants to flow out of the cell
Concentration of Na/ K inside and outside of the cell
Na more outside
K more inside
Where do neurotransmitters bind to on the postsynaptic cell?
Either ligand gated ion channels vs G protein coupled receptors
What is the difference between white and grey matter?
Gray unmyelinated
White myelinated
