Ch 7: Nervous Tissue Flashcards
What are the 3 functions of the nervous system?
Sensory (sense changes through sensory receptors)
Integrative (analyze incoming sensory info, make decisions regarding appropriate behaviors)
Motor (respond to stimuli)
What is the order things go through?
Sensory Receptor —— (through sensory input) —– Integration —— (brain and spinal cord) —— (through motor input) —– Effector
What are the 2 types of Motor Inputs?
Somatic and autonomic
Which input is afferent?
Sensory
Which input is efferent?
Motor
Where are most neuron cell bodies located in?
The CNS
What do dendrites do?
They receive information
What do axons do?
Send information through the action potential
What is the PNS?
Peripheral nervous system
(nerves come out of spinal cord and brain)
What is the CNS?
Central nervous system
(spinal cord and brain)
What is neuroglia?
Not electrically excitable
Make up about half the volume of the nervous system
can multiply and divide
What wraps around the axon?
Myelin Sheath
Where does the Schwann cells live?
in the PNS
Where does the oligodendrocytes live?
in the CNS
What are the 2 types of potentials?
Action Potential
Graded Potential
Which potential can communicate over short and long distances?
Action Potential
Which potential can communicate over short distances only?
Graded Potential
Production of an AP or a GP depends on:
Existence of a resting membrane potential
Existence of certain ions channel
What do Ligand-Gated channels respond to?
Chemical stimuli (ligand binds to receptor)
What do Voltage-Gated channels respond to?
Direct changes in membrane potential (voltage)
What can a voltmeter measure?
Potential (charge) difference across membrane of resting cell
Resting membrane potential of a resting neuron is approx what?
70 mV
What side of membrane is negatively charged relative to outside?
Cutoplasmic
Potential is generated by what?
Differences in ionic composition of ICF and EFC
Na+ / K+ pump
What is depolarization?
Decrease in membrane potential
Moves to 0 and above
What is Hyperpolarization?
Increase in membrane potential
Away from 0
Changes in Membrane Potential produce what 2 types of signals?
Graded potential
Action Potential
Where does Action Potential occur?
IN muscle cells and axons of neurons
For an axon to “fire”, what needs to happen?
Depolarization must reach threshold voltage to trigger AP
What is All-Or-Nothing when it comes to AP?
An AP either happens completely or doesn’t happen at all
AP graph
SEE THE NOTES
Does AP die out?
No it self propagates
What is the Presynaptic neuron?
Neuron conducting impulses toward synapses (sends info)
What is the Postsynaptic neuron?
Cell transmitting electrical signal away from synapse
Receives info
May be another neuron, muscle fiber, or gland cell
What are the 3 ways the Neurotransmitter can be removed from the synaptic cleft?
- Diffusion
- Enzymatic degradation
- Re-Uptake into Axon terminal
What are reflexes?
Rapid, predictable, and involuntary responses to stimuli
Reflexes occur over neuron pathways called what?
Reflex Arcs
