Lecture 1B: CNS Organization Flashcards
What is a nucleus in terms of nerves?
Group of dendrites and nerve cell bodies in CNS
How many pairs of spinal and cranial nerves are there in the PNS?
Spinal-31
Cranial-12
What is a ganglion in terms of nerves?
Groups of dendrites and nerve cell bodies in the PNS
What is a commissure?
Tract in the CNS that crosses f rom one side to another
What is the difference between white and gray matter?
White is myelinated
What does the splanchnic nerve supply?
Viscera
What is a reflex arc?
Pathway that leaves from and returns to the CNS
What is the difference between somatic and visceral pathways?
Somatic carries signals to skeletal muscle
Visceral carries signals to smooth or cardiac muscle
What is the excitation of a neuron typically due to?
Influx of Na+ ions
What is the inhibition of a neuron typically due to?
Influx of Cl- ion or efflux of K+ ion
T/F: An action potential is reached no matter how many synapses fire simultaneously.
False, the action potential is determined by how many synapses fire simultaneously
What is the somatosensory axis?
Pathway that carries sensory signal from peripheral receptors to higher brain centers
Where do the 3 series’ of afferent neurons (of the somatosensory axis) each lead to?
Primary- From peripheral receptors to CNS
Secondary- Primary neurons to thalamus
Tertiary- Secondary neurons to cerebral cortex
What is the skeletal motor nerve axis?
Pathway of transmission of action potential from higher brain cetners to skeletal muscles
What is acetylcholine secreted by and is it excitatory or inhibitory?
Pyramidal cells, alpha motor neurons, preganglionic neurons of ANS, postganglionic neurons of parasympathetic system, some postganglionic neurons of sympathetic system
Excitatory