True/False. The cell body of the neuron does not contribute to action potential generation.
True. It is only important in making ATP and creates the biochemistry responsible for cellular function.
What is the most common type of neuron branching connection?
Multipolar, having many dendrites to receive information (and “vote”). But only one axon
How can you tell a dendrite from axon?
If it has receptors for neurotransmitters, then it is dendritic. If not, it is an axon
True/False. There are neurons that have more than one axon
False. There can be only one axon
____ neuron has its axon hillock right at the dendrites, and immediately send the signal down to release neurotransmitter at the axon terminals
Unipolar
Where are unipolar neurons commonly found?
Sensory parts of the body such as finger tips
Why is the reason that unipolar neuron’s cell boy is far away from the dendrites?
Because it is for sensory, soma is somewhere else being protected.
True/False. There exists a type of neuron without any axons.
True. They are called anaxonic, and that is all we need to know.
Where do the dendrites send their signals to create an action potential?
The dendrite integrate signals at the axon hillock, and “vote” to see whether to generate an action potential
Where are graded potentials seen, and where are action potentials seen?
Graded- seen in dendrites, like ripples. Action potential – down the axons
What is the reason that action potential only fires in one direction?
The refractory membrane that immediately follows the action potential that is in progress.
What are the locations of synapse formation?
Axodendritic, axosomatic, and axoaxonic (inhibitory synapse)
What are the factors that determines how fast a nerve signal travels along the nerve fiber?
Diameter of the fiber – larger fibers have more SA and conduct signals more rapidly
Presence or absence of myelin
What is the covering directly over the myelin sheath on the axon called?
Neurilemma
What is the covering that wraps around the entire myelinated axon called?
Endoneurium
What is the difference between myelination in the CNS and PNS?
Oligodendrocytes in the CNS act on small portion of MANY axons (arm-like process). Schwann cells of the PNS act on one portion of a SINGLE axon
How is summation generated?
Threshold voltage is achieved by multiple excitations (ripple building)
What is involved in a reflex arc?
Sensory to CNS, specifically interneuron which is confined to the CNS, to motor
The nervous system is divided into ______ and ____ divisions
CNS and PNS
Cranial nerves belong to ______ nervous system.
Peripheral
The PNS is subdivided into _____ and ______.
Motor and visceral (sensory)
Autonomic nervous system is part of the _____ functional division
Motor Visceral motor (which is autonomic)
True/False. Enteric Nervous system arise from the brainstem and spinal cord (CNS)
FALSE. Enteric nervous system is its own system, has influence by visceral motor (autonomic), but has no components in CNS.
What is the difference between visceral and somatic motor activity?
Somatic motor is voluntary (skeletal muscle). Visceral motor is not (smooth muscle contraction).
_____is released by the preganglionic neuron at the postganglionic neuron in both parasympathetic and sympathetic nervous system
Acetylcholine
Preganglionic neuron of the parasympathetic nervous system is ______.
Long
Preganglionic neuron of the sympathetic nervous system is _____.
Short
Postganglionic neuron of the sympathetic nervous system releases _____ and/or ____.
Acetylcholine, norepinephrine
Sympathetic spinal nerves come out of _______ and _____ regions of the spinal cord.
Thoracic, lumbar. (THORACOLUMBAR)
Parasmpathetic spinal nerves come out of ______ and the ____ region of the spinal cord.
Carnium, sacrum. (Cranio-sacral)
What exits the cervical plexus?
Neither sympathetic nor parasympathetic. Phrenic nerve exits there, C3, C4, C5 keeps you alive.
Which system are the cranial nerves a part of?
PNS. With the EXCEPTION of CN II- Optic Nerve.
Where do cranial nerve ganglia originate in?
CNS
True/False. Only parasympathetic nerves are found in cranio cavity.
True
Further subdivision of the autonomic nervous system is ________ and _______.
Parasympathetic, sympathetic nervous system.
What is the mechanism behind a blown pupil after a head injury?
Because the brain is swelling, it compresses on the parasympathetic nerve, and it is no longer able to constrict the pupil. Sympathetic nerves do not stem from the brain itself, so it is still functioning, it will dilate the eye via. T1 nerve.
