PNS Exam 1
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PNS Exam 1
What are the
major components of the
True or false: Nuclei are groups of cell bodies in the PNS.
are groups of cell bodies in the
Dorsal root ganglia are associated with which type of cell?
: surrounds one fiber.
: surrounds several fibers creating a fascicle.
: surrounds groups of fascicles.
What is an a/k/a for
: synthesizes proteins.
The axon does not have Nissel Bodies, but dendrites can have Nissel bodies.
Which part of the neuron contains chromosomes?
Double layered membrane with phospholipids & pores.
Allows communication between inside & outside of nucleus via pores connecting to the ER.
What is the main function of
ATP (energy) production
What are the 2 main function of
1. Forms the
of the neuron.
2. Aids in
: smaller (10).
: smallest (3-7).
True or false? Axons are completely covered in Nissel Bodies.
: axons do not have any Nissel Bodies.
Axons conduct action potentials.
Which process of a neuron is an
extension of the cell body
Contains Nissel Bodies.
Can have large branches where as axons do not.
True or false: larger axons conduct action potentials faster than smaller axons.
Myelenated fibers conduct faster than unmyelenated fibers.
The synaptic cleft allows for diffused neurotransmitters to attach where?
The post synaptic membrane.
The synaptic cleft has enzymes to break down NT's.
: moving down the axon away from the cell body (soma).
: moving back up the axon toward the cell body (soma).
Histogenesis of neurons (from inside to outside):
: stem cell, pluripotent, begin development.
: differentiates into neuroblasts or glialblasts.
: mature neurons.
Which zone of histogenesis is determined, but still immature?
The intermediate zone.
Name the 6 microgilal cells.
: injury response, mechanical & metabolic support.
: forms myelin in the CNS.
: CSF production.
: phagocytosis (immunity of the CNS).
: myelenation in the PNS, axonal regrowth, & metabolism.
: flattened schwann cell, similar to astrocytes.
Which migroglial cell is responsible for forming scar tissue in damaged brain areas?
What is the number 1 type of brain cancer?
What is the most common form of gliomas?
: very rare.
Which dermatome innervates the nipple?
: big toe.
: back of thigh.
What type of receptors respond to a stimulus?
What is the name for the territory from which a sensory unit can be excited?
Responds to one sensory unit.
More sensitive areas are smaller.
The transformation of a stimulus into an electical signal is described by what term?
Discriminative touch & kinesthetic stimulation.
Carried by myelenated type A axons.
True or false: myelenated type C axons are responsible for carrying pain, touch, & temperature sensations.
unmyelenated type C
axons are responsible for pain, touch, & temp sensations.
Rapidly adapting responses are associated with which type of receptors?
Responds quickly & maximally.
Will stop responding even when the stimulus continues.
There is a refractory period before it will respond again.
Slowly adapting responses are assocated with which type of receptors?
Will continue to respons to a stimulus without a refractory period.
Name the 3 types of
Free nerve endings
: pain & temp.
Name the 3 types of
: light touch, type A.
: shearing (drag) forces.
Mnemonic for remembering which receptors are slow adaptors:
erkel cells (non-encapsulated).
Rapid = PMF.
Reflexes are a predictable response to a stimulus which will happen every time.
Sensory limb & motor limb.
What is the term used to describe a stem fiber & all of its endings?
What is the functional unit of the motor system?
The motor unit.
Name at least 2 characteristics associated with extrafusal muscle fibers.
1. Alpha neurons (via grey matter).
2. Results in movement of skeletal muscles (motor unit).
3. Gamma motor neuron -> muscle spindle.
4. The more neurons that are involved, the more intricate the movement.
(muscle spindles) = gamma motor neurons = proprioception.
True or false: golgi tendon organs are found at the muscle-tendon junction.
What are the 4 functions of golgi tendon organs?
Measuring the force
of contractions (strong or weak).
: self control of inhibition.
from excessive contraction.
in the force of muscle contractions.
Freely ending unmyelenated nerve fibers are responsible for pain & excitatory reflexes. Where are they found?
What is an a/k/a for the
Involves the whole limb.
Thus several spinal segments.
Has crossed effects
: simultaneous & opposite pattern of activity in the contralateral limb.
Which lobe integrates sensory information from joints, muscles, & skin?
The parietal lobe.