Peripheral nervous system Flashcards
Do neurons replicate?
No
What is the center of integration?
The brain
What does the PNS consist of?
Nerves
Ganglia
What are ganglia?
Aggregated of neurons located along the pathway of the PNS
(cluster of cell bodies of neurons)
What are axons packed into nerves based on?
Topographical distribution (PNS)
Their function (CNS)
Are receptors innervated?
Yes as they change energy into a nerve signal
What are the nerves that bring the signal from the PNS to the CNS?
Afferent/sensitive
What are the nerves that bring the signal from the CNS to the PNS?
Efferent/effector
What kind of nerves are most of our nerves?
Mixed
What are mixed nerves?
Nerves that contain both sensitive and motor fibers (both afferent and efferent)
Can nerves have multiple branches?
Yes they can have many “exists” and therefor bring neurons to many points
In resting neuron what happens to sodium?
It is actively pumped out the cell by the sodium potassium pump
What gives the neuron the resting potential of -70?
The active pumping by the sodium potassium pump of the sodium from inside to outside the cell
Is the membrane of a neuron permeable to ions?
No
Are the sodium channels open or closed when the neuron is at rest?
Closed
What happens when a neuron is stimulated?
Sodium channels are opened and sodium rushes inside the neuron
What is the average of the max action potential/spike
+40mV
What happens when the action potential is propagated and reaches the terminal?
Calcium channels are opened and the signal is transmitted between neurons and neurons or effector cells by neurontransmitters being released into the synapses
How do vesicles know when they are at the presynaptic part of the membrane?
They roll along the membrane until they reach the pre-synaptic part which has internal receptors that signal to begin exocytosis
Is axonal trafficking regulated?
Yes highly
2 types of neurotransmitters
Excitatory
Inhibitory
2 types of nerves in the PNS (dependant on origin)
Spinal nerves
Cranial nerves
How many pairs of cranial nerves do we have?
12
How many pairs of spinal nerves do we have?
31
2 functional components of the PNS
Somatic nervous system
Autonomic (visceral) nervous system
Which part of the PNS can we control?
The somatic nervous system
Parts of the autonomic nervous system
Sympathetic
Parasympathetic
(Enteric)
Names of the 3 layers of the meninges
Dura
Arachoid
Pia
How many roots does each spinal nerve originate with?
2
Anterior
Posterior
Where does the fusing of the 2 root of the spinal nerve take place?
Right before the intervertebral foramen
How many of the spinal nerves are mixed?
All of them (no exceptions)
Why do the spinal nerves have 2 roots?
Because they are mixed nerves and the motor and sensory have different origins in the spinal chord
Which fibers belong to the posterior root?
Sensory
Which fibers belong to the anterior root?
Motor
How many pairs of cervical nerves?
8
How many pairs of thoracic nerves?
12