Lecture 7 Flashcards
What are the three systems of the nervous system?
CNS, PNS, enteric nervous system (involved in controlling GI tract)
What is an example of PNS cells lying in the CNS?
Neurons innervating muscle (motoneurons)
How many pairs of peripheral nerves enter/exit the brain and spinal cord?
43
How can you find the C8?
Bump on neck
How can you find the T1?
Sticks out further
What are the cranial, thoracic, lumbar and sacral nerves called?
Cranial: C1-C8
Thoracic: T1-T12
Lumbar: L1-L5
Sacral: S1-S5
Which spinal nerves are fused together?
sacral
Do cranial and spinal nerves have a round cross-section?
no; flattened
Where are the cell bodies located?
in the spinal cord
What are neurovascular bundles?
Bundled axons wrapped by endoneurium, bundled by perineurium, bundled by epineurium with blood vessels
How many pairs of cranial nerves are there?
12
What does the ocular motor nerve do?
Moves eye muscle
What does the Abducens control and which bits are sensory/motor?
Lateral rectus
1 motor bit while others are sensory
Wht does the facial nerve control and which bits are sensory/motor?
Facial expression
1 sensory bit while others are motor
What does the one sensory bit of the facial nerve control?
Corda timpani
Taste nerve in anterior 2/3 of tongue
What does the vestibulocochlear innervate?
Vestibular and cochlear system
Which cranial nerves leave the forebrain?
I and II
Which cranial nerves leave from the brainstem?
III to XII (XI + spinal cord)
Which nerve contains 80% of PNS outflow?
Vagus nerve (X)
Where do the nerves of the sympathetic nervous system originate from?
T1-T2 and L1-L3 of spinal cord
Which type of neuron originates from the T1-T2 and L1-L3?
Preganglionic neuron
What forms a lump in the PNS?
Ganglia collections of neurone soma
What is the sympathetic chain?
Ganglion form a chain along the length of the thoracic spinal cord
What can the T1 ganglion be fused with?
infused cervical gang
How do the fibers reach the ganglia?
White rami (short myelinated nerves)
Do the white rami just travel through the sympathetic trunk?
No; they also travel through splanchnic nerves to prevertebral ganglia
What does innervation of the viscera lead to?
Vasoconstriction
Bronchiodilation
Glandular secretion
Reduced gut motility
Where do the signals go in the white rami?
Up the root
Where do the axons reach in the somatic neurons?
Go straight to muscle
Where do the axons reach from the autonomic nervous system?
Motor axons connect with another cell in a ganglion, this cell innervates muscle or gland
Pre-ganglionic axons myelinated
Post-ganglionic axons are not
Where are the sympathetic ganglia near?
Spinal cord
Where are the parasympathetic ganglia near?
Targets; 1:4+ = pre: post-ganglionic
What type of ganglia form the sympathetic chain?
Paravertebral ganglia
In the sympathetic system the _ fibers are short
pre-ganglionic
In the parasympathetic system the _ fibers are long
pre-ganglionic
The parasympathetic chain does not exist. How do the parasympathetic ganglia spread?
Spread all over the place close to targets or embedded so they are very short
How many postganglionic neurons can one preganglionic sympathetic axon synapse with?
20; and can innervate several effectors
How many postganglionic neurons can one preganglionic parasympathetic axon synapse with?
4-5; all supply same effector
What receptors do sympathetic and parasympathetic pre-ganglions use?
ACh and N2 receptors
Sympathetic post-ganglionic are _
adrenergic (except to sweat glands: ACh)
Parasympathetic are ?
cholinergic
