Week 2 Flashcards
Hod many neurons are required to conduct impulses in the ANS?
Both divisions of the ANS conduct impulses from the CNS to the effector organ using a series of two multipolar neurons.
How many neurons are required to pass impulses in sensory & somatic motor innervation?
Passage of impulses from CNS to the sensory ending or effector organ involves a single neuron
Where are pseudounipolar neurons located?
Where are multipolar neurons located?
Dorsal/posterior root
Ventral/anterior root
Where does the sympathetic preganglion neuron synapse?
On the post ganglionic neuron outside of the central nervous system in teh autonomic ganglion. Then it travels through the spinal nerve, ventral ramus, white ramus communicans and into the sympathetic chain ganglia.
Where are sympathetic preganglionic neurons located?
CNS from T1-L2
Where are parasympathetic preganglionic neurons located?
Craniosacral - they are located in the CNS at CN III, CN XII, CN IX, CN X and S2, S3, S4
Where are postganglionic sympathetic nerve cell bodies located?
Sympathetic chain ganglia
What are the 4 options for preganglionic neurons?
- ascend to higher level
- terminate with postsyn neurons of ganglion at that spinal level
- transverse the sympathetic trunk without terminating - form splanchnic (visceral) nerves
- descend to terminate at a lower Paravertebral level
Where are preganglionic sympathetic cell bodies located?
Intermediolateral cell column
How many white rami communicates are present in the body?
28 - 14 pairs of white rami associated with spinal cord segments T1-L2
How do paravertebral ganglia receive their innervation?
White rami
Where do postganglionic sympathetic neurons to the head have their cell bodies?
Paravertebral ganglia
What nerve supplies the prevertebral (pre-aortic) ganglia with preganglionic neurons?
Splanchnic nerves
What do the cells of the adrenal medulla (of adrenal gland) secrete?
Epinephrine
What do preganglionic neurons of the sympathetic & parasympathetic nervous system release?
ACh! -that binds to nicotinic receptors.
What happens to ACh in the sympathetic nervous system?
It binds to nicotinic receptors on postganglionic nerves and nicotinic receptors on the adrenal medulla. Then the adrenal medulla releases epinephrine which binds to the beta2 receptor (inhibitory) on the lungs which cause the lungs to relax!
What do post-synaptic sympathetic neurons release?
NE that binds to beta1 receptor on the heart (causing it to beat fast) & alpha1 receptor on the blood vessel (causing it to constrict).
In the parasympathetic nervous system, what do postganglionic nerve fibers relase? What does it bind and do?
ACh - it binds muscarinic receptors of the lungs, heart & blood vessels - causes rest & digest (slower heart rate, dilated blood vessels, etc.)
Where are gray communicating ramus and white communicating ramus?
Gray - all spinal nerves (there are 62 - 31 pairs)
White - T1-T12 & L1-L2
If upper trunk of brachial plexus is damaged, what signs & symptoms do we see?
Muscocutaneous nerve – innervates the biceps & other flexors - there will be weakness in ability to flex the forearm at the elbow
What connects the ventral primary ramus to the sympathetic chain ganglia?
The communicating rami
