11. Neurology Flashcards
describe the makeup of the esophagus
- internal circular layer + external longitudinal layer
- upper ⅔ is both smooth and skeletal muscle
what landmarks define the thoracic region of the esophagus
T1 → esophageal hiatus
what are the 4 constriction points of the esophagus
- Upper esophageal sphincter (cricopharyngeus muscle)
- Aortic arch
- Left bronchus
- Lower esophageal sphincter (esophageal hiatus of thoracic diaphragm)
describe the course of the vagus nerve and where branch points are
superior thoracic aperture (L laryngeal, pulmonary and inferior cardiac branches)
→ posterior mediastinum (esophageal branches)
→ proximal to abdomen (anterior and posterior vagal trunk)
what structures does the L recurrent laryngeal branch loop under to return to the larynx
under aortic arch and ligamentum arteriosum
which nerve branch is derived from the L vagus nerve?
R vagus nerve?
L: anterior vagal trunk
R: posteRioR vagal trunk
describe the course of the phrenic nerve
superior thoracic aperture
→ between mediastinal parietal pleura and fibrous pericardium
what does the phrenic nerve innervate
- diaphragm
- sensory info from central diaphragmatic and mediastinal pleura and pericardium
which intercostal nerves are typical
3-6
- Rami communicantes
- Collateral branches
- Lateral cutaneous branches
- Anterior cutaneous branches
- Muscular branches (supply intercostal ms, subcostal ms, and transversus thoracis)
rami communicantes connects what
intercostal nerve to sympathetic trunk
where are the collateral branches of typical intercostal ns found
superior edge of rib inferior to the intercostal space
what do the lateral cutaneous branches of typical intercostal ns become?
innervate?
become anterior and posterior branches
supply skin of thoracic wall
T4-6 breast
what do the anterior cutaneous branches of typical intercostal ns supply
anterior aspect of thoracic wall
T4-6 breast
what do the muscular branches of typical intercostal ns supply (3)
- intercostal muscles
- subcostal muscles
- transversus thoracis muscle
which intercostal nerves are atypical
1, 2, 7-11
what is significant about the 1st atypical intercostal nerve
1st: no cutaneous branches, majority of superior portion joins brachial plexus
what is significant about the 2nd atypical intercostal nerve
- travels in costal groove as a typical n w/ small part joining brachial plexus,
- lateral cutaneous branch supplies skin and subcutaneous tissue of axilla (INTERCOSTALBRACHIAL N .)
what is significant about the 7-11th atypical intercostal nerves
- begins as intercostal but as they travel anteriorly
- run out of ribs and transition to THORACOABDOMINAL N.
general principles of ANS
- sympathetic stimulation is usually ___
- parasympathetic stimulation is usually ___
S: catabolic
PS: anabolic (normal fxn, conserve energy)
general principles of ANS
- ___ system distributes to all vascular area of the body
- ___ has a limited distribution (head, neck, and trunk viscera, never ___
- sympathetic
- parasympathetic, never in body wall or extremities
general principles of ANS
- glandular secretion is stimulated by ___; except ___
- ___ can indirectly decrease non sweat gland glandular secretion through ___
- parasympathetic, except sweat glands
- sympathetic, vasoconstriction
vasoconstriction of what arteries is not under sympathetic control
coronary a
***PS control via cardiac plexus
what region is the sympathetic system found
thoracolumbar T1-L2
describe presynaptic sympathetic fibers
- length
- cell bodies
- course
- short
- CBs in lateral horns of spinal cords
- always travel in anterior root into anterior ramus
- quickly exit anterior ramus into PARAvertebral ganglion
describe post synaptic sympathetic fibers
- long
- CBs in paravertebral or prevertebral ganglia
describe paravertebral vs prevertebral ganglia
PARA: linked vertically to form sympathetic trunk BL to vertebral column; 3 ganglia also exist in C/L/P regions
PRE: ganglia and corresponding plexuses surround the main unpaired branches of abdominal aorta (celiac, superior mesenteric, aorticorenal, inferior mesenteric)
what 3 options do presynaptic sympathetic fibers in the thorax have after entering paravertebral ganglia
- synpase on postsynaptic neuron of same level
- ascend or descend to synapse on postsynaptic neuron of different level
- exit without synapsing, become an abdominopelvic splanchnic nerve and head to postsynaptic neuron in prevertebral ganglion
what are the 3 main sympathetics in the thorax
- thoracic sympathetic trunk
- cardiopulmonary splanchnic nerves (cardiac and pulmonary branches)
- abdominopelvic splanchnic nerves
what happens in the thoracic sympathetic trunk
presynaptic sympathetic nerve fibers synapse on postsynaptic cell bodies
where are the CBs of the cardiac splanchnic nerve?
where do they synapse?
where are fibers sent?
- CB at T1-5/6,
- synapse in cervical and thoracic sympathetic trunks
- → superficial and deep cardiac plexuses
where are the CBs of the pulmonary splanchnic nerve?
where do they synapse?
where are fibers sent?
- CB at T2-3,
- synapses in thoracic sympathetic trunk
- → pulmonary plexus
describe the course of the abdominopelvic splanchnic nerves
thoracic sympathetic trunk → prevertebral ganglia in abdomen
where does the greater splanchnic nerve arise from?
where does it send its fibers?
T5- 9/10
→ esophageal plexus and celiac ganglion (plexus)
where does the lesser splanchnic nerve arise from?
where does it send its fibers?
T10/11
→ celiac and superior mesenteric ganglion (plexus)
where does the least splanchnic nerve arise from?
where does it send its fibers?
T12
→ aorticorenal ganglion
what is responsible for parasympathetic innervation to the thorax and what structures are innervated
- vagus nerve
- lungs, bronchi, pleurae, heart, and pericardium
what are the branches of the vagus nerve
- superior, middle and inferior cardiac branches
- pulmonary branches
- esophageal branches
which branches of the vagus nerve originate in the neck and descend through the superior thoracic aperture and join the cardiac splanchnic n. to form the cardiac plexus?
neck: superior and middle cardiac branches
which branches of the vagus nerve originate in the thorax and what do they form?
- inferior cardiac branch, forms cardiac plexus w/ cardiac splanchnic n.
- pulmonary branch, forms pulmonary plexus with pulmonary splanchnic n.
after producing pulmonary branches, what happens to the vagus nerve?
becomes indistinguishable from esophageal plexus that covers inferior 2/3 of esophagus
what provides sympathetic stimulation to the pulmonary plexus?
what effect does it have (3)?
- pulmonary splanchnic nerves
- bronchodilator; vasoconstrictor; inhibits glands
what provides parasympathetic stimulation to the pulmonary plexus?
what effect does it have (3)?
- pulmonary branches of vagus nerve
- bronchoconstrictor; vasodilator, stimulates glands
what provides sympathetic stimulation to the cardiac plexus?
what effect does it have (3)?
- cardiac splanchnic nerves
- increases HR and force of contractions, vasomotor to pericardium
what provides parasympathetic stimulation to the cardiac plexus?
what effect does it have (3)?
- superior, middle and inferior cardiac branches of vagus nerve
- decreases HR and force of contractions, vasoconstrictor to coronary arteries
where would you find the superficial and deep cardiac plexuses?
superficial: covers anterior surface of aorta
deep: anterior to bifurcation of trachea, posterior to aortic arch and superior to bifurcation of pulmonary trunk
the superficial cardiac plexus is continuous with what?
aortic plexus
- continues into abdomen feeding into intermesenteric plexus
what provides sympathetic stimulation to the pulmonary plexus?
what effect does it have (2)?
- greater splanchnic nerve
- inhibits peristalsis and glands
what provides parasympathetic stimulation to the pulmonary plexus?
what effect does it have (2)?
- esophageal branches of vagus nerve
- stimulates peristalsis and glands
