Anatomy Flashcards
which 3 nerve types does the cardiac plexus contain?
- sympathetic nerves
- parasympathetic nerves
- visceral afferent nerves
where do the sympathetic nerves to the heart come from?
cardiopulmonary splanchnic nerves
which route do cardiac visceral afferents follow to get back to the CNS?
the route of cardiopulmonary splanchnic nerves (where the sympathetic nerves go). (Not just sensory afferents, but also REFLEX afferents - from the baroreceptors)
what is the sensory route of a sharp prod in the chest (T5 dermatome)?
- skin mechanoreceptors stimulates in T5 dermatome (specifically the ANTERIOR RAMUS (which supplies the anterolateral chest wall) - since it’s the anterior chest wall being prodded)
- AP passes through posterior rootlet (sensory) then synapses with CNS and is propagated centrally
- pain pathway crosses over at spinal cord: prod on right is perceived by left side of brain
parietal lobe and frontal lobe are separated by the ___
central sulcus
postcentral gyrus of parietal lobe is somatosensory/ somatomotor?
somatosensory
postcentral gyrus of frontal lobe is somatosensory/ somatomotor?
somatomotor
sources of sharp (somatic) central chest pain?
- Herpes Zoster virus
- muscle, joint, bone
- parietal pleura and fibrous pericardium
sources of dull (visceral) chest pain?
- tracheitis
- ruptured aneurysm of aortic arch
- oesophagitis
- angina
- MI
- gastritis
- cholecystitis
- pancreatitis
- hepatitis
phrenic nerve is anterior/ posterior to lung root?
anterior
vagus nerve is anterior/ posterior to lung root?
posterior
path of right vagus nerve?
passes down lateral surface of trachea, ten forms a vagal plexus on oesophagus - and passes down with oesophagus to reach abdomen
path of left vagus nerve?
crosses aortic arch, dives deep to form a plexus
which range of levels do the visceral afferents from the heart enter the spinal cord?
cervical ganglia and T1-T5 spinal nerves
what causes referred and radiating pain?
a lack of precision in route taken by visceral afferents to the spinal cord
what is an MI?
irreversible death of part of the myocardium due to occlusion of its arterial blood supply
what are the branches of the right coronary artery?
- anterior interventricular artery
- right marginal artery
what are the branches of the left coronary artery?
-diagonal (lateral) branch
-circumflex artery
-left anterior descending (LAD)
left marginal artery
what are common sites for coronary atherosclerosis?
- RCA
- left (main stem) coronary artery
- circumflex branch
- anterior interventricular branch (LAD)
where is the oesophageal plexus?
on the superficial surface of the oesophagus
which types of nerves make up the oesophageal plexus?
-parasympathetic nerves from the vagus nerve
-sympathetic nerves from both sympathetic chains)
These nerves innervate the oesophageal smooth muscle, oesophageal arterioles and the mucus glands of the oesophageal mucosa
what is the function of the azygous vein?
to drain blood from the intercostal spaces (the intercostal veins drain into the azygous vein) into the SVC (the anterior parts of the intercostal spaces are drained via the internal thoracic/ internal mammary veins).
where is the azygous vein?`
it runs up the side of the thoracic vertebral column, and then arches anteriorly, to drain into the SVC
what is the thoracic duct? what is its function?
It is the largest lymph vessel in the body. It carries chyle (lymph and emulsified fats) - (if it ruptured into the pleural cavity - would be called a “chylothorax”).
Its function is to collect most of the lymph from the body (apart from from the right thorax, arm, head and neck - which are all drained by the right lymphatic duct) and drain into the systemic circulation at the left venous angle (junction between the left subclavian and left brachiocephalic vein).
where is the thoracic duct?
it commences in the superior retroperitoneum, passes through diaphragm via aortic hiatus, ascends through posterior mediastinum at the left side of the azygous vein, posterior to the oesophagus, at level of sternal angle - it passes left towards the left venous angle
the thoracic aorta is anterior/ posterior to the lung root?
posterior (and left of the midline)
what are the branches of the thoracic aorta?
coronary arteries
brachiocephalic trunk
LCC artery
L subclavian artery
bilateral posterior intercostal arteries (1 per intercostal space)
branches from the anterior surface (bronchial arteries, oesophageal arteries, mediastinal arteries, pericardial arteries, phrenic arteries)
what are the landmarks at the axial plane of the superior/ inferior mediastinum border?
the sternal angle and the T4/T5 vertebrae
what makes up the thoracic inlet (outlet)?
ribs 1, T1 vertebrae, jugular notch
what structures are the in anterior mediastinum (between sternum and fibrous pericardium)?
thymus (gland/ lymphoid organ producing T lymphocytes in childhood) –> it becomes replaced by fat after puberty
what structures are in the middle mediastinum?
pericardium heart (parts of great vessels) oesophagus tracheal bifurcation thoracic duct (which lies behind oesophagus)
what are the structures in the posterior mediastinum?
azgous vein (drains posterior intercostal veins into SVC)
sympathetic chains (R and L: has a ganglion at each intercostal space)
thoracic duct (between azygous vein and oesophagus)
thoracic aorta
oesophagus
vagus nerves (these descend and form plexuses, they then have vagal trunks passing through diaphragm with oesophagus)
trachea and 2 main bronchi
what is the aorta called once it passes through the diaphragm?
abdominal aorta
what are the bilateral branches from the aorta in the mediastinum?
posterior intercostal arteries
what are the anterior branches from the aorta’s anterior surface in the mediastinum?
bronchial arteries oesophageal arteries mediastinal arteries pericardial arteries phrenic arteries
what does the right lymphatic duct drain?
the right thorax, right arm, right half of the head
drains into the right venous angle
what does the left lymphatic duct drain?
the rest of the body
drains into the left venous angle - between the Left internal jugular and the LSV
superficial lymphatics accompany superficial veins. What do deep lymphatics accompany?
deep veins
how does lymph drain from the lungs?
right lymphatic duct
tracheobronchial lymph nodes
thoracic duct (L lymphatic duct)
bronchopulmonary lymph nodes
where is the cisterna chyli?
found in the abdomen (it’s the start of the thoracic duct)
what is the path of the R vagus nerve?
it’s lateral to the trachea
passes onto oesophagus - where it forms the vagal plexus
branches vagal trunks - which pass into diaphragm
the right recurrent laryngeal nerve (branch of the R vagus) and loops under the subclavian artery)
with what structure does the R phrenic nerve pass through the diaphragm with?
the IVC
path of the L vagus nerve?
descends and crosses over the arch of aorta
passes onto oesophagus and forms part of the vagal plexus and trunk - which passes through to abdomen
recurrent laryngeal branch (branch of the left vagus) hooks under the ligamentum arteriosum and also the arch of aorta - then heads back to the larynx
what structures are in the superior mediastinum?
brachiocephalic veins and SVC arch of aorta trachea oesophagus thoracic duct phrenic nerves vagus nerves recurrent laryngeal branches
what clinical use are the internal jugular veins and the femoral veins?
they are common access points in central venous cannulation / catheterisation
does the R recurrent laryngeal artery enter the chest?
no, it’s already branched off the R vagus and hooked back up before reaching the chest
what kind of nerves are in the phrenic nerves?
anterior rami of C3, 4 and 5
somatic motor to diaphragm
somatic sensory to diaphragmatic parietal pleura, diaphragmatic parietal peritoneum, fibrous pericardium, mediastinal parietal pleura
where can pain from the diaphragm be referred to? Why?
the shoulder tip phrenic nerve (C3,4,5) supraclavicular nerves (C3,4) So there is overlap - they plug into the spinal cord at the same levels- so brain refers pain to a more superficial structure
which nerve types does the vagus contain?
CNX
somatic sensory for palate, laryngophrarynx and larynx
somatic motor for pharynx and larynx
autonomic parasympathetic for thoracic and abdominal organs
recurrent laryngeal branches (supply larynx and pharynx)
what nerve types does the vagus contain after giving off the recurrent laryngeal branches?
parasympathetic nerves only
