Lecture 2: Organisation of the Autonomic Nervous System & Thoracic Walls Flashcards
What do the somatic and autonomic nervous systems do?
Somatic - sensory to body walls
Autonomic - innervation of viscera
What is characteristic of the parasympathetic nervous system?
Craniosacral
Long preganglionic fibres and short postganglionic fibres that synapse near viscera
Run in vagus nerve (cranial nerve 10)
What is characteristic of the sympathetic nervous system?
Thoracolumbar
Short preganglionic fibres and long postganglionic fibres
Synpase in sympathetic trunk or prevertebral ganglia
Run in splanchnic nerves
What information do sensory fibres bring to the CNS?
Touch, pressure and pain
Where are the white and grey communicating rami present?
White distal, grey proximal
What does the grey communicating rami contain?
Postganglionic neurons
Where can sympathetic preganglionic fibres synapse?
Sympathetic trunk, continue up the sympathetic trunk or synapse in the visceral ganglion
What is the visceral afferent neuron?
Sensory neuron innervating the viscera
What does the visceral afferent neuron do?
Relays info about pain from the viscera
What pathway does the visceral afferent neuron follow?
Sympathetic
What is referred pain?
Perception of pain in areas other than the site of pain
Why does referred pain occur?
Common spinal segmental origin
Where is pain from paired viscera referred to?
Area of skin on same side
Where is pain from unpaired viscera referred to?
Midline then same side as viscera in pain
What is the function of the thoracic wall?
Protection, mechanical basis of breathing
Which ribs are true, false and floating and why?
- Ribs 1-7 are true ribs and attach directly to sternum via costal cartilage
- Ribs 8-10 are false ribs and attach to costal cartilage of rib above
- 11-12 are floating ribs and have no attachment
- Cartilage contributes to mobility of thoracic cage
Which ribs are atypical?
1,2,10,11,12
What runs in the costal groove and why?
Intercostal nerves, protection
What is the plane of louis?
Angle at manubriosternal junction
At what vertebral level is the plane of louis?
T4/5
What movement do thoracic vertebrae permit?
Rotation
Where do the ribs articulate with the thoracic vertebrae?
Costotransverse joint, costovertebral joint
What are the features of the external intercostals?
Anteroinferior, elevate ribs, deficient medially - external intercostal membrane
What are the features of the internal intercostals?
Posteroinferior, laterally depress ribs and medially elevate
What are the features of the innermost intercostals?
Deficient posteriorly, fragmented, similar role to internals, posteroinferior
How is the neurovascular bundle arranged in the intercostal spaces?
VEIN
ARTERY
NERVE
Where does the neurovascular bundle sit in the intercostal spaces?
Right under the rib
What muscles does the neurovascular bundle run between?
Internal and innermost
How does the ventral ramus give rise to the intercostal nerves?
Ventral ramus runs in groove and changes name to intercostal then gives off lateral and anterior branches
Where is the posterior intercostal artery from?
Descending (thoracic) aorta
Where is the anterior intercostal artery from?
Internal thoracic artery
What does pec major do?
From clavicle to sternum and adducts arm
What does pec minor do?
Coracoid to ribs 3-5 - rib elevation
What does subclavius do?
Anchor clavicle
What does serrates anterior do?
Protract scapula
What does serrates posterior do?
Depresses ribs 9-12, elevates ribs 2-5
