Sympathetic vs parasympathetic ns Flashcards
Fill in the divisions of NS table
Fill in the table
What organs does the sympathetic NS supply
Eye – pupil dilation
Bronchioles – bronchodilation
Heart – increase heart rate & force of contraction
Blood vessels – vasoconstriction
Adrenal glands – secretion of adrenaline
GI tract – decreases activity
Bladder – urine retention
What organs does the parasympathetic NS supply
Eyes – constrict pupils, accommodates lens to focus close up
Salivary glands – stimulates secretion
Bronchioles – bronchoconstriction
Heart - decrease heart rate
Blood vessels – vasodilation
GI tract – increase activity
Bladder – urination
Describe sympathetic pathways to head, neck, thorax, abdomen & pelvis
After exiting spinal cord, neurons enter sympathetic trunk
They can then travel to:
Head via cranial cervical ganglion
Neck via cervicothoracic ganglion
Thorax via middle cervical or cervicothoracic ganglia
Abdomen via splanchnic nerves, then coeliac, cranial mesenteric or caudal mesenteric ganglia
Pelvis via splanchnic nerve & then caudal mesenteric ganglion
Describe fibre distribution of vagus nerve
80% sensory fibres
Ear, skin & larynx
Gut distention, pain & blood pressure
Taste
20% motor fibres
Parasympathetic organs & glands
Motor to larynx/pharynx
10th cranial nerve
How does the vagus nerve leave the CNS & skull
Exits as series of rootlets from lateral surface of medulla oblongata
Between IX & XI
Exit skull through jugular foramen with IX & XI
How is the vagus nerve distributed around the head & neck
Below base of skull, vagus nerve gives off:
Auricular branch – to external acoustic meatus
Pharyngeal branch – to pharynx
Cranial laryngeal nerve – to larynx
Continuing caudally, vagus nerve joins sympathetic trunk to form vagosympathetic trunk
How is the vagus nerve distributed around the thorax
Vagus nerve enters thorax at thoracic inlet
Then gives off:
Recurrent laryngeal nerve
Cardiac branches – to cardiac plexus supplying heart
Bronchial branches – to pulmonary plexus supplying lungs
What is idiopathic laryngeal hemiplegia
Unilateral laryngeal paralysis
Horses & dogs
What is Horner’s syndrome
Damage to sympathetic nerves in vagosympathetic trunk
Usually one sided
Loss of supply to:
Smooth muscle in periorbital tunic
Smooth muscles of iris dilators
Resulting in:
Enophthalmos: globe retracts into orbit due to tone in retractor bulbi muscles – allows 3rd eyelid to come into view
Miosis: constricted pupil
What is vagal indigestion
Ruminants (mainly cattle)
Chronic disease
Chronic paralysis with poor motility
Surgery required
