The Brain and the ANS Flashcards
What are the areas of the brain
Forebrain - cerebrum and diencephalon
Cerebrum
Diencephalon
Midbrain
Pons
Medulla
Hindbrain - pons, medulla, cerebellum
Brainstem
Cerebellum
Name some of the parts of the brainstem
Midbrain
Cerebral peduncles
Pons
Medulla
Medullary pyramids
Name some parts of the cerebrum
Right and left hemispheres
Primary motor, somatosensory, visual, auditory and olfactory cortices
Corpus callosum
Lobes: frontal, parietal, temporal, occipital
Uncus of the temporal lobe
Central sulcus
Parieto-occipital sulcus
Longitudinal fissure
Lateral fissure/sulcus
Pre- and post-central gyri
Name some parts of the cerebellum
Hemispehres
Folia
Vermis
Tonsils
Cerebellar peduncles
What are the functions of the sympathetic nervous system
Innervates smooth muscle of blood vessels, eye lid and iris
Innervates sweat glands
Innervates arrector pili muscles (hari follicles)
Decreases secretion from salivary and lacrimal glands
What are the functions of the parasympathetic nervous system
Innervates smooth muscle of iris and muscles in ciliary body
Innervates lacrimal, salivary and mucosal glands
Innervates smooth muscle of respiratory and GI tract
Describe the sympathetic innervation to the head and neck
Pre-ganglionics branch off spinal cord at T1/2 -> ascend up the sympathetic chain to superior cervical ganglia
The fibres synpase in the ganglia -> post-ganglionics ascend into the head and neck via the ICA and the ECA in a sympathetic plexus around the arteries
Describe the course of sympathetic post-ganglionics that run with the ICA and what they innervate
Post-ganglionics that run with ICA run towards the eye
The fibres run with the ophthalmic artery after the ICA -> run with either CN III or CN Va once in the orbit
Innervate superior tarsal muscle and dilator pupillae
What do the sympathetic post-ganglionics that run with the ECA innervate
They innervate the sweat glands and blood vessels of the external face
What sign is seen when the superior cervical ganglia are compressed. What may compress the ganglia
Ganglia may be compressed by pathology involving apex of the lung or pathology involving the ICA
Horner’s syndrome is seen:
- Miosis - innervation to dilator pupillae lost
- Partial ptosis - innervation to superior tarsal muscle lost. Still have innervation to levator palpebrae superioris so not full ptosis
- Anhidrosis - innervation to sweat glands lost
Describe the parasympathetic innervation to the head and neck (generally)
Parasympathetics arise from parasympathetic nuclei in the brainstem
They then hitch-hike on one of 4 CNs
THen they enter a ganglia - cranial nerve runs straight through while PNS fibres synpase
Post-ganglionics leave ganglia and hitch-hike on to a branch of CN V -> go to target tissues
What are the parasympathetic nuclei, which CN does the nerve run in and what ganglia do the fibres go to
Edinger Westphal -> CN III -> ciliary ganglion
Superior salivary -> CN VII -> submandibular and pterygopalatine ganglia
Inferior salivary -> CN IX -> otic ganglion
Dorsal motor -> CN X -> ganglia in walls of tissues
Describe the ciliary light reflex arc if light is shone in the left eye
Light in left eye -> sensory afferent in left retina (CN II)
CN II fibres go back to brain with some branches leaving CN II to enter midbrain where they connect with both the left and right EWN
Parasympathetics from EWN leave brainstem with CN III
Fibres pass via ciliary ganglion -> reach sphinter pupillae
Causes direct light reflex in left eye and consensual light reflex in right eye
How do parasympathetics from the facial nerve reach target tissues - what nerve branches do they take and which ganglia do they synpase at
Greater petrosal nerve - pterygopalatine ganglion
Chorda tympani nerve - submandibular ganglion
Which branch of the glossopharyngeal nerve do parasympathetics run in
The tympanic nerve intially -> parasympathetics exit middle ear as lesser petrosal nerve to innervate parotid
