neuro lec 6 Flashcards
briefly describe the embryology of the nervous system (3)
- neural plate develops in ectoderm
- sides of neural plate come together to form neural groove
- neural folds fuse at midline to form neural tube, caudal end becomes spinal cord
what is the notochord?
- axis of embryo
- future site of vertebrae
what do neural crest cells give rise to?
peripheral nervous system
what type of condition would problems at the caudal end of the neural tube cause? what about at the cranial end?
- caudal: spina bifida
- cranial: anencephaly
what does the neural tube differentiate into? (3)
- Prosencephalon (forebrain)
- Mesencephalon (midbrain)
- Rhombencephalon (hindbrain)
where are the nuclei of the cranial nerves located?
in the CNS
which cranial nerves develop from the tel? die? mes? met? mye?
- tel: 1
- die: 2
- mes: 3, 4
- met: 5, 6, 7, 8
- mye: 9, 10, 11, 12
what is the order of the cranial nerves? what is their general function (sensory/motor/both)?
- olfaction (sensory)
- optic (sensory)
- oculomotor (motor)
- trochlear (motor)
- trigeminal (both)
- abducens (motor)
- facial (both)
- vestibulocochlear (sensory)
- glossopharyngeal (both)
- vagus (both)
- accessory (motor)
- hypoglossal (motor)
what is the trigeminal nerve derived from? what is it responsible for?
- pharyngeal arch 1
- chewing muscles
what is the facial nerve derived from? what is it responsible for?
- pharyngeal arch 2
- facial expression
what is the glossopharyngeal derived from? what is it responsible for?
- pharyngeal arch 3
- swallowing muscles
what is derived from pharyngeal arches 4 and 6?
- 4: superior laryngeal branch of vagus nerve (soft palate muscles)
- 6: recurrent laryngeal branch (laryngeal muscles)
which cranial nerves are somatic/efferent? what is their function?
- 3, 4, 6, 11, 12
- move skeletal muscles
which cranial nerves are somatic/afferent? what is their function?
- 5, 9
- conscious sensation
which cranial nerves are autonomic/efferent? what is their function?
- 3, 7, 9, 10
- unconscious control of smooth muscles/glands (parasympa)
which cranial nerves are autonomic/afferent? what is their function?
- 10
- unconscious senses of smooth muscles/glands
which cranial nerves are “special efferent”? what are they derived from? what is their function?
- 5, 7, 9, 10
- derived from brachial arches
- voluntary and reflexive control (“both”)
which cranial nerves are “special afferent”? what is their function?
- 1, 2, 7, 8, 9, 10
- conscious and unconscious sensation (“both”)
complicated CN and really complicated CN
straight to cheat sheet
which __cephalon are olfactory and optic nerves from?
- olfactory: telencephalon
- optic: dienecephalon
Neuroepithelial olfactory cells send axons through the _______ of the ethmoid bone to synapse in the olfactory bulb to olfactory tract.
cribriform plate
define anosmia and ageusia
- anosmia: loss of smell
- ageusia: loss of taste
purpose of optic nerve?
vision
injury prechiam leads to loss of vision in…
injury postchiasm leads to loss of vision in…
- prechiasm = monocular loss
- postchiasm = homonymous hemianopia
what is a scotoma?
blind spot
purpose of oculomotor nerve? (2) where is the motor nucleus?
- controls eye movements and eyelid elevation
- pupil constriction and lens accommodation (parasympa)
- upper midbrain
define strabismus, diplopia, and ptosis
- strabismus: lazy eye
- diplopia: double vision
- ptosis: eye lid droop
purpose of trochlear nerve? where is the motor nucleus?
- superior oblique eye muscles
- midbrain
what are the 3 branches of the trigeminal nerve? where is the motor nucleus?
- opthalmic, maxillary, mandibular
- pons
which cranial nerve do dentists numb?
trigeminal
what are some symptoms of trigeminal nerve damage?
- trigeminal neuralgia (pain spasms)
- paralysis/weakness of jaw muscles
purpose of abducens nerve? where is the motor nucleus?
- lateral rectus muscles (lateral gaze)
- tegmentum of pons
slide 255
i cant
what is bell’s palsy?
contralateral facial droop
why is hyperacusis a symptom of facial nerve damage?
because facial nerve is connected to stapedius muscle which plays a role in acoustic reflex
purpose of vestibulocochlear nerve? (2)
- hearing (hair cells in cochlea)
- balance (hair cells in SCCs)
slide 264
also cant
symptoms of glossopharyngeal nerve damage? (3)
- glossopharyngeal neuralgia (nerve pain)
- allodynia (pain for nonpainful stimulus)
- difficulty swallowing
what are the 3 special efferent branches of the vagus nerve? which aspects of speech are they related to?
- pharyngeal (resonance)
- superior laryngeal
- recurrent laryngeal (phonation)
which parasympa organs does the vagus nerve innervate? is this afferent or efferent?
- heart, lungs, intestines etc
- efferent
symptoms of vagus nerve damage? (3)
- dysphagia
- dysphonia
- palatal asymmetry
which muscles are related to the accessory nerve? (2)
- sternocleidomastoid
- trapezius
symptoms of hypoglossal nerve damage?
- tongue protrusion toward weak side
- fasciculations
what does the hypoglossal nerve innervate?
- most muscles of tongue
- only genioglossus is not bilaterally innervated
