Neuro Anatomy/physiology Flashcards
Failed closure of anterior neuropore leads to what developmental anomaly?
Anencephaly
What 2 clinical findings occur in anencephaly?
Absent forebrain and calvarium (skull cap) –> “Frog-like” appearance
Why does anencephaly present w/ polyhydramnios?
Absent forebrain = absence of swallowing center
Anencephaly is a/w what maternal condition?
Diabetes mellitus type 1
Failed closure of posterior neuropore leads to what 3 developmental anomalies?
Spina bifida occulta, meningocele, meningomyelocele
Developmental anomalies 2/2 failed closure of posterior neuropore are caused by a defect in what structure?
Posterior vertebral arch
Spina bifida occulta?
Failure of posterior vertebral arch to close. No structural herniation. Intact dura mater. Tuft of hair or skin dimple at level of vertebral defect.
Meningocele?
Failure of posterior vertebral arch to close. Meninges herniates through bony defect in spinal canal. Dura mater not intact.
Meningomyelocele?
Failure of posterior vertebral arch to close. Meninges and spinal cord herniate through bony defect in spinal canal. Dura mater not intact.
Neural tube defects are a/w low levels of what vitamin?
Folic acid
Alar plate?
Embryonic structure that forms dorsal/posterior horn (sensory) of spinal cord
Basal plate?
Embryonic structure that forms ventral/anterior horn (motor) of spinal cord
Neural tube gives rise to what 3 primary vesicles?
Forebrain (prosencephalon) Midbrain (mesencephalon) Hindbrain (rhombencephalon)
Forebrain gives rise to what structure(s) in 5 secondary vesicle stage?
TelencephalonDiencephalon
Midbrain gives rise to what structure(s) in 5 secondary vesicle stage?
Mesencephalon
Hindbrain gives rise to what structure(s) in 5 secondary vesicle stage?
MetencephalonMyelencephalon
Telencephalon:Adult derivative of wall?Adult derivative of cavity?
Adult derivative of wall = Cerebral hemispheresAdult derivative of cavity = Lateral ventricles
Diencephalon:Adult derivative of wall?Adult derivative of cavity?
Adult derivative of wall = ThalamusAdult derivative of cavity = 3rd ventricle
Mesencephalon:Adult derivative of wall?Adult derivative of cavity?
Adult derivative of wall = MidbrainAdult derivative of cavity = Aqueduct of Sylvius
Metencephalon:Adult derivative of wall?Adult derivative of cavity?
Adult derivative of wall = Pons and cerebellumAdult derivative of cavity = Upper part of 4th ventricle
Myelencephalon:Adult derivative of wall?Adult derivative of cavity?
Adult derivative of wall = MedullaAdult derivative of cavity = Lower part of 4th ventricle
Holoprosencephaly?
Incomplete division of forebrain (prosencephalon) into 2 hemispheresNormally, forebrain divides into 2 hemispheres in week 5 of embryonic development
Holoprosencephaly is a/w what 2 conditions?
Patau syndrome (trisomy 13) and fetal alcohol syndrome
Most severe form of holoprosencephaly is a/w what eye abnormality
Cycloplegia - fusion of eyes
Holoprosencephaly is a/w what genetic mutation?
Sonic hedgehog (Shh) signaling pathway
Arnold-Chiari malformation type 1?
Congenital underdevelopment of posterior fossa that results in caudal extension of cerebellar tonsils through foramen magnum
Arnold-Chiari malformation type 2?
Congenital underdevelopment of posterior fossa that results in caudal extension of medulla and cerebellar tonsils/vermis through foramen magnum
Arnold-Chiari malformation type 2 is a/w what 2 conditions?
Meningomyelocele and non-communicating hydrocephalus Note - Meningomyelocele usually leads to leg paralysis below defect
Dandy-Walker malformation?
Partial or complete absence of cerebellar vermis with cystic dilation of 4th ventricle
Dandy-Walker malformation is a/w what 2 conditions?
Meningocele and non-communicating hydrocephalus
Arnold-Chiari malformation type 1 is a/w what condition?
Syringomyelia
Syringomyelia?
Fluid-filled cavity (syrinx) within spinal cord that enlarges over time and damages adjacent structures within spinal cord
Syringomyelia most often occurs at what level of spinal cord?
C8-T1
What are 2 spinal cord structures/tracts are affected by syringomyelia? Symptoms?
Anterior white commissure = site of decussation of 2nd order neurons of lateral spinothalamic tract –> b/l loss of crude touch, pain, and temperature sensationAnterior (motor) horns = motor neurons in lateral corticospinal tract synapse in anterior (motor) horns –> LMN lesion = areflexia, flaccid paralysis, fasciculations, , and ATROPHY OF INTRINSIC HAND MUSCLESSyringomyelia spares dorsal column –> preservation of fine touch, proprioception, pressure, vibration, stereognosis, and graphesthesiaStereognosis = ability to perceive and recognize form of an object using cues from texture, size, spatial properties, and temperatureGraphesthesia = ability to recognize writing on skin purely by sensation of touch
Syringomyelia v. amyotrophic lateral sclerosis (ALS)
No sensory deficits in ALS
Anterior 2/3 of tongue derived from what brachial arches?
1st and 2nd
Posterior 1/3 of tongue derived from what brachial arches?
3rd and 4th
Muscles of tongue derived from?
Occipital myotomes
Motor innervation of tongue? Exception?
Hypoglossal nerve (CN XII)Palatoglossus muscle innervated by vagus nerve (CN X)
Anterior 2/3 of tongue - General sensory innervation (touch, pain, pressure, and temperature)?
Mandibular branch of trigeminal nerve (CN V3)
Posterior 1/3 of tongue - General sensory innervation (touch, pain, pressure, and temperature)?
Glossopharyngeal nerve (CN IX)
Posterior aspect of tongue root - General sensory innervation (touch, pain, pressure, and temperature)?
Vagus nerve (CN X)
Anterior 2/3 of tongue - Gustatory innervation (taste buds)?
Chorda tympani, a branch of facial nerve (CN VII)
Posterior 1/3 of tongue - Gustatory innervation (taste buds)?
Glossopharyngeal nerve (CN IX)
Posterior aspect of tongue root - Gustatory innervation (taste buds)?
Vagus nerve (CN X)
What structure delineates anterior 2/3 of tongue from posterior 1/3 of tongue?
Terminal sulcus
Terminal sulcus is a/w what embryonic structure?
Foramen cecum
What are the 3 components of neurons?
Dendrites - Receive inputCell bodyAxons - Send output
Which components of neurons can be stained for Nissl substance?
Nissl substance = rERCell body and dendrites stain positive for Nissl. No rER in axons.