Neuro Anatomy/physiology

Question 1

Failed closure of anterior neuropore leads to what developmental anomaly?

Answer 1

Anencephaly

Question 2

What 2 clinical findings occur in anencephaly?

Answer 2

Absent forebrain and calvarium (skull cap) –> “Frog-like” appearance

Question 3

Why does anencephaly present w/ polyhydramnios?

Answer 3

Absent forebrain = absence of swallowing center

Question 4

Anencephaly is a/w what maternal condition?

Answer 4

Diabetes mellitus type 1

Question 5

Failed closure of posterior neuropore leads to what 3 developmental anomalies?

Answer 5

Spina bifida occulta, meningocele, meningomyelocele

Question 6

Developmental anomalies 2/2 failed closure of posterior neuropore are caused by a defect in what structure?

Answer 6

Posterior vertebral arch

Question 7

Spina bifida occulta?

Answer 7

Failure of posterior vertebral arch to close. No structural herniation. Intact dura mater. Tuft of hair or skin dimple at level of vertebral defect.

Question 8

Meningocele?

Answer 8

Failure of posterior vertebral arch to close. Meninges herniates through bony defect in spinal canal. Dura mater not intact.

Question 9

Meningomyelocele?

Answer 9

Failure of posterior vertebral arch to close. Meninges and spinal cord herniate through bony defect in spinal canal. Dura mater not intact.

Question 10

Neural tube defects are a/w low levels of what vitamin?

Answer 10

Folic acid

Question 11

Alar plate?

Answer 11

Embryonic structure that forms dorsal/posterior horn (sensory) of spinal cord

Question 12

Basal plate?

Answer 12

Embryonic structure that forms ventral/anterior horn (motor) of spinal cord

Question 13

Neural tube gives rise to what 3 primary vesicles?

Answer 13

Forebrain (prosencephalon) Midbrain (mesencephalon) Hindbrain (rhombencephalon)

Question 14

Forebrain gives rise to what structure(s) in 5 secondary vesicle stage?

Answer 14

TelencephalonDiencephalon

Question 15

Midbrain gives rise to what structure(s) in 5 secondary vesicle stage?

Answer 15

Mesencephalon

Question 16

Hindbrain gives rise to what structure(s) in 5 secondary vesicle stage?

Answer 16

MetencephalonMyelencephalon

Question 17

Telencephalon:Adult derivative of wall?Adult derivative of cavity?

Answer 17

Adult derivative of wall = Cerebral hemispheresAdult derivative of cavity = Lateral ventricles

Question 18

Diencephalon:Adult derivative of wall?Adult derivative of cavity?

Answer 18

Adult derivative of wall = ThalamusAdult derivative of cavity = 3rd ventricle

Question 19

Mesencephalon:Adult derivative of wall?Adult derivative of cavity?

Answer 19

Adult derivative of wall = MidbrainAdult derivative of cavity = Aqueduct of Sylvius

Question 20

Metencephalon:Adult derivative of wall?Adult derivative of cavity?

Answer 20

Adult derivative of wall = Pons and cerebellumAdult derivative of cavity = Upper part of 4th ventricle

Question 21

Myelencephalon:Adult derivative of wall?Adult derivative of cavity?

Answer 21

Adult derivative of wall = MedullaAdult derivative of cavity = Lower part of 4th ventricle

Question 22

Holoprosencephaly?

Answer 22

Incomplete division of forebrain (prosencephalon) into 2 hemispheresNormally, forebrain divides into 2 hemispheres in week 5 of embryonic development

Question 23

Holoprosencephaly is a/w what 2 conditions?

Answer 23

Patau syndrome (trisomy 13) and fetal alcohol syndrome

Question 24

Most severe form of holoprosencephaly is a/w what eye abnormality

Answer 24

Cycloplegia - fusion of eyes

Question 25

Holoprosencephaly is a/w what genetic mutation?

Answer 25

Sonic hedgehog (Shh) signaling pathway

Question 26

Arnold-Chiari malformation type 1?

Answer 26

Congenital underdevelopment of posterior fossa that results in caudal extension of cerebellar tonsils through foramen magnum

Question 27

Arnold-Chiari malformation type 2?

Answer 27

Congenital underdevelopment of posterior fossa that results in caudal extension of medulla and cerebellar tonsils/vermis through foramen magnum

Question 28

Arnold-Chiari malformation type 2 is a/w what 2 conditions?

Answer 28

Meningomyelocele and non-communicating hydrocephalus Note - Meningomyelocele usually leads to leg paralysis below defect

Question 29

Dandy-Walker malformation?

Answer 29

Partial or complete absence of cerebellar vermis with cystic dilation of 4th ventricle

Question 30

Dandy-Walker malformation is a/w what 2 conditions?

Answer 30

Meningocele and non-communicating hydrocephalus

Question 31

Arnold-Chiari malformation type 1 is a/w what condition?

Answer 31

Syringomyelia

Question 32

Syringomyelia?

Answer 32

Fluid-filled cavity (syrinx) within spinal cord that enlarges over time and damages adjacent structures within spinal cord

Question 33

Syringomyelia most often occurs at what level of spinal cord?

Answer 33

C8-T1

Question 34

What are 2 spinal cord structures/tracts are affected by syringomyelia? Symptoms?

Answer 34

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

Question 35

Syringomyelia v. amyotrophic lateral sclerosis (ALS)

Answer 35

No sensory deficits in ALS

Question 36

Anterior 2/3 of tongue derived from what brachial arches?

Answer 36

1st and 2nd

Question 37

Posterior 1/3 of tongue derived from what brachial arches?

Answer 37

3rd and 4th

Question 38

Muscles of tongue derived from?

Answer 38

Occipital myotomes

Question 39

Motor innervation of tongue? Exception?

Answer 39

Hypoglossal nerve (CN XII)Palatoglossus muscle innervated by vagus nerve (CN X)

Question 40

Anterior 2/3 of tongue - General sensory innervation (touch, pain, pressure, and temperature)?

Answer 40

Mandibular branch of trigeminal nerve (CN V3)

Question 41

Posterior 1/3 of tongue - General sensory innervation (touch, pain, pressure, and temperature)?

Answer 41

Glossopharyngeal nerve (CN IX)

Question 42

Posterior aspect of tongue root - General sensory innervation (touch, pain, pressure, and temperature)?

Answer 42

Vagus nerve (CN X)

Question 43

Anterior 2/3 of tongue - Gustatory innervation (taste buds)?

Answer 43

Chorda tympani, a branch of facial nerve (CN VII)

Question 44

Posterior 1/3 of tongue - Gustatory innervation (taste buds)?

Answer 44

Glossopharyngeal nerve (CN IX)

Question 45

Posterior aspect of tongue root - Gustatory innervation (taste buds)?

Answer 45

Vagus nerve (CN X)

Question 46

What structure delineates anterior 2/3 of tongue from posterior 1/3 of tongue?

Answer 46

Terminal sulcus

Question 47

Terminal sulcus is a/w what embryonic structure?

Answer 47

Foramen cecum

Question 48

What are the 3 components of neurons?

Answer 48

Dendrites - Receive inputCell bodyAxons - Send output

Question 49

Which components of neurons can be stained for Nissl substance?

Answer 49

Nissl substance = rERCell body and dendrites stain positive for Nissl. No rER in axons.