ORGANIZATION AND DEVELOPMENT Flashcards by Luiz Felipe Blanco

Central Nervous System (CNS)

consists of?

is developed from?

CNS consists of the

BRAIN + SPINAL CORD

CNS is develop from the

NEURAL TUBE

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PERIPHERAL NERVOUS SYSTEM (PNS)

consists of ?

derives from?

neurons which axons grow out of neural tube

neurons derived from neural crest

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PNS

which neurons are derived from neural tube?

skeletal motor neurons

preganglionic autonomic neurons

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PNS are formed by 12 pairs of cranial nerves and 30 pairs of spinal nerves

TRUE OR FALSE?

FALSE

cranial nerves - 12 pairs

spinal nerves - 31 pairs

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PNS

which strutures are derived from neural crest cells ?

sensory neurons

postganglionic autonomic neurons

(cell bodies are found in ganglia)

Chromaffi cells

(neural crest cell migrate into the adrenal mdulla to form postganglionic sympathetic neurons)

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Neurulation begins in the …

(week)

THIRD WEEK

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CNS and PNS derived from …

ecto, meso or endoderm?

ECTODERM

(neuroectoderm)

notochord overlying ectoderm to form the neural plate (neuroectoderm)

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WHEN and HOW neural tube is formed?

By the end of the THIRD WEEK

neural folds grow over mildline and fuse

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Neural crest cells also formed from neuroectoderm

TRUE OR FALSE?

TRUE

during the closure of neural folds, neural crest cells are formed

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Neural tube closuring

rostral neuropore closes at …

caudal neuropore closes at…

ROSTRAL

day 25

CAUDAL

day 27

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Failure to close

rostral consequences …

caudal consequences…

substances increase ?

ROSTRAL

anencephaly (polyhydramios)

CAUDAL

spina bifida

ALPHAFETOPROTEIN and AChE are increased

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Alphafetoprotein may also be elevated in…

Gastroschisis and omphalocele

AFP levels are low in pregnancy of Down syndrome fetus

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NEURAL TUBE

the sequence is TRUE or FALSE?

3 primary vesicles –> 5 primary vesicles –> brain and spinal cord

TRUE

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NEURAL TUBE

alar plate = motor

basal plate = sensory

TRUE OR FALSE?

FALSE

alar plate (sensory) and basal plate (motor) are separated by sulcus limitans

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NEURAL TUBE

3 primary vesicles?

FOREBRAIN

MID BRAIN

HINDBRAIN

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NEURAL TUBE

5 primary vesicles

TELENCEPHALON + DIENCEPHALON

(forebrain)

MESENCEPHALON

(midbrain)

METENCEPHALON + MIELENCEPHALON

(hindbrain)

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TELENCEPHALON

structures

neural canal remnant

CEREBRAL HEMISPHERES

MOST OF BASAL GANGLIA

LATERAL VENTRICLES

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DIENCEPHALON

structures

neural canal remnant

THALAMUS + HYPOTHALAMUS + SUBTHALAMUS + EPITHALAMUS (PINEAL GLAND) + RETINA + OPTIC NERVE

THIRD VENTRICLE

MESENCEPHALON

structures

neural canal remnant

MIDBRAIN

CEREBRAL AQUEDUCT

METENCEPHALON

structures

neural canal remnant

PONS and CEREBELLUM

FOURTH VENTRICLE

MYELENCEPHALON

structures

neural canal remnant

MEDULLA and SPINAL CORD

CENTRAL CANAL

CONGENITAL MALFORMATIONS

anecephaly

(cause, main consequence and markers)

Failure of anterior neuropore to close

brain does not develop

incompatible with life

AFP and AChE (increase)

CONGENITAL MALFORMATIONS

spina bifida occulta

Failure of posterior neuropore to close

mildest form

vertebrae fail to form around spinal cord

asymptomatic (tuft oh hair)

+
normal AFP

CONGENITAL MALFORMATIONS

spina bifida with meningocele

Meninges protude through vertebral defect

increase in AFP

CONGENITAL MALFORMATIONS spina bifida with meningomyelocele

Meninges + spinal cord protude through vertebral defect + increase in AFP + seen with Arnold-Chiari Type II

CONGENITAL MALFORMATIONS spina bifida with myeloschisis

Most severe + spinal cord externally + AChE and AFP increase

CONGENITAL MALFORMATIONS Arnold-Chiari type I

cerebellar tonsilis down through foramen magnum + Most commom Mostly Asymptomatic Often association with syringomyelia

CONGENITAL MALFORMATIONS Arnold-Chiari type II

cerebellar vermis down through foramen magnum + often symptomatic obstructive hydrocephaly (IV ventricle) often meningomyelocele

CONGENITAL MALFORMATIONS Dandy-Walker

Failure to form Luschka and Magendie + dilatation of IV ventricle + agenesis of cerebellar vermis and splenium of the corpus callosum

CONGENITAL MALFORMATIONS Holoprosencephaly

Incomplete separation of cerebral hemispheres (one ventricle in telencephalon + Patau (trisomy 13)

PNS general organization

PNS NEUROTRANSMITTERS/RECEPTORS NT of all preganglionic neurons?

**AChE**

PNS NEUROTRANSMITTERS/RECEPTORS receptor of ALL postganglionic neurons?

NN | (neuronal nicotinic receptor)

PNS NEUROTRANSMITTERS/RECEPTORS NT of ALL PARASYMPATHETIC POSTGANGLIONIC NEURONS?

AChE

PNS NEUROTRANSMITTERS/RECEPTORS receptor of ALL parasympathetic sites in periphery

M (muscarinic receptor) heart, smooth muscle and glands

PNS NEUROTRANSMITTERS/RECEPTORS NT of sympathetic postganglionic neurons

1. NE (noripinephrine) 2. Epi (epinephrine) 3. Ach (acetylcholine)

PNS NEUROTRANSMITTERS/RECEPTORS receptors of sympathetic sites in periphery

alpha or beta (NE) heart, smooth muscle, glands + muscarinic (ACh) sweat gland, piloerector muscles + alpha or beta (Epi) various organs - transported via blood

PNS NEUROTRANSMITTERS/RECEPTORS somatic motor neuron (NT + receptor in periphery)

ACh + Nm (muscle nicotinic receptor) skeletical muscle

PANS overview

MOST IMPORTANT THINGS

SANS overview

MOST IMPORTANT THINGS

SANS Gray Rami

Gray rami are postganglionics that rejoin spinal nerves to go to the body wall

PANS Hirschsprung's disease (cause + main consequence)

Missing terminal ganglia in wall of rectum + infant cannot pass mecanium

SANS Horner's Syndrome (cause + clinic)

Lesion in the Superior Cervical Ganglion + ipsilateral ptosis, miosis, anhydrosis