ORGANIZATION AND DEVELOPMENT Flashcards
Central Nervous System (CNS)
consists of?
is developed from?
CNS consists of the
BRAIN + SPINAL CORD
CNS is develop from the
NEURAL TUBE
PERIPHERAL NERVOUS SYSTEM (PNS)
consists of ?
derives from?
neurons which axons grow out of neural tube
+
neurons derived from neural crest
PNS
which neurons are derived from neural tube?
skeletal motor neurons
+
preganglionic autonomic neurons
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
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)
Neurulation begins in the …
(week)
THIRD WEEK
CNS and PNS derived from …
ecto, meso or endoderm?
ECTODERM
(neuroectoderm)
notochord overlying ectoderm to form the neural plate (neuroectoderm)
WHEN and HOW neural tube is formed?
By the end of the THIRD WEEK
+
neural folds grow over mildline and fuse
Neural crest cells also formed from neuroectoderm
TRUE OR FALSE?
TRUE
during the closure of neural folds, neural crest cells are formed
Neural tube closuring
rostral neuropore closes at …
caudal neuropore closes at…
ROSTRAL
day 25
CAUDAL
day 27
Failure to close
rostral consequences …
caudal consequences…
+
substances increase ?
ROSTRAL
anencephaly (polyhydramios)
CAUDAL
spina bifida
+
ALPHAFETOPROTEIN and AChE are increased
Alphafetoprotein may also be elevated in…
Gastroschisis and omphalocele
AFP levels are low in pregnancy of Down syndrome fetus
NEURAL TUBE
the sequence is TRUE or FALSE?
3 primary vesicles –> 5 primary vesicles –> brain and spinal cord
TRUE
NEURAL TUBE
alar plate = motor
basal plate = sensory
TRUE OR FALSE?
FALSE
alar plate (sensory) and basal plate (motor) are separated by sulcus limitans
NEURAL TUBE
3 primary vesicles?
FOREBRAIN
+
MID BRAIN
+
HINDBRAIN
NEURAL TUBE
5 primary vesicles
TELENCEPHALON + DIENCEPHALON
(forebrain)
MESENCEPHALON
(midbrain)
METENCEPHALON + MIELENCEPHALON
(hindbrain)
TELENCEPHALON
structures
+
neural canal remnant
CEREBRAL HEMISPHERES
+
MOST OF BASAL GANGLIA
+
LATERAL VENTRICLES
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
- NE (noripinephrine)
- Epi (epinephrine)
- 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
