Lec 01A- CNS Development and Brain Divisions Flashcards
What are the 3 stages of neural tube development?
- neural plate
- neural folds
- neural tube
Where is the neural groove located?
between the neural folds
When does the nervous system form?
End of 2nd week - End of 8th week
What does the trophoblast form?
placenta
What is the part of the trophoblast that remains cellular?
cytotrophoblast
What causes the trophoblast for form lacunae?
syncytiotrophoblast
What does the embryonic disc form?
notochord
What does the notochord form?
neural plate (thickened embryonic ectoderm)
After how many days does the neural plate, primitive node, and primitive streak form?
19 days
After how many days do the neural fold, neural groove, and somites form?
20 days
After how many days do the Anterior and Posterior neuropore form?
23 days
Superior/Anterior/Cranial neuropore closes by day _______
27
Inferior/Posterior/Caudal neuropore closes by day ________
30
What are the 2 subdivisions of the neural tube?
- Tripartite brain
- Pentapartite brain
What does the cranial end of the neural tube form?
brain
What does the caudal end of the neural tube form?
spinal cord
What are the 3 divisions of the Tripartite brain?
- Prosencephalon (forebrain)
- Mesencephalon (midbrain)
- Rhombencephalon
What are the 5 divisions of the Pentapartite brain?
- Telencephalon (prosencephalon)
- Diencephalon (prosencephalon)
- Mesencephalon
- Metencephalon (rhombencephalon)
- Myelencephalon (rhombencephalon)
Pentapartite brain telencephalon lumina
lateral ventricles I and II
Pentapartite brain telencephalon floor
- basal ganglia
- olfactory lobes and nerves
Pntapartite brain telencephalon roof
cerebral hemispheres
Pentapartite brain diencephalon lumen
3rd ventricle
Pentapartite brain diencephalon roof
epithalamus
Pentapartite brain diencephalon walls
thalamus
Pentapartite brain diencephalon floor
- hypothalamus
- infundibulum
Pentapartite brain mesencephalon lumen
cerebral aqueduct of Sylvius
Pentapartite brain mesencephalon roof (Tectum)
- Superior colliculi
- Inferior colliculi
Pentapartite brain mesencephalon floor
Tegmentum
Pentapartite brain metencephalon lumen
part of 4th ventricle
Pentapartite brain metencephalon roof
cerebellum
Pentapartite brain metencephalon floor
pons
Pentapartite brain myelencephalon lumen
rest of 4th ventricle
Pentapartite brain myelencephalon main part
medulla oblongata
Pentapartite brain myelencephalon roof
posterior choroid plexus
What does the posterior choroid plexus produce?
CSF
3 Pentapartite brain myelencephalon medulla nuclei
- vestibular nuclear complex
- sensory nuclei
- portions of reticular formation
Pentapartite brain myelencephalon medulla pyramids
lateral corticospinal tracts
Pentapartite brain myelencephalon medulla olives
site of nuclei related to cerebellum
3 Pentapartite brain myelencephalon medulla vital reflex centers
- cardiac center
- vasomotor center
- centers related to respiration
2 Pentapartite brain Metencephalon pons nuclei
- cranial nerve nuclei (V-VII)
- pontine nuclei
What is the pontine nuclei?
relay between cerebrum and cerebellum
2 Pentapartite brain Metencephalon pons centers
- sleep center
- respiratory centers
What are the 2 parts of the Pentapartite brain Metencephalon?
- pons
- cerebellum
Pentapartite brain Mesencephalon nuclei
cranial nerve nuclei (III-IV)
Pentapartite brain Mesencephalon roof (Tectum)
- Superior colliculi = visual
- Inferior colliculi = auditory/olfactory
3 Pentapartite brain Mesencephalon Tegmentum
- red nucleus
- substantia nigra
- various tracts
What are peduncles?
large pairs of fiber tracts
Inferior peduncles of cerebellum
connects medulla»_space; spinal cord
Middle peduncles of cerebellum
connects to pons
Superior peduncles of cerebellum
connects to midbrain
3 functions of cerebellum
- coordinate skeletal muscle movements
- maintain equilibrium and posture
- synergic control of muscle activity
Thalamus
major relay center for afferent/efferent information to and from cerebrum and other brain areas
Epithalamus
- habenular nuclei
- emotional and visceral responses to odors
- has pineal body
Hypothalamus
- mamillary bodies
- olfactory reflexes and emotional responses to odors
What are the 2 nuclei in the hypothalamus?
- supraoptic nuclei
- paraventricular nuclei
6 functions of hypothalamus
1- Controls/integrates ANS 2- Visceral activity 3- Intermediary between nervous and endocrine systems 4- Controls normal body temperature 5- Maintains extracellular fluid volume 6- Biorhythm oscillator
3 parts of telencephalon
- olfactory bulbs
- basal nuclei (ganglia)
- cerebral cortex
Function of basal ganglia of telencephalon
subconscious motor control and muscle tone
Cerebral cortex of telencephalon characteristics
- divided into paired lobes
- surface with gyri and sulci
What is anencephaly?
failure of cranial end of neural tube to close
What is Arnold-Chiari deformity?
- inferior cerebellum and medulla are elongated
- protrude into vertebral canal
- medulla and pons = small and deformed
How does Arnold-Chiari deformity manifest?
- hydrocephalus
- malformation of lower cranial nerves (deafness & tongue, facial muscle, lateral eye movement weakness)
What is spina bifida occulta?
- failure of inferior neuropore to close
- vertebral arches fail to develop in caudal area
- normal spinal cord function
What is spina bifida cystica?
- sac-like cyst at caudal end of spine
- spinal cord and/or meninges in cyst
- impaired spinal cord function
- LE dysfunction
- impaired bladder and bowel function
What is a meningocele?
- form of spina bifida cystica
- meninges in sac (only)
- impaired spinal cord function
What is a meningomyelocele?
- form of spina bifida cystica
- meninges & spinal cord in sac
- abnormal growth of spinal cord
- LE paralysis
- bowel and bladder dysfunction
- loss of lower limb sensation
What is meloschisis?
- failure of caudal neural folds to close
- most severe defects
What is holoprosencephaly?
- failure of prosencephalon to divide into 2 cerebral hemispheres
- facial defomities
What are the 3 facial deformities of Holoprosencephaly?
- single orbit with 2 eyes, 1 eye, or no eye
- Proboscis-type nose located above the eye
- cleft lip and palate
