CNS Development/Subdivisions Flashcards
What stage and time-line relationship does the nervous system present?
The nervous system develops in the 2-8 weeks during the embryonic stage.
What are the temporal stages of neural tube development?
Neural plate, fold, tube.
What histological change occurs in the neural plate?
Simple cuboidal to simple columnar
Cuboidal= Ectoderm Columnar= Neural Plate
What sequence does the neural plate undergo?
The plate folds along the anterior/posterior axis forming the neural groove.
How is the neural tube finalized?
Opposing edges of the neural folds fuse along anterior/posterior axis.
Separates from the simple cuboidal ectoderm.
What days due the cranial and caudal pores finalize themselves.
27 and 30, respectively.
What are the primary subdivisions of the Neural Tube? And What is the brain called at this point?
Prosencephalon
Mesencephalon
Rhombencephalon
Tripartite Brain
What are the secondary subdivisions of the brain?
And what is the brain called?
Prosencephalon
- Telencephalon
- Diencephalon
Mesencephalon
Rhombencephalon
- Telencephalon
- Diecephalon
Pentaparite Brain
What do the 4 ventricles contain and what is it from?
CFS and it is a dialyate of blood or a derivative.
What are the anomalies in the neural tube?
Crainial
- Anencephaly
- Holoprosencephaly
Caudal
- Spina Bifida Occulta=hidden
- Spina cystica x 3
Anencephaly?
Failure of cranial closure.
Holoprosencephaly?
Failure of left and right cerebral hemispheres from prosencephalon.
Eye deformations
Proboscis-type nose
Cleft lip/palate.
Spina Bifida?
Folate…DNA
Occulta
Failure of inferior neuropore
Spinal cord normal
Cystica X 3
Sac-like cyst at end of spine.
Meninges may be present
Bladder and bowel function impairment
SB Meningocele?
Only meninges
Severity various
SB Meningomyelocele?
Meninges and spinal cord
Abnormal growth of spinal cord
Lower extremity paralysis
Bowl and bladder dysfunction
SB Myeloschisis?
Most severe
Failure of neural folds to close
What is Arnold-Chiari Deformity?
Inferior cerebellum and medulla elongate/protrude in vertebral canal
Medulla/Pons deformed
Hydrocephalus
Lower cranial nerves affected 6, 7, 8
- Deafness
- Weakness in tongue, face, and lateral eye motions
What are the structures of the Telencephalon?
Lumina=Lateral ventricles I,II
Floor
Basal ganglia=voluntary motor action
Olfactory lobes and nerves
Roof
Cerebral hemisphere
What are the structures of the Diencephalon?
Lumen
3rd ventricle
Roof
Epithalamus
Wall
Thalamus
Floor
Hypothalamus & infundibulum
…Hormones discussed from last term
What are the structures of the Mesencephalon?
Lumen
Cerebral aqueduct
Roof
Superior/inferior colliciuli =vision
Floor
Tegmentum
What are the structures of here Metencephalon?
Lumen
Part of 4th ventricle
Roof
Cerebellum
Floor
Pons
What the structures of the Myelencephalon?
Lumen
Rest of 4th ventricle
Main
Medulla oblongata
Roof
Posterior choroid plexus
What are the functions of the Telencephalon structures?
Olfactory=smelling
BasalGanglia=
subconscious motor control/tone
Cerebral Cortex=gyri and sulci
Hills and valleys
What are the functions of the Diencephalon structures?
Thalamus=major relay center for afferent/efferent from/to cerebrum
Epithalamus=Habenular nuclei for emotional/visceral recall. Pineal body
Hypothalamus=
Mammillary bodies for olfactory reflexes and emotional recall
Supraoptic/paraventricular nuclei
Controls ANS
Intermediary for nervous and endocrine
Regulates Temperature
Regulates Extracellular fluid volume
Biorhythms/Oscillation
What is the structure and what are the functions of the Cerebellum?
Cortex with Peduncles= Form fiber track connections
- Inferior to medulla and spinal cord
- Middle to pons
- Superior to midbrain
Coordinate biomechanics
Balance/posture/position
Proper firing patterns for synergism
What are the functions of the Mesencephalon structures?
Nuclei of CN 3-4
Tectum=roof
- Superior colliciuli= visual reflexes
- Inferior colliciuli= auditory & olfactory
Tegmentum
- Red nucleus
- Substantial Nigra= Parkinson’s Disease
What are the functions of the Metencephalon structures?
Pons
CN 5-8
Pontine nuclei= relay for cerebrum and cerebellum
Center for sleep and respiratory
Cerebellum
What are the functions of the Myelencephalon structures?
Medulla
Nuclei for Vestibular nuclear complex=balance Sensory=incoming Reticular formation=reptilian brain 1. Alert Center=fight or flight
Pyramids
Lateral corticospinal tracts
Olives
Nuclei related to cerebellum
Vital Reflex Centers
Heart, Vasomotor, Respiration
What are the 3 objectives for this lecture?
- Describe development of neural tube.
- Describe anomalies in neural tube development
- Neural tube divisions and subunit development with functions.
