Flashcards in Physio II Lecture IA Deck (51):
Stages in neural tube development
1. Neural Plate
2. Neural folds
3. Neural tube
Time line for the formation of nervous system occurs during what embryonic stage?
End of second week to end of eighth week
What are the subdivisions of cranial end of neural tube
Pentapartite brain and tripartite brain
Tripartite brain is made up of what?
What do the three parts of the growing pentapartite brain divide into?
Prosencephalon into->telencephalon (most anterior) and diencephalon
Mesencehpalon: does not divide
rhombosephlon divides into -> metencephalon and myelencephalon
Where is the cerebral aquaduct?
between the third and fourth ventricle
What are the parts of the telencephalon primordia?
Lumina-lateral ventricles I and II
Floor-basal ganglia (nuclei) and olfactory lobes and nerves - tracts
What are the parts of the diencephalon primorida?
floor....hypothalamus and infundibulum
What are the parts of the mesencephalon primordia?
Lumen....cerebral aqueduct (of Sylvius)
Roof=tectum: superior and inferior colliculi
What are the parts of the metencephalon primordia?
Lumen-part of the forth ventricle
What are the parts of the myelencephalon primordia?
Lumen-rest of fourth ventricle
Main part - medulla oblongata
Roof- posterior choroid plexus
What is the myelencephalon's main part, the medulla oblongata, composed of?
Nuclei, pyramids, olives, vital reflex centers, and various nonvital centers
What does the myelencephalon medulla nuclei make up?
Vestibular nuclear complex
Portions of reticular formation
What do myelencephalon medulla pyramids consist of?
Lateral corticospinal tracts
What are the myelencephalon medulla olives the site of?
Site of nuclei related to cerebellum
Metencephalon pons nuclei makes up what?
1. Cranial nerve nuclei V-VII
2. Pontine nuclei: Relay between cerebrum and cerebellum
What do the metencephalon centers make up?
The mesencephalon tectum (roof) consists of what?
Superior colliculi (visual reflexes)
Inferior colliculi (auditory and olfactory reflexes)
What does the cerebellum have?
Has a cortex
What are the functions of the cerebellum?
Coordinate skeletal muscle movement
Maintain equilibrium and posture
Synergic control of muscle activity
What is the diencephalon thalamus?
Major relay center for afferent and efferent information to and from cerebrum and other areas of the brain......olfactory does not pass through
What is the diencephalon epithalamus?
Habenular nuclei involved in emotional and visceral responses to odors and pineal body
What is the diencephalon hypothalamus?
Mamillary bodies involved in olfactory relexes and emotional responses to odors
Supraoptic and paraventricular nuclei
What is the function of the diencephalon?
Controls and integrates ANS
Associated with many kinds of visceral activity
Intermediary between nervous and endocrine systems
Controls normal body temp
Maintains extracellular fluid volume
What are the parts of the telencephalon?
Basal nuclei (ganglia)
And cerebral cortex
What is the function of the telencephalon basal nuclei (ganglia)?
Subconscious motor control and muscle tone
What is anecephaly?
Failure of cranial end of neural tube to close
What is arnold-chiari deformity?
Inferior cerebellum and medulla are elongated and protrude into vertebral canal
Medulla and pons are small and deformed
Hydrocephalus-blockage of fluid flow
Malformation of lower cranial nerves: deafness; tongue, facial muscle, lateral eye movement weakness
What is spina bifida occulta?
Results from a failure of the inferior neuropore to close
Vertebral arches fails to develop in caudal area
Spinal cord function is usually normal
What is spina bifida cystica?
Characterized by a sac=-like cyst at the caudal end of spine
Spinal cords and/or meninges may be found in the cyst
Spinal cord function may be impaired
May be lower extremity dysfunction
Bladder and bowl function may be impaired
What is menigocele?
Form of spina bifida cystica
Only meninges found in sac
Spinal cord function may be impaired
Signs and symptoms vary depending on location and severity of malformation
What is meningomyelocele?
Form of spinal bifida cystica
Both meninges and spinal cord are found in sac
Always results in abnormal growth of spinal cord
Lower extremity paralysis
Bowel and bladder dysfunction
Loss of sensation to lower limbs
What is myeloschisis
Failure of caudal neural folds to close
Most severe of the defects
What is holoprosencephaly?
Failure of prosencephalon to divide into two cerebral hemispheres
Often associated with facial deformities
--single orbit with two eyes or one eye or no eye
--probosics type nose located above eye
--cleft lip and palate
When does superior (anterior or cranial) neuropore closes?
by day 27
When does inferior (posterior or caudal)neuropore closes?
By day 30
Caudal end forms the....
Subdivision of cranial end of neural tube
Tripartite brain and then pentapart brain
Myelencephalon medulla various nonvital centers are what?
Hick up, vomiting and diarrhea
Cranial nerve nuclei III-IV
Substantia nigra (pankinsons)
Telencephalon cerebral cortex
Divided into paired lobes
Surface with gyri and sulci
What does the myelencephalon medula vital reflex centers make up?
Centers related to respiration
What are the parts of the metencephalon?
Pons and cerebellum
What are the parts of mesencephalon?
Nuclei, tectum (roof) and tegmentum
What does the mesencephalon nuclei make up?
The cranial nerve nuclei III-IV
What does the mesencephalon tegmentum make up?
Red nucleus, substantia nigra, various tracts
The cerebellum is connected to other parts of the brain via what?
Large pairs of fibers tracts called penuncles
What is each part of the cerebellum connected to?
Inferior connected to medulla and spinal cord
Middle connected to pons
Superior connected to midbrain
What are the parts of diencephalon?
Thalamus, epithalamus, and hypothalamus