CNS Development And Brain Subdivisions Flashcards
When does the formation of the nervous system occur?
During the embryonic stage (end of second week to end of eigth week).
What must occur in order for simple cuboidal epithelium to become a neural plate?
The simple cuboidal epithelium must become simple columnar epithelium.
When the neural plate folds along the anterior-posterior axis to form the neural groove, what are also formed?
Neural folds
Neural folds cannot form unless what happens to the epithelium?
The epithelium must become columnarized.
The folding process of the neural tube occurs along what regions?
Cranial and caudal regions.
What do opposing edges of neural folds form, what what does it separate from?
They form the neural tube, which separates from the simple cuboidal ectoderm.
What neuropore closes first?
Superior neuropore (Day 27)
What are the regions of the tripartite brain?
Prosencephalon
Mesencephalon
Rhombencephalon
The prosencephalon gives rise to what two divisions of the pentapartite brain?
Telencephalon
Diencephalon
The mesencephalon gives rise to what region of the pentapartite brain?
Mesencephalon;
It is the relay center for information in the brain.
The rhombencephalon gives rise to what regions of the pentapartite brain?
Metencephalon
Myencephalon
You are conducting an experiment on olfactory reflexes and emotional responses to odors in the diecephalon. What structures should you study?
Hypothalamus (suparaoptic and paraventricular nuclei).
What region of the brain controls and integrates ANS?
Diencephalon
What is a function of the diencephalon:
A. Intermediary between nervous and endocrine systems
B. Controls normal body temperature
C. Maintains extracellular fluid volume
D. Biorhythm oscillator
All of the above
What is the disorder that occurs when the cranial end of the neural tube fails to close?
Anencephaly
You encounter a still-born fetus who has a single orbit, as well a a nose above the orbit. When conducting an autopsy, what will be of significance in the prosencephalon?
It will have failed to divide into two cerebral hemispheres.
This is known as holoprosencephaly.
Spina bifida is the result of what?
A failure of the inferior neuropore to close.
It occurs in CAUDAL regions.
You encounter a patient who has spina bifida, but you are not sure what type of spina bifida they have. You note that they do not have vertebral arches in caudal areas, but spinal cord function is normal. What type of spina bifida does the patient most likely have?
Spina bifida occulta
You are performing an ultrasound on a patient and note that the fetus has a sac-like cyst at the end of the spine. What type of spina bifida does the fetus most likely have?
Spina bifida cystica
You encounter a patient who has spina bifida cystica. Upon examination of the sac at the caudal region of the spinal cord, you note that meninges are only found in the sac. What type of spina bifida cystica does the patient most likely have?
Meningocele
You encounter a patient with spina bifida cystica. You note that meninges and spinal cord are found in a sac in the caudal region of the spinal cord. The patient also has lower extremity paralysis. What type of spina bifida cystica does the patient most likely have?
Meningomyelocele
What is the most severe of the spina bifida cystica disorders?
Myeloschisis
It is the failure of the caudal neural folds to close.
What are some characteristisc of Arnold-Chiari Deformity?
Inferior cerebellum and medulla are elongated and protrude into vertebral canal.
Meduall and pons are small and deformed.
Hydrocephalus
Malformation of lower cranial nerves.
You encounter a patient who has hydrocephalis, deafness, tongue, facial muscle and lateral eye movement weakness. An MRI scan shows that the patient has a small, deformed medulla and pons, and the medulla protrudes into the vertebral canal. What disorder does the patient most likely have?
Arnold-Chiari Deformity
The telecephalon is important for what type of function?
Motor function
What are the lumina, floor and roof of the telencephalon primordia?
Lumina: lateral ventricles
Floor: basal nuclei, olfactory lobes and nerves
Roof: cerebral hemispheres
What are the lumen, roof, walls and floor of the diencephalon?
Lumen: third ventricle
Roof: epithalamus
Walls: thalamus
Floor: hypothalamus and infundibulum
What are the lumen, roof, and floor of the mesencephalon?
Lumen: cerebral aqueduct
Roof: superior and inferior colliculi
Floor: tegmentum
What are the lumen, roof and floor of the metencephalon?
Lumen: part of the fourth ventricle
Roof: cerebellum
Floor: pons
What are the lumen, main part and roof of the myelencephalon?
Lumen: rest of the fourth ventricle
Main part: medulla oblongata
Roof: posterior choroid plexus
What are the components of the medulla (myecephalon)?
Nuclei
Pyramids
Olives
Vital reflex centers
Various nonvital centers
The reticular formation is associated with states of arousal and samples incoming sensory information. The reticular formation is found in which brain structure?
The nuclei of the myencephalon
Lateral corticospinal tracts are associated with the motor systems that carry information from the cerebral cortex to the spinal cord. They are found in what region of the medulla (myencephalon)?
Pyramids
What are the three vital reflex centers found in the medulla?
Cardiac center
Vasomotor center
Centers related to respiration
What cranial nerves are found in the nuclei of the pons?
Cranial nerves V - VIII.
They relay between the cerebrum and cerebellum.
What centers are found in the pons?
Sleep centers
Respiratory centers
What cranial nerves are found in the nuclei of the mesencephalon?
Cranial nerve nuclei III - IV
What are the components of the mesencephalon?
Nuclei
Tectum (superior and inferior colliculi for vision, hearing and olfactory reflexes).
Tegmentum
What are the three components of the tegmentum of the mesencephalon?
Red nucleus
Substantia nigra
Various tracts
How is the cerebellum connected to other parts of the brain?
Via peduncles.
Inferior -> medulla and spinal cord
Middle -> pons
Superior -> midbrain
What are the functions of the cerebellum?
Coordinate skeletal muscle movements
Maintain equilibrium and posture
Synergic control of muscle activity
What are the three regions of the diencephalon?
Thalamus
Epithalamus
Hypothalamus
What is the function of the thalamus?
Major relay center for afferent and efferent information to and from cerebrum and other areas of the brain.
What is the function of the epithalamus?
Nuclei in this region are involved in emotional and visceral responses to odors.
What are the stages in the development of the neural tube?
Neural plate
Neural folds
Neural tubeq
