Lecture 1- CNS development and brain divisions Flashcards
when does the formation of the nervous system occur
during the embryonic stage (end of 2nd week to end of 8th week)
what are the stages (in order) of neural tube development
neural plate–> neural folds –> neural tube
what type of tissue is covering the embryo
simple cuboidal epithelium (ectoderm)
what type of transition occurs in the epithelium during the formation of the neural plate
simple cuboidal epithelium along dorsum of embryo becomes simple columnar epithelium (neural plate)
what fuses together to form the neural tube
opposing edges of neural folds fuse along the anterior-posterior axis
when is the superior/anterior/cranial neuropore closed by
day 27
when is the inferior/posterior/caudal neuropore closed by
day 30
what are the 3 parts of the tripartite brain
prosencephalon, mesencephalon, rhombencephalon
what are the 5 parts of the pentapartite brain
telencephalon and diencephalon
mesencephalon
metencephalon and myelencephalon
define anencephaly
failure of cranial end of neural tube to close and is incompatible with life
define holoprosencephaly
failure of prosencephalon to divide into 2 cerebral hemisphere
what facial deformities are often associated with holoprosencephaly
single orbit with 2 eyes, 1 eye or no eye
proboscis-type nose located above eye
cleft lip and palate
describe spina bifida occulta
results from failure of the inferior neuropore to close
vertebral arches fail to develop in caudal area
spinal cord function is usually normal
describe spinal bifida cystica
characterized by sac-like cyst at the caudal end of spine
spinal cord and/or meninges may be found in cyst
spinal cord function, bladder and bowl function may be impaired
may be lower extremity dysfunction
describe meningocele 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
describe meningomyelocele spina 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 of lower limbs
describe myeloschisis spina bifida cystica
failure of caudal neural folds to close
most severe of the defects
describe arnold-chiari deformity
inferior cerebellum and medulla are elongated and protrude into vertebral canal
medulla and pons are deformed and small
hydrocephalus
malformation of lower cranial nerves (deafness, tongue, facial muscle, lateral eye movement weakness)
what does the lumina of the telecephalon primordia give rise to
lateral ventricles (1 and 2)
what does the floor of the telecephalon primordia give rise to
basal nuclei (ganglia) olfactory lobes and nerves
what does the roof of the telecephalon primordia give rise to
cerebral hemispheres
what does the lumen of the diencephalon primordia give rise to
third ventricle
what does the roof of the diencephalon primordia give rise to
epithalamus
what does the walls of the diencephalon primordia give rise to
thalamus
what does the floorof the diencephalon primordia give rise to
hypothalamus and infundibulum
what does the lumen of the mesencephalon primordia give rise to
cerebral aqueduct (of sylvius)
what does the roof=tectum of the mesencephalon primordia give rise to
superior and inferior colliculi
what does the floor of the mesencephalon primordia give rise to
tegmentum
what does the lumen of the metencephalon primordia give rise to
part of 4th ventricle
what does the roof of the metencephalon primordia give rise to
cerebellum
what does the floor of the metencephalon primordia give rise to
pons
what does the lumen of the myelencephalon primordia give rise to
rest of 4th ventricle
what does the main part of the myelencephalon primordia give rise to
medulla oblongata
what does the roof of the myelencephalon primordia give rise to
posterior choroid plexus
what nuclei are located in the medulla (myelecephalon)
vestibular nuclear complex
sensory nuclei
portions of reticular formation
what is the reticular formation associated with
state of arousal
what do the pyramids of the medulla consist of
lateral corticospinal tracts
what are olives of the medulla
site of nuclei related to cerebellum
what vital reflex centers are located in the medulla
cardiac center
vasomotor center
centers related to respiration
what nuclei and centers are located in pons
nuclei: cranial nerve nuclei V-VIII, pontine nuclei
centers: sleep center and respiratory centers
what do pontine nuclei do
relay between cerebrum and cerebellum
what nuclei are in the mesencephalon
cranial nerve nuclei III-IV
what comes from the roof (tectum) of the mesencephalon
superior and inferior colliculi
what reflexes are associated with superior colliculi
visual reflexes
what reflexes are associated with inferior colliculi
auditory and olfactory reflexes
what is associated with the tegmentum of the mesencephalon
red nucleus
substantia nigra
various tracts
how is the cerebellum connected to other parts of the brain
via large pairs of fibers tracts called peduncles
what do inferior peduncles connect
connect to medulla and spinal cord
what do middle peduncles connect to
pons
what do superior peduncles connect to
midbrain
what are the functions of the cerebellum
coordinate skeletal muscle movements
maintain equilibrium and posture
synergic control of muscle activity
what gives rise to the thalamus and what is the role of the thalamus
diencephalon
role: major relay center for afferent and efferent info to and from cerebrum and other areas of the brian
what gives rise to the epithalamus and what is its role
diencephalon gives rise to it
habenular nuclei located here are involved in emotional and visceral responses to oder and the pineal body is located here
what are the maxillary bodies of the hypothalamus involved in
olfactory reflexes and emotional responses to odors
what nuclei are located in the hypothalamus
supraoptic and paraventricular nuclei
what are the function sod the hypothalamus
controls and integrates ANS
associated with many kinds of visceral activity
intermediary between nervous and endocrine systems
controls normal body temperature
maintains extracellular fluid volume
biorhythm oscillator
what are the basal nuclei (ganglia) that arises from the telencephalon involved in
subconscious motor control and muscle tone
