OS III - Neuroanatomy Flashcards
What does the central part of ectoderm differentiate into?
The neural plate
What does the neural plate form? Week 4.
Neural plate forms the neural tube in 4th week.
what cause the neural tube to differentiate along dorsal and ventral axis?
Growth signaling factors
- Shh - sonic hedgehog
- BMP - bone morphogenic protein
Where does Shh, sonic hedgehoge come from?
notocord
where does BMP come from?
Growth signal factor from ectoderm.
Along what axis does the neural tube form?
The Rastro-caudal axis.
What does primary neurulation involve? 2
- Columnirization of the exhisting epithelium
- roling or folding of the epithelium.
What does secondary neurlation involve? 2
- Condensation of mesenchyme to form a rod
- rod undergoes epithelial transition to form neural tube.
What are the two mechanisms that can form neural tube from neural plate?
Primary and secondary neurulation.
How many waves of closure to close neural tube and when?
- 5 separate waves of closure
- days 19-21
Where does closure of neural tube happen first?
Closure begins in brain stem region and near the upper spinal cord.
Where does neural tube closure happen after the upper spinal cord and brain stem close?
The head and neck close after the brain stem and upper spinal cord.
Where does the last of the neural tube closure happen?
caudal region, sacraum
- It fuses with the rest of the spinal cord
What type of nerualation forms the sacral neural tube?
secondary neurulation.
what need to close for complete CNS formation?
Rostral and caudal neuropores.
What is anencephaly?
- lack of skull and cerebrum formation
- only brain stem is intact
Failure of what causes anencephaly?
Failure of second wave closure of neural tube where the head and neck close
What is spina bifida
Incomplete formation of spinal cord and overlying vertebrae that remain unfused and open.
What are three of the variable degrees of severity of spina bifita?
- spina bifida occulta
- meningocele
- myelomeningocele
Failure of what causes spina bifida?
Incomplete closure of caudal neuropore, at the junction of waves one and 5.
- junction of primary and secondary neurelulation
What differentiate the CNS recions?
Dialations and flectures of neural tube.
what are the 4 regions of the CNS?
- hindbrain
- midbrain
- diencephalon
- telencephalon
What does the Hindbrain consist of? 2
Medulla
Pons
myelencephalon - medulla
metencephalon - Pons
What does the mid brain consist of? 1
Mesencephalon - midbrain
What is the diencephalon mad of? 3
Thalamus
Hypothalamus
epithalamus
What is the telencephalon made of ?
The cerebral hemispheres.
what does the neural tube space become?
spinal canal
ventricles of brain stem and cerebral hemispheres
What direction is caudal
toward spinal cord
what direction is Rostral?
toward front of brain
What ensure that the optical axes are at right angles to vertebral column
Cephalic flexure
What is the cephalic flexure related to?
cranial base flexion
What is the pontine flexure
Areas of 4th ventricle and pons enlargement
What is derived from edge of pons?
cerebellum
What is the gray matter of the spinal cord divided into?
sensory
autonomic
motor
What is white matter divided into?
Ascending tracts (mostly dorsal) Descending tracts (more ventral)
What are functionally specific areas of grey matter?
Rexed’s lamina
Of the grey matter in spinal cord, what are the dorsal, intermediate and ventral areas responsible for?
Dorsal - sensory
Intermediate - autonomic
Ventral - motor
What does the dorsal horn of the spinal cord convey?
Convey sensations to neurons into lamina 2-5.
- tactile
- proprioceptive
- pain
- temperature
What do second order neurons from the dorsal horn do?
- send info to local spinal areas
- ascend to brain stem and thalamus
What is the intermediate region of the gray matter of spinal cord a site for?
Preganglionic autonomic neruons
- visceral motor VM
- autonomic
What is the ventral horn a site for?
Efferent motor neurons that project to skeletal muscle groups. (exiting)
What does the white mater of the spinal cord separate into?
Dorsal funiculi
ventral funiculi
lateral funiculi
what are the spinal tracts of white matter formed by?
Axons of ascending and descending neurons
What is the function of the dorsal funiculus?
Dorsal columns carry tactile info to the brain stem and thalamus
What tracts make up the lateral funiculus? 3
- lateral corticospinal tract
- spinocerebellar tracts
- anterolateral system
What does the lateral corticospinal tract do?
Lateral corticospinal tract is the major descenting motor tract from cortex
What is the function of the spinocerebellar tracts?
tactile and proprioceptive information to the cerebellum
What conveys pain and temp to the thalamus?
the anterolateral system of the lateral funiculus
what are the two parts of the ventral funiculus? 3
- anterior (ventral)corticospinal
- vestibulospinal
- reticulospinal
What part of the ventral funiculus makes up the descending motor pathways from cortex?
anterior corticospinal
What part of ventral funiculus makes up the descending motor pathway from the brain stem? 2
- vestibulospinal tract
- reticulospinal
What tract surrounds grey matter and interconnects various spinal levels?
propriospinal tract.
What does the brain stem contain?
- regulatory centers
- cranial nerves
- sensory pathy
- motor pathways
- reticular foramen
What regulatory centers does the brain stem contain?
respiration
cardiovascular
gi
swallow, vomit, cough, pneumotaxic
What are the cerebellar peduncles for?
Input and output tracts between cerebellum and pons
What do the different regions of the cerebellum regulate?
- muscle coordination
- motor planning
- procedural memory
- balance
- eyemovement
What are the 5 key parts of the midbrain?
- substantia nigra
- periaqueductal grey (PAG)
- superior/inf colliculi
- Red nucleus
- cerebral peduncle
What is the substantia niagra for?
Midbrain
- dopamine modulation of motor control
What is the Periaqueductal grey for of the midbrain?
regulates pain and stress responses
What regulates pain and stress responses?
periaqueductal grey of the midbrain. PAG
what does the superior and inferior colliculi do?
Superior - looks
Inferior - listens
What does the inferior colliculi of midbrain do?
listens - help locate where sound is coming from
What is the red nucleus of midbrain a part of?
Red nucleus is a part of the descending motor pathway
What is the cerebral peduncle used for.
sensory and motor pathways to and from spinal cord, brain stem and cortex.
what makes up the sensory and motor pathways to and from the spinal cord, brain stem and cortex
cerebral peduncle of midbrain
What are the nuclear regions of the diencephalon
thalamus
hypothalamus
epithalamus
What contains the pineal gland
eipthalamus
what are the paired structures that flank the third ventricle?
hypothalamus
What does the thalamus contain?
several nuclei that process and distribute sensory and motor information to and from the cerebral cortex
What direction does information move through the thalamus?
to and from cerebral cortex
What type of information is distributed through the thalamus?
both sensory and motor
What is the anterior pituitary derived from?
- ectoderm primordial
- Rathke pouch from primitive oral cavity
what system of vessels extend from hypothalamus into anterior pituitary?
Portal system of vessels
What is the posterior pituitary derived from?
neural tube
what connects the posterior pituitary to the hypothalamus?
neurosecretory axons that release hormones into blood
Which part of pituitary is connected to hypothalamus via axons and which is connected bvia blood vessels
Blood vessesl - anterior
axons - posterior
What type of axons extend into posterior pit?
neurosecretory neuronal axons
What are the 4 areas of the motor cortex?
- primary
- premotor
- supplementary
- brocas speech area
where is the motor cortex?
frontal lobe
What are the 4 areas of the somatosensory cortex?
primary
secondary
association
wernikes language area
where is the somatosensory cortex?
parietal lobe
three areas of auditory cortex of temporal lobe?
primary
secondary
associaton
what are the three parts of occipital lobe, visual cortex
primary
secondary
association
what is the insula?
gustatory
visceral
emotional cortex within the lateral sulcus
Reticular formation is often associated with what?
arousal
attention
motivation
wakefulness
what direction of flow of info through reticular formation?
neurons receive general sensory input and project it into the cortex , limbic structures and spinal cord
Where is reticular foramen? what is it?
it is in the brain stem area, it is make up of nuclei along the medial axis
what are the 5 basal ganglia
gaudate putamen globus dallidus substantia nigra subthalamus
What are the caudate and putamen basal ganglia called together?
striatum
What basal ganglia are embedded in central white matter?
striatum - caudate/putamen
GP - globus pallidus
What basal ganglia is in the mid brain? 2
substantia nigra
subthalamus
What 3 parts make up limbic cortex?
- orbital/ medial prefrontal cortex
- cingulate gyrus
- parahippocampal gyrus
What are the 5 parts of the limbic system
- limbic cortex
- ant/med dorsal thalamic nuc
- hippocampus
- amygdala
- ventral stratum
What does the ventral striatum (basal ganglia) include?
nucleus accumbens
shape of limbic system
C shaped cluster of structures that extends into temporal lobe
where is hippocampus in relation to lobes?
temporal lobe
what interconnects cortical regions of brain?
white matter axon bundles
what type of whie matter axon bundles interconnect cortices
superior longitudinal
occipito frontal fascuculi
what fibers connect local gyri
arcuate fibers
what connects the hemispheres?
corpus callosum
along what axis are cortices connected?
longitudinal
Signs of Spina bifida occulta
Tuft of hair, incomplete vertebral arch but spinal cord and dura matter remain in proper place.
What is spina bifida meningocele?
Spinal cord remains in place but the dura mater balloons out of spinal column
What is spina bifida myelomeningocele
Where both spinal cord and dura is outside the vertebral column.
