Brain Anatomy Flashcards
What is gastrulation?
The process in embryonic development through which the gut develops.
Give a brief explanation of how the CNS develops in an embryo.
Around week 3 in development part of the ectoderm thickens to form the neural plate.
The plate starts to fold upwards and towards itself creates a neural groove in the middle.
The sides of the grooves called the neural folds come together and meet at the top. This fusion creates the neural tube which will eventually become the brain and the spinal cord.
Encephilisation then occurs
What is encephilisation?
Occurs during embryogenesis
The neural tube reshapes and buldges to form three primary vesicles.
The prosencephalon (forebrain)
The mesencephalon (midbrain)
The rhombencephalon (hindbrain)
And the final section of the tube becomes the spinal cord.
What happes to the prosencephalon in the development of the forebrain?
Evaginates to produce two secondary brain vesices calles the telencephalic vesicles. These branch out of the ‘stem’ diencephalon which has optic vesicles.
What does the telencephalon develop into?
Cerebral cortex and basal ganglia
What does the diencephalon develop into?
The hypothalamus
The thalamus
The retina
What does the hindbrain develop into?
The cerebellum, pons and medulla.
How does CSF flow from the lateral ventricle into the spinal canal?
The lateral ventricle flows into the third ventricle.
Flows into the cerebral aqueduct into the fourth ventricle then into the spinal canal.
What areas of the human brain are significantly enlarged?
Mainly the cerebral cortex, lots of sulcus and gyrus allow more neural connections to fit into the skull.
The cerebellum is also well developed.
What are the brain flexures in embryology?
The cephalic flexure - in the mesencephalon bends allowing the cerebral cortex into the skull
The cervical flexure - in the rhombencephelon allows the spinal cord down the brack
The pontine flexure - fold between the metencephalon and the myelencephelon.
Why does the cerebellum and cerebral cortex grow rapidly to dominate the postnatal CNS?
Proliferation of neural progenitor cells.
What are the different cortical lobes in the brain?
Broadly speaking each lobe processes different types of information and has different functions.
Frontal lobe
Parietal lobe
Occipital lobe
Temporal lobe
Insula.
What are the basal ganglia?
What is their function?
Nuclei located deep to the cerebral hemispheres
Main role is in motor processing, may also help in motor learning, emotional regulation, reward and reinforcement of ideas.
Consists of the caudate, putamen, ventral straitum, globus pallidus and the ventral pallidum.
What is the ventral straitum?
Layers of grey and white matter connecting the caudate and the putamen??
Containes the nucleus accumbens.
What is the dorsal striatum?
A combined name for the caudate and the putamen.
What structures are located inferior to the thalamus?
The subthalamic nucleus
The substantia nigra
What is important about the substantia nigra?
Is the first area of nerves to die in parkinsons disease.
Key area for the production of dopamine.
What is the ventral palladium?
Part of the basal ganglia
Located inferior to the nucleus accumbens and globus pallidus.
How does the structure of the globus pallidus split?
Splits into the external and internal nuclei.
What does the substantia nigra split into?
Pars compacta and the pars reticulata.
What makes up the brain stem?
The midbrain
The pons
The medulla
What section of the brain and the third and fourth ventricle in?
Third ventricle is in the diencephalon (forebrain).
Fourth ventricle sits in the hindrain
Connected by the cerebral aqueduct in the midbrain.
What is the function of the thalamus?
Controls the relay of information between the brain hemispheres and the spinal cord.
What is the function of the midbrain?
Involved in visual and auditory reflexes dorsally
Involved in motor functions ventrally.
What is the function of the pons?
The point of communication between the cerebellum and the rest of the CNS
What is the function of the medulla oblongata?
Co-ordinates subconscious sensorimotor integration.
What is the function of the cerebellum?
Is the motor control centre
Clinical test of function is the finger to nose
Role in proprioception and motor commands
Conditions of the cerebellum often struggle with balance and co-ordination.
Shown to be stimulated in finger tapping, verb generation, mental rotation of letters and emotional picture ranking.
What is medulloblastoma?
The most common paediatric primary brain tumour.
63% of embryonal intracranial tumours
4% of all childhood cancers
Grows in the cerebellum, affects balance and coordination.
What is cerebellar agenesis?
Is complete absence of the cerebellum
Saw in a 24 year old mouther admitted to hosptial in CHina with dizziness, nausea and vomiting.
History discovered she could only stand at 4yrs, walk at 7yrs, speak at 6yrs and had mild mental retardation.
What three categories is the cortex classified into?
How are they different?
Paleocortex
Archicortex
Neocortex
They have a different histological arrangement, the neocortex has six layers compared to he paleo with 3 and the archi with 4.
The neocortex is the most abundant in the human cerebral cortex.
Why are the different histological layers of the brain important functionally?
The thickness of the layers in different brain regions varies greatly, this is likely due to each region having a different function.
What are brodmann areas?
Brain regions defined by different thickness in the 6 histological layers, these layers likely have different function.
There are 52 areas in total
What does M1-BA4 stand for?
Primary motor cortex
M1 - motor 1
BA4 - brodmann area 4
What is the primary motor cortex?
A region of the brain that produces a topographic map of the body.
Is where motor commands originate
The density of the neurons that generate information is proportional the degree of motor control in that region of the body.
e.g more in lips less in elbow.
What is the primary somatosensory cortex?
S1 - BA1/2/3
Has a topographic map of the body, recieves incoming information.
Comprises general sensations such as touch, pain and proprioception.
The density of neurons is proportional to the level of sensitivity in the area, for example more in the tongue and less in the trunk.
What is the primary auditory cortex?
A1-BA41
Has a topographic map of sound frequency corresponding to the apex and base of the cochlea.
Responsible for conscious perception of sound.
What is the primary visual cortex?
V1-BA17
The visual word is projected onto a topographic map, scale is relatively even as wants to view the world in the correct dimensions.
How can the anatomy of the brain help describe the complexity of the human mind?
Human brain has a larger cerebrum than other mammals, allows for more neurons and electrical activity.
What is this green brain lobe called?
Parietal lobe
What is the blue lobe called?
The frontal lobe
What is the yellow lobe called?
The temporal lobe
What is the red lobe called?
The occipital lobe
What is the pink lobe called?
The ínsula
This is during embryological brain development. What are the blue structures called?
Tencephalon
Diencephalon
Optic vesicles
What are the orange and green structures in this image?
The midbrain and the hindbrain
What is the purple structure in this embryo?
The sometes or mesoderm
What is the orange structure in this image?
The spinal cord in a embryo starting to develop
What structure is highlighted in green?
The putamen, is one of the basal ganglia
What structure is highlighted in green?
The caudate nucleus, this is one of the basal ganglia
What are the three yellow structures shown in axial section?
The head of the caudate nucleus
The putamen
The globus pallidus
What is CN?
The caudate nucleus
What is put?
The putamen
What is Acb/ace?
The nucleus accubens.
What is GPe and GPi?
The. Globulus pallidus split into the external and internal sections.
What is VP?
Ventral palladium
What is ST?
Subthalamic nucleus
What is SNc and SNr?
The substantia nigra
This is split into the pars compacta and the pars reticulata
Why do some structures in the image appear more brain?
Staining
These areas contain more melanin
What Brodman area is red 1?
Premotor area
BA 6
What brodmann area is red 2?
The supplementary motor area
Area 6
What brodmann area is red 3?
Primary motor cortex
Area 4
What brodmann area is green q1?
The visual cortex
BA 17. 18. 19.
What brodmann area is green 2?
The somatosensory cortex
BA 3. 2. 1.
What brodmann area is green 3?
The auditory cortex
BA 41 42
What brodmann area is the yellow area?
The posterior parietal cortex
BA. 5. 7.
What brodmann area is pink?
Inter temporal cortex
Area 20. 21. 37.
What brodmann area is blue?
The prefrontal cortex
What brodmann area is black?
Gustatory cortex
Area 43
