brain anatomy 2 Flashcards
Explain the development of the brain
In the beginning from the zygote the
fetus starts developing and, at gestational day 19, we already have a rudimental NS. It is a flat structure, named neural plate made by not very differentiated cells. At day 22 the
extremities fold up creating the neural groove which closes up after a couple of days leaving a hole inside. That hole is the rudimental central canal from which the ventricles will start emerging. In the fetus, at day 40, we observe a flexure of the frontal part and, later, a flexure in the pontine structures. From these modifications the main vesicles appear, creating the root for the proper NS.
Name the 5 vesicles that appear from development (from top to bottom)
- telencephalon
- diencephalon
- mesencephalon
- metencephalon
- myelencephalon
the last 2 emerge from the a vesicle called the rhombencephalon
The telencephalon hosts the neocortex. Give some info
The neocortex is the most external and developed part
of our brain, organized in a way to play a role in the majority of the most complex brain functions
(see later). The neocortex in humans is full of circumvolutions, which are there to maximize the
amount of cortical surface in the smallest volume (this to avoid we have a huge head!).
Name the 4 visible and 2 extra lobes in the telecephalon/ the brain
- frontal
- parietal
- temporal
- occipital
and the internal lobes: - insular
- limbic
What are gyri?
Each lobe is also further divided in subregions, mostly
identified by the presence of gyri, bumps formed by
the circumvolutions.
Where does the area of Broca reside?
As an example in the gyrus
frontalis inferior (GFI) we have the area of Broca, critical for production of speech
Where does the area of Wernicke reside?
in the gyrus temporalis superior we have the area of Wernicke, important for language comprehension.
Describe the placement of the lobes
- frontal: at the front
- parietal: aan de bovenkant en naar achteren toe
- temporal: at the bottom front
- occipital: at the far back
What is the main role of the frontal lobe?
Action cortex, executive function (decision making), organization of complex behaviours, planning and initiation of voluntary movements
Broca
What is the main role of the parietal lobe?
language processing, intergration sensory info, spatial awareness, somatosensory processing
What is the main role of the temporal lobe?
visual memory, language comprehension and emotional association
What is the main role of the occipital lobe?
visuo-spatial processing, motor perception
What is the main role of the insular lobe?
consciousness, emotions, perception, self-awareness, interpersonal experience, homeostasis
What is the main role of the limbic lobe?
emotions, learning, memory, reward and homeostasis
What are sulcus?
As said the gyri can be highlighted by the circumvolutions. What makes them visible is the indentation of the cortical mantle. That we name sulcus.
Which sulci make the division between the frontal, parietal and temporal lobe?
the central sulcus and the lateral sulcus
What is the function of the white matter?
The WM comprises the bundles of fibers (axons) that leave a specific gray matter region (GM, either cortical or subcortical) to allow the communication between brain regions and between brain and spinal cord.
Name the 3 different types of white matter fibers
- association
- commissural
- projection
fibers
Name the differences between the 3 different types of white matter fibers
the association fibers connects different cortical regions with each other at the level of the same hemisphere. Whereas the commissural fibers connect on the different hemispheres. The projection fibers connect from the cortex to the spinal cord
Name one example of each of the different types of white matter fibers
- association fiber: U-fiber
- commissural: corpus callosum
- projection: The third is made by the fibers leaving the cortex, converging into the corona radiata and which via the internal capsula reach the pyramid in the
meyelencephalon and then the spinal cord to transduce motor information to the muscles.