Lecture 12 - the Ancient Forebrain - Hypothalamus and Thalamus Flashcards
What are the wrinkles in the brain called?
Gyri and Sulci
Gyri - raised ridges of tissue
Sulci - rifts and valleys
What do the 4 lobes correlate to?
Frontal = Motor/Cognition Parietal = Sensory Occipital = Vision Temporal = Auditory
What parts of the brain can be seen from a ventral perspective?
spinal cord, the brainstem and the midbrain of the medulla and the pons
What is the cerebral hemisphere split by?
lateral fissure
lateral fissure is a major landmark in normal brains
What are fissures?
Enlarged Sulci
What are the other 2 lobes in the brain?
Insula and Limbic Lobe
What does the nervous system develop from?
neural tube (in which contains a space in the middle)
What does the space in the neural tube become?
the ventricles of the brain, where csf flows for homeostasis and support
What shape do the lateral ventricles adopt around the brain?
a C shape
What are the ventricles to neuroanatomists?
They are landmarks for particular regions of the brain
What does the forebrain consist of?
Cerebral hemispheres Limbic System Hypothalamus Thalamus Basal Ganglia
What does the embryo regionalise itself into?
Three germ layers
endoderm - Gives rise to gut, liver, lungs
mesoderm - gives rise to muscle and connective tissue
ectoderm - gives rise to skin (epidermis) and the nervous system
What is induced very early after gastrulation?
notochord andthe neural plate
what do signals from the notochord cause?
uneven proliferation and closing of the neural plate
What happens during the fusion event?
the neural plate forms a continuous and separated neural tube which is the precursor to the nervous system
In early stages of neural development, what provides important signalling cues?
the neural tube is still in close proximity to the mesoderm somites and notochord and also the epidermal cells of the ectoderm
and these provide important signalling cues
What does neural tube developing in different ways along the rostrocaudal axis cause?
cells in different regions of the neural tube will start to acquire regional identities
So we have formation of the different early brain regions and also the spinal cord. Driven by signals from the surrounding ectoderm and mesoderm.
What structures develop at the caudal end?
there is the spinal cord which is continuos with the hind, then mid then forebrain made up of the diencephalion and most rostrally the telencephalon
What specialist structures can we see at this early stage?
we can see that the thalamus and hypothalamus of the forebrain (diencephalon) are adjacent to the midbrain
The telencephalon including basal nuceli are next to this already suggesting a proximity which is also found in the adult brain.
What does grey matter structure mostly contain?
neuronal bodies
What does the hypothalamus control?
various autonomic body actions
hypothalamus receives afferent information and also send efferent information into various brain structures including the cortex, the brainstem and down the spinal cord.
Where is the hypothalamus located?
It is located inferiorly to the thalamus and lies adjacent to the third ventricle
What part of the hypothalamus controls feeding?
lateral hypothalamus
What can lesions in the ventromedial section cause?
over-eating
