Anatomy and Cell Biology 3319 Lecture Notes - Lecture 4: Cerebral Hemisphere, Grey Matter, Basal Ganglia
1 May 2018
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Lecture 004: Cerebral Hemispheres
What are the major boundaries in the cerebral
cortex?
Cerebral hemisphere takes up a very large
proportion of our brain. Very critical for humans.
Encephalization
● Cerebral hemisphere is so developed that
it is involved in most functions
Cerebrum
● Cerebral Cortex
○ Thin layer on the outside
○ Gray matter
○ Superficial cortical layer
○ Neuronal cell bodies
● Cerebral white matter
○ Incredible number of connection between the neurons gives the cerebrum its
efficiency
○ Deep layer (underneath the gray matter)
○ White matter
○ Fibers that connect cell bodies to other cortical areas and brain
1. Commissural fibers: Keep the 2 halves of the cerebrum communicating
with each other
2. Projection fibers: Lets the cerebral cortex communicate with the rest of
the brain
3. Associations fibers: Lets the cerebral cortex communicate with itself
● Deep gray matter
○ Still part of the cerebrum
○ Basal ganglia
○ deepest layer of large collections of neuronal cell bodies
Cerebral Hemispheres Overview
● 83% of total brain mass, sensory and motor, association, cognition
Increased number of neurons in the superficial gray matter is what allowed humans to develop
our increased processing, integration and cognitive abilities
● However increase this lead to a bit of physical problem
● How do we fit that increased layer of gray matter into a (relatively) small skull?
○ Do so by FOLDING
Folds help us distinguish anatomic areas of the brain.
find more resources at oneclass.com
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● There are 2 types of folds
○ Sulci: Smaller
○ Fissures: Deeper
● Gyri
○ The ridges
Cerebrum divided into 5 major lobes (paired)
● Frontal, Parietal, Temporal, Occipital, Insular
The 5 lobes of the brain are separated by sulcus
● Central sulcus
○ Divides the frontal and parietal lobes
● Parietal occipital sulcus
○ Divides the parietal and occipital lobes
○ More dominate on the midline than the
lateral view
● Lateral/Sylvian fissure
○ Divides the temporal lobe from the frontal
and parietal lobes
○ The c-shaped growth of the cerebrum cause a large mass of tissue on the
basolateral part of the cerebrum sticking out (temporal lobe)
● The 5th lobe is hidden from the exterior view
○ Pulling apart the Lateral/Sylvian fissure reveals the insular lobe
Recall: there is always a divide between the sensory and motor neurons
● Sensory-motor division is
maintained at the level of the
cerebral cortex via the central
sulcus
○ Motor is anterior
○ Sensory is posterior
Precentral gyrus
● The primary somatomotor cortex
is here
● Responsible for the movement of
the limbs and torso
Postcentral gyrus
● Primary sensory cortex is here
● Sensory information,
tactile/vibration/sensations
Lobes can be divided into many different gyri by the many sulcus
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Cerebral hemisphere takes up a very large proportion of our brain. Cerebral hemisphere is so developed that it is involved in most functions. Incredible number of connection between the neurons gives the cerebrum its efficiency. Deepest layer of large collections of neuronal cell bodies. 83% of total brain mass, sensory and motor, association, cognition. Increased number of neurons in the superficial gray matter is what allowed humans to develop our increased processing, integration and cognitive abilities. However increase this lead to a bit of physical problem. Folds help us distinguish anatomic areas of the brain. The 5 lobes of the brain are separated by sulcus. More dominate on the midline than the lateral view. Divides the temporal lobe from the frontal and parietal lobes. The c-shaped growth of the cerebrum cause a large mass of tissue on the basolateral part of the cerebrum sticking out (temporal lobe) The 5th lobe is hidden from the exterior view.
