M5s3 Central Nervous System - The Brain Flashcards
Regions of the brain
-brain is large organ housed and protected by the skull
-regions of brain
Cerebrim -> composed of telencephalon and diencephalon
Brainstem -> composed of midbrain, pons, medulla
Cerebellum
- refer to image in goodnotes for general location
Cerebrum: Feature of the telencephalon
-cerebrum makes up bulk of brain
-telencephalon makes up bulk of cerebrum
-responsible for sensory signals, sending out motor signals and decision making
Features of telencephalon:
Cerebral hemispheres:
-Made up of two paired hemispheres: right and left cerebral hemisphere
-two hemispheres separated by longitudinal fissure
Cerebral cortex:
-outer layer of the cerebrum
-if able to touch brain, would touch this part
-in coronal section, distinguished from other neural tissue by its dark grey colour
Sulci and Gyri
-in additional to longitudinal fissure, cerebrum has other smaller fissures, or grooves, which create folds in cerebrum
-folding increases the surface area of neural tissues, which increases functional capacity of the tissue
-fissures and grooves = sulci
-Lumps and bumps between sulci = gyri
Sulci specifically:
-creates boundaries of the lobes and divide the brain into regions with different functions
Precentral sulcus- creates anterior boarder of motor cortex
Central sulcus - divides frontal and parietal lobes. Also divides the motor from the sensory cortex
Postcentral sulcus - creates posterior border of the sensory cortex
Parietal-occipital sulcus - divides parietal and occipital lobes. This sulcus more prominent on medial surface of hemisphere
Lateral sulcus- divides temporal lobe from the frontal and parietal lobes
IT IS ALSO IMPORTANT TO NOTICE THEIR MIDSAGGITAL SECTION LIKE PARIETO-OCCIPITAL SULCUS MORE PROMINENT IN THE MIDSAGITTAL SECTION, WHILE LATERAL SULCUS IS ABSENT. REFER TO GOODNOTES
Gyri specifically:
Precentral Gyrus (Motor Cortex) - responsible for sending motor output signals. It is located anteriorly to the central sulcus
Postcentral Gyrus (Somatosensory Cortex) - responsible for receiving sensory input related to touch and feel. Located posteriorly to the central sulcus
Lobes of the cerebrum
-each of 4 have own functions
-named after overlying skull bone
-frontal lobe, parietal lobe, occipital lobe, temporal lobe
Grey matter of the brain
-consists of the nerve cell bodies, short inter neurons, and glial cells
-found in the cerebral cortex and the inner areas of the brain
White matter of the brain
-consists of bundles of nerve fibres and axons
-found in inner regions of cerebrum
-a specialized region of white matter, known as corpus callous, connects the two hemispheres of the brain
3 categories of what matter tracts based upon their structures they connect and the type of communication they facilitate:
Association- facilitate communication within one hemisphere
Commissural - facilitate communication between 2 hemispheres. Word “commissure” commonly refer to site where two structures join. Ex. Corpus callosum which runs horizontally to connect the two sides of the brain
Projection fibres - facilitate communication between different levels of the CNS, such as between the brain and spinal cord
- refer to goodnotes please
What is Lissencephaly
-aka smooth brain syndrome
-characterized by a lack of development of sulci and Gyri of the brain
What is the function of having folds through the cerebrum
-folding of the cerebrum increases the surface area of the neural tissue, leading to greater capacity for functioning
What are some symptoms of lissencephaly
-results in limited mental capacity
-resulting in severe intellectual disability and slowed physical development
-usually incompatible with life beyond 10 years
What is a treatment for severe seizures
-cutting the corpus callosum to prevent the spreading of seizures from one side of the brain to another
-this procedure does not stop the seizures from occurring, but reduces their severity
Corpus callosum
-white matter connection between right and left hemispheres of the brain
Cerebrum: Diencephalon
-second layer, deep to the telencephalon
-central core of the cerebrum, surrounded by the cerebral hemispheres
-responsible for sensory and motor relay into and out of the brain, as well as control the autonomic nervous system
Areas:
-diencephalon encloses a structure known as the third ventricle
-composed of the thalamus and hypothalamus
Thalamus:
-deep brain structure with two bodies, one per hemisphere
-responsible for relaying sensory information, except sense of smell, to other parts of brain
Hypothalamus:
-small structure below the thalamus that is connected to the pituitary gland
-controls the release of hormones through the pituitary glands
- refer to goodnotes
Brainstem general info
-area of the brain that connects the brain to spinal cord
-situated just below the diencephalon and comprised of the midbrain, the pons, and the medulla oblongata
-the Brainstem is very important as it contains many autonomic reflex centres and white matter tracts necessary for human functioning and survival
Brainstem: midbrain
-most superior aspect of the Brainstem
-anteriorly, the midbrain consists of large white matter tracts that make up for the cerebral peduncles
-from a posterior-lateral view, the midbrain has 2 pairs of raised bumps, known as the superior and inferior colliculi
- refer to goodnotes
Brainstem: pons
-structure in the middle of the Brainstem
-located anterior to the 4th ventricle and the cerebellum
-important to note that pons has fibers connecting it to the cerebellum, allowing for communication between the structures
*refer to goodnotes
Brainstem: medulla oblongata
-aka medulla
-most inferior structure of the Brainstem
-continuous with spinal cord
*refer to goodnotes
Cerebellum
-structure that is appended to the back of the Brainstem and sits underneath the occipital lobe of the cerebrum
-functions to coordinate motor activity
- refer to goodnotes for image
What are two protective measures the brain has
Meninges and ventricles
Meninges
-three connective tissue membranes protecting the structures of the CNS
Dura Mater
-most superficial and tough of the meninges
-composed of a double layer of connective tissue that attaches firmly to the skull
-dura mater means “tough mother”
Projection of dura mater, dura mater also invaginates into:
The longitudinal fissure, creating the falx cerebri between the cerebral hemispheres
The traverse fissure between the cerebrum and cerebellum, known as the tentorium cerebelli
In the space at the midline of the cerebellum, known as the falx cerebelli
Arachnoid mater
-loosely covers the brain
-creates an area called subarachnoid space
-space filled with cerebrospinal fluid (a protective fluid) and blood vessels
Pita mater
-firmly attached to the cerebral cortex
-innermost layer of the meninges
-pia mater means “gentle mother”
*refer to goodnotes
