Week 3: Brain, Cisterns, and Ventricles Flashcards
Why is the brain folded?
• It increases surface area which allows for more neurons to fit in a smaller space
• Creates more space for higher functions including thoughts and actions
What are gyri and sulci?
•Each hemisphere contains neural tissue arranged in numerous folds called gyri
•The gyri are separated by shallow grooves called sulci
The forebrain is composed of
Cerebrum, Thalamus, Hypothalamus, Pituitary gland, Limbic system, Olfactory bulb
This structure connects the 2 hemispheres and is made of ________ matter
•Corpus callosum
•White matter
The diencephalon consists of what structures? How would you describe the location of these structures within the brain?
•Thalamus and hypothalamus
•Central portion of the brain around the 3rd ventricle
From superior to inferior list the parts of the brainstem
Midbrain, Pons, Medulla Oblongata
Describe the location of the cerebellum in the brain
Attaches posteriorly to the brainstem and occupies the posterior cranial fossa
List the landmarks (sulcus/fissure) that separate the lobes of the brain
•Central sulcus: separates frontal lobe from parietal lobe
•Lateral fissure (aka Sylvia’s fissure): separates the temporal lobe from the frontal and parietal lobe
•Parieto-occipital sulcus: separates the parietal lobe from the occipital lobe
Describe the parts of the lateral ventricles and the lobes they are located in
These ventricles lie within each cerebral hemisphere and are
separated at the midline by a thin membrane known as the septum pellucidum. The lateral ventricles consist of a central portion called the body and three extensions: the frontal (anterior), occipital (posterior), and temporal (inferior) horns. The junction of the body and the occipital and temporal horns form a triangular area termed the trigone (atria).
The lateral ventricles communicate inferiorly with the third ventricle via the paired interventricular foramen (foramen of Monro)
Where is the third ventricle located and what structure surrounds it?
The third ventricle is a thin, slitlike structure, located midline just inferior to the lateral ventricles. The anterior wall of the third ventricle is formed by a thin membrane termed the lamina terminalis, and the lateral walls are formed by the thalamus. The third ventricle communicates with the fourth ventricle via a long, narrow passageway termed the cerebral aqueduct (aqueduct of Sylvius)
•The thalamus surrounds the third ventricle
Describe the location of the fourth ventricle
The fourth ventricle is a diamond-shaped cavity located anterior to the cerebellum and posterior to the pons. Separating the fourth ventricle from the cerebellum is a thin membrane forming the superior and inferior medullary velum
How does CSF flow from the 3rd to 4th ventricles?
CSF exits the ventricular system through foramina in the fourth ventricle to communicate with the subarachnoid space within the basal cisterns. The major exit route is the median aperture (foramen of Magendie), located on the posterior wall of the fourth ventricle, which communicates with the
cisterna magna. There are two lateral apertures, termed the foramen of Luschka, which communicate with the cerebellopontine angle cistern. From the fourth ventricle, CSF continues into the spinal cord via the central canal.
Describe gray and white matter and their locations in the brain
•Gray matter: neuron cell bodies. The cerebral cortex, the outermost portion of the cerebrum, is composed of gray matter approximately 3 to 5 mm thick.
•White matter: myelinated axons. Deep in the cortex is the white matter, which contains fibers that create pathways for the transmission of nerve impulses to and from the cortex. The largest and densest bundle of white
matter fibers within the cerebrum is the corpus callosum
