1 - Overview of CNS Flashcards
What are the major reflections made by folds of the dura mater and what does each separate?
- Falx cerebri - between cerebral hemispheres
- Tentorium cerebelli - between cerebrum and cerebellum
- Falx cerebelli - between cerebellar hemispheres
- Diaphragma sellae - covers pituitary
What is the outermost meninge? What layers is it composed of?
The dura mater: composed of a periosteal and a meningeal layers.
What is located between the periosteal and meningeal layers of the dura mater? Name them.
The dural venous sinuses: superior sagittal, inferior sagittal, straight, transverse, sigmoid, cavernous, superior petrosal, and inferior petrosal.
Name the four types of brain herniations?
- Subfalcine
- Central
- Transtentorial
- Tonsillar
What is the location of a subfalcine brain herniation?
Cingulate gyrus under falx cerebri.
What is the location of a central brain herniation?
Brainstem towards foramen magnum.
What is the location of a transtentorial brain herniation?
Medial temporal lobe through tentorial notch.
What is the location of a tonsillar brain herniation?
Cerebellar tonsils through foramen magnum.
What is the second layer of meninges? What is in it and what is deep to it?
Arachnoid mater, doe snot dip into sulci and fissures except where it follows falx and tentorium.
CSF in subarachnoid space where blood vessels are located.
What are arachnoid villi?
Projections of arachnoid and subarachnoid space that project into dural venous sinuses to reabsorb CSF.
What is the deepest meninges layer? Describe it.
The pia mater: faithfully follows brain contours.
Forms perivascular sheath,.
Separates the subarachnoid space from the perivascular spaces (Virchow-Robin spaces).
What separates the left and right hemispheres of the cerebrum? What connects these structures?
The Septum pellucidum.
The corpus callosum are nerve fibers that connect the cerebral hemispheres.
What are Brodmann’s areas?
Map of cerebral cortex based on the cellular architecture.
Define a sulcus, fissure, and gyrus?
Sulcus: groove on surface of the brain
Fissure: deep furrow of cleft
Gyrus: prominent, rounded elevation on the surface of the cerebrum.
What fissure separates the cerebral hemispheres?
The sagittal/longitudinal fissure.
What does the lateral sulcus/sylvian fissure separate?
The frontal and parietal lobe from the temporal lobe.
What does the central sulcus separate?
Located in coronal plane, separates the frontal and parietal lobes.
Where is the cingulate sulcus located?
Above the corpus callosum; it curves around and forms the marginal ramus.
What is a trick that can be sued to locate the central sulcus?
Trace the cingulate sulcus and jump forward one gyrus to find the central sulcus.
Where is the parietooccipital sulcus?
Between the parietal and occipital lobes.
Where is the calcarine fissure located?
Within the occipital lobe.
What is the function of the frontal lobe?
Higher cognitive functions, control of voluntary movements, and motor area for speech.
What are the gyri of the frontal lobe?
Precentral gyrus - the primary motor cortex
Frontal gyri:
- Superior: premotor and supplementary motor cortex
- Middle: premotor and supplementary motor cortex
- Inferior gyrus
Orbital gyri
Gyrus recti
What are the parts of inferior gyri of the frontal lobe?
Opercular: left hemispheres = Broca’s area
Triangular: left hemisphere = Broca’s area
Orbital
Other than the notable gyri, what is located in the frontal lobe?
The olfactory sulcus and the anterior paracentral lobule.
What is the function of the parietal lobe?
Conscious sensation and association cortices.
Touch, temperature, pressure, pain, body position (proprioception).
Integrates sensory information together.
What is in the post central gyrus of the parietal lobe?
The primary sensory cortex and Brodmann’s areas 3, 1, and 2.
What structures are located in the parietal lobe?
Postcentral sulcus and gyrus, intraperietal sulcus, superior parietal lobule, inferior parietal lobule, precuneus, and posterior paracentral lobule.
How would you go about finding the supramarginal gyrus (part of inferior parietal lobe) in the lab?
By following the lateral sylvian fissure back; the supramarginal gyrus caps that lateral fissure at the end.
How would you go about finding the angular gyrus (part of the inferior parietal lobe) in lab?
By following the superior temporal gyrus back, it will come to a dead end and the capping gyrus at the end will be the angular gyrus.
Where are the supramarginal gyrus and the angular gyrus located? What shape are they?
In the inferior parietal lobe.
Both are upside-down horseshoe shaped.
What is the function of the temporal lobe?
Comprehension of language.
Hearing.
What are the gyri of the temporal lobe?
Temporal gyri:
- superior - containing the primary auditory cortex (wernicke’s area)
- middle
- inferior
Lateral occipitotemporal/fusiform gyrus
What is the function of the occipital lobe?
Vision and interpretation of visual images.
What are the structures of the occipital lobe?
Preoccipital notch
Calcarine fissure
Striate cortex: primary visual cortex and Brodmann’s area 17
Cuneus
Lingual gyrus
What are the functions of the limbic lobe?
Feel Feed Fight Flight Fornication
What are some key gyri and sulci of the limbic system?
Cingulate sulcus and gyrus, parahippocampal gyrus, and the uncus.
What are two important structures located in the limbic lobe? Where are they located in relation to each other?
The hippocampus and the amygdala.
Amygdala is located anterior to the hippocampus (you know you’re anterior enough to be looking at the amygdala when the slit near the hippocampus disappears).
What is the insula and where is it located?
Structure responsible for taste and integrated pain response.
Visible when you pull apart the slylvian fissure.
What is the function of the basal ganglia (aka nuclei)?
Precise control of voluntary movement.
What are the components of the basal ganglia?
The caudate nucleus: lateral portion of the lateral ventricle
Lenticular nuclei: putamen and globus pallidus
What is the diencephalon and what are its components?
Middle part of the brain.
Thalamus, hypothalamus, epithalamus(pineal gland), subthalamus, and the mamillary bodies.
Where is the thalamus located and what is its function?
Third ventricle.
Transmits all sensation (except olfaction) to cerebral cortex.
What is the function of the hypothalamus and the epithalamus?
Hypothalamus: endocrine and ANS function
Epithalamus (pineal gland): plays role in sleep/wake cycle
What is the function of the cerebellum?
Process sensory information to regulate movement.
Makes movements fluid.
What are the components of the cerebellum?
Vermis - “worm-like”
Cerebellar hemispheres
Cerebellar tonsils - near foramen magnum
What is the function of the brainstem?
Homeostasis.
Sensory, motor, and ANS innervation of the head and neck.
What are the components of the brainstem?
The midbrain, pons, medulla, and cranial nerves.
What are the components of the midbrain?
Tectum: superior and inferior colliculi (roof-like)
Tegmentum: cerebral peduncles
Describe the route that CSF takes through the ventricular system.
- Lateral ventricles
- Interventricular foramen of monro
- Third ventricle
- Cerebral aqueduct of Sylvius
- Fourth ventricle: 2 lateral aperatures (forman Luschka) and 1 medial aperature (foramen Magendie)
- Central canal of spinal cord
What structure separates the lateral ventricles?
The Septum pellucidum.
What are the three horns of the lateral ventricles?
Frontal/anterior horn
Temporal/Inferior horn
Occipital/Posterior horn
CSF is made by the _____ _____ by ______ cells which line the ventricles.
Choroid plexus.
Ependymal cells
