Study Guide Cerebrum Half Midterm #2 Flashcards
Basal nuclei (aka basal ganglion)
Isolated centers of grey matter in central cerebrum
Corpus Striatum is made up of the ___ and ___
Caudate nucleus and lentiform nuclei
Caudate nucleus
Is a C-shaped grey matter nucleus. Stretches over the thalamus and then descends to the lentiform nucleus.
The lentiform nucleus is divided into two parts
Putamen and the palladium (globus pallidus)
Putamen makes up what portion of the lentiform nucleus
The putamen Is the lateral part of the lentiform nucleus. It is a dark grey collection of soma and axons.
The palladium makes up what portion of the lentiform nucleus
The palladium makes up the medial portion of the lentiform nucleus
The putamen and palladium of the lentiform nucleus have a thin layer of ____ in between
White matter
Difference in color between the palladium and the putamen
Putamen- dark grey
Palladium- light grey
The palladium of the lentiform nucleus receives input from ___ and sends ____ signals from basal nuclei to the extern structures such as the thalamus
The striatum
Efferent
Claustrum
An area of grey matter located laterally to the lentiform nucleus (specifically, the putamen). Unknown function. Boarded by white matter.
The claustrum is separated from the lentiform nucleus by a layer of white matter called
The external capsule
Fornix
White matter pathway the takes hippocampal axons to other parts of the brain
Hippocampus
Extension of the cerebral cortex. Involved in transforming short term memory into long term memory. Technically not apart of the cerebrum.
Three areas of white matter in the deep cerebrum
- Fornix- takes hippocampal axons to other parts of the brain
- Internal capsule
- Corona radiata- project from internal capsule to the cerebral cortex
Types of white matter fibers in the cerebrum
Association fibers, commissural fibers, and projection fubers.
Association fibers
Fiber in white matter of the cerebrum.
Connect different parts of the cerebral cortex within the same hemisphere.
- Short association fibers (within a lob)
- Long association fibers (between lobes)
Commissural fibers
Contralateral connecting fibers.
Connect portions of the cerebral cortex in one hemisphere with its partner in the other hemisphere. They must cross from one hemisphere to the other by one of four cerebral commissures.
- Corpus collosum
- Anterior commissure
- Posterior commissure
- Habenular commissure
Four types of cerebral commissures
- Corpus collosum- the largest.
- Anterior commissure (olfactory tract limbic system)
- Posterior commissure (Pretectal nuclei dinger westphal)
- Habenular commissure (between left and right thalamus)
Projection fibers
Fiber in white matter of the cerebrum.
Start in the cerebrum, but end elsewhere in the nervous system. These will all travel in the corona radiata and internal capsule.
Overall,
Deep grey matter (2)
Deep white matter (3)
Deep grey: Basal nuclei and hippocampus
Deep white: Fornix, internal/external/extreme capsule, corona radiata
Anterior and posterior limbs of internal capsule
Anterior limb is between the caudate nucleus and the lentiform nucleus.
The posterior limb is between the corpus striatum structure and the thalamus.
Visual pathway and optic nerve go through
LGN in the thalamus. Thalamus is right by the posterior limb of the internal capsule.
ON goes to LGN. Fibers project from the LGN to the cortex, loop through the posterior limb of the internal capsule.
Right and left cerebral hemispheres are ___ at birth. But one hemisphere becomes more dominant. ~90% are ___ hemisphere dominant
Identical.
90% are left hemisphere dominant, which controls right side of body.
What develops in the dominant side of the brain
Handedness, language and speech.
What develops in the non-dominant side of the brain
Spacial perception, face recognition, auditory understanding
Which is deeper- a fissure or a sulcus
Fissure is deeper than sulcus
Lateral sulcus separates which two lobes
Separates frontal from temporal
Central sulcus separates which two lobes
Frontal and parietal
Calcarine sulcus separates which lobe into two
Divides superior and inferior occipital lobes
Parieto-occipital sulcus
Sulcus that divides parietal from occipital lobe
Divisions of the corpus collosum
Most anterior- genu
body
Most posterior- Splenium
Where are genus
Anterior portion of the corpus collosum
Middle of the internal capsule (between anterior and posterior divisions)
Start at palladium and name structures laterally
Palladium– putamen– (together, form the lentiform) external capsule
– claustrum – extreme capsule
Grey matter covering the cerebral hemispheres. Where it is thinnest, where is it thickest?
thinnest at the bottom of the sulcus and thickest at the crest of the gyrus
What happens if the posterior commissure is affected?
Consensual pupillary response will not occur. Posterior commissure communicates info about light form the pretectal nucleus to the edinger westphal.
Leaving the cortex? Must pass through ___
Corona radiata- found within the white matter
Leaving the brain through the brain stem/spinal cord? Fibers must pass through___. Ex: motor outputs
Fibers must pass through internal capsule. Motor output.
Is the cortex grey or white matter. And what comprises it?
Grey. Soma, unmeylinated axons and dendrites.
Layers of the cortex
6 distinct layers. Contains sensory neurons, motor neurons, and interneurons (usually inhibitory).
Many - molecular Elephants -external granular Eat -external pyramidal Icecream - internal granular Great -ganglionic or internal pyramidal Mood - multiform
Are internueorns usually excitatory or inhibitory
Inhibitory
Layers of the cortex- 1-6. where are they located
1 is the most superficial
6 is the deepest, up against the white matter.
What kind of cell is a pyramidal cell?
A multipolar neuron. Contains 1 single axon with many dendrites. Typically has a long axon.
Body looks like a triangle.
(2) Orientation of cortex fibers
Radial or tangential
Radial fibers of the cortex
Pyramidal cell axons are radial. Pass through multiple layers in the cortex.
Tangential fibers of the cortex
Typically stay in one layer. Usually more associated with interneurons.
Homotypical cortex vs heterotypical cortex
Homotypical- Retains 6 layer layout from fetus to adulthood. Defined layers.
Heterotypical- Change in orientation over time. Plasticity with learning and development. Difficult to distinguish.
Homotypical is more common (90% vs 10%)
Where is Betz cell soma in relation to other pyramidal cell bodies
Soma are deeper in the cortex relative to pyramidal cells associated with association fibers.
Two types of heterotypical cortex
- Granular type. Which is when the granular layers (2 and 4) are more defined than the agranular layers (3 and 5)
- Agranular type. Which is when the agranular layers (3 and 5) are more defined than the granular layers (2 and 4)
Locations of granular type heterotypical cortex
Post central gyrus and auditory
Locations of agranular type heterotypical cortex P
Precentral gyrus (motor) and frontal lobes
Brodmann 4
Located in the precentral gyrus, which is in the frontal lobe. Anterior to the central sulcus and parietal lobe.
Primary motor cortex. Contains agranular heterotypical.
Projection fibers found here.
Which lobe is the precentral gyrus in
The frontal lobe
Secondary motor area
Brodmanns 6 is the main one. Also 8, 44, and 45. Has a lot of input from sensory, which sends projections into the primary area. And the primary area will send a response.
Brodmanns 6, 8, 44, and 45 are located where and what input does it receive
It is located anterior to the primary (Brodman 4) in the frontal lobe. And receives input from sensory. Controls motor activity based on experience and external cues.
Can also send info to the primary cortex and get a response from it as well.
What parts of the precentral gyrus are associated with head and neck motor? Which parts are associated with lower extremities?
Referencing Brodman 4.
The lateral part of the gyrus is associated with head and neck.
The apex and down into the sulcus are associated with lower extremities.
Brodmann areas 1, 2, and 3
Primary somatosensory in the parietal lobe immediately posterior to the central sulcus.
Receives sensory innervation from all over- anywhere in the body basically.
Secondary sensory area
Brodmann 40. Below and posterior to brodmann 3 (Sensory)
Name the Brodmann number associated with:
- Motor
- Secondary motor
- Sensory
- Secondary sensory
- Somatic sensory association
- 4
- 6, 8, 44, 45
- 1, 2, 3
- 40
- 5, 7
Brodmann 40
Secondary sensory located posterior to the central sulci and the sensory area. More towards central brain.
Parietal lobe. Associated with pain and tactile discrimination.
Brodmann 5 and 7
Somatic sensory association cortex. Posterior to sensory cortex. More towards top of brain.
Many connections to other areas in the cortex. Likely integrates all info.
Ex: Something touches arm. Associates touch with arm and to look and to determine what it is and so on.
Four ventricles of the CSF
Right and left lateral ventricles
Third ventricle
Fourth ventricle
Which cells secrete and move CSF
Ependymal cells produce CSF for movement in subarachnoid space
How do the four ventricles of CSF work together
Lateral ventricles drain into the third ventricle via the inter ventricular foramen.
The their ventricle drains into the fourth ventricle, which is in the brainstem, via the cerebral aqueduct (very thin duct)
The CSF then rains into the central canal of the spinal cord or into the subarachadonic space via two lateral (luschka) and medial (magendie) openings.
Lateral ventricles drain into the third ventricle via the ____
Inter ventricular foramen of monroe.
Choroid plexus
Production of CSF in lateral ventricles via active, pressure independent process from blood that is passing through the capillaries of the plexus.
How does CSF drain
Drains into dural venous sinus via pressure dependent process. Passive process.
Where is the 4th ventricle located
in the brain stem
Which two areas/cells can produce CSF
Choroidal plexus in the roof of the lateral ventricles or the 3rd ventricles.
Ependymal cell
Genu
Bend
