SDL 5 - FOREBRAIN, VENTRICLES & CSF Flashcards
What is the forebrain (cerebrum) made up of?
The cerebral hemispheres and the diencephalon
What are the 4 components of the diencephalon?
- Thalamus
- Hypothalamus
- Epithalamus
- Subthalamus
Label structures A - L
A - thalamus
B - hypothalamus
C - mammillary body
D - pituitary stalk
E - optic chiasm
F - foramen of monroe
G - corpus callosum
H - septum pellucidum
I - anterior commisure
J - interthalamic adhesion
K - choroid plexus of IIIrd ventricle
L - pineal gland
Is the cerebral cortex made up of grey or white matter?
The cerebral cortex is the outer layer of the cerebrum
this consists of grey matter (nerve cell bodies)
What is meant by the terms ‘sulci’ and ‘gyri’?
Gyri are the folds/ridges on the surface of the brain
the sulci are the shallow grooves that surround the gyri
What is the lateral surface of the frontal lobe made up of?
precentral gyrus and the superior, middle and inferior frontal gyri
Where is the precentral gyrus located?
Where are the superior, middle and inferior frontal gyri located?
Precentral gyrus:
- immediately in front of the central sulcus
Superior, middle and inferior frontal gyri:
- these are broad, parallel gyri
- they extend anteriorly from the precentral gyri
the precentral and superior frontal gyri extend over onto the medial surface of the frontal lobe, which is completed by a portion of the cingulate gyrus
What is the inferior surface of the frontal lobe made up of?
A series of orbital gyri
What is the major gyrus of the parietal lobe?
Postcentral gyrus
this extends over onto the medial surface of the parietal lobe
another portion of the cingulate gyrus forms an additional part of the medial surface of the parietal lobe
What is the medial surface of the occipital lobe bisected by?
Calcarine sulcus
the primary visual cortex surrounds the calcarine sulcus and extends to the tip of the occipital pole
What are the 5 long parallel gyri that cover the temporal lobe?
- Superior temporal gyrus
- Middle temporal gyrus
- Inferior temporal gyrus
- Occipito-temporal gyrus
- Parahippocampal gyrus
Where are the superior, middle and inferior temporal gyri of the temporal lobe located?
They are on the lateral surface of the temporal lobe
the inferior temporal gyrus extends around onto the inferior surface, where it lies next to the occipito-temporal gyrus
What cortex is located in the superior temporal lobe?
Primary auditory cortex
What is the medial edge of the temporal lobe flanked by?
The medial edge of the temporal lobe is flanked by the parahippocampal gyrus
at its anterior end it folds back on itself to form a bump called the uncus
Which gyri are found in the limbic lobe?
The limbic lobe is formed by the cingulate gyrus and the parahippocampal gyrus
it can only be appreciated in the medial surface of the brain
Label the sulci and gyri on the lateral surface of the left cerebral hemisphere
Label the gyri of the medial surface of the right cerebral hemisphere
What is meant by the terms primary motor cortex and primary sensory cortex?
Primary motor cortex:
- generates nerve impulses that control the execution of movement
- precentral gyrus
Primary sensory cortex:
- processes somatic sensations e.g. touch, temperature, nocioception
- postcentral gyrus
Which functional areas of the cortex would be affected by blockage of the posterior cerebral artery?
The posterior cerebral artery supplies the occipital lobe
It also supplies the posteromedial temporal lobe
Blockage to the PCA would affect the visual cortex, which is supplied by the PCA and MCA
Which cerebral arteries supply the primary projection cortex for general sensory information?
The middle cerebral artery supplies the frontoparietal somatosensory cortex (for face and arm)
The anterior cerebral artery supplies the primary somatosensory cortex for the leg and foot
Which cerebral arteries supply the primary auditory cortex?
Middle cerebral artery
What are the three types of fibres making up the white matter core of the cerebral hemispheres?
- Association fibres
- Commissural fibres
- Projection fibres
What is meant by ‘association fibres’?
They connect cortical areas within the same cerebral hemisphere
What is meant by commissural fibres?
Fibres that connect the 2 hemispheres of the brain
the major examples are the corpus callosum (great cerebral commisure) and the anterior commisure that connects the temporal lobes
What is meant by ‘projection fibres’?
Afferent and efferent fibres that connect the cortex with the lower parts of the brain and the spinal cord
e.g. Corona radiata and internal capsule
What is the term used to refer to the grey matter structures found within each hemisphere?
The grey matter structures found deep inside each hemisphere are collectively referred to as the basal ganglia
What are the principal basal ganglia?
Lentiform nucleus:
- consists of globus palidus and putamen
caudate nucleus
- also substantia nigra in the midbrain
- Subthalamic nucleus in the diencephalon
What is the corpus striatum?
A collective term describing the lentiform nucleus and the caudate nucleus within the basal ganglia
What is the major function of the basal ganglia?
Control of voluntary motor movements
Also involved in procedural learning, habit learning, eye movements, cognition, and emotion
Label the following structures
Where are the corpus striatum and internal capsule located?
What are the 3 anatomical divisions of the internal capsule?
- Anterior limb
- Genu
- Posterior limb
Where is the ventricular system of the brain derived from?
The central canal of the embryonic neural tube
Which components of the ventricular system are located in the diencephalon, midbrain and pons?
Diencephalon:
- third ventricle
Midbrain:
- cerebral aqueduct
Pons:
- fourth ventricle
Label the ventricular system
At which points does the ventricular system communicate with the subarachnoid space?
The fourth ventricle commiunicates with the subarachnoid space via:
- Lateral apertures (foramina of Luschka)
- Median aperture (foramen of Magendie)
What is choroid plexus?
A plexus of cells that produce cerebrospinal fluid within the ventricles of the brain
What happens if circulation of CSF is obstructed?
There are bottlenecks in the circulation of CSF, both inside and outside of the ventricular system
If circulation is disrupted, CSF production continues unabted and hydrocephalus results
At which sites is the circulation of CSF most likely to become obstructed?
Stenosis of the cerebral aqueduct
blockage in the interventricular foramen of Monroe
