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Flashcards in Neuro Anatomy 1 Deck (67):

What are the gyri of brain?

The rolls of the cerebral cortex


What are the Sulci of the brain?

The grooves between the gyri


What is the central sulcus?

A large fissure separating the frontal from parietal lobes


What is the lateral sulcus?

A large fissure separating the temporal lobe from the parietal and frontal lobes


Where is Insula in brain?

Forms the floor of the Lateral Sulcus


What are the Opercula (lips)?

The parts of the temporal, frontal and parietal lobes that overlie the insula


What is the Corpus Callosum?

A large bundle of white matter connecting the two hemispheres


What and where is the Falx Cerebri?

An arched crescent of dura lying in the longitudinal fissure between the two hemispheres.


Where is Superior Sagittal Sinus?

Where the falx cerebri attaches to the cranium


Where is Inferior Sagittal Sinus?

At the free border of the falx cerebri


What is the tentorium cerebelli?

The dura formin a thick fibrous roof over the posterior cranial fossa and cerebellum


Where is the straight sinus?

Within the tentorium cerebelli at its attachment to the falx cerebri


What and Where is Tentorial Inscisure?

A horseshoe-shaped space between the free concave border of the tentorium and the dorsal sellae (upper surface) of the sphenoid bone.


Where are transverse sinuses?

Run along the line of attachment of tentorium cerebelli to occipital bone.


Where is cavernous sinus?

Lies lateral to body of the sphenoid


What is the Trigeminal cave?

Lies next to the apex of petrous part of temporal bone and envelops the roots of the trigeminal nerve


What is the Diaphragma Sellae?

A small, circular, horizontal fold of dura matter which forms the roof of the pituitary fossa.


What is the Falx Cerebelli?

A small, vertical, sickle-shaped reflection of dura separating the two lobes of cerebellum.


What are the two layers of dura matter?

The Outer Endosteal Layer - lines the interior of the skull, adhering to and sending BVs and fibrous processes into the cranial bones.
The Inner Meningeal Layer - completely envelopes the CNS; it continues as tube of dura seen around the spinal cord and provides tubular sheaths for the cranial nerves.


Are the two dura layers fused?

Mostly. In places the inner layer separates from the skull to form Dural Folds. They support the sub-divisions of the brain and partially divide the cranial cavity into three areas, the right and left hemispheres and the posterior cranial fossa (where cerebellum lies).


What and Where are Dural Venous Sinuses?

A system of communicating blood-filled spaces where dural folds attach to the skull.


Where is parietal lobe?

Extends from central sulcus anteriorly to the imaginary parietoccipital fissure posteriorly


How many lobes in parietal lobe and what is function?

Two parietal lobes - dominant one is usually the left.
Important for perception, interpretation of sensory information and formation of the idea of a complex, meaningful motor response.
The supra marginal and angular gyrus of the dominant lobe are concerned with language and mathematical operations.
Non-dominant lobe (normally right) is important for visuospatial functions.


Functions of frontal lobe

Involved in motor function, problem solving, spontaneity, memory, language, judgement, personality, impulse control and behaviour (social and sexual).
Also site of Olfaction


Purpose of pre-frontal cortex

Important for higher cognitive functions and determination of personality.


Purpose of posterior portion of frontal lobe

Contains motor and premotor areas


What is Broca's area?

Found at the inferior frontal gyrus and is important for language production and comprehension.


What structures are found in the temporal lobe?

Contains the primary auditory cortex, hippocampus, amygdala and Wernicke's area


What is Wernicke's area?

Located in the superior temporal gyrus of left hemisphere and is concerned with understanding the spoken word..


Give some functions of the temporal lobe

Short term memory, equilibrium, emotion


Where is the occipital lobe and what does it contain

Located at posterior aspect of the brain.
Contains primary visual and visual association cortex.


What is the Limbic system?

Surrounds the medial margin of the hemisphere.
Includes hippocampus, fornix, amygdala etc and is involved in emotion, memory, behaviour and olfaction.


Purpose of hippocampus

Involved in long term memory function.


Purpose of amygdala

Important in motivationally significant stimuli, such as those related to reward and fear.


How does the Limbic system operate?

Operates by influencing the endocrine system and autonomic NS.
It's highly interconnected with the brains pleasure centre. Here the nucleus accumbens - has a role in sexual arousal and highs experienced with recreational drugs.


What is the arachnoid matter

Layer that encloses the brain, loosely following the contour of the meningeal layer of the dura.


Where are Subarachnoid Cisterns

Where the arachnoid spans the gyri of the brain, these cisterns exist and are spaces between the arachnoid and the pia matter. They are full of CSF


What is the Foramen of Magendie

a midline communication between the IVth ventricle and the subarachnoid space


What is the Foramen of Luschka

a lateral communication between the IVth ventricle and subarachnoid space


Where is Cerebellomedullary Cistern?

Subarachnoid Cistern that lies in the angle formed by the dorsal surface of the medulla and the inferior surface of the cerebellum


Where is Pontine Cistern?

Subarachnoid Cistern on ventral surface of the pons


What is contained in Interpenduncular Cistern?

Subarachnoid Cistern that contains the circle of Willis


What is contained in Cistern of Lateral Fissure

Subarachnoid Cistern containing the Middle Cerebral Artery and bridges the Lateral Sulcus on each side


What is the Superior Cistern

Subarachnoid Cistern containing the great cerebral vein (of Galen) and the pineal gland and is found between the posterior end (splenium) of corpus callous and the superior surface of the cerebellum.


What are Cisterna Ambiens

Group of subarachnoid cisterns which completely encircle the midbrain.


Describe the Blood-Brain Barrier

On surface of brain are arteries that lie in subarachnoid space. As the vessels pass into substance of brain they take with them prolongations of Pia Matter and some of subarachnoid space (forms a layer around the vessel).
As vessel penetrates deeper, the Tunica Media thins and prolongation of subarachnoid space narrows.
At capillary network level, the basement membranes of endothelial cells and pia fuse. The pia acts as a barrier between the BVs and neurological tissue.


What are the Meninges layers in order

Pia matter, Arachnoid, Dura


How does appearance of superficial cerebral veins differ to arteries?

Superficial cerebral veins are easily distinguished by their dark colour, due to fixed and coagulated blood being visible through their thin, fragile walls.
Arteries look paler, having thicker, muscular walls and are not so easily torn.


How does the BB Barrier retard or prevent passage of substances from circulation into nervous tissue?

-Endothelial cells of capillaries
-Basement membrane, which lies between the endothelial cells and astrocytic end-feet. Is formed from the true basement membrane and pia
-Astrocytic end-feet themselves


Describe the arterial blood supply to the brain

-Vertebral Arteries provide 20% of total supply. Supply the Posterior Cerebrum and contents of the Posterior Cranial Fossa.
-Internal Carotid Arteries provide 80% of total supply. Supply the Anterior and Middle parts of the Cerebrum and Diencephalon.


Describe the arterial blood supply to the brain

-Vertebral Arteries provide 20% of total supply. Supply the Posterior Cerebrum and contents of the Posterior Cranial Fossa.
-Internal Carotid Arteries provide 80% of total supply. Supply the Anterior and Middle parts of the Cerebrum and Diencephalon.


Describe the course of the Internal Carotid system

Internal Carotid Artery arises at bifurcation of Common Carotid at level of the upper border of Thyroid Cartilage and ascends to the base of the skull where it enters the Temporal Bone to lie in the Carotid Canal.
Artery pursues a tortuous course, piercing the dura the forms the roof of Cavernous Sinus to enter cranial cavity.
When reaches Anterior Perforated substance at medial end of Lateral Sulcus it divides into its terminal branches - the 'Anterior and Middle Cerebral Arteries'.
This part of cerebral circulation called the Anterior Circulation.


What terminal branches of Internal Carotid Artery?

Anterior and Middle Cerebral Arteries


Where does Anterior Cerebral Artery supply?

Corpus Callosum and medial aspects of hemispheres


Where does Middle Cerebral Artery supply?

Middle Cerebral Artery is largest of terminal branches of Internal Carotid Artery. Supplies the majority of lateral surface of hemisphere and deep structures of anterior cerebral hemisphere via its Anterior Perforating Branches


Purpose of Anterior Communicating Artery

Connects together the two Anterior Cerebral Arteries and provides Anterior Perforating Branches.


Purpose of Posterior Communicating Artery

Connects the Internal Carotid and Vertebro-Basilar systems via the Posterior Cerebral Artery


How do cerebral veins differ to normal veins

Veins in brain drain blood back towards the heart. The cerebral veins differ in that they first drain into the dural venous sinuses which are channels formed between the 2 dura layers.


What are two groups of internal cerebral veins

Internal Cerebral Veins
-Run within the substance of brain tissue and end when they reach the brain surface where they become external cerebral veins
External Cerebral Veins
-Run on the surface of the brain crossing the subarachnoid space to drain to the Dural Venous Sinuses


What are Dural Venous Sinuses

Connect major cerebral veins to internal jugular veins. The major venous sinuses can be identified in attached borders of falx cerebri, tentorium cerebelli and floor of cranial cavity.


Name the Dural Venous Sinuses

Inferior Sagittal Sinus (inferior margin of falx cerebri)
Superior Sagittal Sinus (superior border of falx cerebri)
Straight sinus (in midline of tentorium cerebelli)
Transverse Sinus (in posterior fixed margin of tentorium cerebelli)
Sigmoid Sinus (deep grove in mastoid part of temporal bone)
Cavernous SInus (beside body of sphenoid bone and contains five cranial nerves and internal carotid artery)
Superior Petrosal Sinus (in attached lateral margin of tentorium cerebelli)
Inferior Petrosal Sinus (in groove between the petrous temporal bone and basal part of occipital bone)


How do intracranial venous sinuses and veins outside the skull communicate?

(A variable number of) Emissary Veins


How is CSF production controlled?

Tight junctions that prevent passage of fluid from the extracellular space of Choroid Plexus into ventricle except via choroidal cells themselves. This allows close control over volume and composition of CSF.


What is the Choroid Plexus

Vascular fold of pia matter covered by an epithelium derived from the ependymal lining of ventricle. Produced by invagination o vessels into ventricles


What is the Choroid Plexus

Vascular fold of pia matter covered by an epithelium derived from the ependymal lining of ventricle. Produced by invagination o vessels into ventricles


How is CSF re-absorbed into the venous drainage of the brain?

Occurs via tufts of arachnoid matter called Arachnoid Villi. (With advancing age these villi tend to calcify an may be visible on x-ray) - or an arachnoid granulation in which subarachnoid space is highly trabeculated and continuous with channel in granulation centre


Ependyma constitutes the CSF-brain barrier

Magendie foramen = Medial aperture
Luschka foramen = Lateral aperture