N4 + N5- Nervous system introduction and spinal cord Flashcards
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What nerves make up the peripheral nervous system?
- 12 pairs of cranial nerves
- 31 pairs of spinal nerves and their branches
what are the 3 primary vesicles of the brain at 4 weeks?
- Prosencephalon
- Mesencephalon
- Rhombencephalon
How are the secondary vesicles formed at 6-8 weeks?
Prosencephalon and rhombencephalon divides into 2 swellings and mesencephalon remains the same
What are the 5 secondary vesicles?
- Telencephalon
- Diencephalon
- Mesencephalon
- Metencephalon
- Mylencephalon
What major derivative of the mature brain does telencephalon form?
Cerebral hemispheres
What major derivative of the mature brain does diencephalon form?
thalamus, hypothalamus
What major derivative of the mature brain does mesencephalon form?
Midbrain
What major derivative of the mature brain does metencephalon form?
Pons, cerebellum
What major derivative of the mature brain does Myelencephalon form?
Medulla oblongata
What structures make ups the brainstem?
- midbrain
- pons
- medulla
What matter is the brain made up of?
- Grey matter
- white matter
what is grey matter made of and where is most of this matter located?
- Huge numbers of neurons, cell processes, synapses and support cells
- outside edge of brain
what is white matter made of and where is most of this matter located?
- Axons (most myelinated) and their support cells
- deep to grey matter
What is an exaggerated sulcus?
fissure
What grey matter structures are located deep in the cerebral hemispheres?
- Caudate nucleus (associated with the ventricles)
- Thalamus (sits on the midline)
- Putamen
What is the internal capsule?
The main white matter fibre tract between the spinal cord and the cerebral hemispheres
Where does the central sulcus run?
Runs superior to inferior and from posterior to anterior
What gyrus sits anterior to the general sulcus?
Precentral gyrus
what gyrus sits posterior to the general sulcus?
postcentral gyrus
What sulcus/fissure forms the temporal lobe?
lateral sulcus or fissure
what fissure slices the brain in half on the coronal plane?
longitudinal fissure
What is the function of the corpus callosum?
The biggest white matter tract which provides communication between the left and right hemisphere
What is the name of the primary visual cortex?
calcarine sulcus
What sulcus splits the parietal and occipital lobes?
Parieto-occipital sulcus
What gyrus and sulcus are superior to the corpus callosum ?
cingulate
What is the name of the place where the two sides of the thalamus adhere?
Interthalamic adhesion
What are the boundaries of the frontal lobe?
- large lobe anterior to the central sulcus and superior to the lateral sulcus
- lobe anterior to a line drawn from the central sulcus down to the corpus callosum (medial)
What are the boundaries of the parietal lobe?
- posterior to the central sulcus, superior to the lateral sulcus (and a backward extension of it), and anterior to a line from the parieto-occipital sulcus to the preocciptial notch
- posterior to the frontal lobe and anterior to the parieto-occipital sulcus (medial)
What are the boundaries of the occipital lobe?
-posterior to a line from the parieto-occipital sulcus to the preocciptial notch
What are the boundaries of the temporal lobe?
- inferior to the lateral sulcus (and a line extending the lateral sulcus posteriorly) and posteriorly by a line from the parieto-occipital sulcus and the preoccipital notch
- the temporal lobe extends from the temporal pole, to a line drawn between the preoccipital notch and the anterior end of the calcarine sulcus (medially)
What is the name and where is the extra lobe/ ‘fifth lobe”?
- insula
- hurried in lateral fissure (to see it, cut away the temporal, frontal and parietal opercula )
what are the 3 layers of the meninges?
- dura mater
- arachnoid mater
- pia mater
Describe dura mater.
outer tough layer of connective tissue
Describe arachnoid mater.
relatively thin layer that is usually apposed to the dura mater. Thin, wispy cords of connective tissue connect this layer to the pia
Describe the Pia mater.
very thin inner layer that is apposed to the surface of the brain. A layer of pia mater accompanies arteries penetrating into the brain. Pia mater follows there gyrus and sulcus
what are the two dural folds?
- Falx cerebri ( invagination of dura mater down hemispheres of brain)
- tentorium cerebelli (separates supra-tentorium space and and the sub-tentroium space)
what do dural folds form when they meet bone?
venous sinuses
what secretes cerebrospinal-spinal fluid?
secreted by specialised cells within the ventricular system of the brain
where does CSF circulate?
around the brain AND spinal cord from the 4 ventricles to the subarachnoid space
what reabsorbs CSF into the dural venous sinuses?
arachnoid granulations
What produces CSF?
Choroid plexus in ventricles
What is the structure of the choroid plexus?
Core of the choroid plexus is blood vessels and it is enclosed in a choroid epithelium
How do the lateral ventricles connect to the 3rd ventricle?
interventricular foramen
what connects the 3rd and 4th ventricles?
cerebral aqueduct (thin canal)
Where does the CSF flow from the 4th ventricle?
Most flows into subarachnoid space and some flows into the central canal
What are cisterns?
in some areas the arachnoid departs substantially from the pia, leaving a relatively large space filled with CSF
Where can you insert a needle without damaging the spinal cord?
below L2
What are the main arteries that supply blood to the brain?
- right and left internal carotid arteries
- vertebral arteries
what forms from the vertebral and internal carotid arteries?
circle of willis
what makes up the circle of willis?
- posterior cerebral
- posterior communications
- middle cerebral
- internal carotid
- anterior cerebral
- anterior communicating
what artery moves in the lateral fissure?
medial cerebral
what does the branches of the anterior cerebral artery supply?
The frontal lobe and most of the parietal lobes
what does the branches of the middle cerebral artery supply?
lateral areas of the frontal, temporal, and parietal lobes
what does the branches of the posterior cerebral arteries supply?
mostly thalamus?
What is the blood supply to the cerebellum?
From vertebral arteries: -Posterior Inferior Cerebellar artery From basilar artery: -Anterior Inferior Cerebellar Artery -Superior Cerebellar Artery
What is the blood supply to the brainstem?
-Midbrain: branches from the termination of the basilar artery and initial segment of the posterior cerebral artery.
Pons: Pontine arteries (paramedian and circumferential)
Medulla: branches from anterior inferior cerebellar artery and posterior inferior cerebellar artery
what is the venous sinuses drainage in the brain?
Superior saggital sinus> confluence of the sinus> tranverse sinus > sigmoid sinus
where eventually does the dural venous sinuses drain?
internal jugular vein
What is the venous drainage of the deep brain and inferior surface?
series of veins that largely empty into the great cerebral vein and then the straight sinus
where does the great cerebral vein and terminal part of internal cerebral vein travel in?
transvers fissure