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Blood Supply of the Brain
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Blood Supply of the Brain
Blood Supply of the Brain
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1
Question
What are the objectives of the lecture on blood supply of the brain?
Answer
By the end of the lecture, students should be able to: 1. Describe the carotid and vertebro-basilar systems. 2. Demonstrate the branches of each system. 3. Describe the course and distribution of anterior, middle, and posterior cerebral artery. 4. Describe the applied anatomy of the anterior, middle, and posterior cerebral arteries. 5. Differentiate between superficial and deep venous drainage system of the cerebral hemispheres.
2
Question
What are the two main sources of blood supply to the brain?
Answer
The brain receives its blood from two sources: A. Internal carotid artery. B. Vertebro-basilar system.
3
Question
What is the circulus arteriosus of Willis?
Answer
The circulus arteriosus of Willis is an arterial circle at the base of the brain formed by the internal carotid and vertebro-basilar systems.
4
Question
What are the four parts of the internal carotid artery?
Answer
The internal carotid artery has 4 parts that run in 4 anatomical areas: 1. 1st cervical, 2. 2nd petrous, 3. 3rd cavernous, and 4. 4th cerebral.
5
Question
Where does the internal carotid artery end?
Answer
The internal carotid artery ends at the anterior perforated substance by giving rise to the anterior cerebral artery (ACA) and middle cerebral artery (MCA).
6
Question
What constitutes the vertebro-basilar system?
Answer
The vertebro-basilar system includes the 2 vertebral arteries which unite to form the basilar artery.
7
Question
From where does the vertebral artery branch off?
Answer
The vertebral artery is a branch from the 1st part of the subclavian artery.
8
Question
What are the anatomical areas the vertebral artery runs through?
Answer
The vertebral artery runs in 4 anatomical areas: 1st before foramen transversarium of C6 vertebra, 2nd through foramina transversaria of the upper 6 cervical vertebrae, 3rd in sub-occipital triangle to enter the skull through foramen magnum, and 4th on the ventral surface of medulla oblongata.
9
Question
Where does the basilar artery end?
Answer
The basilar artery ends at the lower border of pons by joining its fellow to form the basilar artery.
10
Question
What arteries branch from the cerebral part of the internal carotid artery?
Answer
Branches of the cerebral part of the internal carotid artery include: - Ophthalmic artery - Anterior cerebral artery - Middle cerebral artery - Posterior communicating artery - Anterior choroidal artery.
11
Question
What branches arise from the cranial part of the vertebral artery?
Answer
Branches of the cranial part of the vertebral artery include: - Anterior spinal artery - Posterior spinal artery - Medullary branches - Posterior inferior cerebellar artery - Meningeal branches.
12
Question
What are the branches of the basilar artery?
Answer
Branches of the basilar artery include: - Pontine branches - Labyrinthine artery - Anterior inferior cerebellar artery - Superior cerebellar artery - Posterior cerebral artery.
13
Question
What areas does the anterior cerebral artery (ACA) supply?
Answer
The anterior cerebral artery (ACA) supplies motor and sensory areas of the contralateral lower limb.
14
Question
What areas does the middle cerebral artery (MCA) supply?
Answer
The middle cerebral artery (MCA) supplies motor and sensory areas of the contralateral upper limb, in addition to speech centers, auditory areas, and the frontal eye field area.
15
Question
What areas does the posterior cerebral artery (PCA) supply?
Answer
The posterior cerebral artery (PCA) supplies the visual areas of the contralateral half of both visual fields.
16
Question
What is the significance of the circulus arteriosus (Circle of Willis)?
Answer
The circulus arteriosus (Circle of Willis) is a large anastomotic circle between the carotid and vertebro-basilar systems, important as an alternate pathway for maintaining blood flow if one vessel is occluded.
17
Question
What is the shape and location of the circulus arteriosus (Circle of Willis)?
Answer
The circulus arteriosus lies in the base of the brain in the interpeduncular cistern in the subarachnoid space and is hexagonal in shape.
18
Question
What arteries are involved in the formation of the Circle of Willis?
Answer
The Circle of Willis is formed by: - Both anterior cerebral arteries connected by a single anterior communicating artery. - Both internal carotid arteries connected to both posterior cerebral arteries by two posterior communicating arteries.
19
Question
What is the venous drainage system of the brain?
Answer
Veins of the brain emerge into the sub-arachnoid space, then pierce the arachnoid mater and meningeal layer of dura mater to drain into cranial venous sinuses.
20
Question
What are the components of the superficial venous drainage system?
Answer
The superficial venous drainage system includes: - Superior cerebral vein to superior sagittal sinus. - Inferior cerebral veins to nearby sinuses, mainly the transverse sinus. - Middle cerebral veins to the cavernous sinus.
21
Question
What is the deep venous drainage system of the brain?
Answer
The deep venous drainage system includes: - Thalamo-striate vein joining the choroidal vein to form the internal cerebral vein. - The internal cerebral veins unite to form the great cerebral vein, which joins the inferior sagittal sinus to form the straight sinus.
22
Question
What arteries supply the internal capsule?
Answer
The arterial supply of the internal capsule is provided by: - Upper 1/2 of both limbs by the MCA. - Lower 1/2 of anterior limb (genu) by the ACA. - Lower 1/2 of posterior limb by posterior communicating and anterior choroidal arteries.