37 Questions
What is the percentage of the body weight that is comprised of the brain?
2%
What is the percentage of total oxygen consumption by the brain?
20%
What is the ranking of cerebrovascular diseases as a cause of death?
3rd
How many primary arteries supply the brain?
4
What is the location of the Circle of Willis?
Subarachnoid cistern
What is the function of the posterior communicating artery?
To connect the internal carotid with posterior cerebral arteries
Which branch of the vertebral artery is the first intracranial branch?
Posterior spinal artery
What is the origin of the posterior inferior cerebellar artery?
Vertebral artery or posterior inferior cerebellar artery
What is the origin of the anterior spinal artery?
Near vertebral artery termination
What is the path of the anterior-inferior cerebellar artery (AICA)?
Runs ventral to 7th and 8th cranial nerves
Where does the labyrinthine artery originate from?
Basilar artery or anterior-inferior cerebellar artery (AICA)
What is the path of the posterior cerebral artery?
Along superior pons border, around midbrain, to medial cerebral hemisphere
What is the origin of the ophthalmic artery?
Internal carotid artery after exiting cavernous sinus
What is the path of the anterior choroidal artery?
Along optic tract, into lateral ventricle’s inferior horn
Which artery is most susceptible to thrombosis?
Middle cerebral artery
What is the path of the basilar artery?
From vertebral artery termination to the lower pons border
What is the circle of Willis?
A circle of arteries formed by the anterior communicating, anterior cerebral, posterior communicating, and posterior cerebral arteries
Which branch of the vertebral artery unites with its opposite side to form a single median trunk along the spinal cord's anterior longitudinal fissure?
Anterior spinal artery
What is the primary function of the meningeal branches?
Supplying the dura mater of the posterior cranial fossa
Which artery accompanies the vestibulocochlear nerve and supplies the internal ear?
Labyrinthine artery
What is the path of the anterior cerebral artery?
Forwards, medially above the optic nerve
Which artery is susceptible to thrombosis and is referred to as the 'artery of cerebral thrombosis'?
Anterior choroidal artery
What is the origin of the posterior spinal artery?
Vertebral artery
Which artery supplies the midbrain, temporal lobe, and occipital pole?
Posterior cerebral artery
What is the path of the ophthalmic artery?
U-shaped bend, enters the orbit via the optic canal
Which artery supplies the frontal, parietal, and temporal lobes?
Middle cerebral artery
What is the termination of the basilar artery?
Dividing into right and left posterior cerebral arteries
What is the primary source of energy for the brain?
Glucose from aerobic metabolism
What percentage of cardiac output is received by the brain?
20%
What is the consequence of a lesion in the posterior cerebral artery?
Symptoms depend on the site of the lesion
What is the function of the anterior communicating artery?
Connecting the two anterior cerebral arteries
What is the consequence of a blockage in the basilar artery?
Reduced blood flow to the posterior cerebral arteries
What is the significance of the Circle of Willis?
It provides collateral circulation in case of arterial blockage
What is the branching pattern of the posterior spinal artery?
It divides into medial and lateral branches
What is the relationship between the right and left vertebral arteries in the Circle of Willis?
They unite to form the basilar artery
What is the effect of minimal mixing of blood streams in the Circle of Willis?
No significant effect on blood flow
What is the origin of the posterior inferior cerebellar artery?
Near the lower end of the olive
Study Notes
Metabolic Activity of the Brain
- High metabolic rate with aerobic metabolism of glucose
- 2% of body weight, receives 20% of cardiac output, consumes 20% of total O2
Cerebrovascular Diseases
- Thrombosis, embolism, hemorrhage; 3rd most common cause of death
- Symptoms depend on lesion site
Arteries of the Brain
- Primary arteries: 2 vertebral arteries, 2 internal carotid arteries
Vertebral Arteries
- Enter skull via foramen magnum, unite at pons to form basilar artery, which divides into posterior cerebral arteries
Internal Carotid Arteries
- Enter cranial cavity via carotid canal and foramen lacerum, course through cavernous sinus, end lateral to optic chiasma dividing into middle and anterior cerebral arteries
Circle of Willis (Circulus Arteriosus)
- Formation: anterior communicating artery, anterior cerebral arteries, basilar artery dividing into posterior cerebral arteries, and posterior communicating arteries connecting internal carotid with posterior cerebral arteries
- Location: interpeduncular subarachnoid cistern
- Function: provides collateral circulation if a major artery is blocked
Blood Stream Mixing
- Minimal mixing between vertebral arteries in basilar artery, anterior cerebral arteries in anterior communicating artery, and internal carotid and posterior cerebral arteries in posterior communicating artery
- Supply: right brain by right vertebral and internal carotid arteries; left brain by left vertebral and internal carotid arteries
Collateral Circulation
- Circle of Willis offers alternative routes if blockage occurs
Branches of Vertebral Artery
- Posterior spinal artery: first intracranial branch, originates from vertebral artery or posterior inferior cerebellar artery, descends on spinal cord's posterior surface
- Posterior inferior cerebellar artery (PICA): largest branch, originates near lower end of olive, winds around medulla oblongata, ascends to pontomedullary junction
- Anterior spinal artery: small branch, originates near vertebral artery termination, descends in front of medulla, unites with opposite side to form a single median trunk along spinal cord's anterior longitudinal fissure
- Meningeal branches: small, supply dura mater of posterior cranial fossa
- Medullary arteries: minute vessels, supply medulla oblongata
Branches of Basilar Artery
- Pontine branches: numerous, short, paramedian vessels, supply pons
- Anterior-inferior cerebellar artery (AICA): originates close to lower pons border, runs ventral to 7th and 8th cranial nerves, loops over flocculus, enters internal acoustic meatus, supplies anterolateral inferior cerebellum
- Labyrinthine artery: long, slender, originates from basilar artery or AICA, accompanies vestibulocochlear nerve, enters internal auditory meatus, supplies internal ear
- Superior cerebellar artery: originates close to superior pons border, runs below oculomotor nerve, around cerebral peduncle, below trochlear nerve, supplies superior cerebellum
- Posterior cerebral artery: originates close to superior pons border, runs along superior pons border, around midbrain, to medial cerebral hemisphere under corpus callosum splenium, supplies midbrain, temporal lobe, occipital pole
Branches of Internal Carotid Artery
- Ophthalmic artery: originates from internal carotid artery after exiting cavernous sinus, runs in a U-shaped bend, enters orbit via optic canal, supplies orbit structures, eyeball
- Posterior communicating artery: originates close to internal carotid artery termination, runs backwards, anastomoses with posterior cerebral artery
- Anterior choroidal artery: long, slender, originates distal to posterior communicating artery, runs along optic tract, into lateral ventricle's inferior horn, ends in choroid plexus, susceptible to thrombosis
- Anterior cerebral artery: smaller terminal branch, runs forwards, medially above optic nerve, close to opposite side artery, joined by anterior communicating artery, around corpus callosum genu, supplies medial frontal lobe, orbital surface, medial hemispheres above corpus callosum to parieto-occipital sulcus
- Middle cerebral artery: larger terminal branch, runs lateral in lateral sulcus, backwards and upwards in posterior ramus, divides into frontal, parietal, temporal branches, supplies frontal, parietal, temporal lobes, most susceptible to thrombosis
Metabolic Activity of the Brain
- High metabolic rate with aerobic metabolism of glucose
- 2% of body weight, receives 20% of cardiac output, consumes 20% of total O2
Cerebrovascular Diseases
- Thrombosis, embolism, hemorrhage; 3rd most common cause of death
- Symptoms depend on lesion site
Arteries of the Brain
- Primary arteries: 2 vertebral arteries, 2 internal carotid arteries
Vertebral Arteries
- Enter skull via foramen magnum, unite at pons to form basilar artery, which divides into posterior cerebral arteries
Internal Carotid Arteries
- Enter cranial cavity via carotid canal and foramen lacerum, course through cavernous sinus, end lateral to optic chiasma dividing into middle and anterior cerebral arteries
Circle of Willis (Circulus Arteriosus)
- Formation: anterior communicating artery, anterior cerebral arteries, basilar artery dividing into posterior cerebral arteries, and posterior communicating arteries connecting internal carotid with posterior cerebral arteries
- Location: interpeduncular subarachnoid cistern
- Function: provides collateral circulation if a major artery is blocked
Blood Stream Mixing
- Minimal mixing between vertebral arteries in basilar artery, anterior cerebral arteries in anterior communicating artery, and internal carotid and posterior cerebral arteries in posterior communicating artery
- Supply: right brain by right vertebral and internal carotid arteries; left brain by left vertebral and internal carotid arteries
Collateral Circulation
- Circle of Willis offers alternative routes if blockage occurs
Branches of Vertebral Artery
- Posterior spinal artery: first intracranial branch, originates from vertebral artery or posterior inferior cerebellar artery, descends on spinal cord's posterior surface
- Posterior inferior cerebellar artery (PICA): largest branch, originates near lower end of olive, winds around medulla oblongata, ascends to pontomedullary junction
- Anterior spinal artery: small branch, originates near vertebral artery termination, descends in front of medulla, unites with opposite side to form a single median trunk along spinal cord's anterior longitudinal fissure
- Meningeal branches: small, supply dura mater of posterior cranial fossa
- Medullary arteries: minute vessels, supply medulla oblongata
Branches of Basilar Artery
- Pontine branches: numerous, short, paramedian vessels, supply pons
- Anterior-inferior cerebellar artery (AICA): originates close to lower pons border, runs ventral to 7th and 8th cranial nerves, loops over flocculus, enters internal acoustic meatus, supplies anterolateral inferior cerebellum
- Labyrinthine artery: long, slender, originates from basilar artery or AICA, accompanies vestibulocochlear nerve, enters internal auditory meatus, supplies internal ear
- Superior cerebellar artery: originates close to superior pons border, runs below oculomotor nerve, around cerebral peduncle, below trochlear nerve, supplies superior cerebellum
- Posterior cerebral artery: originates close to superior pons border, runs along superior pons border, around midbrain, to medial cerebral hemisphere under corpus callosum splenium, supplies midbrain, temporal lobe, occipital pole
Branches of Internal Carotid Artery
- Ophthalmic artery: originates from internal carotid artery after exiting cavernous sinus, runs in a U-shaped bend, enters orbit via optic canal, supplies orbit structures, eyeball
- Posterior communicating artery: originates close to internal carotid artery termination, runs backwards, anastomoses with posterior cerebral artery
- Anterior choroidal artery: long, slender, originates distal to posterior communicating artery, runs along optic tract, into lateral ventricle's inferior horn, ends in choroid plexus, susceptible to thrombosis
- Anterior cerebral artery: smaller terminal branch, runs forwards, medially above optic nerve, close to opposite side artery, joined by anterior communicating artery, around corpus callosum genu, supplies medial frontal lobe, orbital surface, medial hemispheres above corpus callosum to parieto-occipital sulcus
- Middle cerebral artery: larger terminal branch, runs lateral in lateral sulcus, backwards and upwards in posterior ramus, divides into frontal, parietal, temporal branches, supplies frontal, parietal, temporal lobes, most susceptible to thrombosis
This quiz covers the cerebrovascular system, including the arteries of the brain, and metabolic activity, including glucose metabolism and oxygen consumption.
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