Neuroanatomy Quiz Lecture 14

The arterial blood is supplied to the brain through two systems:

vertebral and carotid systems

The arteries course through the

subarachnoid space

Oxygenated blood reaches the carotid and vertebral through the

aorta

Anterior communicating artery

communication between the two hemispheres

Anterior choroidal artery

direct branch from internal carotid artery, supplies the choroid plexus of lateral ventricles

Common carotid artery

external carotid artery (goes to face and neck) and internal carotid artery

The aorta sends oxygenated blood to the

right carotid artery from the brachiocephalic trunk and left carotid artery from the aorta

Vertebral arteries arise from

the subclavian arteries

Internal carotid artery gives rise to 4 arteries:

ophthalmic (structures in orbit, forehead skin and nose bridge), retinal (retina), anterior cerebral (anterior cerebral hemisphere ipsilateral frontal portion). middle cerebral (ipsilateral, temporal, parietal, and frontal lobes)

Anterior communicating branch

connects anterior cerebral arteries of both brain hemispheres

Posterior communicating branch

connects the posterior cerebral arteries to the internal carotid arteries

Lenticulostriate artery

from middle cerebral artery, supplies the internal capsule and basal ganglia

Vertebral arterial system arises from the

subclavian arteries

The artery supplies to

brain stem, cerebellum, occipital lobe, parts of thalamus

Initial branches of vertebral arterial system are

posterior inferior cerebellar artery and anterior spinal artery

Basilar artery are

vertebral arteries from left and right join to form this, along the anterior ventral surface of the brain

Basilar artery from posterior to anterior

anterior inferior cerebellar arteries, labyrinthine arteries (supplies the inner ear) internal auditory, pontine arteries, superior cerebellar arteries, posterior cerebral arteries (supplies occipital region of ipsilateral side)

Cerebral arterial circle of willis

surrounds the pituitary, mammillary bodies and optic nerves

Arteries in circle of willis

anterior communicating, left anterior, left internal carotid, left posterior communicating, left posterior cerebral, and basilar artery

Areas and parts of the brain that the branches of the arteries innervate: anterior cerebral artery

anterior frontal lobe, medial structures, extends along corpus callosum

Areas and parts of the brain that the branches of the arteries innervate: middle cerebral artery

internal structures and lateral aspects of cerebrum, insula and lateral fissure

Areas and parts of the brain that the branches of the arteries innervate: posterior cerebral artery

occipital lobe, third and fourth lateral ventricles

Venous drainage

removing blood from the cranial activity, remove waste products, maintains the CSF volume and pressure in the head

Path of venous drainage

small veins on the surface of the brain, to dural venous sinuses (jugular foramen of the skull to internal jugular vein) and ophthalmic veins and facial veins

Parts of the auditory system

outer, middle, and inner ear

Outer ear

collects sound waves

Middle ear

tympanic cavity, contains 3 ossicles (malleus, incus, and stapes), ossicles conduct vibrations between tympanic membrane and oval window of inner ear and modify sound before it reaches cochlea, 2 muscles attached to the malleus (tensor tympani muscle) and stapes (stapedius muscle) can contract to reduce the vibration reaching the cochlea

Inner ear

osseus labyrinth, inside the temporal bone, containing fluid called perilymph, membranous labyrinth contains endolymph, houses the semicircular canals, vestibule containing utricle, saccule, and cochlea, communicates with middle ear through the oval window and round window, contains cochlea for hearing and vestibular apparatus for balance and positional sense

Auditory system pathway

hair cells to bipolar neurons to brainstem cochlear nuclei to MGN of thalamus to primary auditory cortex (Area 41) in superior temporal gyrus

Main layers of the eye

fibrous tunic (cornea and sclera), vascular tunic (choroid, iris, lens, and ciliary body), neural tunic (retina)

Main layers of the retina

optic nerve fiber layer (axons to optic nerve (II)), ganglion cell layer, inner plexiform layer, inner nuclear layer (bipolar, horizontal, and amacrine cells), photoreceptor cell layer

Eye accomodation

change of lens thickness to focus the light onto retina

Brain regions important in vision

primary visual cortex (area 17, occipital lobe), parietal cortex (‘where’ information), and lateral temporal cortex (details of the visual input such as letters, numbers, etc.)

Optic chiasm

both eyes visualize both sides of the visual field, optic tracts contain axons from contralateral visual field