Brain and Cranial Nerves Flashcards
What are the 3 parts of the brain stem?
- midbrain
- pons
- medulla oblongata
What are the 4 lobes of the brain?
- occipital
- parietal
- frontal
- temporal
What lobe of the brain contains the visual cortex?
Occipital lobe
What is the anatomical name for the little brain?
Cerebellum
What is the function of the midbrain?
Motor movements of the eye, and in auditory and visual processing
What is the function of pons?
- control of breathing
- communication between parts of brain
- hearing
- taste
- balance
What is the only cranial nerve that arises directly laterally from the pons?
Trigeminal nerve - CN V
How many pairs of cranial nerves are there?
12
What are protective coverings for the brain and spinal cord?
Meninges
What are the 3 layers in meninges?
- Dura matter
- Arachnoid matter
- Pia matter
Does the dura matter receive pain?
Yes
What are the 2 layers of the dura matter?
- periosteal
- meningeal
What forms when the 2 layers of dura matter come apart?
Dural venous sinuses
What is the feature of the arachnoid matter?
arachnoid granulations which reabsorb CSF
What space contains CFS?
Subarachnoid space
How is CFS constantly recycled?
Via granulations into the dural venous sinuses
Where does the pia matter lay?
follows the contours of the brain exactly
What artery lies between the 2 layers of the dura matter?
Middle meningeal artery
Where does the vertebral artery travel once it has left the subclavian artery?
Travels via the transverse foramina of cervical vertebrae (entering at C6)
Where does the vertebral artery enter the brain?
foramen magnum
What do the right and left vertebral arteries joint together to form?
basilar artery
What does the common carotid artery split into?
right and left internal carotid arteries
Where do the internal carotid arteries enter the brain?
via carotid canal
What is the circle of Willis?
an arterial anastomosis - a network of connecting arteries
What is the importance of the circle of Willis?
If there is blockage of one supply source then the brain will continue to be perfused with arterial blood due to the circle.
What artery supplies the medial aspect of the right cerebral hemisphere?
right anterior cerebral artery
What artery supplies the posterior aspect of the right cerebral hemisphere?
right posterior cerebral artery
What artery supplies the lateral aspect of the left cerebral hemisphere?
Left middle cerebral artery
Where is the confluence of the dural venous sinuses?
the internal occipital protuberance
What sinus becomes the right internal jugular vein and where?
right sigmoid sinus at the jugular foramen
What gland is found between the cavernous sinuses?
pituitary gland
What is the function of cerebral veins?
Return venous blood directly from the brain tissue back towards sinuses
How many ventricles are in the brain?
4
Where is CFS made?
lateral ventricles 1 and 2
What is the function of arachnoid granulations?
recycle CFS
Somatic sensory nerves are from?
skin, mucosa, fascia, bone, skeletal muscle
somatic motor nerves supply?
motor muscle
What nervous system are parasympathetic nerves part of?
autonomic nervous system
Special sensory nerves are from?
special sense organs
What cranial nerves are special sensory?
CN I - olfactory
CN II - optic
CN VIII - vestibulocochlear
What cranial nerves are mixed?
CN III - oculomotor
CN V - trigeminal
CN VII - facial
CN IX - glossopharyngeal
CN X -
What cranial nerves are somatic motor?
CN IV - trochlear
CN VI - Abducent
CN XI - Accessory spinal
CN XII - Hypoglossal
Where do olfactory receptor cells pass through?
Cribriform plate
What is it called where the optic nerves cross over information?
Optic chiasma
What is the function of the olfactory nerve?
sense of smell
What is the function of the optic nerve ?
sense of sight
What are the 2 parts of the visual fields of the optic nerve?
temporal and nasal
What perceives the nasal field of the optic nerve?
temporal part of the retina - no cross over
What perceives the temporal field of the optic nerve?
nasal part of the retina - cross over at chiasma - perceived by right side of brain
What is the function of the oculomotor nerve (CN III)?
Eye muscles (somatic motor)
sphincter pupillae muscle (parasympathetic)
What muscle raises the eyelid?
levator palpebral superioris
How would you clinically test the optic nerve?
pupillary light reflex
What does the trochlear nerve supply?
superior oblique muscle (extra-ocular)
What is the only cranial nerve to emerge from the posterior aspect of the midbrain?
Trochlear nerve (CN IV)
What does the abducent nerve supply?
Lateral rectus muscle (extra-ocular)?
Where does the abducent nerve lie?
junction between pons and medulla
What are the 3 parts of the trigeminal nerve (CN V)?
Va - ophthalmic
Vb - maxillary
Vc - mandibular
Where does the separate motor root of the trigeminal nerve join?
sensory part of Vc at foramen ovale
What is the only cranial nerve to directly emerge from the pons?
Trigeminal nerve (CN V)
Where does the trigeminal motor root sit?
deep to the trigeminal ganglion
What does CN Va supply?
skin of upper face
What does CN Vb supply?
skin of mid face
What does CN Vc supply?
- sensory to skin of most of lower face
- motor to muscles of mastication, ABD, mylohyoid and 2 tensors
What are the 3 cranial fossae?
anterior
middle
posterior
What cranial nerves enter the anterior fossa?
Olfactory CN I
What cranial nerves enter the middle fossa?
CN II - CN VI
What cranial nerves enter the posterior fossa?
CN VII - CN XII
Where does CN Va exit?
superior orbital fissure
Where does CN Vb exit?
foramen rotundum
Where does CN Vc exit?
foraminal valley
What does the trigeminal ganglion contain?
sensory fibres from Va, Vb and Vc join.
cell bodies of CN V peripheral sensory neurones
What is the function of the cavernous sinus?
removes venous blood from the cranial cavity
What artery sits below the trigeminal ganglion at foramen spinosum?
middle meningeal artery
What gland sits inferior to diaphragm sellae?
pituitary gland
