Brain and Meninges Flashcards
where is the danger area on the scalp
the loose areolar tissue layer
what is the dura mater
tough outer covering of the brain: periosteal and meningeal layers
what is the arachnoid mater
thin, avascular membrane, enters the longitudinal fissure (between cerebral hemispheres)
what is the pia mater
thin, delicate membrane, closely invests surface of the brain and roots of the cranial nerves
what are the arachnoid granulations
small projections of arachnoid mater through the dura mater to drain CSF
what is the vasculature and innervation to the dura mater
primarily the trigeminal nerve (general afferents) and the middle meningeal artery
what are the leptomeninges
the thin meninges (pia and arachnoid)
where are the trabeculae
they extend downward from the arachnoid and become continuous with the pia mater
what is the only real space within the meninges
the subarachnoid space (CSF and blood vessels fills the space)
what is meningitis
infection of the leptomeninges, usually viral but also bacterial and fungal (route is usually blood borne- or direct trauma, ear or sinus infection)
What are the 5 early and 3 later symptoms of meningitis
early: headache, fever, drowsiness, nausea, stiff neck
later: photophobia, ecchymosis (rash), and seizures
what is the treatment for meningitis
antibiotics for bacterial type
what are some complications of meningitis
brain damage, hearing loss, death in severe bacterial infections
what are diploic veins
they drain the diploic space (veins in the middle of the skull)
what causes a extradural or epidural hemorrhage
middle meningeal artery- usually a blow at the pterion (least common type but recovery is high)
what causes a subdural hemorrhage
bridging veins- usually child abuse (shaken baby) or falls in the elderly. symptoms can be slow to appear and likelihood of recovery is lower
what causes a subarachnoid hemorrhage
cerebral artery- usually a ruptured aneurysm, thunderclap headache, can be rapidly fatal but emergent intervention can lead to a complete recovery
what are the 3 dural partitions
falx cerebri, tentorium cerebelli and diaphragma selli (on sella turcica)
what are dural partitions and their function(s)
projections of meningeal layer of dura mater into the cranial cavity, support/protect/insulate the brain, and provide pathways for venous drainage
what happens in the telencephalon/cerebrum
speech, language, thought, emotion, interprets visual and spatial information (frontal, parietal, occipital, and temporal lobes)
what happens in the cerebellum
coordinates muscle movement and controls balance
what happens in the brain stem (mesencephalon, pons, and medulla oblongata)
reflexes and crucial, basic life functions (heart rate, breathing, blood pressure)
what happens in the diencephalon (thalamus, and hypothalamus)
relay information to appropriate brain centers for processing, control pituitary hormones
what is another name for the pituitary gland
the hypophysis
how many pairs of true cranial nerves are there
10- from the brain stem
which 2 cranial nerves are not “true” cranial nerves
1 and 2: they are CNS projections covered by meninges
where does CN 1 originate from
the cerebrum
where does CN 2 originate from
diencephalon
what do the vertebral arteries supply
the brainstem, cerebellum and posterior part of the cerebrum
what do the internal carotid arteries supply
most of the cerebrum and diencephalon
where do the vertebral arteries come from and go
branch of subclavian arteries, pass through intervertebral foramina C1-6, enter cranial cavity through foramen magnum and form basilar artery
where do the internal carotid arteries come from and go
arise at bifurcation of common carotid artery in neck, enter cranial cavity through carotid canals, pass medially then forward through cavernous sinus,
what is the circle of willis
internal carotid and basilar arteries are joined in anastomotic circle by the posterior communicating arteries and the anterior communicating arteries
what is an intracerebral hemorrhage
rupture of an artery within the brain
what is a subarachnoid hemorrhage
rupture of an artery at the surface of the brain
what is an aneurysm
vessels with a defect, there are no symptoms of an aneurysm until it ruptures
what are symptoms of a ruptured intracranial vessel
thunderclap headache, neck stiffness, and vomiting
what are the treatments for a ruptured intracranial vessel
control intracranial pressure; surgery to ligate the artery if it is accessible; endovascular procedure for deeper ruptures
what is a cerebrovascular accident
medical term for a stroke
what is a less common type of a cerebrovascular accident
a ruptured intracranial vessel
what is a more common type of a cerebrovascular accident
a blocked cerebral vessel (70-80%)
what is a cerebral thrombosis
clot forms within the brain, usually because of atherosclerosis of cerebral artery
what is a cerebral embolism
clot travels from elsewhere, usually from atherosclerosis of carotid bifurcation or atrial fibrillation
what are some symptoms of a blocked cerebral vessel
onset sudden and severe for an embolism, more gradual for a thrombosis: blurry or decreased vision, severe headache, weakness, numbness or paralysis (usually one side of body), dizziness, loss of balance or coordination
what is a treatment for a blocked cerebral vessel
clot-busting therapy
what are 3 foramens that emissary veins exit the skull
parietal foramen, occipital foramen and mastoid foramen
what happens if the internal carotid artery ruptures in the cavernous sinus
there is an anterio-venous fistula
where is the CSF produced
in the choroid plexus (all ventricles)
where does the CSF circulate
in the subarachnoid space
how is the CSF returned to the venous system
through the arachnoid granulations
what is hydrocephalus
increase in CSF, usually from partial obstruction of flow or decreased absorption related to inflammation or bleeding within ventriclesputs pressure on the brain
what can cause infants to have hydrocephalus (3)
premature birth, infection during pregnancy, abnormal development of CNS
what are the symptoms of infant hydrocephalus
unusually large head, bulging fontanelle, eyes fixated downward, sleepiness, poor feeding
when do kids and adults get hydrocephalus
lesions, tumors, meningitis, mumps, stroke, trauma
what are the symptoms of hydrocephalus in kids and adults
headache, impaired vision, loss of balance, sleepiness, and cognitive decline
what is the treatment for hydrocephalus
shunt from ventricle to abdomen or heart, ventriculostomy
What branches does the internal carotid give off as it makes its way to the cavernous sinus
posterior communicating arteries, middle and anterior cerebral arteries
