Flashcards in Chapter 19 Deck (24):
Support systems of neurons and glial cells:
ventricles, meninges and the cerebrospinal fluid (CSF)
arterial supply, veins and venous sinuses and mechanisms to regulate blood flow
Three layers of meninges that cover brain and spinal cord:
Surrounds the brain and consists of an outer layer firmly bound to the inside of the skull and an inner layer.
Is a delicate membrane loosely attached to the dura.
Is tightly apposed to the surfaces of the brain and spinal cord
What is most CSF secreted by?
Flow of CSF:
from lateral ventricles into 3rd via interentricular foramina
from 3rd to 4th via cerebral awueduct
How does CSF exit the 4th ventricle?
entering the subarachnoid space (SAS) via lateral & medial foramina
Transient ischemic attack
brief, focal loss of brain function with a full recovery from neurologic deficits within 24 hours
neurologic deficits from vascular disorders that persist more than 1 day and are stable
deficits that increase intermittently over time
an embolus or thrombus lodges in a vessel, obstructing the blood flow
causes 80% if strokes
Downstream vessels are deprived of blood, and the extravascular blood exerts pressure on the surrounding brain
causes sudden, excruciating headache with a brief (a few minutes) loss of consciousness
deficits are progressive
Chief symptom of vertebral artery dissection:
pain, usually in the posterior neck or occiput and spreading to the shoulders.
Vertebrobasilar artery ischemia
The most common signs are gait and limb ataxia, limb weakness, oculomotor palsies, and oropharyngeal dysfunction
Occlusion of Anterior Cerebral Artery
personality changes with contralateral hemiplegia and hemisensory loss
Occlusion of Middle Cerebral Artery
homonymous hemianopia combined with contralateral hemiplegia and hemisensory loss involving the upper limb and face (cortical branches)
contralateral hemiplegia that equally affects the upper and lower extremities and the face (the deep branches)
Occlusion of Posterior Cerebral Artery
contralateral hemiparesis, eye movement paresis or paralysis affecting muscles controlling eye movements (midbrain branches)
Complete occlusion of the basilar artery causes
death as a result of ischemia of brainstem nuclei and tracts that control vital functions.
Partial occlusions of the basilar artery can cause
tetraplegia, loss of sensation, coma, and cranial nerve signs