Support Systems Flashcards
What are the 2 fluid systems that support the neurons and glial cells and overall function of the nervous system?
- Cerebrospinal fluid (CSF) system
- Vascular system
Where is CSF primarily formed?
in the ventricles
Where does CSF circulate before it is absorbed into the venous circulation?
through the ventricles and into the subarachnoid space
What are the 3 meninges that cover the brain and spinal cord?
- Dura mater
- Arachnoid
- Pia mater
Most CSF is secreted by ________ in the ventricles, however some CSF is formed by _______ leaking into the ventricles.
choroid plexuses
extracellular fluid
Describe the path in which CSF flows
1) From lateral ventricles into the third ventricle (via the interventricular foramina)
2) From the third ventricle into the fourth ventricle (via the cerebral aqueduct)
3) From the fourth ventricle into the subarachnoid space (via the lateral and medial foramina)
4) It then flows around the brain and spinal cord until it is reabsorbed into the venous sinuses
What are 3 common disorders of the CSF system?
- Epidural and subdural hematomas
- Hydrocephalus
- Meningitis
What is CVA synonymous with?
stroke
A CVA can be classified by what 3 things?
- pattern of progression
- etiology/cause
- arterial location
What are the 3 patterns of progression?
- Transient ischemic attack
- Completed stroke
- Progressive stroke
What is a TIA?
A brief, focal loss of brain function with a full recovery from neurologic deficits within 24 hours
What is a completed stroke?
neurologic deficits from vascular disorders that persist more than 1 day and are stable
When does a brain infarction occur?
when an embolus or thrombus lodges in a vessel, obstructing the blood flow
Obstructions of blood flow in small, deep arteries result in _____ infarcts
lacunar
Brain infarcts cause __% of strokes.
80
Which cerebral artery has the highest incidence of ischemic stroke?
middle cerebral
Which type of stroke results in the worst deficits within hours of onset?
hemorrhage
What does a subarachnoid hemorrhage cause?
sudden, excruciating headache with a brief (a few minutes) loss of consciousness
Describe blood flow off of the vertebral artery
Basilar artery which is then divided into the posterior cerebral artery
What are the 2 branches of the internal carotid artery?
- Anterior Cerebral Artery
- Middle Cerebral Artery
__% of ischemic strokes affect the brainstem and cerebellar regions
20
What is the chief symptom of vertebral artery dissection?
pain, usually in the posterior neck or occiput and spreading to the shoulders
What are the most common signs of vertebrobasilar artery ischemia?
- gait and limb ataxia
- limb weakness
- oculomotor palsies
- oropharyngeal dysfunction
What are the most common symptoms in cerebellar infarction?
- dizziness and/or vertigo
- an inability to sit upright without support
- difficulty walking
- nausea and vomiting
- dysarthria
- headache
What does a complete lesion of the basilar artery cause?
death
What does partial occlusion of the basilar artery cause?
tetraplegia, loss of sensation, coma, and cranial nerve signs
What does occlusion of the anterior cerebral artery cause?
personality changes with contralateral hemiplegia and hemisensory loss
What does occlusion of the middle cerebral artery cause?
homonymous hemianopia combined with contralateral hemiplegia and hemisensory loss involving the upper limb and face
What is the stereotypic standing posture on the hemiparetic side in patients following middle cerebral artery occlusion?
- adduction at the shoulder
- flexion at the elbow
- extension throughout the lower limb
