CNS PT-1 Test II Flashcards
What are the Neuroglia?
Astrocytes (buffers / detoxifiers)
Oligodendrocytes (Produce Myelin)
Ependymal Cells (Produce CSF)
Microglia (Macrophage)
What are the Major Levels of the CNS & ARAS?
Spinal Cord Level
Lower Brain or Subcortical Level (Subconcious level)
- Medula, Pons, hypothalamus, cerebellum, basal ganglia
Higher Brain or Cortical Level
-Cerebral cortex helps direct Lower Brain level
Ascending Reticular Activating System (ARAS)
- Brainstem from medulla to diencephalon
- Relays environmental stimuli to Cerebral Cortex
What is the Role of the Cerebral Cortex?
Performs associative activities such as thinking, learning, and remembering.
What is the Role of the Thalamus?
Interprets sensory messages such as pain, temp, and pressure.
What is the role of the Hypothalamus?
Controls homeostatic functions such as body temp, respiration, and Heartbeat.
What is the role of the Cerebellum?
Coordinates muscle tone, posture, and balance.
What is the role of the Brainstem?
Regulates Heartbeat and breathing, plays a role in consciousness.
Barrier Systems in the Brain.
BBB
A series of high resistance tight junctions between endothelial cells as well as astrocytes with processes on capillary walls
Blood-CSF barrier
Formed by tight junctions between choroid epithelial cells
Both Barriers
Produce cytokines, and Astrocytes can act as APCs
How does Wallerian degeneration work in the PNS?
Post nerve transection, nearby peripheral nerve cells will reinnervate the damages nerve / muscle.
How does Wallerian degeneration work in the CNS?
Macrophages clear, astrocytes enlarge, proliferate, and a glial scar blocking axonal growth.
Reactions of Glial injury.
Astrocytes
Can suffer acute cell injury due to hypoxia/hypoglycemia, and toxic injuries causes cellular swelling.
Oligodendrocytes
Injury or apoptosis of oligodendrocytes is a feature of acquired demyelinating disorders
Intracranial Pressure (ICP)
The pressure inside the cranial cavity.
Normal <or></or>
<p>Intercranial Hypertension (ICH) >or = 20 mmHg</p>
<p> </p>
<p>Components</p>
<p>Cerebral parenchyma 80%</p>
<p>CSF 10%</p>
<p>Blood 10%</p>
</or>
How does the brain manage ICP?
Displacement of CSF into the thecal sac
Decrease of cerebral Venous volume of the Cerebral Venous blood by Vaso Constriction.
Normal Pressure Hydrocephalus
Enlarged ventricular size, but with normal Pressures on Lumbar puncture
Communicating
NPH Idiopathic NPH Pathophysiology
Cerebrovascular disease
-HTN, CAD, and PAD
Decreased CSF absorption
Increased Central Venous Pressure
Neurodegenerative disorder
Secondary NPH Pathophysiology
Intraventricular or subarachnoid hemorrhage (aneurysm or trauma) and prior acute or ongoing chronic meningitis.
Clinical Triad of NPH
Gait Difficulty
Cognitive deficits
Urinary incontinence
Clinical Manifestations of Increased ICP
Global Symptoms
Headache
Decreased consciousness
Vomiting