Ch. 16 Study Flashcards
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What is a tumor?
A mass of cells whose growth is uncontrolled and that serves no useful function.
Tumors can be malignant (cancerous) or benign (harmless).
What distinguishes malignant tumors from benign tumors?
Malignant tumors are not encapsulated and can produce metastases.
Benign tumors are typically encapsulated.
How do tumors damage brain tissue?
By compression and infiltration, which can destroy brain tissue or block CSF flow, causing hydrocephalus.
From where do most tumors originate in the brain?
From other cells in the brain or from metastases originating elsewhere in the body.
What are the most serious types of brain tumors?
Metastases and gliomas, which are derived from various types of glial cells.
What is a meningioma?
An encapsulated, benign tumor consisting of cells that typically make up the dura mater or arachnoid membrane.
What are tumor initiating cells?
Cells in malignant gliomas that originate from the transformation of neural stem cells.
What is the role of radiation therapy in tumor treatment?
Used after neurosurgery to remove as much tumor as possible and target remaining cells.
What is chemotherapy?
The administration of drugs that cause rapidly dividing cells, such as cancer cells, to die by interfering with their DNA replication.
What is a seizure?
A period of sudden, excessive activity of cerebral neurons.
What can seizures cause if the motor system neurons are involved?
A convulsion, which is uncontrollable activity of the muscles.
What are the two distinctions of seizures?
Partial seizures and generalized seizures.
What are simple partial seizures?
Seizures that cause changes in consciousness but do not cause loss of consciousness.
What is a grand mal seizure?
The most severe form of generalized seizure, accompanied by convulsions.
What occurs before a grand mal seizure?
The person may experience an aura, likely caused by excitation of neurons surrounding a seizure focus.
What is the tonic phase of a grand mal seizure?
The phase where all of a person’s muscles contract forcefully and the person holds a rigid posture for about 15 seconds.
What is an absence seizure?
A generalized seizure where the child may stop what they are doing and stare off into the distance for a few seconds.
What percentage of patients with seizure disorders show evidence of hippocampal damage?
Approximately 50 percent.
What is the most common cause of seizures?
Scarring, which may be produced by an injury, stroke, developmental abnormality, or a growing tumor.
What do nearly all genes associated with seizure disorders control?
The production of ion channels.
How are seizure disorders typically treated?
With anticonvulsant drugs that increase the effectiveness of inhibitory synapses.
What are the two major types of strokes?
Hemorrhagic and ischemic strokes.
What causes hemorrhagic strokes?
Bleeding within the brain, usually from a malformed blood vessel or one weakened by high blood pressure.
