Neurological disorders
Next, we'll cover a few neurological disorders, which involve observable dysfunction in the nervous system: brain tumors, epilepsy, and migraine.
1) First, watch these videos:
2) Then, answer these questions to test your understanding:
1. Which of the following is a cell type that a glioma would most likely originate from?
- A. astrocyte
- B. neuron
- C. Schwann cell
- D. meningeal cell
Show Answer
Correct answer: A
Gliomas are a category of brain tumors that begin in glial cells. The most common glioma is astrocytoma, which arises from the glial cells called astrocytes.
2. The term for a large, long-lasting depolarization followed by a train of action potentials that often precedes a seizure is:
- A. afterhyperpolarization
- B. paroxysmal depolarizing shift
- C. temporal summation
- D. depolarization block
Show Answer
Correct answer: B
A paroxysmal depolarizing shift is a hallmark of epileptiform activity in neurons. It’s characterized by a prolonged depolarization, often lasting hundreds of milliseconds, followed by a high-frequency burst of action potentials. This pattern can be recorded in neurons during seizure onset.
3. In general, neural activity during seizures is:
- A. increased
- B. decreased
- C. unchanged
Show Answer
Correct answer: A
Although mechanisms can vary slightly for different types of seizures, in general seizures are caused by excessive and synchronized electrical activity in the brain. In a typical seizure, large groups of neurons fire at the same time, leading to spikes in neural activity. During a seizure, this abnormal neural activity can spread due to the failure of inhibitory mechanisms, leading to widespread abnormalities in brain function.
4. Which type of seizure begins in a localized region of one cerebral hemisphere, but can spread to involve additional brain areas?
- A. absence seizure
- B. generalized (tonic-clonic) seizure
- C. focal (partial) seizure
- D. myoclonic seizure
Show Answer
Correct answer: C
In seizures called focal seizures, excessive neural activity begins in one specific area of the brain called the seizure focus, but it can also propagate to other areas of the brain.
5. The headache phase of a migraine is typically thought to be attributable to activation of this cranial nerve:
- A. CN V (trigeminal)
- B. CN VII (facial)
- C. CN IX (glossopharyngeal)
- D. CN X (vagus)
Show Answer
Correct answer: A
The headache phase of a migraine is thought to be attributable to activation of the trigeminal nerve, a cranial nerve that acts as the main sensory nerve for the head. The trigeminal nerve supplies a variety of pain-sensitive structures, which might explain the characteristic head and eye pain of migraine. Activation of the trigeminal nerve also prompts the release of neurotransmitters that can dilate cranial blood vessels and further stimulate and sensitize pain receptors.
