Anatomy Unit III Scenarios

Dr. Westwood experienced tingling and eventually numbness in his lips. Which of the following is an appropriate medical term for this feeling of tingling.

parasthesia

Which of the following disorders also results from an infection of anterior gray horn neurons?

polio

Depolarization of the neuron occurs when ______.

positively charged sodium ions rush into the neuron

Based on the anatomical location of the blisters, which of Sarah's peripheral nerves is affected by this disease process? (Hint: see chart on page 445 of our textbook)

posterior femoral cutaneous nerve

What type of��pathway is transmitting the impulse that results in the feeling of paresthesia in Sarah's thigh?

somatic sensory

After recovering, Dr. Westwood decided to learn more about neurotoxins. In conducting his research, he learned about a toxin called batrachotoxin (BTX). BTX also binds to voltage-gated sodium ion channels. Dr. Westwood reviewed experiments with neurons exposed to BTX, which showed that after depolarizing, the membrane potential remained positive for an extended length of time. Repolarization of these neurons was often extremely delayed. Which of the following could help explain this result?

BTX prevents voltage-gated sodium ion channels from inactivating.

If West Nile virus invades the anterior gray horn of the spinal cord, what cells types and parts would most likely be damaged?

Cell bodies of motor neurons

Which of the following is the most reasonable explanation for why meningitis (an infection in the meninges) would damage the spinal cord?

Meningitis would create physical pressure on the spinal cord due to inflammation

Paralysis is a term used to describe the loss of muscle function. If tetrodotoxin's effect is on neurons, why did Dr. Westwood experience paralysis?

Muscles contract after receiving signals from motor neurons. Since TTX prevents the generation of action potentials in these neurons, the ability of a motor neuron to generate this signal will be inhibited. The result would be the emergence of paralysis in the affected areas. Sodium ions also contribute to the action potential generated in muscle cells, so TTX inhibits muscle activity directly.

A patient with severe West Nile virus impacting the anterior gray horn would likely exhibit

Paralysis of some muscles

Which spinal nerve root(s) are most likely to be involved?

S1-S3

Which of the following describes why Dr. Westwood experienced paralysis?

The tetrodotoxin prevented the motor neurons from sending signals to skeletal muscle.

Which of the following best describes a voltage-gated sodium ion channel?

a protein embedded in the cell membrane of a neuron

Define the term ischemia.

abnormal decrease in blood flow to an organ

Based upon the historical and physical exam findings, what specific language area (functional area) of Samuel's cerebral cortex has been damaged as the result of his stroke?

left Broca's area

Based upon Samuel's right hemiparesis, what specific anatomical area of Samuel's cerebral cortex (including right or left) has been damaged as the result of his stroke?

left precentral gyrus

When a neuron is at rest, the cytoplasmic (inside) side of the cell is ______.

negatively charged relative to the outside of the cell

Which region of Sarah's cerebral cortex is active during the perception of her pain? (Hint: You may need to look in chapter 13 for help with your answer. Also, look at the names of the areas. They tell you something.)

primary somatosensory cortex