Patient A was administered a compound that blocks voltage gated calcium channels.

I really only need help with patient A....

Patient A was administered a compound that blocks voltage gated calcium channels. Patient B was administered strychnine, which inhibits acetylcholinesterase. Patient C was administered curare, which binds to (and blocks) ligand gated sodium channels. Predict the consequences of each of these situations with regard to what is happening at the neuromuscular junction and subsequent muscle contraction. (6 pts.)


Patient A- ****NEED HELP WITH PATIENT A ONLY!!!****

Patient B- At neuromuscular junction continuous presence of acease inhibitor will allow continuous stimulation of muscle fibers. Therefore muscles will stay contracted.

Patient C- Sodium channels blocked would stop contraction of muscle fibers and cause paralysis.



PART TWO

This section is a review of the discussion in lab regarding motor unit summation and multiple wave summation, as well as the Physioex computer experiment performed in lab.

1. Discuss briefly the differences and similarities between motor unit summation and multiple wave summation. (2 pts.)

The difference between motor unit summation and multiple wave summation is that motor unit summation is done by increasing the strength of a stimulus while multiple wave summation is achieved by increasing the frequency of the stimulus.

In addition there are similarities among the both. Muscles are stimulated to contract by electrical signals, usually from the brain. These waves of electricity can be piled on top of each other, causing increased strength and duration of muscle contraction. Motor recruitment involves sending signals to multiple parts of the muscle at once, resulting in one quick, strong contraction. Summation is similar in that it increases contractile force.

2. What is meant by a motor unit ratio? What types of muscles would have a large ratio (1:1,000) and which type would have a small ratio? (2 pts.)

A motor unit ratio is defined as a single motor neuron plus all of the muscle cells it innervates. Motor unit ratios are larger in weight bearing and postural muscles. Types of muscle that would have a larger ratio are the gastrocnemius and quadriceps. Muscles which are used for fine muscle control are small motor unit ratios. Types that would have a small ratio are the eyes and fingers.