Question 10:

You need to watch the following slowmation before answering the question below:

Multiple Sclerosis is a medical condition that affects the nervous system. It was first described by the French neurologist Charcot in 1868. This disease can, to varying degrees, interfere with the transmission of nerve impulses throughout the brain, spinal cord and optic nerves.

Patients with multiple sclerosis face many difficulties, ranging from moving about and communicating, to pain and digestive issues.
By referring to the slowmation above, and with reference to the transission of nerve signals,  explain why a patient with multiple sclerosis may have difficulty with one of the following: walking, digesting food, or speaking.  
(3 marks).


Sample Answer: 

Human beings have neurons and these neurons are what transmits signals and messages to other parts of the body, to move, talk and digest. 
Multiple sclerosis affects the myelin sheath of the neuron, so the signal cannot travel down the neuron effectively. 

a) For walking, the neuron would normally send the message to a skeletal muscle, as shown in the slowmation. The muscle contracts. In MS, the signal is not transmitted as efficiently, because the nodes of Ranvier of the neuron are affected. Therefore, the person would experience difficulty walking.

b) For digesting food, the neuron would normally send the signal to a salivary gland, as shown in the slowmation. The salivary gland will secrete an enzyme to break down the food. Therefore, in a MS patient, the neuron cannot transmit the signal effectively, and the patient can't digest the food as well. 

c) For speaking, the neuron would need to send the signal to another neuron, as shown in the slowmation. The neuron will then transmit the signal to the mucles in the mouth allowing the person to talk. It is a complicated process, where one neuron communicates with the next. Therefore, in MS,  as the patient's neurons are affected and aren't able to transmit messages as well as normal, the speech becomes slurry and hard to understand. 


The transmission of signals involves neurotransmitter released from the pre-synaptic to the post-synaptic membrane. Therefore, in MS, neurotransmitter release is expected to be delayed, as neurons can't transmit signals as efficiently and quickly as they should in a healthy individual. 

Teacher comment:

This question is a band 6 question. The students needs to extrapolate the answer to an unfamiliar situation, and use cause and effect to explain. Those students who have an extensive understanding of the  transmission of messages across neurons would be able to answer this question easily. I would not  deduct marks if the student  doesn't mention the words in italic, such as Nodes of Ranvier , myelin sheath, and salivary gland. 
They just  need to show me that they understand the process, and how MS affects walking, digesting OR talking. They need need to link the neuron damage to the effect (difficulty walking etc...).

They only need to comment on one of the points above (a, b or c). 

Marking Guidelines:

3 marks: 

Student shows extensive knowledge of how a neuron transmits signals to parts of the body.
Student explains (cause and effect) that a fault in a neuron will lead to a significant outcome, eg difficulty walking, eating  and digesting food.
Student shows understanding of what happens after the signal reaches the synaptic membrane. 
An understanding of the implication of MS on a person's life.


2 marks 

Student demonstrates a sound knowledge of how a neurons transmit signals to parts of the body, with or without reference to the synapse. 
Student   is able to explain how a fault in a neuron can lead to a significant outcome. (cause and effect).

1 mark:
Student demonstrates a sound knowledge that neurons transmit signals to parts of the body, with no reference to how they do so, and, with no reference to any of the points above (a, b, or c).

Further reading 
I have found this link on the BOS ARC website. It is worth reading as it answers a lot of those questions we don't get to ask in class, such as what happens when a student is away for a long time, or a teacher is away on assessment day , and the big questions on grading and behind the scenes at the BOS, and so much more. It is titled 'HSC Assessment in a Standards-Referenced Framework - A Guide to Best Practice.' You can print it out and have a read, or access it online.
http://arc.boardofstudies.nsw.edu.au/go/hsc/

MS is a disease that can affect people we work with, people we look up to, and even family.
How can we help? Check the links below:

http://www.msaustralia.org.au/
http://www.mssociety.org.au/supportus.asp