INTRODUCTION

To complete this assignment, you will need to integrate your knowledge of what you have      learnt about experimental design in Weeks 1- 4 of Research Based Physiology (PHYS20009), together with the principles and knowledge about some of the physiological systems you have learnt in Human Physiology (PHYS20008). It is highly recommended that you review the           information you have learnt from Human Physiology about action potentials, synaptic           transmissions, nerves and muscle integration and skeletal muscles as part of this assignment. From Research-based Physiology (PHYS20009) review your notes from the online videos,        tutorials, workshops and your demonstrator feedback for Practical Workshops 2 - 4. These will all help you prepare for this assignment.

Objectives

The objectives of this task to determine you develop the following concepts in experimental design:

!  hypothesis formulation

!  factors to control for in experimental design

!  model systems appropriate for testing physiological mechanisms           !  data analysis, including data presentation, and statistical analysis choices

These objectives will be determined in the context of the nervous system, nervous control of skeletal muscles, and skeletal muscle function, together with the concepts underlying these physiological systems.

By the end of this task you should also be able to:

•    Develop independent and critical thinking

•   Written communication skills

Reference material

Silverthorne (7th Ed), Chapters 8, 12 and 13.

Tortora and Derrickson (2nd Asia Pacific Ed), Chapters 10.1-10.6, 12.3-12.6, 13.3, 16.2 Human Physiology (PHYS20008) lectures 4 - 6, 9 - 12.

Research-Based Physiology (PHYS20009) lectures 1 - 4

You do not need to cite references for this assignment.

WORD LIMIT: 750 words ± 5%

PART 1:

S,onDAio:

In the Marvel Research Laboratory Dr Hulk has been coming up with a                         secret

formula to turn any animal (human or any mammal) into a super

powerful force. This magic elixir will give the recipient sudoA sdoop

Dnp sudoA s】Aon6】V. He has finally come up with a compound that

he wants to test. Indeed, when he gave the compound to his first

laboratory rats Dr Hulk observed the rats had:

1.   }Ds】oA AoD,】ion 】imos when stimulated‘

2.   they could ,DAA( 6AoD】oA woi6V】)6AoD】oA s】Aon6】V(

3.   and they could carry weight for D lon6oA doAiop o}】imo )6AoD】oA onpuADn,o(.

Dr Hulk wants to test this formula further to determine the site of action for his compound. He wants to determine where the compound might be producing its effects. He wants to identify the si】o o}D,】ion and 】Vo mo,VDnism by which his compound is producing its effects

He has recruited you to his laboratory to help him determine the

i)    si】o o}D,】ion Dnp

ii)   mo,VDnisms o}D,】ion

of his elixir. You are intrigued by this compound and agree to work with him.

ouos】ion T(                                                                                                      )C0 mDA才s(

Using your knowledge of physiology, ipon】i}( b do】on】iDl mo,VDnisms in,lupin6 】VoiAsi】o o} D,】ion where this formula could be working to produce any of the effects observed by Dr Hulk.

No】o: You can choose from any of the observations above. You need to make it clear in your description which observation your proposed mechanism relates to.

!  The physiological mechanisms must be accurate.

!  You may choose any, or all of the observations recorded by Dr Hulk.

!  You do not have to propose mechanisms for each observation but you must identify4

mechanisms that relate to the observations.

!   For example, you may choose to propose 4 mechanisms on how the formula might

increase strength. Or you may propose 2 mechanisms for faster reaction time, and 2 mechanisms on greater endurance. The choice is all yours!

You will be assessed on the appropriateness and accuracy of the mechanism to the               observation indicated, and the explanation for how this mechanism relates to the observation.

To study this potion further, you will need to conduct a number ofexperiments.

Question 2)

Write a manipulation hypothesis for your study, using one of the mechanisms you have identified in Question 1.

!    It should be obvious from your hypothesis which mechanism you have chosen to

examine so you do not need to repeat it here.

!    Remember the components that goes into a good hypothesis.

Question 3)

a)  To test your hypothesis, describe what type ofpreparation (see note below) you would     choose to use in your experiment.                                                                  5 marks

b)  Explain in detail your rationale for choosing this preparation.

!  Justify how will this preparation allow you to test your chosen mechanism. You should be

specific on the sites of action and the mechanism that you are examining.          10 marks

Note: You don’t need to know the exact name of the preparation, but you need to describe whetheryou wish to use cells, tissue, organ or whole organism.

!  You should identify the exact components you wish to include in your experimental model. !  Justify how this preparation will allow you to test your proposedmechanism in your

hypothesis in Question 2.

!  You should explain what you want to test and whether cells, tissue, organ or organism will

allow you to test your proposedmechanism.

!  You should clearly specify how and why this chosen preparation will allow you to test your

proposed mechanism.

Since the observation was initially made in a rat, you will continue your experiment in rats too.

You will be assessed on your logic and explanation for your choice of preparation. You will also be assessed on the continuity with your proposed mechanism (i.e. does your chosen             preparation actually test the proposed mechanism).

[Reflect on the example given above, can it be more detailed? What additional information or   explanation could be provided to better explain how an isolated blood vessel might allow you to specifically test the proposed mechanism?]

Question 4)

Design an experiment to test your hypothesis.

Include (but not limited to) the following points in your experimental design:

!    Consider whether you would use serial or parallel controls and explain your reasoning. !    What factors should be controlled for in the experiments and why?

!    What will you measure and when?

!    Provide a brief experimental timeline of your experimental design.

Be sure to revisit the notes on experimental design and study the feedback provided in your Week 3 In-Class Group Task.

Note: Dr Hulk has an amazing laboratory and has all the equipment you might need. However, this is not a magical lab and reality of what you can observe still applies.

!  You should limit your measurements to factors and mechanisms discussed in Workshop 3 -

Model Systems.

!  Do not worry about HOW you will measure it, or what equipment you will use.

!  Focus on WHATyou will measure and how this will address your proposed mechanism, and

the factors that you should control for in your experimental design.

!  The limitations identified in Week 3 Workshop should be considered and applied in your

experimental design.

!  You will be assessed on the detail of what you are measuring and whether this addresses

your proposed mechanism in Question 2. The appropriateness of your experimental design in answering your hypothesis will also be important. 

PART 2:

Your lab mate, Carly Kul, has been studying the effect of another compound, Lavblod, on the arterial blood pressure of rats. She has some preliminary data that suggests this drug may   lower blood pressure and thus has potential as an anti-hypertensive drug.

She wants your advice on how she should go about presenting and analysing her data to determine if Lavblod is indeed lowering blood pressure. Carly would like to know if the  application of Lavblod is decreasing arterial blood pressure in rats.

Read through her experimental protocol below, look at her data and answer the questions that follow.

Experimental Protocol:

The rats were kept in a constant temperature environment while they were provided with free access to food and water. For 7 consecutive days, the mean arterial pressure of the rats was    measured daily using a non-invasive method (tail cuff). The tail cuff method allowed the        researchers to measure blood pressure in a conscious rat quickly. The new compound Lavblod was given to the rat in their food from day 8 for another 7 days, while mean arterial pressure   continued to be measured from each rat daily.

Experimental Data:

The data table is available on LMS as an Excel Download.

Question 5

Using GraphPad Prism, present Carly’s data graphically and analyse her data statistically. In your answer you should:

!  Include the Graph plotted from GraphPad Prism (export as a JPG image and insert into your

submission)

A.   Explain why you have chosen to present her data in the way that you have chosen

B.   State the type of data analysis that you have included (consider what type of statistical analysis is appropriate for this type of data)

!  Justify your choice with a detailed explanation of the rationale for the statistical

analysis chosen

C.   Report the P-value from the statistical analysis you have conducted using GraphPad Prism.

D.   From your statistical analysis, what is your conclusion from Carly’s preliminary data about the efficacy of her drug Lavblod?

In your answer, you should explain any manipulation (if any) you have done to the data to produce your graphs and statistics. If you have grouped data together, you should identify what data were grouped and how.

In this question ~10 marks is allocated to the graphical presentation of the data including   the rationale, ~10 marks is allocated to the statistical analysis and the relevant explanation.

Note: You will need to think about the organisation of the data and how you copy and paste this data into GraphPad Prism.

First, consider the type of data that is collected and what is the most appropriate type of graph and statistics to present and analyse this data, respectively. Consider the message or