Lab 4-Respiratory System PDF

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Practical 4: the respiratory system 1. DISSECTION OF A SHEEP’S PLUCK Materials          

Sheep’s Pluck (1 for demonstration) Foot pump or bellows Scalpel Beaker of water Microscopes (compound and dissecting) Microscope slides (cross section of trachea and oesophagus) Laptops/Ipads for Visual body and Lab chart (1 between 3 students) Powerlabs (Spirometers) Disposable mouthpieces Noseclips

Dissection The purpose of this activity is:   

to find out about the structure of the lungs to find out how our lungs move as we breathe to relate the structure of the lungs to how they work when we breathe

1)

Note the general shape and size, colour and texture of the lungs.

2)

Identify:  Trachea – the main tube bringing air into and out of the lungs.  Cartilaginous rings in the trachea – these are horseshoe-shaped and keep the trachea open for the passage of air, but allow the tube to bend and flex easily.  The bronchi – the right bronchus leads from the trachea to the right lung and the left bronchus to the other lung.  The first bronchioles – these are the finer tubes dividing off the bronchi.  Any vessels linking the lungs to the heart. Arteries have thick, rubbery walls. Veins have much thinner walls. Feel inside these vessels with your fingers and feel the texture and strength of both vessels. Try to describe what you feel.

BIO1203 Human Anatomy and Physiology

 The pleural membrane – this is a thin layer of connective tissue covering the whole of the lungs.  The pericardium – this is a layer of tissue surrounding the heart. 3) 4)

Try to inflate the lungs and observe how they respond. Cut a small piece of spongy lung tissue to examine more closely. Drop it into a beaker of water and observe it.

Questions 1)

The nutrient blood supply of the lungs is provided by? (a) the pulmonary arteries, (b) the aorta, (c) the pulmonary veins, (d) the bronchial arteries.

2)

Why do you think the lungs float?

3)

The lungs are mostly elastic tissue. What is the role of the elastic tissue?

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BIO1203 Human Anatomy and Physiology

2. PRACTICAL ACTIVITY: EVALUATING LUNG FUNCTION The purpose of this activity is to measure parameters of spirometry that are used in evaluating lung function (using the PowerLab). You will record your results in the table below. Your results

Predicted

%Predicted

Forced Vital Capacity (FVC) (L) Forced Expired Volume in One Second (FEV1) (L) (FEV1 / FVC) x 100 (%)

Procedure: 1) Add the filter to the spirometer and place a noseclip on the volunteer. 2) Start recording. Have the volunteer breathe normally for 30 seconds. Then ask the volunteer to inhale maximally and then exhale as forcefully and fully as possible until no more air can be expired. After a few seconds, the volunteer should let their breathing return to normal. Stop recording. 3) Repeat step 3 twice more, so that you have three separate forced breath recordings.

4) Analyse the recording that you feel looks the best. 5) To calculate the forced vital capacity (FVC) (L), place the Marker on the peak inhalation of “Volume,” and move the Waveform Cursor to the maximal expiration. Read off the result from the Range/Amplitude display, disregarding the negative sign. 6) To measure forced expired volume in one second (FEV1), place the Marker on the peak of the volume data trace, move the Waveform Cursor to a time 1.0 s from the peak, and read off the volume value. Disregard the negative sign.

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BIO1203 Human Anatomy and Physiology

7) Calculate the percentage ratio of FEV1 to FVC for your results. Use the maximum values of FEV1 and FVC, and use the following equation: (FEV1 / FVC) x 100 (%). 8) Calculate the predicted values for FVC and FEV1 using the Table below. For example, using the parameters from the Table, the predicted FEV1 for a 25year-old, 165 cm female would be calculated as: 9) Predicted FEV1 = (0.0342 x height – (0.0255 x age) – 1.578 = (0.0342 x 165) – (0.0255 x 25) – 1.578 = 3.43 L Index

Sex

Height (cm)

Age (years)

Constant

♀

0.0491 x height

-0.0216 x age

-3.590

♂

0.0600 x height

-0.0214 x age

-4.650

♀

0.0342 x height

-0.0255 x age

-1.578

♂

0.0414 x height

-0.0244 x age

-2.190

FVC (L)

FEV1 (L)

10) Calculate the percentage of predicted values using the following equation: Your Result x 100 / Predicted result x 100

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BIO1203 Human Anatomy and Physiology

Questions 1)

How do your measured values compare to your predicted values? What could you do if you found that your values were lower than normal?

2)

Define FVC and FEV1 and what are they measuring?

3)

Select the best answer out of the following: When the inspiratory muscles contract (a) the size of the thoracic cavity is increased in diameter (b) the size of the thoracic cavity is increased in length (c) the volume of the thoracic cavity is decreased (d) the size of the thoracic cavity is increased in both length & diameter.

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BIO1203 Human Anatomy and Physiology

3. COMPUTER BASED ACTIVITY 1 The purpose of this activity is to learn the anatomy of the respiratory system. Resource: Visible Body Atlas (AIO or iPad) Activities: Open the Visible Body Human Anatomy Atlas 1) Click onto quizzes on the top left hand corner.

2)

Click onto the respiratory system quizzes and then 10. Full Respiratory. Undertake the experiment. Press start and after 60 seconds of recording data, click the record data button.

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BIO1203 Human Anatomy and Physiology

1. HISTOLOGY OF THE LUNG The purpose of this activity is to learn the anatomy of the trachea. Procedure: 1) Examine the slide of the cross section of the trachea and oesophagus, using the low power of your microscope. 2) Make a drawing and label the parts of the trachea and oesophagus. Refer to the figure below to assist you with this.

Record what you observe here:

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BIO1203 Human Anatomy and Physiology

Questions 1.

Is the trachea part of the conducting or respiratory zone? What is the purpose of the conducting and respiratory zones?

Select the best answer out of the following:

1. Moving from the mouth to the lungs what is order of the structures? a) larynx → trachea → bronchi → alveoli b) trachea → bronchi → alveoli → larynx c) bronchi → trachea → larynx → alveoli d) trachea → larynx → bronchi → alveoli

2. Which of the following maintains the patency (openness) of the trachea? a) pseudostratified ciliated epithelium b) C-shaped cartilage rings c) surfactant production d) surface tension of water

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BIO1203 Human Anatomy and Physiology

2. DISCUSSION POINTS / NOTES

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