POST-LAB DISCUSSION: Lung Dissection

1. Check completed observations (handout).

2. Write statement re: assigned question on A3 paper. Present to the class.

3. Summarize lung structure, behavior and interconnection (Respiration systems chart and video clip).

4. Build model (handout to be completed next lesson)

1. Locate the trachea. What do you observe about its structure? What other structures are found near the trachea?

2. Follow the trachea down to locate the right and left bronchus. Note size difference between trachea and bronchi.

3. Feel the texture of the lungs. Gently squeeze them. What makes them feel like this? Compare the texture of the lung tissue with the trachea. Why are they built of different tissue?4. Are the two lungs of the same size?5. What do the lungs contain? You may not be able to identify specific structures- remember the alveoli are very small (however, when spread out ,they cover the size of a tennis court. THINK!! Surface area). Describe the tissue.6. Locate the position of the heart- you will see the severed arteries and veins. Do you think there is a relationship between the large tube lying between the lungs and the severed arteries/veins? Can you name this tube?7. Look more carefully at the cut edge of the lung. Examine it carefully. Is there a structure that covers the lungs?8. Gently insert the rubber tubing down the trachea and one of the bronchi and

gently blow into the tubing, watching for the lung to inflate a little. Do not over inflate. Notice the elasticity of the tissue. How is the lung designed to perform its behavior?

Procedure:

1. Explain how the design of the following structures relates to its behavior. a. Why is the trachea made up of rings of cartilage? b. What is the main difference between the esophagus and the trachea? c. Do the bronchi have cartilage reinforcing? Explain.

2. The lung is an ideal structure for gas exchange in land-based organisms. Describe the feel and appearance of the lung tissue. How is its shape related to its behavior? What other features make the lung efficient in its work?

3. One function of the small intestine is to absorb food. One function of the lungs is to absorb oxygen. Point out the basic similarities in these two structures that help to speed up the process of absorption.

4. Trace the pathway of air as it enters the nasal passages to the lungs and back.

5. Name the small air sac where O2 and CO2 are exchanged. Describe changes in blood composition as these gases pass through these structures in the lungs.

6. Describe a situation where a structure is affected by disease or an injury. What are possible consequences to its behavior?

DISCUSSION QUESTIONS:

RESPIRATORY

TRACT

Bronchi

Epiglottis

TRACHEA

TUBULAR PASSAGEWAY FOR AIR

Bronchioles

http://www.youtube.com/watch?v=HiT621PrrO0

Respiration Video

Building A Model Lung

1. Design your own working model of the lung using the materials given below:

transparent plastic bottle, balloon, rubber sheet (plastic glove), clay, Y-tube, tape/ rubber band, other accessories

2. Complete the handout for the model building activity.

DIAPHRAGMDome-shaped muscle attached to rib cage that contracts& flattens out during breathing

Observe what happens to the

diaphragm.

BREATHING

Air Composition

Inhaled air

Nitrogen N2 – 79%

Oxygen O2 – 20%

CO2 – 0.04%

Others - 0.96%

Exhaled air

Nitrogen N2 – 79%

Oxygen O2 – 16%

CO2 – 4%

Others - 1%

Breathing in - inhaling

• Rib cage– expands

• Diaphragm– moves downward

• Pressure– reduces inside lung

• Result – air is drawn into the lungs

Breathing out - exhaling

• Rib cage– contracts

• Diaphragm– moves upward / inward

• Pressure– increases inside lung

• Result – air is pushed out of the lung

Breathing – The Lungs• Breathing animation

Write a paragraph explanation/ summary on how breathing works. Discuss the role of the ribcage and the diaphragm and how these creates a pressure difference so breathing can take place.

"nature hates a vacuum" http://www.biosci.ohiou.edu/introbioslab/Bios170/diffusion/Diffusion.html

Breathing – The Alveoli

• Diffusion– The movement of gas from an area of

high concentration to an area of low concentration.

http://patrickpoon.com/etp/Diffusion.html