BioK notes for IG - 2g Gas Exchange in Humans

Exexel IG Bio 2g Gas exchange in Humans

Gas exchange in Humans (2g)

Learning outcomes (Students will be assessed on their ability to):

2.44 describe the structure of the thorax, including the ribs, intercostal muscles, diaphragm, trachea, bronchi, bronchioles, alveoli and pleural membranes

2.45 understand the role of the intercostal muscles and the diaphragm in ventilation

2.46 explain how alveoli are adapted for gas exchange by diffusion between air in the lungs and blood in capillaries

2.47 understand the biological consequences of smoking in relation to the lungs and the circulatory system, including coronary heart disease

2.48 describe experiments to investigate the effect of exercise on breathing in humans.

N.B. The workbook is strucutured in two parts. The first outlines activities that will help you develop notes that can be used later for revision. The second is a set of summary questions designed to help you test your understanding.

https://bioknowledgy.wikispaces.com/ (Chris Paine)

https://bioknowledgy.wikispaces.com/


Note development

2.44 describe the structure of the thorax, including the ribs, intercostal muscles, diaphragm, trachea, bronchi, bronchioles, alveoli and pleural membranes

1. Add a label (k) to show the location of the pleural membrane.




2. Complete the table to label and annotate all the parts of the respiratory system:

Letter Structure Outline the function

a abdomenAbdominal muscles assist in breathing, they relax to aid inhalation and contract to aid exhalation.n.b. this is an extension to what is required at IGCSE

b

c

d

e

f

g

h

i

j

k Pleural membrane

2.45 understand the role of the intercostal muscles and the diaphragm in ventilation

3. Define (using the Bioknowledgy key term flashcards) the following key terms: Breathing:

Ventilation:

Inhalation:

Exhalation:



http://quizlet.com/_cf69y


4. Complete the table below to describe the key events of involved in ventilation:

Inhalation Exhalation

Diaphragmrelax (rises, becomes dome shaped)

Abdominal muscles (not required at IGCSE)

relax contract

External intercostals muscles

Internal intercostals muscles

Lung Volume

Air pressure in lung increases

Movement of Air

Diagram / screenshot

2.46 explain how alveoli are adapted for gas exchange by diffusion between air in the lungs and blood in capillaries

5. Define (using the Bioknowledgy key term flashcards) gas exchange:



http://quizlet.com/_cf69y


6. Capillaries deliver deoxygenated blood to and carry oxygenated blood from the alveoli of the lungs. The diagram below show a simplified diagram of gas exchange occurring in an aveoli.

Adapted from i-Biology (http://i-biology.net/ibdpbio/06-human-health-physiology/03-gas-exchange/)

Label the diagram. Include the following: oxygen carbon dioxide aveoli alveolus capillary red blood cell (erythrocyte) lining of the alveolus (one cell thick) lining of the capillary (one cell thick) oxygenated blood leaving deoxygenated blood arriving carbon dioxide diffuses from the blood to the air in alveolus oxygen diffuses from the air in the alveolus to the blood



http://i-biology.net/ibdpbio/06-human-health-physiology/03-gas-exchange/


7. Explain how the structural adaptations of alveoli suit them to their function of gas exchange:

Thin wall -

Rich capillary network -

Increased Surface area : Volume ratio -

Moist -

n.b. you can remember these structural adaptations by remembering them as TRIM.

8. How is the concentration gradient of oxygen and carbon dioxide maintained between the alveolus and the blood?




2.47 understand the biological consequences of smoking in relation to the lungs and the circulatory system, including coronary heart disease

9. Complete the table to summarise the key biological consequences of smoking. Refer to the green book (Edexcel IGCSE Biology) p30 - 34 and the C4B video for help.

Disease / Effect

Symptoms Linked to smoke particles, tar, nicotine or carbon monoxide?

How do the components of cigarette smoke cause/increase the risk of acquiring the disease?

Bronchitis cilia damaged by chemicals in the smoke

smoke particles irritate the lining of the airways causing more mucus to be secreted

Mucus is not cleared properly Infections (e.g. pneumonia) of

the lung become more likelyEmphysema shortness of breath

mild exercise such as walking becomes very difficult

No cure, usually results in death

Lung cancer Tar (contains carcinogens)

Carcinogens damage/mutate the DNA of cells

Damaged cells begin to divide uncontrollably forming tumors

Heart Disease

Low birth weight



http://youtu.be/1x-_jusxsSc


2.48 describe experiments to investigate the effect of exercise on breathing in humans.

n.b. this experiment is best done in pairs. Be careful not to exercise to hard and also make sure you talk to your teacher before participating if you have asthma or any other condition that affects your breathing.

10.Sort the statement below into a useable method to determine the volume of a normal breath.

Order Step

Inset the end of a plastic tube into the neck of the bottle.Empty the water bottle.Breathe a normal breath out. The air breathed out should displace some of the water in the bottle.Pour the water from the water bottle into a large (1l) measuring cylinder.

volume (ml/cm3) of water in the measuring cylinder = volume (ml/cm3) of a normal breath.Mark a line to show the level of the water.Carefully unscrew the cap.n.b. whilst the neck of the bottle remains under water the bottle should stay full of water.Fill a large plastic soft drink bottle (1l) completely with water and screw the cap in place.Invert the drinks bottle and place just the neck of the bottle under water in the sink (or trough).Fill the water bottle up to the marked line.

11.Carry out the method to determine the volume of a normal breath and record the result below.

Volume of a normal breath = ___________ cm3




12.Take a photo of the setup before you breath out and a photo afterward you have breathed out. Label the photos and paste them below. The photos will help you remember how to use the equipment more clearly.




13.Measure the number of breaths you take each minute, both at rest and after 1 minute of exercise. Using the volume of breath and breaths per minute calculate your breathing rate. Record all the results in the table below.

Breaths per minute

Breathing rate (cm3 per minute)

= breaths per minute x volume of each breath

At rest

After 1 minute of exercise

14. Identify and explain three weaknesses/limitations with either the method or the equipment. Suggest an improvement for each weakness.

a.

b.

c.




Summary questions:

1. The diagram shows parts of the human thorax.

a. Name structures labeled. (2)

X ______________________________________

Y ______________________________________

b. People with asthma sometimes have difficulty in breathing. This happens when the small air tubes of their lungs become narrow. This makes it more difficult to get air into and out of their lungs. Name the small air tubes in the lungs. (1)

____________________________________________

It is possible to find out how asthma affects breathing by using apparatus called a peak flow meter. The person breaths as hard as possible into the meter as shown in the diagram below. If the person has asthma, low readings are obtained.

c. What is the reading on the peak flow meter? (1)

_______________________________________




Readings were taken every morning and evening for seven days from a healthy person and from a person with asthma. The results are shown on the peak flow chart below.

d. Use the chart to find the day on which breathing was most difficult for the person with asthma. (1)

_______________________________________________

e. The healthy person’s readings are different from the person’s with asthma. State two ways in which they are different. (2)

f. A person blowing into a peak flow meter obtained a reading of 230. Does this suggest that this person suffers from asthma? Explain your answer. (2)

g. Drugs used to relieve asthma are called bronchodilators. Suggest what these drugs do. (1)

2. The diagram shows the human respiratory system.

a. Label the structures. (4)




b. Complete the following sentences to describe the exchange of gases takes place in the alveoli of the lungs. (4)

There are millions of alveoli which give a very large

_______________________________________________.

It is here that_______________________________________________ from the air passes into the

blood through the very thin walls of blood vessels called

_______________________________________________.

At the same time _______________________________________________ leaves the blood.

3. List A names some of the structures in the thorax. List B gives the function of each structure, but in a different order. Draw a straight line from each structure in List A to its function in List B. One has been done for you. (3)

4. Complete the passage by writing a word, or words, in each empty space. (5)

To breathe in, the _______________________________________________ muscles contract. This

moves the _______________________________________________ upwards and outwards. The

_______________________________________________ moves downwards. These movements

_______________________________________________ the volume of the lungs. The

_______________________________________________ of the air in the lungs decreases and air

moves in from outside.




5. Join each of the listed structures from the respiratory system to its correct function. (4)




6. Explain how the movement of the rib cage and diaphragm causes air to move into the lungs. (3)

7. Changes take place in the thorax to cause inhaling.

a. Name the type of tissue that makes up most of the diaphragm. (1)

b. Explain how the change in the position of the diaphragm causes inhaling. (2)




8. The structure of the thorax is shown below.

a. Label the structures of the thoracic cavity. (5)

b. Through which structure does oxygen enter the blood? (1)

9. Number the list below to correctly order the processes involved in inhaling.

Step Process

The volume of the thorax increases

Air is sucked into the lungs

The diaphragm muscle contracts and moves down

The air pressure inside the thorax decreases




10. The diagram shows alveoli in a lung.

a. Name TWO features of an alveolus which are essential for efficient gas exchange. (2)

b. Explain how gases are exchanged in an alveolus. (3)

11. Gas exchange takes place in an alveolus.

a. Name gas X. (1)

b. name gas Y . (1)

b. Gas Y is a product of respiration. Name another product of respiration is also breathed out. (1)




12. After sprinting 100 metres Faisa is breathing heavily. Also, she has cramp in her leg muscles. Explain why Faisa has cramp. (4)

13. The table shows the amount of carbon monoxide in the blood of car drivers in a city during the day and during the night.

a. Name two sources of the carbon monoxide in the blood of the drivers. (2)

b. Suggest why people driving during the day have more carbon monoxide in their blood than people driving during the night. (1)

c. The table lists parts of the breathing system. Tick one box to show the part where carbon monoxide passes into the blood. (1)

c. Carbon monoxide is poisonous. It combines with haemoglobin in red blood cells. Explain why this is harmful to the body. (2)


part of breathing system tickalveolibronchidiaphragmribstrachea



14. Nicotine is an addictive drug found in tobacco. It enters the blood when tobacco smoke is inhaled. Nicotine is broken down by an enzyme and its effect stops. In some people the enzyme works quickly. In other people the enzyme works slowly. The graph shows nicotine levels in the blood of two smokers, Sharon and Tracey.

a. The graph shows that Sharon smoked five cigarettes. How many cigarettes did Tracey smoke?(1)

b. The enzyme for breaking down nicotine works more slowly in Sharon. How does the graph show this? (1)

c. Why did Tracey smoke more cigarettes than Sharon? Use only the information given above. (1)

d. A company is producing a substance that will make the enzyme work more slowly. If smokers use this substance, it may help to reduce the number of cases of lung cancer. Suggest how this could happen. (3)




e. Research over many years has shown that smoking cigarettes causes several diseases. Name one disease that can be caused by smoking cigarettes. (1)

15. Patches and gum are two methods used to help people stop smoking. Three groups of smokers took part in trials of these methods. The results are shown below.

average number of cigarettessmoked on

group method day 7 day 14 day 211 wear patch 2 5 42 chew gum 3 8 83 no help 6 15 12

a. Why is group 3 needed in this experiment? (1)

b. Suggest why many smokers find it difficult to give up smoking. (1)

c. Cigarette smoke damages cilia that line the internal membranes of the lungs. Explain why damage to cilia increases the risk of lung infections. (2)

d. Choose words from the box to complete the following sentence.(2)

cancer cystic fibrosis emphysema measles

Smoking cigarettes causes diseases such as ______________________________ and

______________________________

e. Name of one part of tobacco smoke that damages lung cells. (1)



BioK notes for IG - 2g Gas Exchange in Humans

Health & Medicine

Transcript of BioK notes for IG - 2g Gas Exchange in Humans