Gas exchange (animals) Pg33-35

Question 1

Where are the lungs located

Answer 1

Thorax

Question 2

What is the thorax

Answer 2

Thorax is the top part of your body

Question 3

What are the lungs surrounded by

Answer 3

pleural membranes

Question 4

What are the lungs protected by

Answer 4

The ribs

Question 5

Where are the intercostal muscles located

Answer 5

The intercostal muscles run between the ribs

Question 6

What is the name of the windpipe

Answer 6

the trachea

Question 7

What is the 2 junctions at the end of the trachea called

Answer 7

The bronchi, each one is called the bronchus, one going to each lung

Question 8

What does the bronchi split into

Answer 8

They split into smaller tubes called the bronchioles

Question 9

what does the bronchioles finally end into

Answer 9

little air bags called the alveoli, this is where gas exchange takes place

Question 10

What happens when you breathe in

Answer 10

• Intercostal muscles contracts (pulls the ribcage up and out)
• diaphragm contracts (flattens)
• Thorax volume increases
• Pressure decreases and draws air in

Question 11

What happens when you breathe out

Answer 11

• intercostal muscles relax (pulls ribcage in and out)
• diaphragm relax (moves into dome shape)
• Thorax volume decreases
• Air is forced out

Question 12

How do you investigate the effect of exercise on breathing rate

Answer 12

• sit down for 5 minutes
• count the number of breaths you take in 1 minute
• do 4 minutes of exercise (running)
• as soon as you stop count your breaths for 1 minute
• repeat and work out mean average for resting and after exercise
• control variable such as same person you are experimenting on and room termperature
  RESULTS:
• breathing rate increases after exercise

Question 13

Why does breathing rate increase after exercise

Answer 13

Your muscles respire more during exercise. They need to be supplied with more oxygen and have more carbon dioxide released, so breathing rate increases

Question 14

How do you investigate the release of carbon dioxide in your breath

Answer 14

• limewater is a solution which turns cloudy if carbon dioxide is present
• Set up two boiling tubes with equal amounts of limewater in each
• connect the boiling tubes with a bung and a mouthpiece
• breathe in and out separately several times
• as you breathe in, air is drawn for boiling tube A, this air contains very little carbon dioxide so it remains colourless
• when you breathe out, the air you exhale bubble through the limewater in tube B. This air contains carbon dioxide produced during respiration so the limewater turns cloudy

Question 15

What gases diffuse in and out of alveoli

Answer 15

Carbon dioxide diffuses out from the blood to the alveoli and oxygen diffuse into the blood from the alveoli

Question 16

How are alveoli adapted for gas exchange

Answer 16

• millions of alveoli so it increases surface area a lot
• moist lining in which gases can dissolve in
• 1 cell thick walls, so short diffusion distance meaning quicker gas exchange
• good blood supply so maintains a high concentration gradient
• wall are permeable - gases can diffuse across easily

Question 17

What can smoking affect

Answer 17

your lungs and circulatory system

Question 18

What can smoking (in general) damage in your lungs

Answer 18

walls of the alveoli, reducing the surface area for gas exchange and leading to diseases such as emphysema

Question 19

What can tar in cigarettes do to your lungs

Answer 19

The cilia (little hairs) in your lungs and trachea. These hairs, along with mucus, catch a load of dust and bacteria before they reach the lungs. The cilia also help to keep the trachea clear by sweeping mucus back towards the mouth. When these cilia are damaged, chest infections are more likely.

Tar also irritates the bronchi and bronchioles, encouraging mucus to form which cannot be cleared easily by damaged cilia - this causes smoker’s cough and chronic bronchitis

Question 20

how does the carbon monoxide from cigarettes affect your lungs

Answer 20

reduces the amount of oxygen the blood can carry. To make up for this the heart beats faster - which leads into increase in blood pressure. High blood pressure damages the artery walls, making the formation of blood clots more likely. Increases the risk of coronary heart disease e.g. heart attacks

Question 21

What chemical does Tobacco smoke also contain

Answer 21

carcinogens - chemicals that can lead to cancer