Biology 🍃 | Gas Exchange in humans | 11

Question 1

What is the difference between respiration and breathing?

Answer 1

Respiration is the chemical reaction that releases energy from glucose by reacting it with oxygen in living cells. Breathing is an anatomical process of inhalation and exhalation: the way that we obtain oxygen and get rid of carbon dioxide.

Question 2

How do we protect the breathing system from pathogens?

Answer 2

From goblet cells, which line the trachea, and cilia beating and pushing mucus up. Pieces of dust get trapped in the mucus, which is wafted up to the back of the throat so that it doesn’t block up the lungs.

Question 3

Gas exchange involves an _ and a _.

Answer 3

Gas exchange involves an alveoli and a capillary.

Question 4

How are gases exchanged in an alveoli?

Answer 4

Deoxygenated blood moves through the capillary, which is parallel to the alveoli, where carbon dioxide diffuses out of the capillary and oxygen (from breathing in) diffuses into the bloodstream.

Question 5

What adaptations do humans have in gas exchange surfaces?

Answer 5

• Alveoli have a large surface area
• A one cell thick wall
• A good supply of oxygen
• A good blood supply

Question 6

How is the blood supply adapted to increase the rate of gas exchange?

Answer 6

There is a constant and fast blood supply provided to the capillaries adjacent to alveoli through the pulmonary artery. This makes it so that there is constantly new deoxygenated blood to be resupplied with oxygen in gas exchange.

Question 7

What is the role of the trachea in the breathing system?

Answer 7

Air passes through the trachea, which goes down the neck into the thorax.

Question 8

What is the proper name for the voice box?

Answer 8

Larynx.

Question 9

What path does air follow from the thorax to the alveoli?

Answer 9

In the thorax, the trachea divides into two branches (the two bronchi), one bronchus to each lung and branching out into smaller tubes called bronchioles.

Question 10

What is the importance of cartilage in the gas exchange system?

Answer 10

• It keeps the trachea stabilized to keep it open and prevent it from losing its form. It keeps it flexible while not rigid so that it doesn’t snap when bent and allows it to expand when filled with air.
• Cartilage at the end of ribs allow them to swing up and down

Question 11

What muscular processes take place during inspiration?

Answer 11

The diaphragm muscle contracts and lowers (this increases thorax volume), and the external intercostal muscles contract, which pulls the ribcage upwards and outwards (this further increases thorax volume). Air thus flows in.

Question 12

What muscular processes take place during expiration?

Answer 12

The diaphragm muscle relaxes and springs up, and the external intercostal muscles relax (dropping the ribcage down), all leading to the volume of the thorax reducing and air being forced out.

Question 13

How does atmospheric pressure play into inspiration and expiration?

Answer 13

When the thorax volume increases, the pressure inside is less than atmospheric pressure, so air from the atmosphere fills in that empty space.

Question 14

When are the internal intercostal muscles used?

Answer 14

During serious exhalation (such as panting or coughing), where the internal intercostal muscles greatly contract, and further drop the ribcage and reduce the volume.

Question 15

What is the diaphragm?

Answer 15

The sheet of muscle that raises and falls to change the size of the thorax.

Question 16

How can we set up an experiment that sets up the differences of inspired vs expired air?

Answer 16

1. Get two test tubes: tube A and tube B
2. In test tube A, have a pipe that connects into the indicator solution, and in pipe B, have that pipe connect to simply the air inside the tube : connect the pipes together in a (TT).
3. Add another, short pipe into tube A that simply connects the air inside the tube to the atmosphere, and another, longer pipe into tube B that connects the solution to the atmosphere.
4. Add corks.

Question 17

How can we carry out the experiment that observes the differences of inspired vs expired air?

Answer 17

1. Using the apparatus set up, breathe in and out gently through rubber tubing: continue doing this till the indicator in one of the tubes changes color
2. The tube in which the second tube is long and connects the liquid to the atmosphere should show that there is more oxygen in inspired air.

Question 18

What are the two indicators usable when testing for the differences of inspired vs expired air?

Answer 18

Limewater or hydrogencarbonate indicator.

Question 19

What are the differences of composition of inspired and expired air?

Answer 19

Inspired air has more oxygen (21% VS 16%)
Inspired air has less carbon dioxide (0.04% VS 4%)
Inspired air’s humidity is variable, whereas it is always high in expired air.

Question 20

What explains the differences in composition of oxygen in inspired vs expired air?

Answer 20

Oxygen is absorbed across the gas exchange surface, then used up by cells in respiration.

Question 21

What explains the differences in composition of carbon dioxide in inspired vs expired air?

Answer 21

Carbon dioxide is made inside respiring cells, diffusing out across the gas exchange surfaces.

Question 22

What explains the differences in humidity in inspired vs expired air?

Answer 22

Gas exchange surfaces, made of mostly living cells, must be kept moist and therefore expired air is more humid.

Question 23

How does exercise have an effect on the rate of breathing?

Answer 23

Cells in our body need oxygen for respiration. This is supplied by the lungs. Therefore, when cells need a lot of oxygen and are quickly respiring in exercise, we breathe in deeper and faster to get more oxygen into blood.

Question 24

How does our brain signal us to inhale and exhale faster when exercising?

Answer 24

Due to high CO2 concentration in our cells, it lowers the pH of the blood and the brain detects this to increase breathing rate and depth.