Topic B- Breathing

Question 1

what is the role of diffusion in gas exchange?

Answer 1

In humans, gas exchange happens all the time in the lungs. The oxygen diffuses from the alveoli into the blood and carbon dioxide from the blood into the alveoli-the carbon dioxide is then exhaled.

Question 2

describe the structure of the thorax

Answer 2

The thorax is the part of your body that lies between your neck and your abdomen (around your stomach), and it includes all of the above. They are vital for gas exchange.

Question 3

describe the structure of the ribs

Answer 3

Your chest wall is supported by the ribs. They are attached dorsally to the backbone in such a way that they can move up and down.

Question 4

describe the structure of the intercostal muscles

Answer 4

Two sets of muscles, the external and internal intercostal muscles, can be found between the ribs. They are antagonistic muscles

Question 5

describe the structure of the diaphragm

Answer 5

The diaphragm, which is a dome-shaped sheet of muscle and elastic tissue, separates the thorax from the abdomen.

Question 6

describe the structure if the trachea

Answer 6

the tube connecting the throat to the bronchi.

Question 7

describe the structure of the bronchi

Answer 7

the trachea divides into two bronchi (tubes). One leads to the left lung, the other to the right lung. Inside the lungs each of the bronchi divides into smaller bronchi.

Question 8

describe the structure of bronchioles

Answer 8

the bronchi branches off into smaller tubes called broncheoli which end in the pulmonary alveolus.

Question 9

describe the structure of alveoli

Answer 9

tiny sacs (air sacs) delineated by a single-layer membrane with blood capillaries at the other end.

Question 10

describe the structure of pleura membranes

Answer 10

pleura membrane is made of two layers; Visceral or Pulmonary pleura covers the outside of the lungs, Parietal or Costal pleura covers inside of the chest wall and extends over the diaphragm.

Question 12

What is the role of the intercostal muscles and the diaphragm, in ventilation?

Answer 12

When you inhale, you…

Relax your

Internal intercostal muscles and

Contract your

External intercostal muscles

When you exhale, your…

External intercostal muscles

Relax and your

Internal intercostal muscles

Contract

Question 13

Explain how alveoli are adapted for gas exchange by diffusion betwen air in the lungs and blood in capillaries

Answer 13

The alveoli have are thin, this allows gasses to diffuse through them easily.
They are small and there are many of them meaning there is a large surface area through which much gas can diffuse at once. It also means there is a lot of surface in contact with the blood stream for gasses to diffuse into.
Alveoli have a moist lining for gasses to dissolve into.

Question 14

Give examples of the consequences of smoking in ralation to the lungs and circulary system, including coronary heart disease.

Answer 14

• Tar can cause cancerous mutations in the lungs.
• Smoke removes the cilia- tiny hairs- which keep the lungs clean.
• Smoking also hardens the arteries, constricting the blood flow and putting strain on the heart, resulting in coronary heart disease.
• lung cancer
• red blood cells become more sticky and are more likely to form blood clots
• heart attack and stroke