4.5 Breathing and gas exchange

Question 1

Why is gaseous exchange so important?

Answer 1

• *** dangerous if carbon dioxide builds up in your body
• Need to get oxygen into your bloodstream to supply your cells for respiration
• Need to get carbon dioxide out from your blood

Question 2

What protects the lungs? What are they surrounded by?

Answer 2

ribcage

pleural membrane

Question 3

What is the % of nitrogen breathed in and out of your body?

Answer 3

in - about 80%

out- about 80%

Question 4

Explain what happens when you breathe out

Answer 4

removes carbon dioxide - rich air from lungs

Question 5

Explain what happens when you breathe in

Answer 5

• oxygen rich air goes into lungs

- oxygen diffuses into bloodstream through gas exchange surfaces of your alveoli

Question 6

Where does gas exchange take place?

Answer 6

alveoli

Question 7

What does the air that you breathe in go down?

Answer 7

Goes through the trachea and splits into two tubes called bronchi (bronchus) one going to each lung.

Question 8

How is air moved out of your lungs

Answer 8

As ribs fall and diaphragm moves up volume of the chest gets smaller = decreased volume means increased pressure in chest so air is forced out the lungs

Question 9

What is the % of carbon dioxide breathed in and out of your body?

Answer 9

in 0.04

out about 4

Question 10

Where does air go when it enters your body?

Answer 10

trachea (windpipe) → bronchi (splits in 2) →bronchioles → alveoli

Question 11

What is the % of oxygen breathed in and out of your body?

Answer 11

in about 20

0ut about 16

Question 12

What separates the thorax from the lower part of your body?

Answer 12

diaphragm (strong sheet of muscle)

Question 13

What is meant by the term gaseous exchange?

Answer 13

Diffusion of gases from an area of high concentration to an area of low concentration

Question 14

LOOK AT DIAGRAM PAGE 60 AND 61

**LEARN ***

Answer 14

LOOK AT DIAGRAM PAGE 60 AND 61

**LEARN ***

Question 15

LOOK AT DIAGRAM PAGE 60 AND 61

**LEARN ***

Answer 15

LOOK AT DIAGRAM PAGE 60 AND 61

**LEARN ***

Question 16

Whats the top part of your body called?

Answer 16

thorax

Question 17

What is the % of nitrogen breathed in and out of your body?

Answer 17

in about 80

out about 80

Question 18

How is air moved in to your lungs?

Answer 18

ribs moved up and out/diaphragm flattens = volume of chest increases= lower pressure in chest
*atmospheric air at higher pressure than chest so air drawn into lungs

Question 19

HOw are gases exchanged in the lungs?

Answer 19

• Lungs contain millions of little sacs = alveoli surrounded by blood capillaries
• Blood passing next to alveoli has returned to lungs from the rest of body so contains lots of carbon dioxide and little oxygen
• Oxygen diffuses out alveolus (high concentration) into the blood (low concentration)
• Carbon dioxide diffuses out of the blood (high concentration) into the alveolus (low concentration) to breathe out

Question 20

Describe adaptions of human gas exchange system and explain how they make it as efficient as possible. - (3 adaptions)

Answer 20

1.Made up of clusters of alveoli (large surface area) - Important for achieving most effective diffusion of oxygen and carbon dioxide
2 Alveoli = rich supply blood capillaries (maintain concentration gradient in both direction)
3 Layer cells between air in the lungs and the blood in the capillaries is very thin (only one cell wide) =Allows diffusion to take place over shortest distance