Breathing and Effects of Smoking

Question 1

_____________ require specialised systems to facilitate gas exchange through diffusion

Answer 1

Complex multicellular organisms

Question 2

What is the pathway of oxygen to the red blood cell?

Answer 2

Nostril, Pharynx (nasal cavity), Epigllotis, Larynx (voice box), Trachea, Bronchi, Bronchioles, Alveoli, Capillary Wall, Red Blood Cells, Tissues

Question 3

What happens during inhalation?

Answer 3

• air is taken into the lungs
• diaphragm contracts
• external intercostals contract
• air flows from high to low presssure, therefore into the lungs
• chest cavity increases in volume
• pressure inside decreases
• atmospheric pressure is higher than in the lungs

Question 4

What happens during exhalation?

Answer 4

• air is released from the lungs
• diaphragm relaxes
• internal intercostals contract
• chest cavity decreasess in volume
• pressure inside increases
• air flows from high to low pressure, therefore exits the lungs

Question 5

Inhaled air has (a)_______ oxygen content, (b)_______ carbon dioxide content

Answer 5

(a) higher
(b) lower

Question 6

Exhaled air has (a)_______ oxygen content, (b)_______ carbon dioxide content

Answer 6

(a) lower
(b) higher
+ water vapour

Question 7

What is the atmospheric air composition of inhaled air?

Answer 7

21% oxygen
0.04% carbon dioxide

Question 8

What is the atmospheric air composition of exhaled air?

Answer 8

17% oxygen
4% carbon dioxide
+ water vapour

Question 9

Why do we breathe?

Answer 9

To deliver oxygen to cells and tissues

Question 10

What is diffusion?

Answer 10

Diffusion is the net movement of particles from and area of high concentration to an area of low concentration. This is a passive process and does not require energy

Question 11

What can make the diffusion rate high? (name 4)

Answer 11

• surface area is large
• distance is short e.g. thin alveolar walls (1 cell tick, thin and flat) and thin capillary walls (1 cell thick and flat)
• if air is moist (oxygen dissolves and diffuses faster)
• steep concentration gradient
• good ventilation (breathing)
• low perfusion (blood flow) removes oxygenated blood

Question 12

How are alveoli adapted for gas exchange?

Answer 12

• large surface area
• thin walls
• surrounded by capillaries
• capillaries are one cell thick (short distance for diffusion)
• lots of microvilli
• moist walls

Question 13

Why does exercise increase the rate and depth of breathing?

Answer 13

It is done to meet increased oxygen demand and to remove excess carbon dioxide produced during exercise.

Question 14

What are some effects of smoking?

Answer 14

• can cause lung disease
• damages airways and alveoli
• tar contains carcinogens, which can cause cancer
• smoking can cause stroke and coronary heart disease (CHD)
• damages blood vessels
• clogs arteries - makes heart beat faster & increases blood pressure

Question 15

What is the pleural membrane?

Answer 15

A thin layer of tissue that lines the lungs