William Lee

Biology- B5 Gaseous Exchange

Key VocabularyTrachea: Also known as the wind pipe.

Trachea

Larynx: The part of the throat that contains the vocal cords. Also known as the voice box.

Epiglottis: A piece of cartilage at the root of the tongue which descends to cover the windpipe during swelling.

Bronchioles: Tiny branches into which bronchus divides into.

Diaphragm: The muscle layer inside the body that separates the chest from the abdomen.

Alveolus: Alveolus are bunch of tiny air sacs

Bronchioles

Alveolus

Aerobic respiration: This is when oxygen is used during the breakdown of glucose. The glucose is oxidized so it is completely broken down to form carbon dioxide and water. A lot of energy is released.

Anaerobic respiration: Take places in animal and plant cells when there is insufficient oxygen. The glucose is only partly broken down. In animals to lactic acid, in plants to ethanol and carbon dioxide.

Diagrams

Alveoli

Alveolar duct

Respiratory Bronchiole (sometimes called terminal bronchiole)

Important Facts- Gas exchange is when we get oxygen from the air into our blood into air. Gas exchange happens by diffusion of gases across the very this walls of the alveoli.

- The alveoli (air sacs) have a moist lining to help dissolve the gases, and are surrounded by many tiny capillaries so that there is plenty of blood for the gases to pass into and out of.- The maximize the amount of diffusion taking place, the alveoli have a huge total surface area; between 70m square and 90m square.

- Gas exchange happens by diffusion of gases across the very thin walls of the alveoli. - When we are taking exercise we breathe much faster than when we are resting. This is because when they are working hard the muscles need more energy, so they must respire faster. This means they need more oxygen and produce more carbon dioxide (the waste product of respiration) - so the breathing rate must go up.

- The air is 100% humidified by the mucus in the nose - Dust particles are trapped by tiny hairs and mucus in the nose (which then travels to the throat to be swallowed) - Air is warmed by the blood vessels, so it is at the right temperature when it reaches the bottom of the throat (The lungs have a strong aversion to cold air)

Quiz1. Why is the left lung smaller than the right?

2. Why do the lungs need a very good blood supply?

3. The surface area of the lungs is roughly the same size as a ____________.

Answer: The left lung is smaller than the right one to give a way for the heart.

Answer: Lungs need a very good blood supply because they oxygenate the blood.

a) Squash court b) Tennis court c) Football pitchtennis court

4. A person at rest breathes between _________times a minute.a) 6~11 b) 12~15 c) 15~22

12~15

5. We lose _________of water every day through breathing.

a) 0.2 liter b) 0.5 liter c) 1 liter d) 1.5 liter

0.5 liter

6. What is the differences between respiration, gas exchange and breathing?

Answer: Respiration is chemical reactions which happen in all living cells, in which food is broken down to release energy, usually by combining with oxygen. Gas exchange is the exchange of the gases across a respiratory surface is removed from it. Gas exchange also takes place during photosynthesis and respiration in plants. Breathing is muscular movements which keep the respiratory surface supplied with oxygen.