1. GAS EXCHANGE & THE RESPIRATORY SYSTEM Answer the first 3 questions on your notetaking guide

2. Did you get them right? What gas is needed for aerobic cellular respiration? Oxygen What gas is a waste product of aerobic cellular respiration? Carbon dioxide

3. All living things that carry on aerobic cellular respiration need to obtain oxygen from their environment and remove carbon dioxide from their bodies.

4. A Definition……… Gas exchange : The physical method that organisms have for obtaining oxygen from their surroundings and removing excess carbon dioxide from their bodies.

5. The Respiratory Surface Gas exchange in an organism takes place through a boundary surface

6. What is it? Respiratory Surface : The surface through which gas exchange takes place in an organism

7. Characteristics of the Surface Thin - walled so diffusion can rapidly take place across it Moist so oxygen and carbon dioxide can be in solution Must be in contact with a source of oxygen Must be in contact with a transport system to carry and distribute the oxygen and carbon dioxide

8. Gas Exchange in Protists Takes place directly through the cell membrane Oxygen dissolved in the water passes through the cell membrane by diffusion Carbon dioxide diffuses out of cell cytoplasm into surrounding water

9. HUMAN RESPIRATORY SYSTEM Functions: 1. Gas exchange: Oxygen in and carbon dioxide out 2. Protection: Filters foreign bodies from the air

10. ORGANS 1.Nostril 2.Nasal cavity: warms and filters the air Lined with mucus membranes and cilia 3. Pharynx: the back of the throat

11. More Parts: 4. Epiglottis: flap of tissue that closes over trachea to prevent choking 5. Larynx: voice box, where vocal chords are located 6. Esophagus: tube for food, part of the digestive system

12. 7. Trachea Also called the windpipe: air passes through this tube to the lungs. Lined with cilia and mucus so more filtering of the air occurs

13. LUNGS 8. The gas exchange organ. Made of many small chambers called alveoli which increase the surface area for gas exchange 9. Pleura: 2 layered membrane that surrounds the lungs

14. Lots of Tubes 10.Bronchi: 2 tubes which lead from trachea into the lungs 11.Bronchial tubes: tubes that branch off bronchi 16.Bronchioles: tiny tubes branching off bronchial tubes 10.Bronchi: 2 tubes which lead from trachea into the lungs 11.Bronchial tubes: tubes that branch off bronchi 16.Bronchioles: tiny tubes branching off bronchial tubes

15. 13. Alveoli: Tiny sacs that are the respiratory surface. Gas exchange happens here!

16. -each bronchiole ends in a cluster of alveoli -one cell thick -moist -surrounded by (15) capillaries: oxygen diffuses into blood and carbon dioxide diffuses out of blood

17. 12. Diaphragm Muscle that separates the chest cavity from the abdominal cavity Function: contracts and relaxes to move air in and out of the lungs