GAS EXCHANGE & THE RESPIRATORY SYSTEM

Answer the first 3 questions on your notetaking guide

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

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

A Definition………• Gas exchange : The physical

method that organisms have for obtaining oxygen from their surroundings and removing excess carbon dioxide from their bodies.

The Respiratory Surface

Gas exchange in an organism takes place through a boundary surface

What is it?

Respiratory Surface : The surface through which gas exchange takes place in an organism

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

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

HUMAN RESPIRATORY SYSTEMFunctions:1. Gas exchange: Oxygen in and carbon

dioxide out2. Protection: Filters foreign bodies from

the air

ORGANS1. Nostril2. Nasal cavity: warms and filters the

airLined with mucus membranes and cilia

3. Pharynx: the back of the throat

More Parts:4. Epiglottis: flap of tissue that closes

over trachea to prevent choking5. Larynx: voice box, where vocal

chords are located6. Esophagus: tube for food, part of the

digestive system

7. TracheaAlso called the windpipe: air passes

through this tube to the lungs. Lined with cilia and mucus so more filtering of the air occurs

LUNGS8. 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

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

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

- 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

12. Diaphragm

• Muscle that separates the chest cavity from the abdominal cavity

Function: contracts and relaxes tomove air in and out of the lungs