Gas Exchange Gas Exchange contd Look back at

Gas Exchange

Gas Exchange (cont’d) • Look back at the aerobic respiration equation. • What 2 substances are needed? • What 2 substances are the waste products?

Gas Exchange (cont’d) • In organisms there are places where oxygen enters and carbon dioxide leaves. • When one gas enters and another gas leaves, that surface is for Gas Exchange • These surfaces have certain characteristics

Characteristics of GE surfaces • The surface must be: 1)Permeable / thin enough to allow for diffusion

Characteristics of GE surfaces • The surface must be: 2) Close to an efficient transport system to take gases to and from the exchange surface.

Characteristics of GE surfaces • The surface must be: 3) Kept moist, to stop cells from drying out and dieing.

Characteristics of GE surfaces • The surface must: 4) Have a large surface area, so that a lot of gas can diffuse at the same time. 5)Good supply of oxygen

Function (physiology) • Lung – Spongy, air-filled organs that are on either side of the heart. EXTRA CREDIT: go to youtube. com search for “balloon lung model” Watch videos, create model, share with class.

Lung

Function (physiology) • Trachea: – Pipe to supply the lungs with air. – Supported by rings of cartilage.

Trachea Lung

Function (physiology) • Larynx – Also known as the voice box – Can tighten muscles known as vocal cords, as air passes over these muscles they vibrate, producing sound.

Larynx Trachea Lung

Function (physiology) • Bronchi – Around your heart, the trachea splits into 2 tubes. These two branches are called the left and right Bronchi. (singular: bronchus) – One bronchus goes into each lung, and then continue to branch into even smaller tubes.

Larynx Trachea Lung Bronchi

Function (physiology) • Bronchioles – Tubes that branch off the bronchi, ending in tiny air sacs called alveoli.

Larynx Trachea Lung Bronchioles Bronchi

Homework 1 -31 -13 10 pts. 1. Correct order: 1. 2. 3. 4. Mouth Trachea Bronchus Alveoli 2. Characteristics of gas exchange 1. 2. 3. 4. 5. Permeable/ thin for diffusion Close to transport system Needs to be moist (if it dries, it dies) Large surface area for diffusion Supply of oxygen 3. The process which removes carbon dioxide from the cell and oxygen from cells is diffusion 6.

Get out your “Flash Cards” 1. Put “Aerobic Respiration” on the back 2. Put the cards in correct order 3. Write these definition in yesterday’s notes 4. Respiration - chemical reactions that breakdown nutrient molecules(glucose) in living cells to release energy 5. Aerobic Respiration - release of large amounts of energy in cells by breaking down food substances (glucose) in the presence of oxygen

Tell me what we have made We made a model of something we are studying in this unit. Look at what you see: 1. Draw it 2. Describe each part and what it represents. Use qualitative and quantitative descriptions 3. Share your ideas with your neighbor

Function (physiology) • Alveoli – At the end of each bronchiole are many tiny air sacs called alveoli. – This is where gas exchange ACTUALLY TAKES PLACE. – Surrounding the alveoli are capillaries, tiny blood vessels. Oxygen diffuses from the alveoli into the capillary, CO 2 is opposite.

What are we really breathing? • The composition of exhaled air (air that is breathed out) is very different from the composition of inhaled air (air that is breathed in).

Composition of Air • Inhaled air has the same composition as normal air, it contains: • 78% nitrogen • 21% oxygen • 1% inert gas such as argon • 0. 04% carbon dioxide • little water vapor • Exhaled air is saturated with water vapor, it contains: • 78% nitrogen • 17% oxygen • 1% inert gas such as argon • 4% carbon dioxide • saturated with water vapor