Growth and Development of different organisms National 5 Biology Key Area 6: The Need for Transport (b) Animal Transport Systems National 4 Biology Key Area 4 Growth and Development of different organisms

By the end of this lesson you will be able to .... Name the different parts of the respiratory system Describe the function of rings of cartilage in the airways Describe the structure of the alveoli Describe the self-cleaning mechanism present in the lungs.

Structure of the Lungs Windpipe (trachea) Has rings of cartilage around it These rings help to keep the windpipe open!

Structure of the Lungs Bronchi (plural) Bronchus (singular) Connects the windpipe to the lungs Also contains cartilage

Structure of the Lungs Bronchioles Smaller tubes which branch out throughout the entire lung End in air sacs

Structure of the Lungs Air sac (alveolus) Air sacs (alveoli) As small as a grain of salt! Completely surrounded by blood capillaries SITE OF GAS EXCHANGE!

http://www.footprints-science.com/flash/Alveoli.swf

TASK: label your diagrams Structure of the Lungs WORD BANK: Trachea Bronchus Bronchiole Alveoli (Air sacs) Lung Rings of cartilage

Air sacs are covered with blood capillaries A single air sac Each air sac is a hollow, thin-walled sac that is covered with Capillaries. This is where gas exchange takes place in the lungs Oxygen enters the blood Carbon dioxide leaves the blood Bronchioles Air sacs

Gas Exchange in an Alveolus Oxygen and carbon dioxide are exchanged through the alveolar walls Deoxygenated blood enters Alveolus is ONE CELL THICK Layer of moisture Alveolus (air sac) CO2 out O2 in oxyhaemoglobin Oxygenated blood leaves Dense blood capillary network

HIGH CONCENTRATION of CO2 LOW CONCENTRATION OF CO2 Alveolus HIGH CONCENTRATION of CO2 LOW CONCENTRATION OF CO2 HIGH CONCENTRATION O2 Blood capillary LOW CONCENTRATION of O2

Why are the alveoli so good at Gas Exchange? Alveoli have a large surface area Alveoli have thin walls (only 1 cell thick!) Alveoli have a good blood supply (surrounded by a dense network of blood capillaries) All of the above allow for more efficient diffusion of gases. Diffusion is the movement of a substance from an area of high concentration to an area of low concentration

Add the arrows to your diagram!

Add the arrows to your diagram! HIGH CONCENTRATION of CO2 in blood LOW CONCENTRATION OF CO2 HIGH CONCENTRATION O2 LOW CONCENTRATION of O2 in blood

Diffusion of Gases in the alveolus There is a high concentration of carbon dioxide in the blood capillary and a low concentration in the alveolus, SO carbon dioxide will diffuse OUT of the blood capillary and INTO the alveoli There is a high concentration of OXYGEN in the ALVEOLUS and a low concentration in the BLOOD CAPILLARY, so OXYGEN will diffuse OUT of the ALVEOLUS and INTO the BLOOD CAPILLARY

Healthy lungs! How are the lungs kept clean? Why are the lungs ‘shiny’ looking? Are the lungs wet or dry? What makes them like this? MUCUS

Mucus Mucus is a sticky substance that lines our respiratory tract It traps dirt particles and micro-organisms like bacteria and some viruses

Microscope Slides Of Cilia light microscope slide (X1000) electron microscope slide X500,000 movement of cilia

Cilia hairs

Special features of the lungs Rings of Cartilage This helps to keep the main airways (trachea and bronchi) open and prevent them from collapsing Mucus and Cilia These help to keep the lungs clean Mucus traps dirt and microorganisms and the rhythmic movement of the cilia beat the mucus up and away from the lungs Stick in your diagram!

How do the lungs keep themselves clean?