structure and function of the lungs
TRANSCRIPT
Lloyd Dean
Respiratory System
Lesson ObjectivesBy the end of the lesson you should be able to:
Describe the structure and function of the respiratory system
Identify, describe and explain the role of the diaphragm and the intercostal muscles in the mechanics of breathing
Explain how the transport of gases is achieved from the respiratory system into the cardiovascular system
Component Structure Function
Epiglottis•Small flap of cartilage Prevents food entering the
trachea
Trachea
•Tube which carriers air•Covered in hairs (Cilia)•Surrounded by C-shaped cartilage rings (Protect)
Also known as the wind pipe; passage for oxygen to travel through
Bronchus
•Cartilage rings•Smooth muscle
Splits trachea into two tube to allow oxygen in right and left lungs
Bronchioles
•Further division of bronchi•Very narrow tubes•Lead to alveoli
Allows oxygen to filter into alveoli
Alveoli
•Air sacs•Thin walls
Site for exchange of gasses
Diaphragm
•Muscle that sits underneath lungs•Attached to the ribs and sternum•Base of thoracic cavity
Enables thoracic cavity to be increased and decreased
Intercostal muscles
•Muscles that sit between the ribs•Internal and external
Enables thoracic cavity to be increased and decreased
Breathing MechanicsFour things need to happen in order for respiratory system to fulfil its function:
1.Inspiration2.External Respiration3.Internal Respiration4.Expiration
InspirationDiaphragm flattens and stretches lungs downward
Intercostals pull the ribcage up and out causing the lungs to stretch
Expansion of air causes a drop in air pressure in the lungs
Air in the lungs is at a lower pressure than the air outside, so air enters the lungs
ExpirationDiaphragm relaxes
Intercostals relax
Lungs recoil
Volume of air in the lungs decreases causing an increase in the air pressure
Air flows from higher to lower pressure so the air flows out of the lungs
Intercostal and Diaphragm Muscles
DiaphragmDome shaped muscleSeparates thoracic
cavity from abdominals
Intercostal MusclesChanges the shape rib cage
during breathing External intercostals contract to
breathe in Internal intercostals contract
during forced breathing out
(Author Unknown, Date Unknown)
(Dugdale, 2009)
Inspiration and Expiration During Exercise
Inhalation and Exhalation
External Respiration
(WebMD, 2009)
•Exchange of Oxygen and Carbon dioxide between the lungs and blood stream
•Occurs at Alveoli
DiffusionOxygen (02) is required in tissues
Carbon dioxide (CO2) has to be removedExchange occurs through Diffusion
Movement of particles from a high concentration area, to a low concentration area
Rule = Diffusion only occurs down a concentration gradient
Concentration (pressure ) oxygen in lungs must be higher than concentration (pressure) in capillaries
Partial Pressure
INHALED % GAS EXHALED %
79.04 Nitrogen 79
20.93 Oxygen 17
0.03 Carbon Dioxide 4
•Individual pressure of a particular gas within a mixture of gases
•Diffusion occurs from high to low concentrations
Exchange of GasesFast rate of diffusion occurs with:Large surface areaSmall distance between areas involved
Other Factors:Capillary sizeMoist surface of alveoliSlow capillary blood flow = Complete OxygenationHaemoglobin – Magnet for oxygen
Internal RespirationExchange of gases in the bodies cellsWorks similar to external respirationCell use of oxygen to make ATP
Gas Exchange
Gas Exchange