Structure and Function of the Lungs

Lloyd Dean

Cardio - respiratory System

Aims Describe the structure of the lungs

Identify the function of the lungs

Recall how lungs perform their function

RecapConcave Discs

Artery

Arterioles

Plasma

Lumen

Venule

Platelets

Capillary

CO2

Tunica Media (Smooth Muscle)

TIME TO DO SOME COLOURING IN! (1 Pack per study buddy)

Rule 1. Have funRule 2. If you find a term that you do not

know then research it on your mobile deviceRule 3. Make as many notes on the sheets

as possible to help with your video!

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

Respiratory Volumes

• Tidal Volume Amount of air moved in and out of the lungs in once breath

Residual Volume Amount of air left in the lungs after exhalation

Vital Capacity Maximum amount of air that can be inhaled and exhaled in

one breath

Gaseous Exchange

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

Neural and Chemical Control of BreathingMedulla Oblongata (Respiratory centre)

Impulses

Stretch receptors

Chemoreceptors

Lactic acid