THE RESPIRATORY SYSTEM

Functions The respiratory system delivers oxygen from the air we breathe into the blood, and removes the carbon dioxide. It brings air from the atmosphere into the lungs Transfers O2 into the blood Removes carbon dioxide from the blood Expels heat and water vapour Allows the vocal cords to create speech as air is breathed out

Anatomy The lungs are the major organ of the respiratory system. They consist of 3 main parts: The conducting system The pleura The diaphragm

The Conducting System THE NASAL CAVITY To warm and clean the air from outside the body THE PHARYNX Where the back of the mouth and the nasal passage meet. Food is passed into the oesophagus, whilst air is passed to the… THE LARYNX The ‘Adam’s Apple’. Contains vocal cords which allow speech as air passes through.

The Conducting System THE TRACHEA The ‘windpipe’. Constructed by rings of hyaline cartilage and sits behind the sternum. Why?? THE BRONCHI The trachea divides into 2 bronchi. Each bronchus feed one of the lungs. THE BRONCHIOLES Each bronchus subdivides into a series of subdividing bronchioles THE ALVEOLI Tiny air sacs. Each alveolus is only one cell thick and is heavily surrounded by capillaries. WHY??

The Pleura The Diaphragm This membrane covers each lung. It is attached to the inside of the chest cavity and the top of the diaphragm. It’s purpose is to prevent friction between the lungs and surrounding body tissue. The Diaphragm This involuntary / smooth muscle contracts/relaxes to aid breathing.

Pressure inside the lungs

GASEOUS EXCHANGE Gases spread from high-concentration areas to low-concentration areas. The blood in the capillaries arriving at the alveoli is low in O2 and high in CO2. Air in the alveoli is high in O2 and low in CO2. Therefore, O2 diffuses into the blood, & CO2 diffuses into the alveoli, where it breathed out.

Gas exchange

The mechanism of gaseous exchange The reverse process occurs in the capillaries that surround the muscle fibres. The muscle fibres are low in O2, which has been used to produce energy (ATP), but high in CO2, which is a waste product. The capillaries however, are high in O2, and low in CO2. Therefore O2 diffuses into the muscle fibres while CO2 moves into capillaries.

Oxygen Uptake by the muscles

Breathing During Inspiration (Breathing In) our muscles between the ribs (Intercostal Muscles) contract pulling the rib cage up and out. The Diaphragm also contracts and flattens. The lungs then expand and air is sucked in.

Breathing During Expiration (Breathing Out) the intercostal muscles relax and the rib cage moves down and in. The diaphragm muscles relax and it moves upwards and becomes more domed shaped. The lungs recoil, and air goes out as the space inside the lungs is reduced.

Control of Breathing The breathing rate and depth of breathing are controlled by the respiratory centre in the brain. The exercise, the muscles are releasing more carbon dioxide as waste. The respiratory centre in the brain detects this and initiates the body to breathe more deeply and more rapidly because more oxygen is needed by the muscles.

Measuring our Lung Capacity Vital Capacity – This is the largest volume of air that can be blown out (expired) after a maximal inspiration. (largest breath) Residual Volume – is the air that remains in the lungs after a maximum expiration. (breathing out as much as as possible)

Measuring our Lung Capacity Tidal Volume – Is the amount of air normally inspired and expired. Inspiratory Reserve Volume (IRV) – Is the air able to be inspired after a normal breath in. Expiratory Reserve Volume (ERV) – is the air able to be expired after a normal breath out

Measuring our Lung Capacity Total Lung Capacity is measured by: TLC = Vital Capacity (VC) + Residual Volume (RV)

Ventilation Ventilation is the amount of air breathed in and out in one minute. It is measured by: Ventilation = Tidal Volume (TV) x Respiratory Rate (number of breathes per min)

Things to Remember During Exercise the things you have to remember are: Tidal Volume INCREASES Ventilation INCREASES Total Lung Capacity INCREASES