Respiratory System: - Lung structure - Ventilation - Gaseous exchange

Thoracic cavity Thorax: -Enclosed in an air-tight compartment, the thorax. -Delineated by the thorax wall and the diaphragm. -The rib-cage consists on 12 pairs of ribs. Each pair articulated by a thoracic vertebra. -They have an oblique movement up and down. -Intercostal muscles attached between the ribs, move the rib-cage.

Thoracic cavity

Lungs structure -The thoracic cavity is separated from the abdominal cavity by the diaphragm (muscle). -The inner surface of the thoracic cavity and outer surfaces of the lungs are lined with a smooth membrane, pleural membrane.

Lungs structure -Trachea -Bronchus (two bronchi) -Bronchiole -Alveoli (cluster of alveolus) -Alveolus (individual air sac)

Lungs structure Alveoli: -Microscopic air sacs (alveoli in grape like cluster). -Capillaries surround the sacs. These are supplied with blood from the pulmonary artery and are drained towards the pulmonary vein.

Ventilation process (movement of air) -Air is drawn into the lungs when pressure is lower than atmospheric pressure. -It’s forced out of the lungs when it is higher. -Air flow comes into the mouth and nose goes through the larynx and trachea. -Air goes into the two bronchi which subdivide into smaller and smaller bronchioles.

Ventilation process

The process is brought about by: -the action of two groups of muscles (intercostal and diaphragm). -Properties of the pleural membrane.

Ventilation process The process is brought about by: -the action of two groups of muscles (intercostal and diaphragm). -Properties of the pleural membrane (it STICKS to the outside of the lungs). When the volume of the chest increases The volume of the lungs also increases The pressure of the lungs decreases

Ventilation process 1. Intercostal muscles contract and pull the rib- cage up and outwards. 3. Lung volume increases and the pressure falls. 2. Diaphragm muscles contract and diaphragm moves downwards.

Ventilation process 1. Intercostal muscles relax and rib-cage falls downwards and inwards, 3. Lung volume decreases and the pressure increases. 2. Diaphragm muscles relax and diaphragm returns to its dome shape. 4. Air is forced out.

Gas exchange (exchange of O 2 and CO 2 ) Gas exchange takes place through a gas exchange surface = Respiratory surface. Diffusion rate is increased: 1.Large surface area. 2.Small distance for molecules to move. 3.Difference in concentration gradients. 4.Rich supply of blood capillaries The process of diffusion takes place.

Gas exchange (exchange of O 2 and CO 2 ) The alveoli surface is: -Thin (one cell, easy access for gases) -Large surface area (many air sacs clusters). -Moist (keep cells alive). -Ventilated (Concentration gradients CO 2 and O 2 kept by constant supply of air from ventilation). -Close to a blood supply.

-The process of gaseous exchange DOES NOT remove all the oxygen from the air. -The air breathed in contains 21% of oxygen. -The air breathed out contains 18% of oxygen. -The air inhaled has 0.04% of CO 2. -The air exhaled has 3% of CO 2. -The rest of the air is mainly nitrogen (its concentration does NOT change. Important to know:

-Temperature of air breathed in is variable. -Temperature of air breathed out is 35C. -The lining of the alveoli is coated with moisture which help oxygen to dissolve. -Some of this moisture evaporates into the alveoli but the rest is breathed out. Air breathed out is saturated with moist Important to know:

Asthma and exercise People who suffer from asthma have trouble passing air along the pressure gradient. Asthma attacks may be caused by pollen, dust, smoke, air pollution. Solutions: -removal of the factor causing the attack. -Use of a bronchodilator which relax the bronchi.

Asthma and exercise During sport, muscles need to increase their energy release (by respiration). This can only be done by increasing the amount of air inhaled. Two ways of doing so: -More breaths per minute -Deeper breaths

-Respiration is NOT used when referring to breathing. -Respiration is the process by which the cells release energy. -Respiration rate = a persons breathing rate. -Respiratory system= lungs+trachea+bronchi. -Ventilation: process of air coming in or leaving the lungs. Important to know:

Diseases Some airborn organisms: -Flu -Measles -Mumps -Smallpox -Chickenpox -Legionnaire’s -Meningitis -Pneumonia -Tuberculosis

Diseases Flu (Influenza): -Highly contagious -Fever -Cough/sore throat -Muscle/body aches -Fatigue -Headaches If severe it can cause pneumonia, bronchitis, death.

Diseases Measles: -Fever -Runny nose -Cough -Red eyes -Sore throat -Rash over the body If severe it can cause bleeding problems and infections in bones and joints. As well as brain inflammation.

Diseases Mumps: -Fever -Headache -Muscle aches -Fatigue -Loss of appetite -Swollen salivary glands If severe it can cause deafness and viral meningitis.

Diseases Smallpox: -Highly contagious -May be fatal -High fever -Head and body aches -Rash of small spots on tongue and mouth. -Pustular rash

Diseases Chickenpox: -Highly contagious. -Blister like rash. -Very itchy. -High fever. -Headache. -Loss of appetite. If severe it can cause bleeding problems and infections in bones and joints. As well as brain inflammation.

Diseases Legionnaire’s: -Shortness of breath -High fever -Muscle aches -Headaches If severe it can cause lung failure and death.

Diseases Meningitis: -Inflammation of the protective membrane covering the brain and spinal cord. -Nausea. -Vomiting. -Increased sensitivity to light.

Diseases Pneumonia: -Coughs -Fever -Difficulty breathing -Fatigue

Diseases Tuberculosis: -Can be fatal is untreated -Coughs -Chest pain -Fatigue -Weight loss -Fever -Chills/sweating spells