Respiratory System trachea bronchus (bronchi) bronchioles

Bronchioles & Alveoli bronchiole alveoli

Nasal Cavity Nasal cavity possess hairs for trapping large dirt particles wall of nasal cavity lined with ciliated epithelium and mucus-secreting cells to trap dirt and bacteria

near surface are numerous blood vessels so incoming air are warmed, moistened & filtered before entering lungs

Pharynx & Larynx

pharynx belongs to both respiratory & digestive system glottis is the opening of larynx and it is covered by epiglottis during swallowing

larynx consists cartilage at the entrance of trachea within the cartilage are two membranes, vocal cords to produce sound waves

Trachea (Windpipe) and Bronchi trachea lies in front of oesophagus and extended into thoracic cavity at the lower end of trachea is divided into two bronchi which subdivides into many bronchioles

each bronchiole terminates in hollow, lobed air sacs called alveoli inner lining of the trachea produces mucus and possess cilia

mucus are used to trap the dirt & germ while cilia are used to waft the mucus towards the throat, it is then either coughed out or swallowed. Those coughed out are called phlegm wall of trachea strengthened by C-shaped cartilages to keep trachea open

Alveoli Adaptations thin wall ( only one-cell thick) short diffusion distance for gases folding shape and numerous alveoli large surface area for diffusion of gases

maintain high concentration gradient of gases moist surface to dissolve gases for diffusion lots of capillaries present

Structure of Lung lungs are protected by the thoracic basket which is made up of vertebrae, ribs and sternum each lung is surrounded by two pleural membranes

the inner membrane is in contact with the lungs and the outer membrane lines against the walls of the thorax and diaphragm between the two membranes is pleural cavity which contains a pleural fluid secreted by the membranes

pleural fluid lubricates the pleura so to reduce friction as the pleural membranes rub against each other during breathing

trachea - have ring of cartilage bronchiole larynx Intercostal muscles trachea - have ring of cartilage pleural fluid left lung left bronchus alveoli heart pleural membranes diaphragm rib

Thoracic Basket (rib cage) sternum ribs vertebrae pleural cavity - absorb shock 2 pleural membranes

Gaseous Exchange in Alveoli atmosphere CO2 O2 Lungs(alveoli) CO2 (by plasma and in form of HCO3- ) O2 + haemoglobin oxyhaemoglobin (by red blood cell) tissue

Gaseous Exchange in Alveoli Deoxygenated blood Lung Pulmonary artery Oxygenated blood Heart Tissue Pulmonary vein Oxygenated blood

air moves out during expiration air moves in during inspiration CO2 deoxygenated blood from pulmonary artery oxygenated blood to pulmonary vein cell in capillary wall plasma cell in alveolar wall mucus red blood cell

Mechanism of Breathing brought about by the action of diaphragm & intercostal muscles divided into two processes : inhalation (inspiration) & exhalation (expiration)

Inspiration (Inhalation) Diaphragm muscle - contract Diaphragm - flattened Intercostal muscle - contract ribs & sternum - move upward & outward

Inspiration (Inhalation) thoracic cavity expands (volume increases) air pressure in lung is lower than atmospheric pressure so air rushes in lungs inflated (expand)

Expiration (Exhalation) diaphragm muscles relax diaphragm becomes dome-shaped intercostal muscles relax ribs and sternum move downwards & inwards

thoracic cavity volume decreases air pressure inside lungs increases air forces out lungs deflated

Walking & Running during exercise at rest lung volume ( cm ) time (seconds) 5 10 15 1000 2000 3000 3 20 during exercise time (seconds) 20 5 10 15 1000 2000 3000 lung volume ( cm ) 3 at rest

Calculations of the Rate and Depth of Breathing From the graphs the volume of air he breathed in per minute at rest and during exercise can be measured :

If the percentage by volume of oxygen in atmospheric air is 21% and that in exhaled air is 16%. Then the volume of oxygen retained in the body per minute can then be calculated : At rest : 18 x 500 x (21-16)% = 450cm3 During exercise : 27 x 2000 x (21-16)% =2700cm3

CO2 remains Constant during Exercise muscles release CO2 ventilation rate increases +  CO2 concentration in blood remains CONSTANT

The graph of Lung capacities

Tidal Volume amount of air entering & leaving the lungs during normal breathing during exercise → can increase volume

Vital Capacity maximum air exhaled after taking the deepest inhalation during exercise → cannot increase the capacity increase only after prolong training

Residual Volume volume of air remaining in the lungs which cannot be expelled even after forced exhalation

Smoking & Health Composition of a cigarette : carbon monoxide + nicotine + tar = cigarette Effects on health : (I) Tar : (i) carcinogenic ( producing cancer ) (II) Nicotine : (i) cause heart diseases

Smokers’ lung

(ii) dependence (iii) retards growth of foetus (III) Carbon Monoxide : (i) combines irreversibly with haemoglobin and prevents it from carrying oxygen + CO haemoglobin carboxyhaemoglobin (ii) decrease in physical fitness (iii) cause air pollution

Smoking and Health Hazards 1.Lung Cancer Smoking increase the risk of lung cancer 2.Heart disease Nicotine increases the workload of heart increase the rate of heart attack

Smoking and Health Hazards 3.Chronic bronchitis Smoking causes inflammation of trachea and bronchitis The severe chronic bronchitis can cause death 4.Emphysema Causes of "smoker's cough" Smoker cough causes damage of alveolar wall in lungs

Passive Smoking Warning DO NOT SMOKE !!!!! process of breathing in smoke from cigarette smokers causes nose, throat & eye irritations Warning DO NOT SMOKE !!!!!