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The respiratory system How do you catch your breath? Respiration • The exchange of gas from cells to the atmosphere • common events occur – – – – Ventilation – the movement of air into or out of the lungs Gas exchange between blood and and air in lungs Gas transport in blood between lungs and the body cells Gas exchange between blood and body cells The system for all of this • Function – – – – – Filter particulates from air Control the air temperature Control the moisture level of the air Participate in the sense of smell (the nose) And helps regulate blood pH • 2 major regions – Upper respiratory tract – Lower respiratory tract Upper respiratory system • Nose – Nostrils – open to the outside world – Hairs – prevent the entry of large particles • Nasal cavity – Hollow space behind the nose – Nasal septum divides into right and left – Nasal conchae – bones that curl out of the lateral walls making passage ways • Are lined with mucus membranes – Warms, moistens, and cleans air Continuing in • Paranasal sinuses – The sinuses are air-filled sacs located with in the the skull bones and open in to the nasal cavity – Reduce weight of skull and affect the quality of the voice • Pharynx – The sorting chamber, sends air to the lungs and food to the stomach (we hope) Lower respiratory tract • Larynx – Enlargement at top of trachea, bottom of pharynx – Prevents foreign matter from entering the trachea – Vocal cords are located here • 2 pair – Upper – false vocal cords – helps close off the trachea – Lower – true vocal cords -this is where all that sound comes from • Opening between is called the glottis Continuing down • Trachea (AKA the wind pipe) – About 2.5 cm in diameter, and 12.5 cm long – Also lined with mucus membranes that trap particles as well as moistens and warms air – Cilia push the particles back up to the pharynx • Smokers destroy these hairs and that is how they get smokers cough – Has about 20 C-shaped cartilage rings to prevent the trachea from collapsing • Open in the back to allow the esophagus to expand Next up... • The bronchial tree – Starts with two main branches – the bronchi (p) bronchus (s) • Right and left, they lead to their respective lungs • Have cartilage rings – The bronchi divide to smaller and smaller tubes • Smaller tubes are called bronchioles • Don't have cartilage rings from here down – Divide down to terminal bronchioles, then respiratory bronchioles » End in the alveoli Where the main work is done • The alveoli (p) alveolus (s) – – – – Tiny microscopic air sacs that lie in a capillary network Made of simple squamous tissue One cell thick Location of gas exchange with the blood • Controlled by diffusion The lungs themselves • Have two – right and left – Hang in the thoracic cavity by the bronchi and some major blood vessels • Wrapped in the pleural membranes – – – Visceral pleural - attached to lung Parietal – attaches to the mediasternium and lines the inner wall of the thoracic cavity Space between (not significant) called the pleural space. A little more about them • Right lung – – Large of the two Three lobes • Left lung – Two lobes • Lungs are cone shaped and are soft Let's breath • Air moves into and out of the lungs because of air pressure • Inspiration AKA inhalation – Diaphragm lowers (contracts) and the rib cage lifts • This cause the air pressure in the thoracic cavity to drop, and air to rush in • Expiration AKA exhalation – Diaphragm raises (relaxes) and the rib cage lowers • This cause the air pressure to increase, and air to leave Air Volumes • Uses a spirometer to measure this • 4 distinct volumes – Tidal volume (resting tidal volume) • The amount of air that enters or leaves during one respiratory cycle (one in and out) – – Inspiratory reserve volume • – Additional air that enters during a forced inhalation Expiratory reserve volume • – Resting volume is the normal amount that leaves (about 500 ml of air) Additional air that leaves during a forced exhalation Residual volume • The amount that doesn't leave (about 1200 ml of air) Capacities • Respiratory capacities – Combination of 2 or more volumes • Vital capacity – – Inspiration reserve + tidal+ expiration reserve Maximum amount a person can breath out after the deepest breath possible • Inspiration capacity – Tidal volume + inspiration reserve volume • Maxmium a person can breath in after resting expiration Capacities continue • Functional Residual capacity – – Expiration reserve volume + residual volume Amount of air that remains in the lungs following a resting expiration • Total lung capacity – – Vital capacity + residual volume About 5800, varies by age and sex Some disorders • Emphysema – the destruction/weakening of the alveoli, severe cases the lungs lose the elasticity, and can not get air out. • Asthma – the constriction of the bronchial tubes, causing less air to reach the alveoli