Respiratory System PDF

The Respiratory System  Between 17 000 and 29 000 breaths a day  Take a deep breath  You just captured 3-4L of air in your lungs!  Breathing is so important that it cannot be left to conscious control! Nasal Cavity Pharynx (throat) Nose Mouth Trach...

The Respiratory System  Between 17 000 and 29 000 breaths a day  Take a deep breath  You just captured 3-4L of air in your lungs!  Breathing is so important that it cannot be left to conscious control! Nasal Cavity Pharynx (throat) Nose Mouth Trachea (Windpipe) Bronchus Lungs Bronchiole Ribs Alveolus Diaphragm Main Parts of the Respiratory System  Trachea  Tube that takes air from the back of the throat down to the lungs  Bronchi (singular: bronchus)  As the trachea approaches the lungs it splits into two bronchi, one bronchus leads to each lung  Alveoli (singular: alveolus)  Tiny air sac surrounded by blood vessels  Lungs contain millions of these  Where gas exchange occurs  The pathway of air  Air from the environment enters: →nose/mouth →pharynx →trachea →bronchi →bronchioles →alveoli  The Trachea  The trachea is supported by rings of cartilage; this keeps it open and allows air to flow freely  The trachea is lined with mucus-producing cells and cilia  Mucus producing cells – secrete mucus that traps dust and other airborne particles  Cilia – sweep the trapped material out of the trachea (wave like motion)  Either swallowed, or expelled by coughing or sneezing Gas Exchange  Alveoli are tiny sacs that fill with air to allow diffusion of gas  Many (millions of) alveoli provide a large total surface area for greater absorption  A thin, single layer of flattened cells are on the wall of each alveolus to decrease the distance that gases need to diffuse across  A dense network of capillaries (tiny blood vessels) surrounding the alveolus to remove CO2 brought from rest of body and to transport O2 to rest of the body  Hemoglobin, the protein found in red blood cells, picks up O2 from the alveoli to transport to the rest of the body Alveolus & Gas exchange Breathing  Involves the diaphragm (a large dome-shaped of muscle underneath the lungs) and the muscles between the ribs.  Is an involuntary process that we can override while talking but only temporarily. Breathing  It is controlled by a part of the human brain that detects the concentration of CO2 in our blood  If CO2 levels increase, the brain sends signals to the diaphragm, and the heart; breathing rate increases and heart beats faster; therefore decreasing CO2 and increasing O2 Breathing  Air entering the lungs --> inhalation  Air exiting the lungs --> exhalation Inhalation  Diaphragm contracts (moves downward), Ribcage expands outwards Exhalation  Diaphragm relaxes (moves upwards), Ribcage moves inwards Breathing  Tuberculosis  infectious disease  caused by bacteria  symptoms include: fever, cough, weight loss, tiredness, chest pain  chest X-ray is one test used to diagnose TB  medical technicians examine stomach or lung secretions SARS  Severe Acute Respiratory Syndrome  spread from a region of China to 37 countries around the world  Canada identified 438 cases; 44 of these patients died  Symptoms: flu-like, high fever, shortness of breath, dry cough, sore throat, headache, muscle pain, and exhaustion  diagnosis is made based on chest X-ray, showing evidence of pneumonia, and positive lab results of cell samples Respiratory System Cancers  Caused mostly by tobacco smoke (first or second hand)  Contains carcinogens which contribute to cancers of the mouth, lungs, larynx, pancreas, esophagus and bladder Chronic Obstructive Pulmonary Disease (COPD)  ~90% of COPD caused by smoking  a chronic, progressive disease that involves both: 1. Obstructive Bronchitis  Long term cough, inflammation and mucus (similar to asthma) 2. Emphysema  Causes permanent damage to the alveoli, they loose elasticity and shape = decrease surface area for gas exchange NO CURE – Damage to alveoli is permanent Effects of Smoking  Known to cause:  Cancer  COPD  Asthma Effects of Smoking  3 Problematic Substances:  Nicotine – addictive, stimulates reward pathway in the brain  Carbon Monoxide – hemoglobin (in your red blood cells) has a greater tendency to bind to carbon monoxide than oxygen (200 times stronger bond)  Tar – accumulates in the alveoli = prevents gas exchange Video !  https://youtu.be/8NUxvJS-_0k