Respiratory System Notes

7.1 Structures of the Respiratory System

• The upper respiratory tract filters, warms, moistens air, and channels it into the lungs.
• The lower respiratory tract exchanges oxygen for carbon dioxide in the bloodstream.

7.2 Breathing and Respiration

• Humans ventilate their lungs through inspiration and expiration.
• The volume of air intake increases with the need for oxygen, like during exercise.
• External respiration occurs in the lungs between the alveoli and blood in the capillaries.
• Internal respiration occurs between the blood in the capillaries and tissue cells.
• Gas exchange occurs through simple and facilitated diffusion.

7.3 Respiratory Health

• Some disorders are specific to the respiratory system, and while technologies can treat them, optimal health may not be restored.
• Smoking causes respiratory diseases. Technologies can alleviate symptoms, but many are untreatable.

Oxygen Importance

• Minutes without oxygen can cause brain damage and death.

Modelling Lungs

• Lungs expand and deflate like a balloon but fill with air differently; they don't need an outside pump.
• The volume of air inside the container changes, affecting the balloons.
• The model would not work if it were not airtight.

Respiration Overview

• The main function of the human respiratory system is to bring oxygen to cells and remove carbon dioxide.
• Respiration requires a large surface area and a moist environment for gas exchange.
• Breathing involves inspiration (inhaling) and expiration (exhaling).
• External respiration is the exchange of gases between air and blood.
• Internal respiration is the exchange of gases between blood and tissue cells.
• Cellular respiration provides energy for cellular activities and helps maintain homeostasis.

The Respiratory Tract

• The lungs are protected within the thoracic cavity.
• The respiratory tract extends from the nose to the lungs and facilitates air movement.

The Upper Respiratory Tract

• Air enters through the nose or mouth. Nasal passages warm, moisten, and clean the air.
• Ciliated cells and mucus trap and expel foreign particles.
• Turbinate bones increase the surface area of the nasal passages.
• The pharynx (throat) is a passageway for both air and food.
• The epiglottis prevents food and drink from entering the trachea by closing over the glottis during swallowing.
• The larynx (voice box) contains vocal cords that vibrate to produce sound. Longer vocal cords produce lower sounds.
• The trachea (windpipe) is a flexible tube supported by cartilaginous arches.

The Lower Respiratory Tract

• The trachea branches into bronchi, which further subdivide into bronchioles within each lung.
• Bronchi contain C-shaped cartilaginous rings, while bronchioles do not.
• Bronchi and bronchioles are lined with cilia and mucus-producing cells.
• The right lung has three lobes, and the left lung has two.
• Each lung is surrounded by a pleural membrane that connects the lungs to the thoracic cavity.
• Bronchioles end in alveoli, where gas exchange occurs. Alveoli are surrounded by capillaries.
• Capillaries link arteries and veins, facilitating the exchange of carbon dioxide and oxygen.
• Elastic connective tissue maintains the position of bronchioles and alveoli.
• Alveoli are lined with a lubricating film to prevent collapse.

7.1 Summary

• The respiratory tract is a passageway for air from the environment to the lungs.
• Respiration includes breathing, external respiration, internal respiration, and cellular respiration.
• The upper respiratory tract warms, moistens, and cleans air.
• The lower respiratory tract contains bronchi, bronchioles, and alveoli, covered by the pleural membrane.

7.2 Breathing and Respiration

• The diaphragm and rib muscles control air pressure inside the lungs, facilitating inhalation and exhalation.
• Inhalation occurs when the rib muscles and diaphragm contract, expanding the thoracic cavity and drawing air into the lungs.
• Exhalation occurs when the diaphragm and rib muscles relax, decreasing the thoracic cavity volume and expelling air.

Respiratory Volume

• Tidal volume is the air volume inhaled/exhaled during normal breathing at rest.
• Inspiratory reserve volume is the extra air volume that can be inhaled beyond a regular breath.
• Expiratory reserve volume is the extra air volume that can be forced out beyond a regular breath.
• Vital capacity is the total volume of gas that can be moved into or out of the lungs (tidal volume + inspiratory reserve volume + expiratory reserve volume).
  Vital\;Capacity = Tidal\;Volume + Inspiratory\;Reserve\;Volume + Expiratory\;Reserve\;Volume
• Residual volume is the gas remaining in the lungs after full exhalation.

Gas Exchange and External Respiration

• External respiration exchanges gases between alveoli and blood in capillaries.

• Gases diffuse through the cell membranes of alveoli and capillaries.
  Diffusion: Molecules move from high concentration to low concentration

• Facilitated diffusion uses protein-based molecules to “carry” oxygen across cell membranes.

• Carbon dioxide diffuses from capillaries into alveoli.

• Blood transports oxygen to tissue cells where internal respiration occurs.

• Hemoglobin carries approximately 99% of oxygen in red blood cells.

• Slightly less than one-quarter (23 percent) of carbon dioxide is carried in the blood by hemoglobin.Approximately 7 percent is carried in the plasma, and approximately 70 percent is dissolved and carried in the blood as bicarbonate ion (HCO_3).

• Carbonic acid (H2CO3) is formed when CO2 reacts with H2O, then dissociates into H+ and bicarbonate ion (HCO_3).

  CO2 + H2O
  ightharpoonup H2CO3
  ightharpoonup H^+ + HCO_3^-

Carbon Dioxide and Respiration Rate

• The concentration of carbon dioxide affects the rate of respiration.

7.2 Summary

• The diaphragm and rib muscles move air into and out of the lungs.
• Lung volume changes with oxygen needs and activity level.
• External respiration occurs in the lungs, internal respiration in the tissues.
• Gases are exchanged via passive and facilitated diffusion.
• Oxygen binds to hemoglobin, and most carbon dioxide is transported as bicarbonate in blood plasma.

Traditional Healing in Modern Times

• Traditional remedies include white willow, boswellia, Seneca snakeroot, and pleurisy root.
• Dr. Malcolm King studies traditional aboriginal remedies for respiratory illnesses.
• Natural products cannot be patented, limiting research funding.

7.3 Respiratory Health

• The respiratory system connects the body's internal environment with the external environment.
• Upper respiratory tract infections are usually caused by viruses or bacteria.

Tonsillitis

• Tonsillitis is an infection of the tonsils, often caused by a viral infection.
• Tonsils can be surgically removed if infections are frequent.

Laryngitis

• Laryngitis is an inflammation of the larynx, often caused by a viral infection or allergies.
• Symptoms include a sore throat and hoarseness.

Lower Respiratory Tract Disorders

• Common causes are infections, obstructive pulmonary disorders (OPD), and lung cancer.

Bronchitis

• Bronchitis is inflammation of the bronchi with mucus production.
• Acute bronchitis is short-term and caused by a bacterial infection.
• Chronic bronchitis is long-term, caused by irritants, and has no cure. Common symptoms include destroyed cilia, inflamed bronchi, and the individual is prone to getting infections.
• The most common cause is cigarette smoking.

Pneumonia

• Pneumonia is when the alveoli in the lungs become inflamed and filled with liquids, interfering with gas exchange.
• Lobular pneumonia affects a lobe of the lung.
• Bronchial pneumonia affects patches throughout both lungs.
• Causes include bacterial and viral infections. There is pneumoncoccal vaccine that can help prevent bacterial infection.
• Viral pneumonias are usually less severe and can be treated with anti-viral medications.

Pleurisy

• Pleurisy is caused by swelling and irritation of the pleura.
• Symptoms include sharp stabbing pain in the chest.
• Treating pleurisy involves treating the cause of the swelling and irritation.

Emphysema

• Emphysema is a disorder where the alveoli walls break down and lose their elasticity.
• Exhaling becomes difficult and almost all cases are caused by smoking.
• Medications can help open up the bronchioles and improve breathing and lung volume reduction surgery (LVRS) is an experimental surgery to help with breathing.

Cystic Fibrosis

• Cystic fibrosis impacts the salt and water balances and causes a liquid coating on the insides of the lungs to become very thick and sticky.
• It is treated with medicines to thin the mucus and antibiotics.
• Gene therapy is a new treatment that can help correct the abnormal gene that caused this disorder.

Asthma

• Asthma is a chronic obstructive lung disease that affects the bronchi and bronchioles.
• During an asthma attack, the bronchi and bronchioles swell, the bronchial muscles tighten, and mucus production increases.
• Asthma can be managed through inhalers (metered dose inhalers and dry powder inhalers) or nebulizers.
• Asthma medications help reduce inflammation in the airways and relax the bronchiole muscles, both of which open up the airways.

Lung Cancer

• Lung cancer is the uncontrolled and invasive growth of abnormal cells in the lungs, which reduces surface available for gas exchange.
• Most cases of lung cancer are caused by smoking.
• Many substances in tobacco smoke are known carcinogens.

Technologies for Detecting and Treating Lung Disorders

• Lung cancer can be detected using a specialized X ray, called a CT scan, that locates abnormalities in the lungs.
• Recently, researchers have developed a a breakthrough technology that pinpoints the cells that are most likely to become cancerous and technology that uses liposomes (microscopic vesicles; a liquid surrounded by phospholipid layers that are filled with cancer fighting drugs)