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)