Chapter 18 - Notes - 2

Chapter 1: Respiration

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The human breathing mechanism • The gas exchange in lung is called breathing. • Allows for gas exchange with the external environment Nasal Cavity • Exposed to air through nostrils • Lined with ciliated (hairs) mucous membrane Function: ____________________________ On to the Pharynx Where the oral and nasal cavity meet. Epiglottis _____________________________ Larynx • Between the Pharynx and your Trachea is you larynx or voice box From the Pharynx to the Trachea • Trachea • Conducts air between the pharynx and bronchi • Kept open by partial rings of ____________ • Line with a ciliated mucous membrane Bronchi (Bronchus) • Trachea splits into two (2) bronchus • Same composition as trachea Bronchioles • Bronchi split up into many bronchiole: • lined mucous membrane but lack cartilage Alveoli • Bronchioles terminate at the alveoli: • Thin, moist, and surrounded by capillaries • This is where _________takes place between the outside and the blood Adaptation of the alveoli for efficient gas exchange 1. ____________________ The lungs have millions of alveoli to provide a large surface area for gas exchange 2. ____________________ The wall of each alveolus is one-cell thick to provide a very short distance for the diffusion of gasses 3. ___________________ The inner surface of each alveolus is moist so that oxygen can dissolve in the moisture before across the alveolus wall. 4. __________________________________________ The blood capillaries help to transport gasses to and from the alveoli quickly.

Inhalation and Exhalation • Caused by changing pressure in the chest cavity

Inhalation Diaphragm muscle ________ Diaphragm __________ Intercostals muscles __________ Ribcage move _______________ Volume of thoracic cavity ____________ Air pressure surrounding the lung _________ Air flows into the lung

Exhalation Diaphragm muscles ________ Diaphragm ___________ Intercostals muscle ________ Ribcage moves _______________ Volume of thoracic cavity ___________ Air pressure surrounding the lung _______ Air forced out of the lung

Content Inhalation air Exhalation air Alveolar air Oxygen 21% 16% 14% Carbon dioxide 0.04% 4% 6% Nitrogen 79% 79% 80% Water vapour Variable Saturated Saturated Temperature Variable 34oC 37oC The transport of oxygen in the human body • Diffusion is the movement of materials from a _______to a ______concentration. In Alveoli Oxygen concentration in alveoli is____, so oxygen diffuses from the ______ to the ______. Carbon dioxide concentration in _______ is greater than in ________, so carbon dioxide diffuses from the _______into the ________ In cell Oxygen concentration in cells is____, so oxygen diffuses from the blood to the cells when it reaches the capillaries. Carbon dioxide concentration in metabolically active cells is _____greater than in capillaries, so carbon dioxide diffuses from the cells into the capillaries

What happens to the oxygen in blood? Oxygen is carried by haemoglobin in a cell called oxyhemoglobin Hemoglobin + oxygen à Carbon dioxide is carried in the plasma of the blood in the form of a bicarbonate ion. Effects of harmful substance on the respiration system Cigarette: Chemical substance Effect on the body nicotine damages heart, blood vessels, nerves tar

causes cancer

carbon monoxide

stops haemoglobin in blood carrying oxygen

hydrogen cyanide

irritate lungs and air passages

ammonia

irritate lungs and air passages

butane

irritate lungs and air passages

Factories: SO2 (damage lung) :CO (easier to combine with hemoglobin) Diseases of the Respiratory System • Asthma narrows the airways by causing an allergy-induced spasms of surrounding muscles or by clogging the airways with mucus. • Bronchitis is an inflammatory response that reduces airflow and is caused by long-term exposure to irritants such as cigarette smoke, air pollutants, or allergens. • Cystic fibrosis is a genetic defect that causes excessive mucus production that clogs the airways.