The Respiratory System - Obj. 12 How (& where) the body exchanges gases (O 2 & CO 2 ) with the outside environment. Closely connected with the circulatory and digestive systems Respiration refers to all parts of the process of supplying oxygen and eliminating carbon dioxide

The Respiratory System cont’d Obj. 12 Most organisms on earth are aerobic i.e. oxygen is needed for their cells to function. It’s needed for cellular respiration (process that uses oxygen to produce energy, and produces carbon dioxide waste).

Two major requirements of every respiratory system 1. The respiratory surface must be large enough for gas exchange to occur fast enough to meet the needs of the organism. 2. Respiration must occur in a moist environment, so that the oxygen and carbon dioxide are dissolved.

The lung The internal respiratory surface that is connected to the air by means of internal passageways. Characteristic of air breathing vertebrates. Lung systems vary by species, but all consist of three basic elements: 1.One or two lungs with a moist respiratory surface. 2.A way to use force to bring air in contact with the lung surface. 3.A circulatory system to carry gases between the lungs and other cells of the body.

Mammalian Respiration Subdivided into 4 categories: Breathing - Inspiration (the act of taking air in) and expiration (breathing out) External Respiration - The exchange of oxygen and carbon dioxide between air and blood. Internal Respiration - The exchange of oxygen and carbon dioxide between blood and the cells of surrounding tissue. Cellular Respiration - complex cellular reactions that take place in the mitochondria of cells (uses O 2 to produce energy and CO 2 )

The Respiratory Tract fig pg So how does air reach the lungs? Lungs are fragile, delicate structures. Located deep within the body in the thoracic cavity (made of bone {ribs} and muscle) which protects them from damage and water loss. -Nasal Cavity -Pharnyx -Glottis -Larnyx -Trachea

The Upper Respiratory Tract - Obj 13 pg Made up of: Nasal Cavity: air enters the nasal cavity through the nose. The air is filtered, moistened and warmed, to protect the delicate surface of the lungs. Pharynx: A section of alimentary canal that connects the mouth and nasal cavity to the larynx and esophagus. Glottis: The opening of the trachea.

Larynx: voice box, houses vocal cords. Trachea: a flexible tube also known as the windpipe. The trachea carries air to the bronchi. The upper respiratory tract is lined with ciliated cells that secrete mucus which traps dust and bacteria. The cilia moves this material up to the nose and mouth where it can be expelled by coughing or sneezing (fig. 10.5).

The Lower Respiratory Tract Obj.13 pg Consists of: bronchi - at armpit level the trachea divides into 2 smaller passages the bronchi (1 is called a bronchus). One bronchus enters each lung. bronchioles - when the bronchi enter the lungs they branch many times to form a network of very fine tubes called bronchioles

alveoli - Each bronchiole ends in a grape like cluster of tiny sacs called alveoli ( singular alveolus). - Their walls are only one cell thick and are next to capillaries, this is where air exchange occurs. - exchange usually takes place via simple diffusion, but some is through facilitated diffusion which allows for more oxygen pickup.

each lung is divided into lobes: right - 3 lobes left - 2 lobes (leaves room for heart) lobes consist of lobules, each of which has its own bronchiole interactive-game

Gas Exchange Gas exchange occurs across cell membranes. Oxygen entering the alveoli dissolves in the fluid lining and diffuses into the bloodstream within the capillaries. Gas diffuses from high to low concentration. O 2 diffuses from air to blood while CO 2 diffuses from blood to air

The Mechanics of Breathing Obj. 14 pg ●Breathing occurs because air moves from an area of higher pressure to lower pressure. ●Intercostal muscles control the air pressure inside the lungs by manipulating the ribs. ●The diaphragm separates the thoracic (chest) cavity from the abdominal (stomach) cavity.

Inhalation happens when... The intercostal muscles contract which lift the rib cage up and out The diaphragm contracts and pulls down The pressure in the lungs decrease with the extra expansion Air moves in

Exhalation happens when... The intercostal muscles relax which allows the rib cage to move down and in The diaphragm relaxes and moves up The pressure of the lungs increases forcing air out.

Respiratory DiseasesObj.15 pg We don’t realize how important our ability to breathe is until it is compromised in some way Disorders and diseases can cause problems in our ability to breathe or exchange oxygen for carbon dioxide. Environmental quality and personal lifestyle choices impact on the health of our lungs and entire bodies.

Common respiratory diseases include: 1) lung cancer 2) pneumonia 3) asthma 4) emphysema ** discuss only 5) bronchitis ** discuss only (fig pg 343).

1.Lung Cancer Lung cancer is the uncontrolled and invasive growth of abnormal cells in the lungs. This is usually the result of cigarette smoking. Symptoms are usually delayed. They include: chronic coughing coughing up blood weight loss and loss of appetite shortness of breath chest pain fever Treatment may be surgery, radiation therapy, and chemotherapy.

2. Pneumonia Pneumonia occurs when the alveoli inflame and fill with liquids. This prevents the intake of oxygen. The main causes of pneumonia include infection by bacteria, viruses, fungi and other agents. lobar (effects a lobe) and bronchial (effects patches of the lung) (Fig 10.16) Treatment with antibiotics is successful as a cure.

3. Asthma - p. 346 & 348 Asthma is extreme sensitivity of the lungs which result in obstruction of the airways. The symptoms occur as attacks. The airway swells, the bronchial muscles tighten and increased mucous is secreted into the airway. This makes breathing difficult. Common triggers include: colds and chest infections exercise and sports exposure to pollen, flowers, grass, plants or trees tobacco smoke, dust, cold air, pets, mould or mildew, air pollution Treatment includes medications and avoidance of triggers.

Impact of Environmental Factors on Asthmatics Obj 16 The following factors have a big impact on asthmatics: Cigarette smoke – A well-known trigger that can cause an asthma attack. Also contains carcinogens, which can cause cancer (lung cancer). Allergens (dust, mould, food) – These are small particles found in the air we breathe. Most are removed in the upper respiratory tract when we inhale, but some make it into the lungs and can cause an allergic reaction that triggers an asthma attack. Perfumes and petrochemical fumes – Odours or fumes that can cause an allergic reaction and trigger an asthmatic attack.