Human Respiratory System Aim: How does your body undergo respiration?

Function of the Respiratory System A.Allows gas exchange between the external environment and internal environment. B.Cilia and mucus membranes line all the internal walls of the respiratory tract. C.Works closely with the circulatory system.

Respiratory Tract

Structures of the Respiratory System A.Nose — air enters through nostrils and passes into nasal cavity. 1. Air is filtered, warm & moistened. B.Air moves past the pharynx (throat) into larynx (voice box) that contains vocal cords.

Upper Respiratory tract

Structures of the Respiratory System C.Trachea (windpipe) — tube that has cartilage rings. 1. Lined with mucus to trap dust, pollen & microbes. 2. Tracheal cells have cilia that move trapped particles towards the pharynx by the beating cilia. 3. Cartilage rings surround trachea to keep it open.

Structures of the Respiratory System D.Bronchi (two cartilage tubes) — the trachea splits into the right & left bronchi, each of which enters the lungs. 1. Looks like an inverted “Y”. 2. Splits into smaller and smaller tubes called bronchial tubes. 3. Bronchial tubes subdivide into smaller and smaller branches called bronchioles.

Structures of the Respiratory System E.Bronchioles — small tubes that are lined with mucus but do not have cartilage rings. 1. They subdivide and end in alveoli.

Structures of the Respiratory System F.Alveoli — also celled air sacs & are the functional unit of the lungs. 1. Site of gas exchange. 2. One cell layer thick, moist & surrounded by capillaries. 3. Capillaries transport deoxygenated blood to the alveoli. 4. CO 2 leaves and O 2 is picked up.

Alveoli

Structures of the Respiratory System G.Lung — made up of the bronchial tubes, bronchioles & alveoli. H.Diaphragm — muscle that forms the floor of the chest cavity.

Gas Exchange A.After inhalation, high concentration of O 2 diffuses into the bloodstream by capillaries. B.Hemoglobin in RBC’s carry the O 2 as oxyhemoglobin. Hb + O 2  HbO 2 Hemoglobin OxygenOxyhemoglobin Hemoglobin OxygenOxyhemoglobin

Gas Exchange C.After exhalation, after cellular respiration cells produce a high concentration of CO 2. D.Hemoglobin in RBC’s carry the CO 2 to the lungs as a bicarbonate (HCO 3 ). CO 2 +H 2 O  HCO 3 Carbon dioxideWaterBicarbonate

Breathing  Moves air into and out of the lungs. A.Inhalation: 1. Ribs move up & out. 2. Diaphragm moves down. 3. This increases the volume of the chest cavity which fills the lungs with air.

Breathing B.Exhalation: 1. Ribs move down & in. 2. Diaphragm moves up. 3. This forces air out of the lung.

Breathing

C.Breathing is regulated by the brain which is sensitive to the concentration of CO 2 in the blood. D.When CO 2 level rises breathing rate increases.

Disorders of the Respiratory System A.Bronchitis — inflammation of the bronchial tubes. B.Asthma — allergic reaction characterized by the constriction of the bronchial tubes which causes difficulty breathing.

Disorders of the Respiratory System C.Emphysema — enlargement & degeneration of the alveoli which results in a decreased lung capacity. Lungs lose elasticity. D.Pneumonia — alveoli become filled with fluid & prevents the exchange of gases.

Pneumonia Emphysema

Disorders of the Respiratory System E.Lung Cancer — tumors form in the lung due to uncontrolled cell division.