TAILIEUCHUNG - Lecture Biology 25 (Human Biology): Chapter 9 - Prof. Gonsalves
Chapter 9 provides knowledge of respiratory system. The main contents of the chapter consist of the following: Respiratory tract, mechanism of breathing, gas exchanges in the body, respiration and health, homeostasis. | Chapter 9 Biology 25: Human Biology Prof. Gonsalves Los Angeles City College Loosely Based on Mader’s Human Biology,7th edition Human Respiratory System Functions: Works closely with circulatory system, exchanging gases between air and blood: Takes up oxygen from air and supplies it to blood (for cellular respiration). Removal and disposal of carbon dioxide from blood (waste product from cellular respiration). Homeostatic Role: Regulates blood pH. Regulates blood oxygen and carbon dioxide levels. Blood Transports Gases Between Lungs and Tissues Human Respiratory System Components: Nasal cavity, throat (pharynx), larynx (voice box), trachea, bronchi, alveoli, and lungs. Pathway of Inhaled Air: Nasal cavity Pharynx (Throat) Larynx (Voice Box) Trachea (Windpipe) Bronchi Bronchioles Alveoli (Site of gas exchange) Exhaled air follows reverse pathway. Human Respiratory System 1. Nasal cavity: Air enters nostrils, is filtered by hairs, warmed, humidified, and sampled for odors as it flows through a maze of spaces. 2. Pharynx (Throat): Intersection where pathway for air and food cross. Most of the time, the pathway for air is open, except when we swallow. 3. Larynx (Voice Box): Reinforced with cartilage. Contains vocal cords, which allow us to make sounds by voluntarily tensing muscles. High pitched sounds: Vocal cords are tense, vibrate fast. Low pitched sounds: Vocal cords are relaxed, vibrate slowly. More prominent in males (Adam’s apple). Human Respiratory System 4. Trachea (Windpipe): Rings of cartilage maintain shape of trachea, to prevent it from closing. Forks into two bronchi. 5. Bronchi (Sing. Bronchus): Each bronchus leads into a lung and branches into smaller and smaller bronchioles, resembling an inverted tree. 6. Bronchioles: Fine tubes that allow passage of air. Muscle layer constricts bronchioles. Epithelium of bronchioles is covered with cilia and mucus. Mucus traps dust and other particles. Ciliary Escalator: Cilia beat upwards and remove trapped .
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