The Respiratory System Sections 10.1 & 10.2

The Respiratory System Learning Goal: To explore the respiratory system of humans. Success Criteria: I know I am succeeding when I can… explain that all organisms require oxygen during cellular respiration in order to release the energy stored in food explain how are cells get oxygen (ventilation and gas exchange) label the respiratory system describe the pathway of air explain the mechanisms of breathing

The Need for Oxygen all animal and plant cells need oxygen to survive cells use oxygen to obtain energy from food in a process called aerobic cellular respiration C6H12O6 + 6O2  6CO2 6H2O energy (glucose oxygen carbon dioxide water energy)

The Need for Oxygen Cont’d… energy is stored in molecules called adenosine triphosphate (ATP) ATP is formed when energy from the breakdown of glucose is used to attach a phosphate group (Pi) onto adenosine diphosphate (ADP) energy for cellular processes is released when ATP reacts with other molecules

Gas Exchange ventilation: brings a supply of air containing oxygen to the lungs and removes air with carbon dioxide

Gas Exchange Cont’d… gas exchange: the process by which oxygen diffuses into the body cells and carbon dioxide diffuses out of the cell occurs at 2 locations lungs (oxygen diffuses into the blood from the lungs and carbon dioxide diffuses out of the blood into the lungs) body cells (oxygen is transported through the bloodstream and diffuses into all the cells of the body, carbon dioxide diffuses out cells into the blood )

The Structure of the Respiratory System Animation

The Pathway of Air air from the outside enters the respiratory system through the nose and mouth air is warmed and moistened in the nasal passages and mouth (protests the thin, delicate tissue of the respiratory membrane) nasal passages are lined with tiny hairs and mucus that filter out and trap dust and other airborne particles, preventing them from entering the lungs

The Pathway of Air Cont’d… air then travels from the mouth or nasal passages into the pharynx glottis remains open so that air flows into the trachea, or windpipe

The Pathway of Air Cont’d… trachea is a semi-rigid tube of soft tissue wrapped around c-shaped bands of cartilage (keeps the trachea open)

The Pathway of Air Cont’d… walls of the trachea are lined with mucus-producing cells (mucus is sticky and traps dust and other particles )and cilia (tiny hair-like structures that sweep foreign substances upward through the trachea, where it is swallowed or coughed or sneezed out)

The Pathway of Air Cont’d… trachea branches into two bronchi each bronchus connects to a lung (enclosed within the thoracic, or chest, cavity an protected by the rib cage) inside the lungs, the bronchi branch repeatedly into smaller and smaller tubes called bronchioles at the end of the bronchioles are clusters of tiny sacs called alveoli Each alveolus is tiny, measuring only 0.1 µm to 0.2 mm (micrometres) in diameter. It is the sheer number of alveoli, approximately 150 million in each lung, that provides the necessary surface area for gas exchange. If the entire surface area inside the lungs were flattened out, it would cover an area about the size of a tennis court!

The Pathway of Air Cont’d… gas exchange occurs at the alveoli respiratory membrane that forms the alveoli is moist (oxygen cannot diffuse across the respiratory membrane unless it is dissolved in a liquid) alveoli are surrounded by a network of capillaries alveoli walls are extremely thin (one cell layer thick), so oxygen and carbon dioxide can easily diffuse across the respiratory membrane into the bloodstream

The Mechanism of Ventilation (breathing) lung ventilation (breathing) depends on negative pressure

The Mechanism of Ventilation (breathing) Cont’d… inhalation diaphragm and external intercostal muscles contract ribs are pulled upward and outward volume of the chest cavity increases air pressure inside the lungs is reduced (atmospheric pressure is greater than the pressure in the thoracic cavity) air flows into the lungs (to equalize the pressure)

The Mechanism of Ventilation (breathing) Cont’d… exhalation diaphragm and external intercostal muscles relax ribs move down and in volume of the chest cavity decreases air pressure inside the lungs increases (atmospheric pressure is less than the pressure in the thoracic cavity) air flows out of the lungs

The Mechanism of Ventilation (breathing) Cont’d… during strenuous exercise or forced exhalation, a second set of intercostal muscles, called the internal intercostal muscles, start contracting and relaxing when they contract, they pull the rib cage downward, increasing the pressure inside the lungs and forcing more air out of the lungs

The Mechanism of Ventilation (breathing) Cont’d… pleural membranes cover the lungs and line the chest cavity space between the pleural membranes is called the pleural cavity pleural cavity is filled with fluid to prevent the membranes from separating and also to allow them to slide past each other easily

The Respiratory System Learning Goal: To explore the respiratory system of humans. Success Criteria: I know I am succeeding when I can… explain that all organisms require oxygen during cellular respiration in order to release the energy stored in food explain how are cells get oxygen (ventilation and gas exchange) label the respiratory system describe the pathway of air explain the mechanisms of breathing

Homework 10.1 questions #1-5 10.2 questions #1-5