2. Respiratory system - Anatomy Function of the respiratory system: The primary function of the respiratory system is to supply the blood with oxygen in order for the blood to deliver oxygen to all parts of the body. The respiratory system does this through breathing. When we breathe, we inhale oxygen (O 2 ) and exhale carbon dioxide (CO 2 ). This exchange of gases is the respiratory system's means of getting oxygen to the blood.

3. Respiratory system The respiratory system can be conveniently subdivided into an upper respiratory tract (conducting zone) and lower respiratory tract (respiratory zone), trachea and lungs. Respiratory system - Anatomy

4. Respiratory system The Pathway 1.Air enters the nostrils 2.Passes through the nasopharynx 3.Passes by oropharynx 4.Through the glottis 5.Into the trachea 6.Into the right and left bronchi, which branches and branches into 7.Bronchioles, each of which terminates in a cluster of 8.Alveoli ONLY in the alveoli the actual gas exchange takes place. Respiratory system - Anatomy

5. Respiratory system The NOSE: Usually air will enter through the nostrils, to the nasal passages. The nasal passages serve as a moistener, a filter, and to warm up the air before it reaches the lungs. The hair existing within the nostrils prevents various foreign particles from entering. Respiratory system - Anatomy

6. Respiratory system PHARYNX & LARYNX: Air travels from the nasal passages to the pharynx (known as the THROAT). After leaving the pharynx it goes to the larynx (VOICE BOX). Food and liquids are blocked from entering the larynx by the EPIGLOTTIS to prevent people from choking during swallowing. TRACHEA: The larynx goes directly into the trachea (WINDPIPE). The trachea is kept open by rings of cartilage within its walls. Respiratory system - Anatomy

7. Respiratory system BRONCHI: Around the center of the chest, the trachea divides into 2 cartilage-ringed tubes called bronchi. The bronchi enters the lungs and spread into a treelike fashion into smaller tubes called bronchial tubes. Respiratory system - Anatomy

8. Respiratory system Lungs: Lungs are about the size of a pair of footballs. The lungs are protected by ribs. The right lung is divided into 3 lobes, the left is divided into two lobes. Respiratory system - Anatomy

9. Respiratory system BROINCHIOLS: The bronchial tubes divide and then subdivide, by doing this, their walls become thinner and have less and less cartilage. Eventually, they become a tiny group of tubes called bronchioles. Respiratory system - Anatomy

10. Respiratory system ALVEOLI: Each bronchiole ends in a tiny air chamber that looks like a bunch of grapes. Each chamber contains many cup-shaped cavities known as alveoli. The walls of the alveoli which are ONLY about one cell thick, which are the respiratory surface. They are thin, moist, and are surrounded by several numbers of capillaries. It is the site of gas exchange. Respiratory system - Anatomy

11. Respiratory system Ventilation: a) Control: Is carried out by the muscles of respiration. It occurs under the control of autonomic nervous system. Respiratory system - physiology

12. b) Inhalation (BREATH IN): The body gets oxygen from the air. Rib muscles contract to pull ribs up and out. The Diaphragm muscle contracts to pull down the lungs. Tissue expands to suck in air. c) Exhalation (Breath out): The body gets rid of other gases that does not need. Rib muscles relax. The Diaphragm muscle relax. Tissue returns to resting position and forces air out.

13. Respiratory system Circulation: 1.Systemic circulation 2.Pulmonary circulation Respiratory system - physiology

14. Respiratory system Gas exchange: As the gas exchange occurs, the acid-balance of the body is maintained as part of homeostasis. Upon inhalation, gas exchange occurs at the alveoli (tiny sacs). The alveolar walls are extremely thin, and permeable to gases. The alveoli are lined with thin pulmonary capillaries, which are thin enough to permit gas exchange. All gases DIFFUSE from the alveolar air to the blood in the pulmonary capillaries, as carbon dioxide diffuses in the opposite direction, from capillary blood to alveolar air. Respiratory system - physiology

15. Respiratory system Internal respiration: Internal respiration is basically the exchange of gasses between the blood in the capillaries and the body’s cells.

16. Respiratory system Facts: In an adult, the lungs take up about 250 ml of oxygen every minute while excreting about 200 ml of carbon dioxide. During an average breath, an adult will exchange from 500 ml to 700 ml of air. At rest we breath 15-18 times a minute exchanging about 500 ml of air. There are some 300 million alveoli in two adult lungs, these provide a surface area of some 160 m² (almost equal to the singles area of a tennis curt and 80 times the area of our skin).