The Respiratory System

1. The Respiratory System • The primary function of the respiratory system is to allow oxygen from the air to enter the blood and carbon dioxide from the blood to exit into the air. • Inspiration –inhalation (breathing in) • Expiration- exhalation ( breathing out)

2. The Nose Functions • Provides an airway for respiration • Moistens and warms entering air • Filters and cleans inspired air • Resonating chamber for speech • Detects odors in the airstream

3. Goblet Cells Respiratory mucosa-contains goblet cells that secrete mucus • Mucus • Stickiness traps inhaled particles • Lysozymes kills bacteria

4. Nasal Cavity • Vibrissae (guard hairs) stiff hairs that filter large particles from the air • Nasal cilia hair-like projections that propel trapped particles towards the throat for digestion by digestive enzymes

5. Nasal Cavity cont. • Rich supply of capillaries warm the inspired air • Nasal conchae – folds in the mucous membrane that increase air turbulence and ensures that most air contacts the mucous membranes • Olfactory mucosa – mucous membranes that contain smell receptors

6. The Pharynx (throat) • Funnel shaped passageway that connects the nasal and oral cavities to the larynx • Three regions of the pharynx • Nasopharynx - air passage • Oropharynx & Laryngopharynx- passageway for air, food, and drink

7. The Larynx (voice box) Functions : • Keeps food and drink out of the airway • Sound production • Anatomical Features: • 9 c-rings of hyaline cartilage form the framework of the larynx (the apex is called the Adam’s apple • Muscular walls aid in voice production and the swallowing reflex • Glottis – the superior opening of the larynx • Epiglottis – prevents food and drink from entering airway when swallowing • False vocal cords – aid in closing the glottis when swallowing • True vocal cords – produce sound when air passes between them

8. The Anatomy of the Larynx Figure 23.4

9. The Glottis Figure 23.5a, b

10. The Trachea (windpipe) • Functions : • Air passageway • Cleans, warms, and moistens incoming air • Anatomical Features : • Rings of hyaline cartilage – reinforce the trachea and keep it from collapsing when you inhale • Traps inhaled debris and propels mucus to the pharynx where it is swallowed

11. The Anatomy of the Trachea Figure 23.6a, b

12. Bronchi Function : • Solely an air passageway Anatomical features : • Left and right primary bronchi branch off from trachea • Once the primary bronchi enter the lungs they are subdivided into smaller tubes: • Secondary bronchi → tertiary bronchi → bronchioles → terminal bronchioles → respiratory bronchioles → alveolar ducts → alveolar sacs

13. The Lungs • Left Divided into 2 lobes Smaller than the right lung Cardiac notch accommodates the heart • Right Divided into 3 lobes • Each lobe is separated by connective tissue and has its own arteries and veins. • Serous membranes-cover the entire surface of the lungs and produce pleural fluid-enables the lungs to expand and contract with minimal friction • Visceral –adheres to the surface of the lung • Parietal- lines the thoracic cavity

14. The Gross Anatomy of the Lungs Figure 23.7

15. The Bronchi and Lobules of the Lung Figure 23.10b

16. The Alveoli Alveoli- tiny sacs that are the final branching of the respiratory tree and act as the gas exchange units of the lung. Alveolar sacs- clusters of alveoli Alveolar cells – allow for diffusion of gases & secretion of surfactant -

17. Alveoli cont. • Surfactants are substances that reduce surface tension of fluid in the lungs and helps make (alveoli) more stable. keeps them from collapsing when an individual exhales • Surface tension-the tendency of molecules in a fluid to be pulled toward the center of the fluid • High surface tension would tend to decrease the surface area of the lungs, thus making it harder to absorb air.

18. Alveolar Organization Figure 23.12a-c