1. Respiratory System It’s a gas!

2. Respiratory System Pathway of Air: Nose/mouth Nasal/oral cavities Pharynx *Epiglottis Larynx Trachea Bronchi Bronchioles Alveoli

3. Oral & Nasal Cavities & Pharynx Warm & moisten air to protect delicate lung tissue. Sticky mucous lining & mucous-covered hairs in nasal cavity filter particles from air.

4. Larynx & Voice Sound produced as 2 ligaments (vocal cords) vibrate when air passes through them. Pitch varies with tension of vocal cords – more tension = higher pitch Volume depends on amount of air forced past them – more air = greater volume. Laryngitis – inflammation of vocal cords due to overuse.

5. Airway Trachea/bronchi Made of rings of cartilage (keeps airway open). Lined with mucous membranes (trap particles) and cilia (sweep particles up and out of airway). Epiglottis closes trachea when swallowing. Bronchi branch into bronchioles Lungs Right is larger (3 lobes) than left (2 lobes). In thoracic cavity, lined w/ pleura (membranes that reduce friction. LARGE surface area.

6. Alveoli & Capillaries Bronchioles terminate in dead-end sacs – alveoli – surrounded by a net of capillaries.

7. Gas Exchange External Respiration - Exchange of gases between atmosphere and blood by diffusion. Internal Respiration – Exchange of gases between blood and cells by diffusion. Diffusion happens when there is a concentration gradient (difference) in a fluid (gas or liquid). *The Respiratory System Respiratory System

8. Oxygen & CO 2 Transport In Blood 97% of oxygen transported on hemoglobin in RBCs. 67% of CO 2 reacts w/ water to form carbonic acid, disassociates into bicarbonate ions (HCO 3 - )

9. Mechanism of Breathing Diaphragm Mechanism of Breathing Mechanics of Breathing 2 Boyle’s Law – pressure exerted by a gas varies inversely with the volume of the gas.

10. Inspiration & Expiration Respiratory System Review - Kahn Academy

11. Regulation of Breathing Brain monitors the concentration of CO 2 in the blood. Why not O 2 ? A: O 2 is carried by hemoglobin inside RBCs, while CO 2 is mostly carried in the plasma.

12. Disorders Asthma – inflammation of the lining of bronchioles causes reduced air flow. Emphysema – alveoli lose elasticity and rupture, reducing surface area and lung capacity.

13. Smoking Tar and particles clog up lungs & paralyze cilia so they can’t clear debris. If a smoker quits, damage may be reversible.