Respiratory System

1. Respiratory System

2. I. Intro • A. Structure • 1. group of passageways that bring air into and out of the lungs • B. Function • 1. Exchanging gases b/n air and body’s cells = RESPIRATION • Gases: O2 & CO2 • C. organs included: • Nose, nasal cavity, sinuses, pharynx, larynx, trachea, bronchial tree, lungs

3. II. Nose • A. nostrils • 1. 2 holes to allow air in • 2. cilia (hair) to filter air • B. nasal cavity • 1. hollow space behind nose • 2. nasal conchae • Bones that curl dividing cavity into passageways • Hold mucous membrane • F: houses many blood vessels that warm air as it comes in so air is = to body temp • Also moistens air • Also filters air

4. III. Pharynx • A. S: passageway for air b/n nasal cavity and larynx • F: • Eventually splits • Trachea = air • Esophagus = food • Also aids in making sounds for speech

5. IV. Larnyx • A. S: structure of muscle and cartilage located at the top of the trachea • Thyroid gland “butterflies” over it • B. F: • 1. passageway for air going into trachea • 2. prevents foreign objects from entering trachea

6. 3. houses vocal cords • False vocal cords • Muscles that close airway for swallowing • True vocal cords • Muscles that make vocal sounds • Work like guitar strings • Muscles tighten and looses for pitch • Loudness based on the air forced through • 4. Epiglottis • Flap-like structure that covers opening of larynx preventing food to go in

7. V. Trachea • A. S: • Flexible, round tube • 2.5 cm diameter, 12.5 cm long • In front of esophagus • Splits into L & R bronchi in thoracic cavity • 20 C-shaped rings of hyaline cartilage • Flexible, but strong so it doesn’t collapse and allows room for esophagus

8. VI. Bronchial Tree • A. passageways from trachea to alveoli • B. primary bronchi • 1. arise from trachea at 5th thoracic vert • 2. 2 main branches = L & R • C. Secondary bronchi • Branch off of primary • D. bronchioles • Small tubes off of secondary

9. E. alveolar ducts • Smaller tubes off bronchioles that lead to alveoli • F. alveoli • 1. microscopic chambers • 2. surrounded by capillaries • 3. provide large surface area for gas exchange • O2 from alveoli to blood • CO2 from blood to alveoli • G. approx. 300 million alveoli

10. VII. lungs • A. S: soft, spongy, cone shaped organs • R & L Lung • R lung has 3 lobes • L lung has 2 lobes – leave room for the heart • Separated by the mediastinum and the heart • Hard tissue that gives separation • Enclosed by the thoracic cavity/rib cage and diaphragm

11. 1. visceral pleura • Membrane that covers lungs directly • 2. parietal pleura • Membrane that connects to mediastinum and rest of body wall • 3. PLEURAL CAVITY • Space b/n pleural membranes • Fluid filled to reduce friction when breathing and for surface tension (explain later)

12. VIII. Breathing • A. inspiration – breathing in • * remember, everything in Science wants to go from H to L • 1. Atmospheric pressure = 760 mm of Hg • Must be lower pressure in the lungs in order for air to enter • A. diaphragm – thin muscle below lungs • Contracts by moving down = expanding lungs • This decreases lung pressure to 758 mm of Hg and air enters lungs

13. B. ALSO – EXTERNAL INTERCOSTAL MUSCLES b/n ribs help by contracting and expanding the rib cage • When the rib cage expands, the lungs also expand b/c of the fluid in the pleural membrane causes everything to stick together by surface tension • Like a wet microscope slide • When the lungs expand, air is “sucked” in • 2. However, if too much ST in alveoli – sides of alveoli may stick together and lungs collapse • A. SURFACTANT – secretion by certain alveoli that cancel surface tension power and don’t let alveoli collapse

14. B. Expiration – breathing out • 1. diaphragm and intercostals relax pushing lungs in • 2. raises lung pressure to 761 and air then exits

15. IX. Respiratory Volumes & Capacities • A. tidal volume • Normal amount of air that enters and exits during regular breathing • Usually 500 c.c. (cubic cm) • B. inspiratory reserve volume • Volume of air that enters lungs when forcing inspiration – in addition to tidal volume • Usually 3,000 cc

16. C. expiratory reserve volume • 1. amount of air expelled from lungs during forced expiration • 2. usually 1,11o cc • 3. RESIDUAL VOLUME = 1200 cc • Left in lungs even after forced expiration • Remains in lungs at all times

17. D. vital capacity • 1. the maximum amount of air a person can exhale after taking the deepest breath possible • 2. usuall 4600 cc • E. total lung capacity • 1. Vital Capacity + Residual Volume = TLC • 2. approx 5800 cc

18. X. Nervous System Control • A. Breathing controlled by respiratory center in medulla oblongata • 1. Rhthmicity Area • Controls rhythm – make sure cycle repeats • In MO • 2. Pneumotaxic Area • Controls rate • In pons

19. XI. Transport of Gases • * Diagrams VERY IMPORTANT • Pg. 348-351 • A. O2 transport • 1. O2 from lungs to blood to tissue • 2. Look at figure 13.21 • P=Pressure • High PO2 in lungs – Low PO2 in blood • O2 diffuses into blood – H to L

20. 3. Look at figure 13.22 • A. hemoglobin – iron containing chemical that carries blood (white dots) • Attaches to O2 that diffused in (black dots) • White HEMO + black O2 = OXY HEMOGLOBIN • B. oxyhemoglobin travels to tissues where O2 is low • C. oxyhemoglobin dumps off its O2 to tissue and recirculates as hemoglobin

21. B. Carbon Dioxide Transport – cellular waste • 1. CO2 from tissue to blood to lungs • 2. Look at figure 13. 23 • A. PCO2 high in tissue, low in blood – H to L • B. CO2 combines with hemoglobin in blood = CARBINOHEMOGLOBIN • 3. Look at figure 13.24 • A. carbinohemoglobin lets off its CO2 in lungs where there is low PCO2 • B. hemoglobin recirculates in blood