1 Respiratory System Chapter 16

2 A) FUNCTIONS -gas exchange (O2 in & CO2 out)-acid:base balance (maintaining pH balance in body) There are two parts to respiration: External = exchange of gases b/w atmosphere & blood Internal = exchange of gases between blood & tissues

3 B. ORGANS 1) Nose - separated from mouth by hard & soft palatesa) warms, moistens, filters air (hair + mucus) b) Important as a ______________________ c) Important for _______________________ d) paranasal sinuses are_________________ Name the 4 paranasal sinuses:

4 B. ORGANS Pharynx: -also called “throat”-common chamber for respiration & digestion -3 sub-divisions: nasopharynx; oropharynx; laryngopharynx

5 Larynx (voice box)  made of cartilagea) -thyroid cartilage = the Adam’s apple (bigger in males) b) -cricoid cartilage at the bottom c) -epiglottis (cartilage inside) blocks fluid & food d) -hyoid bone (anchors muscles of tongue) e) –corniculate cartilage-seen from behind-attaches to __

6 Swallowing deglutinationThyroid cartilage moves up. Epiglottis covers opening to trachea.

7 Larynx (voice box) -vocal chords suspended inside for sound production. -glottis = the opening What would you call the inflammation of the larynx? -vocal chords are very sensitive to smoke & heat (cancer)

8 Trachea (windpipe) -flexible tube (2.5 cm x 12.5 cm)-carries air to lungs -20 “C” shaped rings to prevent tracheal collapse -why do you think the rings are “C” not “O” shape? -lined with cilia to remove debris Movie

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10 a)-branches from the trachea to the lungsBronchi a)-branches from the trachea to the lungs b)-as bronchi split they become smaller and smaller c)-surrounded by hyaline cartilage plates Movie

11 e)-eventually there is no more cartilage = bronchiolesf)-bronchioles are surrounded by smooth muscle only g)-bronchioles changes size in response to ANS stimulation. -NOTE: asthma mainly affects bronchioles Movie

12 trachea  bronchi  bronchioles  alveolar ducts  alveoli

13 Alveolar ducts & Alveoli-alveolar ducts = connect the bronchioles to the alveoli -alveoli = -tiny, grape like chambers (~300 million/lung!) -site of gas exchange -single cell layer thick (like what other structure?) -How many layers of cells b/w air & blood in alveoli?

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15 7) Lungs a)- everything beyond the primary bronchib)-sponge like due to alveoli c)-left lung 2 lobes, right lung 3 lobes (Why is this different?)

16 7) Lungs (con’t) d)-found in the pleural cavity, filled w/ serous fluid e)-visceral pleura = wrapped around lungs f)-parietal pleura = coats the thoracic cavity “pneumothorax” = a hole into this cavity -there is a vacuum between the two pleural layers -pleural cavity is filled with serous fluid (lubricant for breathing)

17 C. PHYSIOLOGY OF RESPIRATION 1) Respiratory Volumes & Capacities-a respirometer can measure air flowing in & out of the lungs -pulmonary “capacities” = sum of 2+ respiratory “volumes” Tidal Volume(TV) = air that enters/leaves with every normal breath Vital Capacity (VC) = take the deepest inspiration & blow it “all” out Residual Volume (RV) = air that stays in the lungs Total Lung Capacity (TLC) = VC + RV

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20 Inspiration “how we get air into our lungs”-air is forced in by atmospheric pressure (760 mmHg at sea level) -air moves IN when pressure inside alveoli < atm. pressure How is pressure inside the alveoli reduced? *by increasing the size of the thoracic cavity How is the size of the thoracic cavity expanded? *diaphragm contracts and pulls down *external intercostal muscles contract  pulling ribs out *pectoralis minor & sternocleidomastoid contract Thoracic cavity expands  pressure dec. w/in alveoli (758 mmHg) air IN

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23 3) Expiration - normally a passive process:a) the diaphragm & external intercostal muscles relax b) alveoli (have elastic tissue) relax & get smaller c) pressure goes UP in the alveoli (761 mmHg) d) air is pushed OUT into the atmosphere Expiration can be active (force yourself to breath out): a) contract abdominal and internal intercostal muscles b) this pushes intestines up into diaphragm c) pressure rises inside alveoli, more air forced OUT

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25 NOTE: alveoli are lined with surfactant to reduce surface tension &NOTE: alveoli are lined with surfactant to reduce surface tension & prevent the alveoli from collapsing.

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27 4) Gas exchange: Oxygen: -moves by DIFFUSION from the alveoli to blood-moves by DIFFUSION from arterial blood to tissues Carbon Dioxide: -moves by DIFFUSION from tissues to venous blood -moves by DIFFUSION from venous blood to alveoli

28 Composition of Air 78% Nitrogen 21% Oxygen 0.04% Carbon Dioxide78% Nitrogen 21% Oxygen 0.04% Carbon Dioxide 0.96% Other gases    Each gas contributes to the pressure produced by air:  Total atmospheric pressure = 760 mmHg  Partial pressure of oxygen = 160 mmHg How do you figure this out? 760 mmHg * = _____________ mmHg

29 Out in the environment Po2 = 160 mm HgFig 16.20

30 5) Gas transportation a) OXYGEN (O2)-most (97 to 98% +) is carried bound to iron in hemoglobin -about 2-3% is dissolved in plasma O2 + Hb  Hb O2 (oxyhemoglobin) -what happens in the tissue? O2 + Hb  Hb O2 (oxyhemoglobin) -more O2 is released if: -high CO2 -high temperature -low pH (acidic)

31 How is Oxygen Transported in Blood?Fig 16.21

32 5) Gas transportation (con’t) b) Carbon Dioxide (CO2)% attached to hemoglobin (carbaminohemoglobin) - 7-9% in the plasma - mainly (64-70%) as a bicarbonate ion (HCO3-) Carbonic Anhydrase CO H2O H2CO HCO H+ carbonic acid bicarbonate ion In rbc’s

33 Carbon Dioxide Moves from Tissues to BloodFig 16.22

34 Carbon Dioxide Moves from Blood to LungIn the alveoli, CO2 from each of the 3 sources moves out of the blood and we breathe it out! Similar to Fig 16.22

35 5) Gas transportation (con’t) c) CO (carbon monoxide)-odorless & colorless gas -produced due to incomplete combustion -poisonous  it binds with Hb at same site as O2 -competes and prevents oxygen from binding -produced due to incomplete combustion (BBQ, smoking… What to do: -call 911 (they need pure O2) -move to fresh air environment -consider purchasing a CO monitor

36 6) Regulation of respiration: (nervous & chemical)a) nervous system regulation: 1) BRAIN -controlled mainly by medulla oblongata -and also by the pons 1) -controlled mainly by medulla oblongata (rhythm and force) -pons (rate) Fig 16.16

37 nervous system regulation (con’t):2) INHALATION REFLEX: medulla sends info to muscles via phrenic nerve __________________ & _____________________ contract ________________________________ Lungs expand and stretch receptors in alveoli are stimulated diaphragm external intercostals - inspiration

38 Regulation of respiration:NOTE: the inhalation reflex results in constant, subconscious cycling 6) Regulation of respiration: a) nervous system regulation (con’t): 2) Inhalation reflex: -medulla sends info via phrenic nerve  diaphragm  contracts -stretch receptors in alveoli stimulated  vagus nerve brings message to medulla  interrupts message to diaphragm  inspiration stops -constant cycling, subconscious Fig 16.18

39 b) chemical regulationMedulla oblongata monitors CO2 & H+ ions in CSF (always) Carotid & aortic bodies monitor O2 ions in blood (back up) CO2 + H2O  H2CO3  HCO3- + H+ Fig 16.18

40 D. ABNORMALITIES

41 1) Asthma -bronchioles constrict & expiration is labored-often an allergic response (dander, pollen,…) -may get worse with cold weather, vigorous exercise or stress -what is in the “inhaler” you might take to help?

42 2) Emphysema (to inflate)-loss of elasticity in the alveoli, you can’t get air out -major cause = smoking (exposure to other chemical vapors can also lead to emphysema) -this is a progressive disease…try to stop the progression! -stale air stays trapped in lungs

43 5) Hyaline membrane disease (respiratory distress syndrome)- primarily a disease of premature infants (lack of surfactant) - can use “Positive End Expiratory Pressure” & artificial surfactant

44 6) Smoking (#1 preventable cause of death!)-anaesthetizes cilia  why is this bad? -irritates mucous membrane  more mucous  “smokers cough” -emphysema, bronchitis, asthma -coronary artery disease, hypertension (nicotine = stress response) -addictive (nicotine) -side-stream smoke is even more dangerous -anaesthetizes cilia (can’t sweep out debris efficiently) -irritates mucous membrane (more mucous produced, cough) -emphysema, bronchitis, asthma -coronary artery disease, hypertension (nicotine releases adrenalin) -addictive (nicotine) -side-stream smoke is even more dangerous -dangerous to developing fetus

45 Tar is laden with carcinogensRespiratory tract (mouth, larynx, lung) Digestive tract (lips/gums/oral cavity, stomach) Urinary tract (bladder)