Lesson_10_Respiration

Lesson_10_Respiration - Dr. Pamela VandeVord BME 50-05...

Info iconThis preview shows pages 1–16. Sign up to view the full content.

View Full Document Right Arrow Icon
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 2
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 4
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 6
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 8
Background image of page 9

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 10
Background image of page 11

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 12
Background image of page 13

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 14
Background image of page 15

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 16
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Dr. Pamela VandeVord BME 50-05 Objectives Following this lesson, you should be able to describe: ° The lungs — Air passageways — Alveoli ° Ventilation — Inspiration and expiration — Respiratory volumes ° Gas exchange — Oxygen transport 0 Hemoglobin — Carbon dioxide transport ° Control of breathing rate Introduction The main function of the respiratory system is to exchange gases between the body and the atmosphere. Our cells need oxygen in order to create energy, and carbon dioxide is a waste byproduct of this process. Therefore, we need to bring oxygen from the atmosphere into our body, and expel the unwanted carbon dioxide from the body. Copyright Mir The MoGraw—Hill Companies. Inc. Permission required lor reproduction ordispiay. Nasal cavny Nostril Pharynx Mouth —— - Larynx Right main bronchus \ -- Trachea Right lung ¥ 7._.— Left main bronchus Lefllung Diaphragm The Lungs The lungs are the major organ of the respiratory system. You have two lungs, right and left. The left is a little smaller, since the heart takes up some space in the chest cavity. Air enters and exits the lungs through the trachea, which is connected to the facial openings of the nose and mouth. Inside the lung, the air passageway of the trachea divides into two bronchi (right and left), and smaller bronchioles to increase the surface area for gas exchange as much as possible. Alveoli Nasal Oxygen- l Pharynx __ :41? cavity rich OXYQBH‘PWr ' ‘: _ blood ' blood (Esophagus) “iv-=5: L f I Lar nx W- at "n9 V L 7 A Bronchiole Trachea r 7 Right _ lung A {. Bronchus f - r . I‘ r 'J-—~ II I I; Bronchlole :fixxu if; f—Tj_.g; -' -_. firfiifi‘ i ll L “ii-RV ._ \III‘ I Diaphragm. #25:?" , . - Blood .Alveoll V." {Heart} capillaries 'I'UrflilllZJ-Eiil' Wm. M | :I'lg'wnri '1" At the very end of the smallest bronchioles, there are small, grape-like clusters called alveoli. Alveoli further increase the surface area of the lungs to the size of a tennis court! Alveoli are thin, air filled sacs, and are the actual site of gas exchange. They are always very close to a pulmonary capillary, so that oxygen and carbon dioxide can cross the walls easily. Alveolus Capillary Alveoli In this diagram, you can see the close contact between an alveolus and a capillary. Notice how oxygen simply diffuses into the blood, and carbon dioxide diffuses into the alveolus. Because the walls are so thin (only 2 membranes to cross) the gases are able to freely diffuse. The gas exchange at the alveolar level is only half the battle... We must also move 1 fresh oxygen-rich air into the lungs, and old carbon dioxide- rich air out of the lungs. To do this, Boyle’s law tells us that i ‘ i / increasing the volume of a \ x, «3‘ b r ”' i * container decreases the pressure “5 ‘5‘ V‘ _ _ "‘ _” i \ l of the gas within that container, Agg‘cggfiggg“ and v1ce versa. Therefore, 1f we pressure (PW) 1ncrease the volume of the lungs, the pressure of the air inside the lungs decreases below atmospheric pressure, and air moves into the lungs. By decreasing the volume of the lungs, we can increase the pressure so gas is expelled. I we I 4—, P9 <P.,1 '—> ‘ :iu’ {Li I I >‘-l—"\ Inspiration Expiration The muscles used for increasing the volume of the o . lungs are the diaphragm and Ventllatlon the rib muscles. Both these sets of muscles are skeletal muscles. When the diaphragm contracts, it lowers, $323: as _ $.32???” and When the rib muscles 23333?” ‘. blamed iLiaTuscyes filmed contract, the ribs raise. This I increases the volume inside the lungs. For expiration, * 1:" Lung : ' "4-71.31 these muscles relax, moving . Diaphragm 1' back to their original positions: p ” the diaphragm moves back up oaaSESQEAJJSiTacts oiaEpiTfigLfiléfi'ies and the rib cage falls back (moves down) (moves up) . . . down. Therefore, inspiration is an active process, contracting muscles, and expiration is passive, relaxing muscles. Ventilation Volumes Air volumes inspired and expired can be visualized on a graph produced by a spirometer. The resting tidal volume is the normal amount you normally breathe in and out. The inspiratory reserve volume is the extra volume of air you can inhale on the deepest breath in, and the expiratory reserve volume is the maximum possible amount you can exhale. The vital capacity is the inspiratory reserve, resting tidal, and expiratory reserve volumes summed. Notice that even after total expiration, there is still a residual volume left in the lungs. This is important to keep the lungs from collapsing. l1? Inspiralfiry - 3 reserve E volume Inspiralow if j,” capacity '2 U": g Vilal _ E : I flaming 7 capaeaty Total :2 tidal lung r“ 3 volume capacity o I J E Expiralory :3 E reaewe _ L": :2 volume} WW'OHB' residual capacity ' Realdual Reeldual volume volume Time Gas Exchange (Ll-399%.?" Atmosphere 0:3 CO: ET J \ Ventilation (1) Alveoli . \ Gas exchange (2) Ll Brloodflow l 02 cog—‘5 Blood flow Pulmonary circulation ,_ l__. ._ U Fli hl Left negart Gas transport (3) heart Ll: Systemic circulation 4/ <— 2 002 :1 ' or i. .A. Gas exchange (4) 1.. 3:- -_- 3-. \_/ Cells Cellular respiration (5) Once the gases have been exchanged in the alveoli, the fresh oxygen must be brought to the tissues. So the oxygenated blood goes through the pulmonary vein into the left side of the heart. The left ventricle pumps the blood out to the systemic circulation. Here, in the capillaries, gases can be exchanged with the cells in the tissues before the process repeats. Oxygen Transport Because blood is a warm fluid, gases do not readily dissolve in it. Although some 02 can be dissolved, it is not nearly enough to satisfy the needs of the body. So a carrier molecule called hemoglobin is required to bind to four molecules of oxygen and transport them to the tissues. Hemoglobin molecules reside in the red blood cells. In the lungs, hemoglobin becomes saturated with oxygen, and in the tissues, it lets the oxygen go so it can diffuse into the cells that need it. Heme Iron group atom (It2 loaded inlungs 02 unloaded a in tissues ‘— Polypeptide chain Hemoglobin saturation (9’0) Hemoglobin Saturation Systemic venous XirrirnLiril ()l (3,. umoadedin fissue capMaues Systemic anenal The way hemoglobin knows to bind O2 in the lungs and release it in the tissues is because of the partial pressures of oxygen in those regions. Notice in the lungs, P02 is about lOOmmHg, so the hemoglobin prefers to be bound to lots of oxygen (4 per hemoglobin molecule). However, in the tissues, the P02 drops to 40mmHg, and the hemoglobin releases some oxygen here. Notice, that even at the lower P02, the hemoglobin is still 80% bound. This is important so you never run out of oxygen! CO2 Transport TISSUE CELL ALVEOLAFISPACEIN LUNG _. \coz produced! _. I 0:32 __ . .-"INTEHSTITIAL 5" ' I 'FLUIE' _ CD: I I (:33 _ _ __ __ _.BLOOD' }' _ . ' " --- .-~"” "" " PLASMA Ca illar WITHIN CO? waii y 002 CAPILLAffi, 'i u/- co, ’J "20 i}. ’ Hemo- Wq _ H2603 g «J globln LA—J releases co ." H20\l .. Hemo- ."neo H2603 an globln i BLOOD Carboniciflj picks up I. HCELL - 3°" (:02 and co, and a :f/k\x .5+ 2 .”+ x. "Co:- * H+ ,x’ "CO3- "' H+ “anxgicarbonete.x" i _- :_ HCO‘ “003 C02 + H20 <2» H2C03 <:> H+ + HCO3' Red blood cells also help circulate CO2 in two ways. First, hemoglobin can bind one molecule of CO2 and carry it along. But also, there is an enzyme called carbonic anhydrase within red blood cells which can change C02 into carbonic. acid (H2C03). This is a weak acid that dissociates into the soluble H+ and HCO3- (bicarbonate ion). Since the bicarbonate ion is soluble, large concentrations can remain in the blood. Once the blood gets to the lungs, the bicarbonate ion is switched back to carbon dioxide so it can diffuse out of the blood and exit the lungs. Pens — —_- '. MedulIa-- —_ Nerve signals trigger contraction of muscles .\_ \\_ .[i _ (I \"'| I.'\ . i 111:; 1/9»! \\ i -. Fiib muscles '.> Diaphragm I .. Control of Breathing Brain Cerebrespinal fiuid . ' BREATHING " - CONTROL CENTERS— stimulated by: 002 increase / pH decrease inblood " Nerve signal indicating 02 decrease 0; sensor -' " ' ' '_ i in artery Although the diaphragm and rib muscles are skeletal muscles (voluntary), there are reflex actions to stimulate an increase in the breathing rate during times of low 02 and high CO2 levels. To do this, there are sensors on the aorta and in the brainstem that can sense the concentrations of O2 and C02. If the CO2 levels are too high, or the 02 levels are too low, nerves from the brain stimulate contraction of the diaphragm and rib muscles. Conclusions The respiratory system is more than just air moving in and out of the lungs. It includes gas diffusion and transport. Gas transport is highly dependent upon the red blood cells floating in the blood since they bind oxygen and carbon dioxide, as well as contain carbonic anhydrase to help dissolution of carbon dioxide. Things to Remember! Contraction of the diaphragm and rib muscles is necessary for inspiration Alveoli are the site of gas exchange with the blood Red blood cells are important for oxygen and carbon dioxide transport around the body Sensors in the aorta and brainstem control the breathing rate ...
View Full Document

This note was uploaded on 08/04/2010 for the course BME 5005 taught by Professor Vandvorde during the Spring '08 term at Wayne State University.

Page1 / 16

Lesson_10_Respiration - Dr. Pamela VandeVord BME 50-05...

This preview shows document pages 1 - 16. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online