Transcript Document
1. THE FUNCTION OF THE RESPIRATORY SYSTEM IS TO CONDUCT AIR IN AND OUT OF THE LUNGS FOR GAS EXCHANGE. 2. EACH LUNG LIES WITHIN A PLEURAL SAC. 3. AIR ENTERS THROUGH THE NASAL CAVITIES. CILIA AND HAIR FILTER DUST AND PARTICLES. BLOOD VESSELS WARM THE AIR AND MUCUS MOISTENS THE AIR. 4. AIR MOVES THROUGH THE PHARYNX, LARYNX, VOCAL CORDS, TRACHEA, BRONCHIAL TUBES, BRONCHI, BRONCHIOLES AND INTO THE ALVEOLI. 5. EACH BRONCHIOLE BREAKS INTO ALVEOLAR SACS. THE ALVEOLI PROVIDE A TREMENDOUS SURFACE AREA FOR GAS EXCHANGE WITH THE BLOOD LOCATED IN THE DENSE CAPILLARY NETWORK THAT SURROUNDS EACH ALVEOLAR SAC. LE 42-23 Branch from pulmonary vein (oxygen-rich blood) Branch from pulmonary artery (oxygen-poor blood) Terminal bronchiole Nasal cavity Pharynx Alveoli Larynx Left lung Esophagus Trachea Right lung Bronchus Bronchiole Diaphragm Heart SEM Colorized SEM 6. TO INHALE, THE DIAPHRAGM CONTRACTS AND FLATTENS. THE RIB CAGE MOVES UP AND OUT, THE CHEST CAVITY VOLUME INCREASES, INTERNAL PRESSURE DECREASES AND AIR RUSHES IN. 7. EXHALE – REVERSE OF INHALE. *How Stuff Works – Animation http://health.howstuffworks.com/adam-200020.htm Rib cage expands as rib muscles contract Air inhaled Rib cage gets smaller as rib muscles relax Air exhaled Lung Diaphragm INHALATION Diaphragm contracts (moves down) EXHALATION Diaphragm relaxes (moves up) 8. GAS EXCHANGE – IN THE ALVEOLI, OXYGEN DIFFUSES DOWN A PRESSURE GRADIENT INTO THE BLOOD PLASMA AND BINDS TO THE HEMOGLOBIN OF THE RED BLOOD CELLS. THIS OCCURS ONLY IF THE MEMBRANE IS PERMEABLE AND MOIST. -THE BLOOD CARRIES THE OXYGEN TO THE TISSUES AND GIVES IT UP WHERE OXYGEN PRESSURE IS LOW AND PH IS LOW. -CO2 IS HIGHER IN THE BODY TISSUES SO IT DIFFUSES INTO THE BLOOD. -CO2 IS RETURNED TO THE LUNGS AND RELEASED DURING AN EXHALE. Exhaled air Inhaled air 160 0.2 O2 CO2 Alveolar spaces 120 27 O2 CO2 104 40 Alveolar epithelial cells Blood entering alveolar capillaries 40 45 O2 CO2 O2 CO2 CO2 O2 Alveolar capillaries of lung Pulmonary arteries Systemic veins Blood leaving alveolar capillaries 104 40 O2 CO2 Pulmonary veins Heart Systemic arteries Tissue capillaries Blood entering tissue capillaries Blood leaving tissue capillaries 40 45 O2 CO2 CO2 O2 Tissue cells < 40 > 45 O2 CO2 100 40 O2 CO2 9. BESIDES SIMPLE DIFFUSION, GAS EXCHANGE RATES ARE AFFECTED BY METABOLIC ACTIVITY AND THE PH OF THE BLOOD. MORE METABOLISM = MORE ACIDITY = HEMOGLOBIN WITH LESS AFFINITY FOR O2 10. BREATHING IS CONTROLLED BY SEVERAL DIFFERENT PARTS OF THE BODY: A. CONSCIOUS BREATHING IS BELIEVED TO BE CONTROLLED IN THE CORTEX OF THE BRAIN. B. UNCONCIOUS BREATHING IS CONTROLLED BY THE PONS AND MEDULLA OF THE BRAIN. C. CHEMORECEPTORS MONITOR THE BLOODS OXYGEN, CARBON DIOXIDE AND PH LEVELS. Cerebrospinal fluid Pons Breathing control centers Medulla oblongata Carotid arteries Aorta Diaphragm Rib muscles