Ch 13-B Respiratory System …

Pulmonary Ventilation … 3. Respiratory Volumes and Capacities *Tidal Volume = define and give volume of air Influencing factors: size, sex, age, … *Inspiratory reserve volume = define and give volume of air

B. External Respiration– gas exchange at alveoli Gases move by diffusion Blood just arriving at lung from Pulmonary Artery: *Oxygen, O2: high or low? Carbon dioxide, CO2: high or low? Blood leaving the lungs via the Pulmonary veins: *O2: high or low? CO2: high or low? (a) External respiration in the lungs (pulmonary gas exchange) Oxygen is loaded into the blood and carbon dioxide is unloaded. Alveoli (air sacs) High O2 Low CO2 Loading of O2 Unloading of CO2 Low O2 High CO2 Plasma Red blood cell Pulmonary capillary

C. Gas Transport in the Blood 1. Oxygen transport: After the initial diffusion, how is the O2 carried in the blood *Most is on: what chemical? *Oxyhemoglobin = ? A small amount is: 2. Carbon Dioxide transport in blood: after diffusing from the body cells into the blood Most is on: 1st reaction CO2 + H2O H2CO3 H+ + HCO3 2nd reaction - requires an enzyme Some is dissolved in the plasma and amino acids of hemoglobin Carbonic Acid Bicarbonate

D. Internal Respiration *= define 1. Oxygen: Opposite to what occurs in lungs *Oxygen diffuses from __________________ to _______________________ Then: Hemoglobin: 2. Carbon dioxide: diffuses from ___________ to _______________

Oxygen is unloaded and carbon dioxide is loaded into the blood. (b) Internal respiration in the body tissues (systemic capillary gas exchange) Oxygen is unloaded and carbon dioxide is loaded into the blood. Tissue cells High CO2 Low O2 Loading of CO2 Unloading of O2 Low CO2 High O2 Plasma Systemic capillary Red blood cell Figure 13.11b

V. CONTROL OF RESPIRATION A. Neural Regulation Medulla—sets rhythm of breathing and contains a pacemaker area CO2 in blood Pons—smooths out respiratory rate Normal respiratory rate 12 to 15 respirations per minute

Brain Breathing control centers Pons centers Medulla centers Afferent Impulses to medulla Efferent nerve impulses from medulla trigger contraction of inspiratory muscles Intercostal nerves Phrenic nerves Breathing control centers stimulated by: CO2 increase in blood (acts directly on medulla centers by causing a drop in pH of CSF) Nerve impulse from O2 sensor indicating O2 decrease Intercostal muscles O2 sensor in aortic body of aortic arch Diaphragm CSF in brain sinus Figure 13.12

B. Chemical Factors (Non-Neural) Influencing Respiratory Rate and Depth Chemical factors: CO2 levels CO2: most important stimulus because it affects blood pH Increased levels of CO2  acidic blood pH  increases rate & depth of breathing to correct O2 levels have a lesser affect due to the reserve of O2 in the hemoglobin

VI. Respiratory Disorders: STUDENTS DO Chronic Obstructive Pulmonary Disease (COPD) Chronic Bronchitis Emphysema Lung Cancer Cystic Fibrosis Infant Respiratory Distress Syndrome Sudden Infant Death Syndrome (SIDS) Asthma Affects of TOBACCO

END 23 slides, excluding diagrams A =17, B=6 29: A=11 and B=18 Total = 95 for this next test