1. Respiratory

2. Respiratory Physiology supply the body with O 2 and to dispose of CO 2 4 things happen with every breath:

5. 1. Pulmonary ventilation ▫air must move into and out of the lungs ▫gases in alveoli are continuously changed and refreshed ▫commonly called breathing ▫completely mechanical process ▫depends on volume changes in the thoracic cavity ▫volume changes lead to pressure changes, which lead to the flow of gases to equalize pressure

6. 2. External respiration ▫gas exchange (O 2 Ioading/CO 2 unloading) between pulmonary blood and alveoli 3. Respiratory gas transport ▫O 2 /CO 2 must be transported to/from lungs and tissue cells of the body ▫via the bloodstream 4. Internal respiration ▫gas exchanges made between blood and tissue cells ▫occurs at systemic capillaries

8. 2 phases of breathing ▫inspiration - air is flowing into the lungs ▫expiration - air is leaving the lungs

9. Inspiration ▫diaphragm and rib muscles contract ▫size of the thoracic cavity increases ▫lungs are stretched to the new, larger size of the thorax ▫intrapulmonary volume increases ▫gases in the lungs spread out to fill the larger space ▫a partial vacuum is produced ▫air is sucked into the lungs ▫intrapulmonary pressure will eventually equal atmospheric pressure

10. Expiration ▫passive process ▫depends on the natural elasticity of the lungs ▫inspiratory muscles relax ▫rib cage descends and the lungs recoil ▫gases inside the lungs are forced more closely together ▫intrapulmonary pressure rises to a point higher than atmospheric pressure ▫gases to flow out to equalize the pressure inside and outside the Iungs

11. Nonrespiratory Air Movements ▫coughs/sneezes – clear the air passages of debris or collected mucus ▫laughing/crying/hiccups/yawning – forced inspiration (a result of reflex activity)

13. Respiratory Volumes and Capacities many factors affect respiratory capacity ▫a person's size, sex, age, physical condition normal breathing moves 500 ml of air (about a pint) into/out of the lungs with each breath ▫a person can inhale much more air (between 2100 and 3200 ml) much of the air that enters the respiratory tract remains in the bronchi and never reaches the alveoli ▫called the dead space volume

14. Respiratory Sounds As air flows it produces two recognizable sounds ▫bronchial sounds - produced by air rushing through the large respiratory passageways ▫vesicular sounds - occur as air fills the alveoli (soft and muffled)

15. Respiratory Sounds As air flows it produces two recognizable sounds ▫bronchial sounds - produced by air rushing through the large respiratory passageways ▫vesicular sounds - occur as air fills the alveoli (soft and muffled)

16. External Respiration, Gas Transport, and Internal Respiration External Respiration the actual exchange of gases between the alveoli and the blood called pulmonary gas exchange involves O 2 pickup by hemoglobin in the lungs and CO 2 is being unloaded from the blood equally fast always more O 2 in the alveoli than there is in the blood O 2 moves from alveoli through alveolar-capillary walls into O 2 -poor blood of pulmonary capillaries as tissue cells remove O 2 from the blood in the systemic circulation, they release CO 2 into the blood concentration of CO 2 is higher in pulmonary capillaries than in alveolar air ▫it leaves the blood to pass into alveoli and be flushed out of the lungs during expiration

17. Gas Transport in the Blood ▫O 2 is transported in the blood in two ways ▫most attaches to hemoglobin molecules inside the RBCs ▫very small amount is carried dissolved in the plasma most CO 2 is transported in plasma smaller amount (20% - 30%) is carried inside the RBCs bound to hemoglobin ▫attaches to hemoglobin at a different site than O 2 so it does not interfere with O 2 transport

18. Internal Respiration ▫gas exchange process that occurs between the systemic capillaries and the tissue cells ▫opposite to what occurs in the lungs (O 2 is unloaded/CO 2 is loaded into the blood) ▫CO 2 diffusing out of tissue cells enters the blood ▫O 2 is released at the same time from hemoglobin ▫O 2 diffuses quickly out of the blood to enter the tissue cells

20. Control of Respiration respiratory muscles are the diaphragm and rib muscles activity is regulated by nerve impulses transmitted from the brain (medulla oblongata and pons) medulla sets the basic rhythm of breathing pons smooths out the basic rhythm of inspiration and expiration ▫impulses between the pons and medulla maintain a rate of 12-15 respirations/minute bronchioles and alveoli have stretch receptors that respond to extreme overinflation ▫limits potential damage to the lungs

22. Factors Influencing Respiratory Rate and Depth Physical Factors ▫talking, coughing, and exercise can modify both the rate and depth of breathing ▫increased body temperature causes an increase in the rate of breathing Volition (Conscious Control) ▫singing, swallowing, holding our breath for short periods ▫voluntary control of breathing is limited ▫respiratory centers ignore messages from the cortex when blood O 2 supply/pH gets low  involuntary controls take over and normal respiration begins again

23. Emotional Factors ▫result from reflexes initiated by emotional stimuli from the hypothalamus Chemical Factors ▫relate to the levels of CO 2 and O 2 in the blood ▫increased levels of CO 2 /decreased blood pH lead to an increase in rate/depth of breathing  when blood O 2 levels drop, impulses are sent to the medulla ▫most important stimulus for breathing is the body's need to rid itself of CO 2 (not to take in O 2 )

24. Homeostatic Mechanisms CO 2 begins to accumulate in blood ▫ blood pH starts to drop ▫breathing deepens and occurs more rapidly ▫more CO 2 is blown off ▫blood pH returns to the normal range if blood starts to become slightly alkaline ▫breathing slows and becomes shallow ▫CO 2 to accumulate in the blood ▫blood pH brought back into normal range

25. Respiratory Disorders respiratory system particularly vulnerable to infections because it is open to airborne pathogens ▫rhinitis, tonsillitis, chronic obstructive pulmonary diseases (COPD), lung cancer

26. COPD ▫exemplified by chronic bronchitis and emphysema ▫major cause of death and disability ▫common features  (1) patients almost always have a history of smoking  (2) dyspnea - difficult or labored breathing that becomes progressively more severe  (3) coughing and frequent pulmonary infections  (4) victims are hypoxic, retain CO 2 (respiratory acidosis), and develop respiratory failure

28. emphysema ▫alveoli enlarge as the walls of adjacent chambers break through ▫chronic inflammation promotes fibrosis of the lungs ▫lungs become less elastic ▫airways collapse during expiration ▫air outflow obstructed ▫patients use an incredible amount of energy to exhale (are always exhausted)

31. chronic bronchitis ▫mucosa of the lower respiratory passages becomes severely inflamed ▫excessive amounts of mucus produced ▫pooled mucus impairs ventilation and gas exchange ▫increases the risk of lung infections (including pneumonias)

33. lung cancer ▫accounts for fully one-third of all cancer deaths in the US ▫strongly associated with cigarette smoking ▫low cure rate ▫overall 5-year survival is about 14% ▫metastasizes rapidly and widely ▫most cases are not diagnosed until they are well advanced ▫the most effective treatment for lung cancer is complete resection (removal) of the diseased lung  the greatest potential for prolonging life and cure  an option for very few patients ▫in most cases radiation therapy and chemotherapy are the only options

34. Developmental Aspects Infant Respiratory Distress Syndrome (IRDS) ▫infants born prematurely (before week 28) ▫develop dyspnea within a few hours after birth ▫alveoli which collapse after each breath ▫use tremendous amounts of energy to keep reinflating alveoli Cystic Fibrosis ▫recessive genetic disorder ▫oversecretion of a thick mucus ▫respiratory passages clog ▫individual at risk for fatal respiratory infections

35. Asthma ▫caused by factors such as allergy or anxiety ▫respiratory passages swell and bronchioles constrict ▫causes patients to wheeze and gasp for air