Chapter 13 The Respiratory System

Respiratory Sounds  Monitored with stethoscope  Normal Sounds  Bronchial sounds – air in trachea and bronchi  Vesicular sounds – air filling alveoli

Abnormal Sounds Crackle Wheezing Rales

External Respiration Oxygen movement into the blood The alveoli always has more oxygen than the blood Oxygen moves by diffusion towards the area of lower concentration Pulmonary capillary blood gains oxygen

External Respiration Carbon dioxide movement out of the blood Blood returning from tissues has higher concentrations of carbon dioxide than air in the alveoli Pulmonary capillary blood gives up carbon dioxide Blood leaving the lungs is oxygen-rich and carbon dioxide-poor

Gas Transport in the Blood 1. Oxygen transport  Most carried in RBCs on hemoglobin (oxyhemoglobin)  Some dissolved in plasma 2. Carbon dioxide transport  Most in plasma as bicarbonate ion (HCO 3 – )  Some carried in RBCs on hemoglobin.

Internal Respiration Exchange of gases between blood and body cells An opposite reaction to what occurs in the lungs Carbon dioxide diffuses out of tissue to blood Oxygen diffuses from blood into tissue

Internal Respiration Figure 13.11

Respiration Summary

 Phrenic & intercostal nerves  Medula - controls rate & depth  Pons - smoothes out respiratory rate  Eupnea - normal rate 12–15 rpm  Hyperpnia - increased respiratory rate often due to extra oxygen needs Neural Regulation

Neural Regulation of Respiration Figure 13.12

Factors Influencing Rate and Depth 1. Physical factors  Increased body temperature  Exercise  Talking  Coughing 2. Volition (conscious control) 3. Emotional factors

4. Chemical factors a. CO 2 levels  Blood CO 2 is main regulatory system  CO 2 = respiration  Changes in CO 2 act on medulla oblongata b. O 2 levels  Changes detected by chemoreceptors in aorta and carotid artery  Information sent to medulla oblongata

Chapter 13 Respiratory Sys – Disorders & Development

Lung Cancer  1/3 of all cancer deaths in the U.S.  Smoking = incidence  Three common types -Squamous cell carcinoma -Adenocarcinoma -Small cell carcinoma

Respiratory Disorders: 1. Chronic Obstructive Pulmonary Disease (COPD)  Chronic bronchitis & Emphysema  Major causes of death & disability in US  Features - History of smoking -Labored breathing (dyspnea) -Coughing & frequent infections -Retain carbon dioxide -Hypoxia & respiratory acidosis -Ultimately develop respiratory failure

Emphysema Emphysema  Alveoli enlarge as chambers break  Chronic inflammation promotes lung fibrosis  Airways collapse during expiration  Much energy to exhale  Over-inflation leads to a barrel chest  Cyanosis appears late in the disease

Chronic Bronchitis  Mucosa of respiratory passages becomes inflamed  Mucus production increases  Pooled mucus impairs ventilation and gas exchange  Risk of lung infection  Pneumonia is common  Hypoxia and cyanosis occur early

Chronic Obstructive Pulmonary Disease (COPD) Figure 13.13

Sudden Infant Death syndrome (SIDS)  Apparent healthy infant stops breathing and dies during sleep  Possible problem of neural respiratory control center  One third of cases appear to be due to heart rhythm abnormalities

Asthma  Chronic inflamed hypersensitive bronchiole passages  Response to irritants with dyspnea, coughing, and wheezing

Developmental Aspects  Fetal lungs filled with fluid  Not inflated til 2 weeks after birth  Surfactant that lowers alveolar surface tension not present until late fetal development; may not be present in premature babies

Developmental Aspects Important birth defects  Cystic fibrosis – thick mucus clogs the respiratory system  Cleft palate  Newborns – 40 to 80 rpm  Infants – 30 rpm  Age 5 – 25 rpm  Adults – 12 to 18 rpm  Rate increases with old age Respiratory Rate Changes Through Life

Aging Effects  Elasticity of lungs  Vital capacity  Blood oxygen levels  Controlling effects of carbon dioxide  Respiratory tract infection