Chapter 13 – Part 4 The Respiratory System

1. Chapter 13 – Part 4The Respiratory System

2. Respiratory Volumes and Capacities • Respiratory capacities are measured with a spirometer • As a person breathes, the volumes of air exhaled can be read on an indicator • Spirometer testing is useful for evaluating losses in respiratory functioning and in following the course of some respiratory diseases

3. Respiratory Sounds • Sounds are monitored with a stethoscope • Bronchial sounds – Produced by air rushing through trachea and bronchi • Vesicular breathing sounds – Occur as air fills the alveoli; soft sounds that resemble a muffled breeze • Diseased respiratory tissue, mucus, or pus can produce abnormal sounds such as rales (a rasping sound) and wheezing (a whistling sound)

4. External Respiration • External respiration – the actual exchange of gases between the alveoli and the blood • Oxygen movement into the blood • Because body cells continually remove O2 from the blood, there is always more O2 in the alveoli than in the blood • Oxygen moves by diffusion towards the area of lower concentration • Pulmonary capillary blood gains oxygen

5. 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

6. Gas Transport in the Blood • Oxygen is transported in the blood in two ways: • Most attaches to hemoglobin molecules inside the red blood cells to form oxyhemoglobin (HbO2) • A very small amount of oxygen is carried dissolved in the plasma • Color change in blood • Oxygen-rich blood = bright red • Oxygen-poor blood = dark red

7. Gas Transport in the Blood • Carbon dioxide transport in the blood • Most is transported in the plasma as bicarbonate ion (HCO3–) • Plays a very important role in the blood buffer system • A small amount is carried inside red blood cells on hemoglobin, but at different binding sites than those of oxygen

8. Internal Respiration • 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

9. Internal Respiration

10. External Respiration, Gas Transport, and Internal Respiration Summary

11. Hypoxia • Hypoxia – Inadequate oxygen delivery to body tissues • Impaired oxygen transport • May be the result of anemia, pulmonary disease, or impaired or blocked blood circulation • Symptoms: • Easy to recognize in fair-skinned people because their skin and mucosae take on a bluish cast (become cyanotic) • In dark-skinned individuals, this color change can be observed only in the mucosae and nailbeds.

12. Carbon Monoxide Poisoning • Type of hypoxia • Odorless, colorless gas that competes vigorously with O2 for the same binding sites on hemoglobin • Crowds out or displaces O2 (hemoglobin binds to carbon dioxide more readily than to oxygen) • Leading cause of death from fire • Dangerous because it kills softly and quietly • Does not produce the characteristic signs of hypoxia – cyanosis and respiratory distress • Instead, the victim becomes confused and has a throbbing headache

13. Neural Regulation of Respiration • Activity of respiratory muscles is transmitted to the brain by the phrenic and intercostal nerves • Neural centers that control rate and depth are located in the medulla • The pons appears to smooth out respiratory rate • Normal respiratory rate (eupnea) is 12–15 respirations per minute • Hyperpnea is increased respiratory rate often due to extra oxygen needs (exercise)

14. Suppressed Medulla Centers • If the medulla centers are completely suppressed, respiration stops completely and death occurs. • Can occur with an overdose of sleeping pills, morphine, or alcohol

15. Neural Regulation of Respiration

16. Factors Influencing Respiratory Rate and Depth • Physical factors (Increased body temp-erature, exercise, talking, coughing) • Conscious control (during swimming, swallowing, singing) • Voluntary control of breathing is limited and the respiratory centers will ignore messages from our wishes when the O2 supply is getting too low. • Emotional factors (Ever been so scared that you gasped or were nearly panting?)

17. Factors Influencing Respiratory Rate and Depth • Chemical factors • Carbon dioxide levels • Level of carbon dioxide in the blood is the main regulatory chemical for respiration • Increased carbon dioxide increases respiration • Changes in carbon dioxide act directly on the medulla oblongata

18. Factors Influencing Respiratory Rate and Depth • Chemical factors (continued) • It is the body’s need to rid itself of carbon dioxide (not to take in oxygen) that is the most important stimulus for breathing in a healthy person.

19. Factors Influencing Respiratory Rate and Depth • Hyperventilation – A rapid and deep breathing pattern • Occurs when carbon dioxide or other sources of acid begin to accumulate in the blood and the pH starts to drop • Different breathing pattern from the hyperpnea of exercise • This blows off more carbon dioxide, which returns blood pH to normal

20. Hyperventilation • When brought on by anxiety attacks, it often leads to brief periods of apnea (cessation of breathing) until the carbon dioxide builds up in the blood again • If breathing stops for an extended period of time cyanosis can occur • The individual may get dizzy and faint • Such attacks can be prevented by having the person breath into a paper bag (raises the CO2 levels in the blood)

21. Factors Influencing Respiratory Rate and Depth • Hypoventilation – Extremely slow or shallow breathing • Occurs when blood starts to become too basic • Allows carbon dioxide to accumulate in the blood and brings blood pH into normal range