The Respiratory System Chapter 23, part 4 The Respiratory System

SECTION 23-9 Gas Pickup and Delivery

Blood in peripheral capillaries delivers O2 and absorbs CO2 Reactions are completely reversible

Figure 23.20 An Overview of Respiratory Processes and Partial Pressures in Respiration PLAY Animation: Respiratory Processes and Partial Pressures in Respiration Figure 23.20a, b

Oxygen transport Carried mainly by RBCs, bound to hemoglobin The amount of oxygen hemoglobin can carried is dependent upon: PO2 pH temperature BPG Fetal hemoglobin has a higher O2 affinity than adult hemoglobin

Figure 23.21 The Oxygen-Hemoglobin Saturation Curve

Figure 23.21 The Oxygen-Hemoglobin Saturation Curve

Figure 23.22 The Effect of pH and Temperature on Hemoglobin Saturation Figure 23.22a, b

Figure 23.23 A Functional Comparison of Fetal and Adult Hemoglobin

Carbon dioxide transport 7% dissolved in plasma 70% carried as carbonic acid buffer system 23% bound to hemoglobin carbaminohemoglobin Plasma transport

Figure 23.24 Carbon Dioxide Transport in Blood

Figure 23.24 Carbon Dioxide Transport in Blood

Summary of gas transport Driven by differences in partial pressure Oxygen enters blood at lungs and leaves at tissues Carbon dioxide enters at tissues and leaves at lungs PLAY Animation: Gas Exchange and Gas Transport

Figure 23.25 A Summary of the Primary Gas Transport Mechanisms Figure 23.25a, b

SECTION 23-10 Control of Respiration

Gas absorption/generation balanced by capillary rates of delivery/removal Homeostatic mechanisms maintain balance Local regulation of gas transport and alveolar function include Lung perfusion Alveolar capillaries constrict in low oxygen Alveolar ventilation Bronchioles dilate in high carbon dioxide

Respiratory centers of the brain Medullary centers Respiratory rhythmicity centers set pace Pons Apneustic and pneumotaxic centers

Figure 23.27 Respiratory Centers and Reflex Controls

Respiratory reflexes Respiratory centers are modified by sensory information including Chemoreceptor reflexes Level of carbon dioxide Baroreceptors reflexes Hering-Breuer reflexes Prevents overinflation Protective reflexes

Figure 23.28 The Chemoreceptor Response to Changes in PCO2

Voluntary control of respiration Regulation of respiratory rate is dependent upon: Conscious and unconscious thought Emotional state Anticipation PLAY Animation: Control of Respiration

SECTION 23-11 Changes in the Respiratory System at Birth

Neonatal Respiration Upon taking the first breath: Inhaled air enters the respiratory passages for the first time The bronchial tree and most of the alveoli are inflated Subsequent breaths complete inflation of the alveoli

SECTION 23-12 Aging and the Respiratory System

The efficiency of the respiratory system decreases with age as: Elastic tissue deteriorates causing lower lung compliance and vital capacity Chest movements are restricted by arthritic changes Some degree of emphysema normally occurs

You should now be familiar with: The primary functions of the respiratory system The organs of the respiratory system and their functions The processes of external and internal respiration The physical principles governing the movement of air into the lungs and the diffusion of gases into the blood The important structural features of the respiratory membrane How oxygen and carbon dioxide are picked up, transported and released in the blood