Respiratory System

Gas exchange in the body

(top): © Dr. Don W. Fawcett/Visuals Unlimited 200 nm matrix intermembrane space outer membrane inner cristae (top): © Dr. Don W. Fawcett/Visuals Unlimited

active site enzyme substrate products enzyme–substrate complex Degradation A substrate is broken down to smaller products. Synthesis Substrates are combined to produce a larger product. product enzyme enzyme–substrate complex active site substrates

Outside cell 2 3 Inside cell electrons transferred by NADH ATP mitochondrion Electron transport chain Citric acid cycle oxygen glucose Glycolysis pyruvate

Glycolysis

Citric Acid Cycle Pyruvate from glycolysis Which was made from pyruvate molecules

Electron Transport chain

Glycolysis and Fermentation

pulmonary artery pulmonary vein lung External respiration Internal respiration heart systemic vein systemic artery tissue cells CO2 O2 Hb plasma RBC Tissue cell fluid systemic capillary O2 exits blood CO2 enters blood H+ HCO–3 Hb H+ + H2O H2CO3

pulmonary artery pulmonary vein lung External respiration Internal respiration heart systemic vein systemic artery tissue cells CO2 H+ HCO–3 O2 Hb H+ Hb + alveolus plasma Pulmonary capillary pulmonary RBC CO2 exits blood H2O H2CO3 O2 enters blood

tumor Fig. 9.13 a. Normal lung b. Lung cancer

brain Respiratory center: region of the brain that automatically regulates breathing Intercostal nerves stimulate the intercostal muscles to contract. Phrenic nerve stimulates the diaphragm to contract.