Respiratory System - D313 Section 2 - PDF

 Two Questions in Two Minutes Some Chemistry! Partial Pressures Gas Exchange Transport of Gases in Blood The Alveoli Respiratory Control Centers Pontine Areas Medullary Areas Peripheral Chemoceptors More Questions!  The Cardiovascular System - 19% of assessm...

 Two Questions in Two Minutes Some Chemistry! Partial Pressures Gas Exchange Transport of Gases in Blood The Alveoli Respiratory Control Centers Pontine Areas Medullary Areas Peripheral Chemoceptors More Questions!  The Cardiovascular System - 19% of assessment The Respiratory System - 17% of assessment The Digestive System - 16% of assessment The Urinary System - 14% of assessment The Reproductive System - 17% of assessment The Immune System - 17% of assessment 1. The ________ circulation picks up oxygen for cellular use and drops off carbon dioxide for removal from the body. a) pulmonary b) interlobular c) respiratory d) bronchial 2. A decrease in volume leads to a(n) ________ pressure. a) decrease in b) equalization of c) increase in d) zero 1. The ________ circulation picks up oxygen for cellular use and drops off carbon dioxide for removal from the body. a) pulmonary b) interlobular c) respiratory d) bronchial 2. A decrease in volume leads to a(n) ________ pressure. a) decrease in b) equalization of c) increase in d) zero  760mm Hg (at sea level) 1 𝑃∝ 𝑉  In general, two muscle groups are used during normal inspiration: the diaphragm and the external intercostal muscles. Thus, inspiration is an active process. Expiration is a passive process and only depends on the relaxation of the previously mentioned muscles. During forced breathing, inspiration and expiration both occur due to muscle contractions.  21% 78% 0.04%  Gas exchange depends on diffusion (a passive process). It is basically getting gases into and out of a solution (the blood), so it’s dependent on partial pressure of the gases. Fortunately, we only have to worry about CO 2 and O2. This transfer occurs during external and internal respiration (which we will come back to), starting with external respiration that occurs between the alveoli and the blood in the pulmonary capillaries.   CA CO2 + H2O H2CO3 H+ + HCO3– Without the carbonic anhydrase catalyst, the reaction is very slow, however with the catalyst the reaction is 107 times faster (up to 106 reactions per second).  The carbon dioxide molecules form a carbamate with the four terminal-amine groups of the four protein chains in the deoxy form of the molecule.  Partial pressure in alveoli Blood moving to tissues Hemoglobin exists in two conformations: a high-affinity R state and a low-affinity T state. CO 2 and H+ help stabilize the T state.  Highly vascular! Basement membranes of the alveolar epithelium and the capillary endothelium are fused! The alveolar wall consists of three major cell types: 1. Type I alveolar cells pneumocytes 2. Type II alveolar cells 3. Alveolar macrophages A type I alveolar cell is a squamous epithelial cell of the alveoli, which constitute up to 97 percent of the alveolar surface area. Type II alveolar cells secrete pulmonary surfactant, a substance composed of phospholipids and proteins that reduces the surface tension of the alveoli. Alveolar macrophages are phagocytic cells of the immune system that removes debris and pathogens that have reached the alveoli.  Course material says 105    Inspiratory Center Outputs  Notice what they don’t respond to. Central Chemoreceptors Muscles of Expiration Acid-sensing ion channels (ASICS) Central chemoreceptors respond to changes in the concentration of H+ and CO2 in cerebrospinal fluid. They promote inspiration.  IX Central Chemoreceptors X Muscles of Expiration Peripheral chemoreceptors (glomus cells) respond to changes in the concentration of H+, CO2 , and O2 in the blood. They promote inspiration and send their afferent signals via the cranial nerves. A little bit Central misleading, Chemoreceptors because the Cortical Control hypothalamus and the limbic system are also involved Muscles of Expiration Cortical control can temporarily override our breathing patterns (holding your breath) or modulate breathing during a stressful situation. Also important for speech, singing, etc.  Central Chemoreceptors Cortical Control Pulmonary- stretch lung afferents (via the vagus Stretch Receptors nerve) Muscles of Expiration Pulmonary stretch receptors are mechanoreceptors found in the lungs. When the lung expands, the receptors initiate the Hering- Breuer reflex, which reduces the respiratory rate.  Central Chemoreceptors Cortical Control Stretch Receptors Muscles of Expiration Proprioceptors, are mechanoreceptors located within the Proprioceptors + muscles Proprioceptors sense movement and stretching and create a stimulus that may also trigger the respiratory centers of the brain. These neural factors are consistent with the sudden increase in ventilation that is observed immediately as exercise begins. Dalton: Partial Pressures of gases allows them to act independently of one another. Henry: Solubility is determined by the partial pressure of the gas above the liquid.