Vertebrate Physiology PCB 3743 Exam 4 Study Guide Anatomy You should know i e be able to label the following organs The basic anatomy of the lungs and alveoli Figure 16 4 and 16 14 The villus in the small intestine Fig 18 10 The hepatic portal vein gallbladder and bile duct Fig 18 23 The pancreas Fig 18 25 18 27 The kidney and a nephron Fig 17 1 17 2 17 5 17 8 Basic anatomy of lungs and alveoli Figure 16 4 and 16 14 Villus in small intestine 18 10 The hepatic portal vein gallbladder and bile duct Fig 18 23 The pancreas Fig 18 25 18 27 The kidney and a nephron Fig 17 1 17 2 17 5 17 8 Chapter 16 Respiration 1 Know the basic anatomy of the lungs alveoli and pulmonary circulation Understand the different intrapulmonary and intrapleural pressures Understand physical properties of the lungs and the role of surfactant and surface tension within the alveoli Know the mechanics of breathing Figure 16 14 a Anatomy i Glottis space between vocal folds which vibrate to create sound ii Larynx voice box holds vocal folds and is attached to trachea iii Trachea tube connecting pharynx to lungs and allows breathing iv v bronchiole branches from bronchi into lungs allow air to reach alveoli vi alveolar sac bunch of alveoli together in a sac that connect to bronchioles vii alveoli each alveolus is a circular ball that increases lung surface area for gas right left bronchus trachea splits into two bronchi which attach each lung exchange viii Type 1 alveolar cell make up structure of all almost all alveolar walls ix Type 2 alveolar cell less common secrete the pulmonary surfactant x diaphragm divides thoracic cavity from abdominopelvic space b Intrapulmonary Intrapleural i Intrapulmonary inside the lungs 1 At rest intrapulmonary pressure atmospheric pressure ii Intrapleural space between the lungs and the chest wall 1 Intrapleural pressure less than atmospheric pressure so lungs kept inflated against chest wall iii Boyle s Law pressure drops as volume increases 1 lowering diaphragm increase in lung volume decrease intrapulmonary pressure suck air into lungs 2 Raising diaphragm increase intrapulmonary pressure force air out c Physical properties of lungs i Compliance amount lung inflates with a pressure change ii Elasticity amount that lung resists inflation and recoils back to resting state lungs stuck to chest wall so always in elastic tension iii Surface Tension film of fluid on inside of alveoli has surface tension attraction of water molecules tending to collapse the alveoli iv Surfactant 1 phospholipid protein detergent that breaks surface tension 2 made by Type 2 alveolar cell v Disorders of surface tension 1 cystic fibrosis genetic defect causes lack of fluid secretion so airway fluid is very viscous 2 acute respiratory distress syndrome ARDS inflammation in lungs leads to excessive accumulation of fluid reduced surfactant release 3 premature infant surfactant not produced until late in gestation just before birth so premature infants have collapsed alveoli unless surfactant is administered 16 14 2 Understand the partial pressure of gases in the atmosphere and blood Understand the different partial pressures of O2 and CO2 at different points of the circulation Understand the regulation of breathing and the control of breathing by CO2 and pH of the blood and CSF a Lung Volume Capacity i Total Lung Capacity gas in lungs after maximum expansion ii Tidal Volume gas breathed in and out at rest iii Vital Capacity gas breathed in and out at maximum inspiration iv Residual Volume gas left in lungs after maximum expiration b Partial pressure fraction of total pressure exerted by particular gas i Example 1 atmospheric pressure is 760 mmHg 2 O2 is 20 of atmosphere 3 PO2 0 20 x 760 152 mmHg ii O2 diffuses from higher PO2 to lower PO2 iii Because O2 is leaving lungs into blood and CO2 is entering lungs from blood PO2 is lower in lungs than in atmosphere and PCO2 is higher in lungs than in blood iv Gas concentration in blood is also measured in partial pressure pressure required to dissolve that much of the gas in the blood v P O2 is high in blood leaving lungs PO2 low in blood leaving tissue vi P CO2 is low in blood leaving lungs PCO2 is high in blood leaving tissue c Control of Breathing i Holding breath hypoventilation allows build up of CO2 ii Faster breathing hyperventilation blows off more CO2 lowers PCO2 in blood iii Restful Breathing Rythmicity area in brainstem set ups rhythm iv Periodic inhalation caused by rhythmic firing of I motor neurons lowering of v diaphragm inspiration Inhalation is terminated by feedback from lung stretch sensors that inhibit inhalation I motor neurons and excite exhalation E motor neurons expiration vi Modulation rhythmic breathing modulated by 1 2 centers in pons pneumotaxic inhibits I apneustic stimulates I 2 Rhythmicity area in medulla 3 Voluntary control from cortex 4 Chemoreceptors in aorta carotid body and brainstem If PCO2 gets too high CO2 HCO3 vii viii Drop in pH in brain make respiratory control centers speed up breathing lower pH more acidic d CO2 and Bicarbonate act as a pH Buffer in the blood i CO2 H20 carbonic acid bicarbonate H ii iii 1 Takes place in CEREBRAL SPINAL FLUID CSF If blood pH is too high basic breathe less to retain CO2 1 more CO2 more bicarbonate more H more acid If blood pH is too low acidic breathe more to blow off CO2 less CO2 less bicarbonate less H less acid 1 e Examples i Rebreathing air paper bag CO2 drops as O2 drops breathing rate increases ii Rebreathing air with CO2 filter O2 drops but CO2 stays low Breathing rate does not increase brain runs out of oxygen iii CO2 levels control breathing 1 Increasing CO2 causes bigger change in breathing than lowering O2 3 Understand the nature of hemoglobin and the loading and unloading of O2 from the hemoglobin a Hemoglobin respiratory pigment picks up oxygen from lungs releases oxygen into tissues increasing oxygen carrying capacity of blood oxygen dissociates from hemoglobin in low pH environment i Consists of 4 protein subunits 2 x alpha 2 x beta subunits and 4 heme molecules centered around iron atom that binds O2 molecule Iron gives blood reddish hue ii Oxyhemoglobin when carrying oxygen iii Deoxyhemoglobin when not carrying oxygen b Dissociation curve proportion of hemoglobin that is carrying oxygen as a function of oxygen concentration in the blood or as a function of pH or temperature etc c 2 3 DPG molecule produced when oxyhemoglobin low causes more oxygen release from hemoglobin 4 Be
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