BIOL 320 1 st Edition Lecture 16 Outline of Last Lecture I Respiratory Zone II Respiratory Membrane III Lungs IV Pleural Cavity V Breathing VI Pressure Relationships VII Forces Acting on Lungs VIII Boyle s Law IX Inspiration X Expiration XI Resistance to Airflow XII Lung Compliance XIII Gas Exchange XIV Oxygen Transport XV Carbon Dioxide Transport Outline of Current Lecture XVI Oxygen Carbon Dioxide Exchange XVII Oxygen Hemoglobin Dissociation Curve XVIII Factors Influencing Hemoglobin Saturation XIX Neural Control XX Depth and Rate of Breathing XXI Hyperventilation XXII Hypoventilation XXIII Gas Imbalance XXIV Developmental Aspects I Digestive System II Digestive Process III Regulation of Digestion IV Peritoneum V Histology of the GI Tract VI Oral Cavity VII Tongue Current Lecture Oxygen Carbon Dioxide Exchange Oxygen Hemoglobin Dissociation Curve Factors Influencing Hemoglobin Saturation Neural Control Dorsal Respiratory Group near base of nerve IX located in the medulla oblongata integrate central peripheral chemoreceptor input to VRG modify rhythm Ventral Respiratory Group o Location medulla oblongata o Two groups of neurons inhale exhale o Function rhythm generating integrating center o Sets eupnia regular breathing rate 12 15 breaths min Pontine Respiratory Centers o Overall functions influence modify activity of medullary centers smoothing out transitions between expirations and inspirations Rhythm Theories 1 Inspiratory neurons pacemakers 2 Reciprocal inhibition of interconnected medullary networks 2 sets of pacemakers most agreed on 3 3 Stretch receptors in lungs establish rhythm Depth and Rate of Breathing Hyperventilation Benefit clear CO2 from system Hypercapnia increased CO2 in blood triggers increased ventilation Voluntary hyperventilation no real increase in O2 in blood but removes CO2 o Dangerous if overdone triggers respiratory alkalosis dizziness Hypoventilation Characteristic slow shallow breathing due to low CO2 in blood Apnea cessation of breathing restarts when CO2 levels high enough to trigger respiration happens to some when sleeping Gas Imbalance The Bends o Mechanism N2 insoluble at atmospheric pressure if return to surface to fast the solubilized N2 comes out of solution quickly o Symptoms dizzy being on fire o Treatment decompression chamber Carbon Monoxide o Mechanism CO has greater affinity to Hb than O2 if CO binds to Hb then it displaces O2 binding hypoxia pass out o Treatment hyperbaric O2 chamber Oxygen Toxicity o Mechanism O2 is a free radical at high pressures destroy tissues particularly highly vascularized tissues Developmental Aspects Fetus o Autonomous respiration 28 week o Lungs filled with fluid o Site of gas exchange is the placenta At Birth o Respiratory center activated o Respiratory rate highest ever in lifetime Childhood Development Respiratory efficiency decrease with old age Digestive System Components alimentary canal GI tract accessory organs GI Tract Function digest and absorb food nutrients GI Tract Organs 1 Mouth 2 Pharynx 3 Esophagus 4 Stomach 5 Small intestine 6 Large intestine Accessory Organs 1 Teeth 2 Tongue 3 Salivary glands 4 Gallbladder 5 Liver 6 Pancreas Digestive Process Regulation of Digestion Mechanical Chemical Stimuli Intrinsic Control short reflex Extrinsic Control long reflex use same system but also involves the brain Local Enteric Nerve Plexi used by both reflexes to effect smooth muscles glands the gut brain Peritoneum Visceral peritoneum located on lines the organ Parietal peritoneum lines the body cavity Peritoneal cavity located between has serous fluid Mesentery double layer of peritoneum that extends from body wall to organ Functions 1 Attaches 2 Contains blood vessels lymphatics and nerves 3 Stores fat Retroperitoneal organs found outside the parietal peritoneum against dorsal body wall Histology of the GI Tract Oral Cavity Boundaries lips plate cheeks tongue Anterior opening mouth Posterior opening oropharynx To withstand abrasion o Epithelial lining SS epithelium o Keratinized gums hard palate dorsum of tongue Lips and Cheeks o Skeletal muscles lips orbicularis oris cheeks buccinators o Oral cavity proper o Labial frenulum Palate o Hard Bones maxilla palatine o Sof Function assists tongue in chewing Main component skeletal muscle Uvula extension closes nasopharynx when swallow Tongue Location mouth orophayrnx Functions 1 mix food with saliva 2 Grip position food 3 Initiates swallow Papillae grippers location of taste buds Intrinsic muscles movement in Extrinsic muscles protrusion of tongue Lingual frenulum string that holds tongue in mouth