BIO 446L 1st Edition Lecture 26 Outline of Last Lecture I. Immune System Contda. Co-stimulation of b cellsb. AntibodiesII. Respiratory Systema. Anatomyb. Pleural membranei. Visceralii. Parietalc. Nasal cavities and olfactory epitheliumi. Structure and functionsd. Anatomy of respiratory epitheliume. Larynxf. Tracheag. Bronchial tree and lungsh. bronchiolesOutline of Current Lecture I. respiratory contda. respiratory bronchioles and alveolar ductsi. alveolib. alveolar and respiratory membraneThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.i. interalveolar septumii. type I and II alveolar cells1. surfactantc. blood flow to the lungsi. pulmonary circulationii. bronchial circulationd. innervation of the lungsII. Digestive Systema. Structuresb. Layers of digestive tractc. Oral cavityi. Tongue and tasted. EsophagusCurrent LectureRespiratory System contd- respiratory bronchioles and alveolar ductso alveoli= where gas exchange occurso respiratory bronchioles lead to alveolar ducts to alveolar sacs to alveolio some alveoli interrupt the wall of bronchioleo alveolar ducts epithelium= elastin and reticular fibers- surface area is very high- alveoli and respiratory membraneo alveolar wall is elastic with reticular fibers and filled with capillarieso interalveolar septum= small amount of ECM and many capillaries alveolar cells are very close together- basement membranes are virtually fused type I alveolar cell= very flat, simple squamous, gas exchange type II alveolar cell= large, interspersed with type I, produce surfactant, replenish type I and type IIo macrophages in septum float around alveoli will attack anything previously missed by elevatorso respiratory membrane air-gas barrier air and blood gas exchange type I alveolar cell wall CO2 into alveoli and O2 into RBC- Alveolar cellso Type II secrete surfactant, which decreases surface tension, expands the lungs, and prevents collapse Surfactant= protein and lipid synthesized by phospholipid, stored in lamellar body, exocytosed into alveolus lining Replaces type I and type IIo Junctions between I and II are very tighto Type I strung around alveoli with type II randomly interspersed along with macrophageso MA: emphysema and chronic bronchitis are COPDs Decrease elastic fibers (trouble exhaling) and decrease alveolar wall (disintegrated)o MA: respiratory distress, heart failure (RBCs in septum), and congestive heart disease- Blood flow to the lungso Pulmonary circulation Blood to lungs Pulmonary arteries bring to lungs Gas exchange at capillarieso Bronchial circulation Bronchial arteries Blood returning to left atrium in the pulmonary veins has a slight admixture of deoxygenated blood from the bronchial veins- Innervation of the lungso Smooth muscle innervated by autonomic nervous system Walls of bronchi Recall sympathetic and parasympathetic responses Vagus—parasympathetic tracts to smooth muscle Lateral gray matter—sympathetic to lung smooth muscleo Skeletal muscle Phrenic and intercostal nerves- Move diaphragm, expand/contract lungsDigestive System- Structureso Mouthanuso Lots of MALTo Mouth esophagus stomach small intestine ilium (of small intestine) large intestine rectum anuso Accessory organs Parotid salivary gland Abdomen: liver, gall bladder, pancreaso Peritoneum—serous membrane Lots of space Visceral—mesentery- Layers of the digestive tracto Tube of digestive tract—present throughout o Insdide Mucosa—epithelial (microvilli), small lamina propia (blood and lymph vessel), smooth muscle, ridged wall (increased SA) Submucosa—blood vessels and nerves- Submucosal plexus= nerve networko Lots of MALTo Enteric nervous system—innervated by autonomic Muscularis= thick smooth muscle, circularly and linearly arranged (allows peristalsis)- Myenteric plexus= nerve networko Enteric nervous systemo Outside Serosa—adventitia Blood vessels and nerves enter tissue- Oral cavity—tongue and tasteo Papillae—bumps on tongue Filiform—pointy, middle tongue, no taste buds, help move food Fungiform—tip of tongue, tast buds, saliva Foliate—sides, taste buds, salivao Taste buds—chemosensors, must receive chemicals dissolved in serum for taste to occur Gustatory nerve—taste budbrain Also some olfactory nerves  Taste pore—dissolved chemicals enter bud and cause action potential- Supporting cellso Valliate papillae On underside of tongeo Senses of taste Sweet, sour, bitter, salty, umami- Esophaguso Muscular tube, mouth stomacho Skeletal muscle primarily in upper esophaguso Skeletal and smooth muscle in middleo All smooth in bottom (autonomic)o Lined with mucosao Nonkeratinized stratified squamous epithelia Lamina propia Layers of gut wall in esophagus Secretion of mucus into lumen Muscularis and adventitia (connective tissue)o Cardiac sphincter—guards entrance into stomach, slightly constricted Where acidic contents of stomach may be