© 2003 Science Press Internet Services FISIOLOGIA DIGESTIVA Clase 5: Secreción y digestión gástrica Dr. Michel Baró Aliste

© 2003 Science Press Internet Services Nutrients provided by animal and vegetable products

© 2003 Science Press Internet Services Digestive process is initiated by sensory signals

© 2003 Science Press Internet Services The effect of discussion, sight, and smell of food

© 2003 Science Press Internet Services Oral cavity has important functions in initial processing

© 2003 Science Press Internet Services

Secreción salival Estímulos gustativos (amargos) Tactiles (lisos)

© 2003 Science Press Internet Services Fases de la secreción gástrica Fase cefálica (30%) Fase gástrica (70%) -reflejos vago-vagales -reflejos entéricos locales -gastrina Fase intestinal Acetilcolinamoco Gastrinapepsinógeno HistaminaHCl

© 2003 Science Press Internet Services The arrival of a swallowed food bolus in the stomach (20-30% de la digestión total)

© 2003 Science Press Internet Services The emptying of food from the stomach

© 2003 Science Press Internet Services Passage of acidic, hyperosmolar gastric chyme into duodenum

© 2003 Science Press Internet Services Glándulas de la mucosa gástrica -80% oxínticas (cuerpo y fondo gástrico) -ácido clorhídrico -pepsinógeno I y II -factor intrínseco -moco -20% pilóricas -moco -pepsinógeno -gastrina Otras enzimas -lipasa gástrica (tributirasa) -amilasa gástrica -gelatinasa capa de moco protector 1mm rico en bicarbonato

© 2003 Science Press Internet Services

Célula parietal u oxíntica ( H+) = 160 mmol/L pH = 0,8 (H+)lum = (H+)pl 1500 cal/L mitocondrias pepsinógeno (42500) pepsina (35000) activa a pH 1,8 a 3,5

© 2003 Science Press Internet Services Producción de ácido clorhídrico anhidrasa carbónica

© 2003 Science Press Internet Services Central nervous system: Regula células secretoras NMD del vago n. tracto solitario hipoglicemia aferentes del gusto y viscerales fondo antro fondo antro SSTR2= receptor somastostatina CCK-B= receptor CCK y gastrina pepsinógeno ácido clorhídrico mucus

© 2003 Science Press Internet Services The parietal cell

© 2003 Science Press Internet Services Stimulation of acid secretion

© 2003 Science Press Internet Services Peptides that affect gastric acid secretion

© 2003 Science Press Internet Services Gastrin effects on ECL cells are shown HDC: histidina decarboxilasa

© 2003 Science Press Internet Services Sources of gastric histamine

© 2003 Science Press Internet Services Interaction between histamine and other hormones Célula Parietal

© 2003 Science Press Internet Services Enterochromaffin-like (ECL) cell receptor

© 2003 Science Press Internet Services Histamine-producing (enterochromaffin-like) cell (a)

© 2003 Science Press Internet Services Histamine-producing (enterochromaffin-like) cell (b)

© 2003 Science Press Internet Services Gastrin: chronology of discoveries

© 2003 Science Press Internet Services Gastrin has multiple physiologic effects

© 2003 Science Press Internet Services Stimulations of gastrin release

© 2003 Science Press Internet Services Depressant factors of gastrin release

© 2003 Science Press Internet Services Human antral gastrin-producing (G) cell (a)

© 2003 Science Press Internet Services Human antral gastrin-producing (G) cell (b)

© 2003 Science Press Internet Services Human antral gastrin-producing (G) cell (c)

© 2003 Science Press Internet Services The G cell

© 2003 Science Press Internet Services Inhibition of gastrin release gastrina (+)

© 2003 Science Press Internet Services Chronology of gastrin-releasing peptide

© 2003 Science Press Internet Services GRP-releasing nerves in human gastric mucosa (a)

© 2003 Science Press Internet Services Gastrin-releasing nerves in human gastric mucosa (b)

© 2003 Science Press Internet Services Gastric distribution of gastrin-releasing peptide

© 2003 Science Press Internet Services Somatostatin chronology, chemistry, and localization

© 2003 Science Press Internet Services Human somatostatin-producing (D) cell (a)

© 2003 Science Press Internet Services Human somatostatin-producing (D) cell (b)

© 2003 Science Press Internet Services Human somatostatin-producing (D) cell (c)

© 2003 Science Press Internet Services Somatostatin functions and receptors

© 2003 Science Press Internet Services Combination that regulates gastric acid secretion

© 2003 Science Press Internet Services Digestión Gástrica

© 2003 Science Press Internet Services Carbohydrate is the major energy source in the diet + sucrosa lactosa %5 boca 30-40% En estómago (Maltosa) 50% Endoglucosidasa

© 2003 Science Press Internet Services Lipids have highest energy content of 3 macronutrients a-grasos esenciales: ac.linoleico ac.linolénico

© 2003 Science Press Internet Services The initial event in lipid digestion in the stomach Formación de gotas de emulsión Más relevante en el Período de lactante pH óptimo 4-5,5 Tributirasa: tributirina o grasa de la mantequilla Gotas de emulsión

© 2003 Science Press Internet Services Average daily protein intake is about g in adults pH óptimo 2 – 3 Inactiva a pH 5 Digestión del colágeno de la carne Proteosas, peptonas, polipéptidos

© 2003 Science Press Internet Services Protein digestion begins in the stomach

© 2003 Science Press Internet Services Vitamin B12 is one of water-soluble vitamins (1 ug diario)

© 2003 Science Press Internet Services FIN