1 / 13

SMALL INTESTINE

SMALL INTESTINE. H.3. SMALL INTESTINE STRUCTURE. SHORT DUODENUM-LIVER & PANCREATIC JUICES ENTER TWO LONG SECTIONS-JEJUNUM & ILLEUM 2 LAYERS OF SMOOTH MUCSLE (CIRCULAR & LONGITUDINAL). MUSCLES CONTRACT & MOVE FOOD ALONG (PERISTALSIS) MUCOSA FORM VILLI

zorana
Download Presentation

SMALL INTESTINE

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. SMALL INTESTINE H.3

  2. SMALL INTESTINE STRUCTURE • SHORT DUODENUM-LIVER & PANCREATIC JUICES ENTER • TWO LONG SECTIONS-JEJUNUM & ILLEUM • 2 LAYERS OF SMOOTH MUCSLE (CIRCULAR & LONGITUDINAL)

  3. MUSCLES CONTRACT & MOVE FOOD ALONG (PERISTALSIS) • MUCOSA FORM VILLI • EACH VILLUS HAS A CAPPILLARY BED & A LACTEAL (SMALLEST VESSEL OF LYMPHATIC SYSTEM)

  4. ABSORPTION • EACH VILLUS HAS MANY MICROVILLI • THEY INCREASE SURFACE AREA FOR ABSORPTION • SOME MOLECULES ARE ABSORBED BY ACTIVE TRANSPORT • EPITHELIAL VILLI CELLS ARE ABUNDANT IN MITOCHONDRIA

  5. PINCYTOTIC VESICLES ARE NEAR THE PLASMA MEMBRANES & ALSO ABSORB MOLECULES INTO VILLI CELLS FROM LUMEN

  6. TIGHT JUNCTIONS • EPITHELIAL CELLS HAVE TIGHT JUNCTIONS BETWEEN ECAH CELL SO THAT NOTHING MOLECULES MOVE IN BETWEEN THE CELLS • ONLY COMPLETELY DIGESTED MOLECULES CAN ENTER THE BLOOD & LYMPH SYSTEM VIA LACTEAL

  7. JUNCTIONS SHARE CELL PROTEINS & ARE SEALED

  8. MECHANISMS FOR ABSORPTION • FACILLITATED DIFFUSION – PROTIEN CHANNELS ALLOW FOR CONCENTRATION GRADIENTS TO DIFFUSE MOLECULES FROM INTESTINAL LUMEN INTO CYTOPLASM OF VILLI CELLS

  9. ACTIVE TRANSPORT – USED WHEN A MARKED CONCENTRATION GRADIENT DOES NOT EXIST & ENERGY IS NEEDED TO TRANSPORT THE MOLECULES INTO THE VILLI CELLS

  10. PINCYTOSIS – ALLOWS SMALL DROPLETS OF FLUIDS TO ENTER THE VILLI CELLS & THEN CONTENTS ARE RELEASED INTO CYTOPLASM & DIFFUSE INTO LACTEAL

  11. WHAT’S NOT ABSORBED? • CELLULOSE • LIGNIN • BILE PIGMENTS (COLON TO FECES) • BACTERIA (NORMAL INTESTINAL INHABITANTS) • INTESTINAL CELLS (BROKEN OFF AS FOOD MOVES THRU LUMEN)

  12. LARGE INTESTINE • REABSORBS H₂O & IONS • NATURALLY OCCURRING BACTERIA RECEIVE NUTRIENTS, WARMTH, & WATER • BACTERIA SYNTHESIZE VITAMIN K • UNDIGESTED MATERIAL IS ELIMINATED AS SOLID WASTE

More Related