lecture_notes_31_(ta)

lecture_notes_31_(ta) - Lecture 31:...

Info iconThis preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon
Lecture 31: Gastrointestinal/Digestive Physiology I Reading: ch 16: pgs 579-626 (pgs 591-639, if using 5 rd edition) Digestive System – has the primary function to transfer nutrients, water, and electrolytes from the food we eat into the body’s internal environment. Plant Photosynthesis : ( SUN S ) Energy + CO 2 + H 2 0 produces organic molecules + O 2 Human Cell Metabolism: organic molecules + O 2 produces Energy + CO 2 + H 2 0 Digestive Organs : (Table 16-1) - Mouth and Salivary Glands ( SALIVA CONTAINS ENZYMES THAT BEGIN BREAKDOWN OF CARBOHYDRATES ) - Pharynx and Esophagus - Stomach - Small Intestine (duodenum, jejunum, ileum) - pancreas (provide secretions to the small intestine) ( SECRETE IMPORTANT MOLECULES ) - liver (provide secretions to the small intestine) - Large Intestine ( THIS IS AFTER THE SMALL I NTEST .) (secum, appendix, colon, rectum) ( THE LAST 4 STRUCTURES ARE ENCASED IN SMOOTH MUSCLE ) Interesting Facts: Total length – of the digestive tract is ~30 feet in a cadaver and ~15 feet in a living human ( QUESTION : WHY IS IT SHORTER WHEN WE ARE ALIVE ? ) Lumen ( “ INSIDE OF TUBE ” ) – of the digestive tract is continuous with the external environment. Important point, because 1) pH – in the stomach can fall as low as 2 ( VERY ACIDIC ) , yet in the body fluids the range of pH compatible with life is 6.8-8.0 ( A NARROW RANGE ) 2) Harsh Enzymes – that hydrolyze (“ CHOP UP ”) food could destroy the body’s own tissues. Therefore, enzymes are synthesized in an inactive form and
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
don’t become active until they reach the lumen. 3) Large intestine – is inhabited by millions of microorganisms that are harmless. These same microorganisms could be lethal if they entered the body proper. ( “ MORE OF THESE THAN CELLS IN OUR BODY ” ( WHO S THE HOST ? ))
Background image of page 2
The wall – of the digestive tract has the same general structure throughout most of its length (Figure 16-3) . The 4 major tissue layers are: 1) Mucosa - lines the luminal surface; highly folded. It is divided into the mucous membrane, lamina propria, and muscularis mucosa. ( IN CONTACT WITH FOOD & DIGESTIVE CONTENTS ) 2) Submucosa - thick layer of connective tissue. Provides the digestive tract with its
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 4
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 05/02/2008 for the course NPB 101 taught by Professor Fuller,charles/goldberg,jack during the Winter '08 term at UC Davis.

Page1 / 6

lecture_notes_31_(ta) - Lecture 31:...

This preview shows document pages 1 - 4. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online