DIGESTION 3

• PERISTALSIS

INTESTINAL MOVEMENTS

INTESTINEFACTS

PERISTALSIS ENDOSCOPY

ITZA ENDOCRINE GLANDINSULINPANCREATIC JUICES HAVE ENZYMES LIKECARBOHYDRASESLIPASESNUCLEASES

THE PANCREAS

Figure 24.18a-c

Figure 24.18 The Pancreas

INSULIN PATHWAY

GLANDS EXOCRINE/ENDOCRINE

Figure 24.22 The Activities of Major Digestive Tract Hormones

Figure 24.22

Figure 24.19b, c

Figure 24.19 The Anatomy of the Liver

HEPATIC

TULAREMIA ( RABBIT FEVER )

• HOLLOW, PEAR-SHAPED ORGAN• STORES, MODIFIES AND CONCENTRATES BILE

THE GALLBLADDER

GALLSTONES

• REABSORB WATER AND COMPACT MATERIAL INTO FECES• ABSORB VITAMINS PRODUCED BY BACTERIA• STORE FECAL MATTER PRIOR TO DEFECATION• HAS 2 PARTS, CECUM AND COLON

LARGE INTESTINE

Figure 24.23a

Figure 24.23 The Large Intestine

Figure 24.23b, c

Figure 24.23 The Large Intestine

• LAST PORTION OF THE DIGESTIVE TRACT• TERMINATES AT THE ANAL CANAL• INTERNAL AND EXTERNAL ANAL SPHINCTERS

• HEMORRHOIDS

THE RECTUM

• REABSORPTION IN THE LARGE INTESTINE INCLUDES:– WATER– VITAMINS – K, BIOTIN, AND B5

– ORGANIC WASTES – UROBILINOGENS AND STEROBILINOGENS

– BILE SALTS– TOXINS

• MASS MOVEMENTS OF MATERIAL THROUGH COLON AND RECTUM– DEFECATION REFLEX TRIGGERED BY DISTENTION OF

RECTAL WALLS

PROCESSES IN THE LARGE INTESTINE

Figure 24.25

Figure 24.25 The Defecation Reflex

• Disassembles organic food into smaller fragments

• Hydrolyzes carbohydrates, proteins, lipids and nucleic acids for absorption

Processing and absorption of nutrients

• Begins in the mouth – Salivary and pancreatic enzymes • Disaccharides and trisaccharides

– Brush border enzymes• Monosaccharides

• Absorption of monosaccharides occurs across the intestinal epithelia

Carbohydrate digestion and absorption

• Lipid digestion utilizes lingual and pancreatic lipases– Bile salts improve chemical digestion by

emulsifying lipid drops– Lipid-bile salt complexes called micelles

are formed–Micelles diffuse into intestinal epithelia

which release lipids into the blood as chylomicrons

Lipid digestion and absorption

• Low pH destroys tertiary and quaternary structure

• Enzymes used include pepsin, trypsin, chymotrypsin, and elastase– Liberated amino acids are absorbed

Protein digestion and absorption

• Water –Nearly all that is ingested is reabsorbed

via osmosis• Ions – Absorbed via diffusion, cotransport, and

active transport• Vitamins –Water soluble vitamins are absorbed by

diffusion– Fat soluble vitamins are absorbed as part

of micelles• Vitamin B12 requires intrinsic factor

Absorption

Figure 24.27 Digestive Secretion and Absorption of Water

Figure 24.27

Figure 24.1

Figure 24.1 The Components of the Digestive System