Unit 3: Animal Anatomy & Physiology Components of The Digestive System II

Components of the Digestive System OrganCommentsFunction 10) small intestine (3 parts) total of 6.2 m in length but only 2.5 cm wide duodenum: 1 st part of the small intestine jejunum & ileum: middle & last sections lined with finger-like villi peristalsis occurs 1.finishes off chemical digestion for all nutrients produces intestinal fluid (more enzymes to digest all nutrients) receives secretions from pancreas & gall bladder mucus also protects from acidity & enzymes 2. absorption of digested food into blood stream villi increase surface area 3. keeps food moving along

Components of the Digestive System Small Intestine

surface area of small intestine is greatly increased by: 1.lining of small intestine has folds 2.folds contain villi (finger-like projections) 3.villi contain microvilli  total surface area of small intestine = area of professional tennis court

Components of the Digestive System Small Intestine

Duodenum Jejunum Ileum Small Intestine

Components of the Digestive System OrganCommentsFunction 7) liver large multi-lobed organ (A) filling most of the abdominal cavity cirrhosis:. 1.stores excess glucose as 2. filters out & breaks down toxic compounds from blood (detoxification) glycogen 3. makes bile breaks down large fat droplets into smaller ones (called emulsification) scar tissue forms from damage by alcohol & drugs

Components of the Digestive System OrganCommentsFunction 8) gall bladder small sac under the liver (H) connected to the liver by the bile duct (J) gall stones. stores bile & sends it to the duodenum (1 st part of the small intestine) crystallized bile J

Components of the Digestive System OrganCommentsFunction 9) pancreas long feather–shaped organ sends pancreatic secretion to duodenum via the pancreatic duct. 1.makes insulin 2.makes pancreatic secretion containing: enzymes which digest proteins, carbs & lipids

Components of the Digestive System OrganCommentsFunction 13) large intestine (colon) (5 parts) total of 1.5 m in length & 6.5 cm wide 1. caecum 2. ascending colon 3. transverse colon 4. descending colon 5. sigmoid colon feces: contain enormous numbers of bacteria peristalsis. undigested waste 1.reabsorb water & minerals from digestive secretions & compact feces 2. produce vitamins B & K & help further digest waste 3. move feces along

OrganCommentsFunction 14) rectummuscular organ at the end of the colon 3 sphincters: 1.entrance of rectum 2.internal sphincter 3.external sphincter anus. 1. stores feces 2. control egestion opening through which feces are egested when sphincters are relaxed

Large Intestine (frames the small intestine) Shorter than small intestine Diameter is much greater Cecum First part of the large intestine, attached is the appendix Colon Main portion of the large intestine Water and dissolved minerals are absorbed Intestinal bacteria help break food down further Bacteria produce vitamin B-12, K and some amino acids

Large intestine completes the process! Any undigested material (feces) passes into rectum from the colon. Feces moves through anal canal and out the anus. Anus has a ring of circular muscle called the anal sphincter.

Large Intestine Cecum

Traverse colon Descending colon Ascending colon Cecum Sigmoid colon Rectum Anal canal Anus Large intestine

endoscope:a narrow instrument with a camera at its tip placed inside digestive tract to view the inner lining can locate ulcers, polyps or tumours colonoscopy

ENDOSCOPE VIDEOS DUODENUM DUODENUM VILLINORMAL COLON

ENDOSCOPE VIDEOS NORMAL COLON 2 PARASITIC WORM IN COLON REMOVAL OF PARASITIC WORMS IN COLON

ENDOSCOPE VIDEOS COLON JAUNDICE

DIARRHEACONSTIPATION cause result danger bacterial infections, allergies, alcohol, food poisoning, etc. irritate intestinal walls peristalsis occurs too fast feces move through too quickly not enough fibre or water in diet to stimulate peristalsis feces move through too slowly not enough water or minerals are reabsorbed feces remain very watery too much water is reabsorbed feces become very dry more time for toxic substances & food additives to be absorbed danger of dehydration loss of minerals (electrolytes) needed for body functions hemorrhoids: blood vessels around anus are torn & bleed during egestion higher probability of colon cancer

DIARRHEACONSTIPATION treatment avoid foods that stimulate peristalsis (ex. fibre) drink plenty of fluids, especially those that contain electrolytes (ex. gatorade) eat high fibre food drink lots of water regular exercise (stimulates peristalsis) laxatives (ex. prunes – natural laxative)

pharynx epiglottis tongue salivary glands esophagus stomach cardiac sphincter pyloric sphincter liver gall bladder bile ductpancreas pancreatic duct small intestine duodenum jejunum ileum ileo-caecal sphincter appendix colon ascending colon transverse colon descending colon sigmoid colon rectumanus

Homework Small Intestine & Large Intestine Worksheet Page 188 # 1, 2, 5, 10

Magazine Ad from the 1930’s

The Movement of Food Peristalsis – alternate waves of contraction and relaxation of muscles in the organ wall. Circular muscles push food ahead from contracting behind, when long. muscles are relaxed. Longitudinal muscles in front of food contract pushing food back, when circ. muscles are relaxed.

Figure 10.15

The Movement of Food Rhythmic Segmentation – mix up partially digested food in intestine. Circular muscles push it back and forth while food stays in same place. Figure 10.16

Components of the Digestive System OrganCommentsFunction 11) ileo- caecal sphincter 12) appendix ring of muscle at the end of small intestine & beginning of the large intestine tiny sac (3) found on the caecum (2) appendicitis:. inflammation caused by bacteria (swells & could burst) keeps digested food in the small intestine allows more time for digestion & absorption function unknown believed to be left over from our evolutionary past 1 2 3

Still the Small Intestine… Differ only slightly from the duodenum. Jejunum (2.5 m) Contains more folds and intestinal glands than duod. Breaks down remaining protein and carbohydrates Ileum (3 m) Fewer and smaller villi Absorbs nutrients Pushes undigested material into large intestine

Components of the Digestive System Large Intestine