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Pancreas, Liver, GB and Small and Large Intestine.

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Presentation on theme: "Pancreas, Liver, GB and Small and Large Intestine."— Presentation transcript:

1 Pancreas, Liver, GB and Small and Large Intestine

2 Pancreas Found posterior to stomach Extends across the abdomen Only gland to produce enzymes to digest every type of food Amylase – carbs Lipase – fats Proteinase - proteins

3 Secretes enzymes into the duodenum Enzymes are mixed with an alkaline fluid that neutralizes the acidic chyme coming from stomach When chyme enters the duodenum the hormone cholecystokinin is released to signal the release of pancreatic juice Hormones also produced by the pancreas Insulin Glucagon

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5 Gallbladder Pear shaped sac found in hollow of liver Bile made by liver is stored in gallbladder Bile storage sac (bile produced in liver) Bile digests fatty food - bile goes into the duodenum from the gallbladder Cholecystokinin signals the gallbladder to release bile Gallstones are crystallized cholesterol which can cause blockages

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7 Liver Largest gland in the body Located on the right side of the body under the diaphragm Consists of four lobes suspended from the diaphragm and abdominal wall by a ligament Connected to the gallbladder via the common hepatic duct Can regenerate if part of it is damaged or removed

8 Metabolic Functions of the Liver Store glycogen Convert glycogen to glucose Create new glucose

9 Metabolism of Carbohydrates Hyperglycemia—excessively high levels of glucose in the blood Excess glucose is stored in body cells as glycogen If blood glucose levels are still too high, excesses are converted to fat Hypoglycemia—low levels of glucose in the blood Liver breaks down stored glycogen and releases glucose into the blood

10 Protein Metabolism Proteins are conserved by body cells because they are used for most cellular structures Amine groups are removed from proteins as ammonia The rest of the protein molecule enters the Krebs cycle in mitochondria The liver converts harmful ammonia to urea which can be eliminated in urine

11 Fat Metabolism Fats and fatty acids are picked up by the liver Uses some fats to make ATP The rest are broken down into simpler compounds and released into the blood Body cells remove fat and cholesterol to build membranes and steroid hormones

12 Fat Metabolism Most cholesterol is produced in the liver (85%) and is not from diet (15%) Cholesterol is not used to make ATP Functions of cholesterol Serves as a structural basis of steroid hormones and vitamin D Is a major building block of plasma membranes

13 Role of the Liver in Metabolism Several roles in digestion Manufactures bile Plays a central role in carbohydrate, fat and protein metabolism Stores glycogen and vitamins Produces cholesterol, blood proteins (albumin and clotting proteins) Detoxifies drugs and alcohol Decomposes red blood cells Degrades hormones

14 Bile Produced by cells in the liver Composition is Yellow/green color – not an enzyme Salt Cholesterol Electrolytes Function— emulsify fats by physically breaking large fat globules into smaller ones Breakdown Red Blood cells

15 Small Intestine The body’s major digestive organ Site of nutrient absorption into the blood Muscular tube extending from the pyloric sphincter to the ileocecal valve Suspended from the posterior abdominal wall by the mesentery

16 Subdivisions of the Small Intestine Duodenum Attached to the stomach Curves around the head of the pancreas Finishes digestion – pancreas and GB attached

17 Subdivisions of the Small Intestine Jejunum Attaches anteriorly to the duodenum 2/5ths of absorption Ileum Extends from jejunum to large intestine 3/5ths of absorption

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19 Small Intestine Anatomy Villi – increase surface area Villi—fingerlike structures formed by the mucosa Microvilli—tiny projections of the plasma membrane (create a brush border appearance) Circular folds (plicae circulares)—deep folds of mucosa and submucosa

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23 Small Intestine Physiology All about absorption and transporting the nutrients to the blood stream Peristalsis moves the chyme through the SI to the LI through the ileocecal sphincter

24 Small Intestine Physiology Mucus – secreted by cells for easy passage and to help absorption Peptidase – breaks down protein Sucrase – breaks down sugars Lipase – splits fats

25 Large Intestine Larger in diameter, but shorter in length, than the small intestine Frames the internal abdomen Reabsorption of water and electrolytes

26 Large Intestine Anatomy Cecum—saclike first part of the large intestine – attached to SI by ileocecal valve Appendix No digestive purpose lymphatic tissue that sometimes becomes inflamed (appendicitis) Hangs from the cecum

27 Large Intestine Anatomy Colon Ascending—travels up right side of abdomen Transverse—travels across the abdominal cavity Descending—travels down the left side Sigmoid—enters the pelvis (S shaped) Rectum and anal canal —also in pelvis

28 Large Intestine Anatomy Anus—opening of the large intestine External anal sphincter—formed by skeletal muscle and under voluntary control Internal involuntary sphincter—formed by smooth muscle These sphincters are normally closed except during defecation

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30 Large Intestine Anatomy No villi present Banded muscles Mucus – lubricate for feces passage Haustra (pocketlike sacs) – pouches for holding fecal material

31 Large Intestine Physiology Little to no digestive function Vitamin B and K – bacteria living in LI produce these vitamins Reabsorb water, vitamins and minerals

32 Large Intestine Physiology Peristalsis and mixing occur 2-3 times a day Mass Movement – movement of material happens in large sections that constrict at once Defecation reflex – forces out rectum when sphincter relaxes


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