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37 Cards in this Set
- Front
- Back
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Submucosal Plexus
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- Controls glandular secretions of mucosa
- contractions of muscularis externa |
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Myenteric Plexus
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- Controls peristalsis
- Contractions of muscularis externa |
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What does saliva do?
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Moistens the food, begins starch and fat digestion - through Salivary Amylase
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Function of Lingual Lipase
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Digests fat activated by stomach acid
Not activated till it hits the stomach |
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Salivation - Parasympathetic
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Salivary glands produce thin saliva, rich in enzymes
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Salivation - Sympathetic
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Salivary glands produce less abundant, thicker saliva, with more mucus
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Esophagus
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25-30 cm long
Nonkeratinized stratified squamous epithelium Esophogeal glands in submucosa Skeletal muscle in upper part and smooth in bottom (voluntary to involuntary phases of swallowing of a food bolus down the esophagus. |
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Innervation and Circulation
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All blood from stomach enters hepatic portal circulation and is filtered through liver before returning to the heart
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Mucosa
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simple columnar glandular epithelium
Lamina propia is filled with tubular glands (gastric pits) Mucus cells secrete mucus |
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Regenerative Cells
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Divide rapidly to produce new cells that migrate to the surface
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Parietal cells
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Secrete HCl and intrinsic factor
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Chief cells
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Secrete pepsinogen
Chyosin and lipase in infancy |
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Enteroendocrine cells
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Secrete hormones and paracrine messengers
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H+ is pumped into the stomach by?
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H+ K+ ATPase
Antiporter uses ATP to pump H+ out and K+ in |
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Intrinsic Factor is essential for what?
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B12 absorption by the small intestine
RBC production (lack causes pernicious anemia) |
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What does pepsin do?
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Protein digestion
secreted as pepsinogen (inactive) HCl converts to pepsin (Active) |
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Lower esophageal sphincter
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is not a real sphincter
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Regulation of Gastric Function
1.) Cephalic Phase |
Sight, smell, taste, or thought of food
Vagus nerve stimulates gastric secretion and motility |
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Regulation of Gastric Function
2.) Gastric Phase |
Activated by presence of food or semi-digested protein --> by stretch or increase in pH
Secretion stimulated by: ACh, histamine, and gastrin |
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Regulation of Gastric Function
3.) Intestinal Phase |
Duodenum regulates gastric activity through hormones and nervous reflexes
Gastric activity increases if duodenum is stretched Enterogastric reflex duodenum inhibits stomach caused by acid and semi-digested fats in duodenum |
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Where is bile produced and stored?
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Produced in the liver and stored in the gall bladder
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Pancreas Endocrine & Exocrine Gland
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- Secretes insulin and glucagon into the blood
- Water, enzymes, zymogens, sodium bicarbonate, & other enzymes are activated by exposure to bile and ions in the intestine |
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Pancreatic Acinar Cells
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Zymogens = proteases
- Trypsinogen - Chymotrypsinogen - Procarboxypeptidase |
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Why is secretin released from the duodenum?
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It's secreted in response to the acidic chyme --> stimulates the ducts to secrete more bicarbonate
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Function of the Duodenum
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Receives stomach acids, pancreatic juice and bile
Neutralizes stomach acids, emulsifies fats, pepsin inactivated by pH increase, pancreatic enzymes BREAKDOWN OF FOOD |
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Function of the Jejunum
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Most digestion and nutrient absorption occurs here
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Functions of the Ileum
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The function of the ileum is mainly to absorb vitamin B12 and bile salts and whatever products of digestion were not absorbed by the jejunum
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Small Intestine
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Simple columnar epithilium and have microvilli with brush border on cells
These brush border enzymes for final stages of digestion |
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Intestinal Crypts
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Pores opening between villi lead to the intestinal crypts
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What are Peyer patches?
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They are populations of lymphocytes that fight off pathogens
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Segmentation
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Mix and chum contents - not move
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Peristaltic Waves
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Gradual movement of contents towards colon
PUSH CHYME along for 2 hours Movement |
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Food in the stomach causes this reflex
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Gastroileal Reflex
Relaxing of valve and filling of cecum |
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Lactose Digestion
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Brush border enzymes act upon oligosaccharides, maltose, sucrose, lactose, and fructose
Lactose indigestible after age 4 in most humans |
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Fructose is absorbed by what and converted to what?
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Absorbed by facilitated diffusion
converted to glucose in the cell |
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The large intestine doesn't have what?
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Circular folds or villi to increase surface area
Don't need this because you don't absorb anything in the large intestine |
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Sodium-Glucose transport protens (SGTP) in membrane help absorb?
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Glucose and Galactose
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