Digestion Lecture 2 Flashcards

Question

Serosa ## Footnote The Stomach

Answer 1

* part of visceral peritoneum * From lesser curvature, it forms the lesser omentum * From the greater curvature, it forms greater omentum

Answer 2

1. Oblique layer * Strengthens the stomach wall * Assists in mixing and churning to form chyme 2. Circular layer 3. Longitudinal layer

Answer 3

* gentle, rippling peristaltic movements * creates chyme by breaking down food, mixing it with secretions of the gastric glands

Answer 4

* Once the food reaches the pyloric sphincter, each mixing wave forces about 3mL of chyme into the duodenum

Answer 5

* It continues acting in the stomach until the churning mixes it with the acidic gastric juices

Answer 6

* Becomes more active in the stomach * acts to digest triglycerides into fatty acids and diglycerides

Answer 7

* * secreted by parietal cells * kills many microbes, denatures proteins, and stimulates the release of hormones that promote flow of bile and pancreatic juice

Answer 8

* secreted by chief cells * Secreted as pepsinogen (inactive form) * WHY? * It is activated once it comes in contact with HCl * Acts to break down certain peptide bonds between amino acids which leaves smaller peptide fragments

Answer 9

* Secreted by chief cells * splits triglycerides into fatty acids and monoglycerides

Answer 10

* Some water * Ions * short chain fatty acids * certain drugs (aspirin) * alcohol

Answer 11

* Plays key role in nutrient digestion and absorption * 90 percent of nutrient absorption occurs in small intestine * Most of remaining 10 percent occurs in large intestine * Average overall length = 6 m (19.7 ft) * Diameter ranges from 4 cm (1.6 in.) near stomach to 2.5 cm (1 in.) near large intestine

Answer 12

1. Duodenum 2. Jejunum 3. Ileum

Answer 13

* 25 cm (10 in.) in length * Segment closest to the stomach * Acts as a “mixing bowl” * Receives chyme from stomach and digestive secretions from liver, gallbladder, and pancreas * Mostly retroperitoneal * **Duodenal glands** produce mucous secretions * Has few circular folds and small villi * Main function is to neutralize acidic chyme

Answer 14

* Between the duodenum and ileum * ~2.5 m (8.2 ft) in length * In the peritoneal cavity * Has numerous circular folds and abundant, long villi * Majority of chemical digestion and nutrient absorption occurs in jejunum

Answer 15

* Final segment of small intestine * ~3.5 m (11.5 ft) in length * Ends at the **ileocecal valve** * Sphincter controlling flow from the ileum into the cecum of the large intestine * Has few circular folds (none in the distal portion) * Villi are relatively stumpy * Submucosa contains aggregated lymphoid nodules

Answer 16

* secretes secretin

Answer 17

* Secretes CCK

Answer 18

* secretes glucose-dependent insulinotropic peptide (GIP)

Answer 19

* Groups of lymphatic nodules in the ileum

Answer 20

* secrete alkaline mucus that helps neutralize gastric acid in the chyme

Answer 21

* Has an outer longitudinal layer and an inner circular layer

Answer 22

* Completely surrounds the small intestine except for majority of duodenum * Retroperitoneal, has adventitia

Answer 23

* Series of transverse folds along the intestinal lining * Permanent feature * compare to rugae * Roughly 800 folds in the small intestine * Mostly in the jejunum * Increase AS for absorption

Answer 24

* Small mucosal projections that increase surface area for absorption * Covered by epithelial cells * Surfaces covered with microvilli * Contains arteriole, venule, blood capillary, and lacteal

Answer 25

* Extensive capillary network in the lamina propria * Carries absorbed nutrients to the hepatic portal circulation

Answer 26

* Transports materials that cannot enter blood capillaries * Example: * Absorbed fatty acids assembled into protein–lipid packages (chylomicrons) too large to diffuse into bloodstream * Transported by lymphatic system to venous circulation

Answer 27

* Smooth muscle Moves villi back and forth, exposing surfaces to intestinal contents * Squeezes lacteal, assisting in lymph movement

Answer 28

* Projections of apical membrane of absorptive cells * Creates a brush border with brush border enzymes

Answer 29

* Carpet of microvilli on the surface of the epithelial cells * Increases surface area for absorption * Contains enzymes that digest materials * Epithelial cells can then absorb breakdown products

Answer 30

* The pancreas has endocrine and exocrine functions * The exocrine functions of the pancreas contribute to digestion

Answer 31

* Delivers exocrine secretions to the duodenum * Joins the common bile duct from the liver and gallbladder and enters duodenum as a common duct at the hepatopancreatic ampulla (ampulla of Vater) * The ampulla opens at the major duodenal papilla

Answer 32

* Branches from the pancreatic duct and empties separately into the duodenum * Occurs in 3–10 percent of the population

Answer 33

* Makes up 99% of Pancreatic tissue * Contain pancreatic acinar cells * Secrete pancreatic enzymes and buffers * EXOCRINE

Answer 34

* makes up 1% of Pancreatic tissue * Secrete hormones (glucagon, insulin, somatostatin, and pancreatic polypeptide) * ENDOCRINE

Answer 35

* About 1200 - 1500 mL of pancreatic juice are produced each day * Combination of mostly water and ions (secreted by epithelial cells lining the duct) and exocrine secretions (enzymes and buffers)

Answer 36

* digests starch * Carbohydrase (breaks down certain starches) * Almost identical to salivary amylase

Answer 37

* digests protein * Break proteins apart into mixture of dipeptides, tripeptides, and amino acids * Secreted as inactive proenzymes * Activated in the duodenum * Active forms include trypsin, chymotrypsin, carboxypeptidase, elastase

Answer 38

* main fat-digesting enzyme

Answer 39

* digest RNA and DNA

Answer 40

* digests protein * released from the pancreas and will reach the small intestine and will encounter enterokinase (a brush-border enzyme) which activates trypsin, which then acts on the other inactive enzymes to activate them

Answer 41

* Largest visceral organ * It is inferior to the diaphragm and occupies most of the right hypochondriac and part of the epigastric region of the abdominopelvic cavity * The gallbladder is a pear shaped sac that is located in a depression of the posterior surface of the liver and hangs from the anterior margin * Wrapped in tough fibrous capsule * Covered by layer of visceral peritoneum

Answer 42

1. Carbohydrate metabolism 2. Lipid metabolism 3. Protein metabolism 4. Processing of drugs and hormones 5. Excretion of bilirubin 6. Synthesis of bile salts 7. Storage of glycogen 8. Phagocytosis 9. Activation of vitamin D

Answer 43

1. Left lobe 2. Right lobe 3. Caudate lobe 4. Quadrate

Answer 44

falciform ligament

Answer 45

* On the posterior surface of the liver

Answer 46

* Located between the left lobe and the gallbladder

Answer 47

* Temporarily stores bile produced by the liver

Answer 48

* Carries bile from the liver and gallbladder to the duodenum

Answer 49

* Make up 80% of the liver * major functional cells of liver * Wide variety of metabolic, secretory, and endocrine functions

Answer 50

* Immune function

Answer 51

* ducts between hepatocytes that collect bile * exits livers as common hepatic duct

Answer 52

* highly permeable blood capillaries receiving oxygenated blood from hepatic artery and deoxygenated nutrient-rich blood from hepatic portal vein * Hepatic sinusoids will converge and deliver blood to a central vein which then drains into the inferior vena cava

Answer 53

* a bile duct * a branch of the hepatic artery * a branch of the hepatic portal vein * Branches from the arteries and veins of each portal area deliver blood to liver (hepatic) sinusoids of adjacent liver lobules

Answer 54

1. A branch of the hepatic portal vein 2. A branch of the hepatic artery proper 3. A bile duct

Answer 55

* Liver contains ~100,000 liver lobules * Hexagonal shape in cross section * Surrounded by six portal triads (one at each corner of the lobule) * Each roughly 1 mm in diameter

Answer 56

* Triangle cornered by three central veins

Answer 57

* the smallest functional * contains a small portal tract at the center and central veins at the periphery * divided into zones 1, 2, and 3

Answer 58

1. Blood enters liver sinusoids from hepatic artery and vein 2. Hepatocytes beside sinusoids regulate solute and nutrient absorption and secretion 3. Stellate macrophages engulf pathogens, debris, damaged cells 4. Sinusoids drain into central vein 5. Hepatocytes secrete bile into bile caniculi 6. Bile caniculi merge to form bile ductules - carry to nearest bile ducts ## Footnote The liver lobule filters and processes blood. Blood from the digestive system and arteries flows through the lobule, where liver cells absorb nutrients, remove toxins, and make bile to help digest fats. Cleaned blood leaves through veins, and bile goes to the digestive tract. The purpose is to keep the body’s blood clean and support digestion.

Answer 59

* Hepatocytes secrete 800-1000mL of bile daily * Mostly water, bile salts, cholesterol, lecithin, bile pigments and several ions * Partially excretory product/partially digestive secretion * Bile salts play role in emulsification (the breakdown of large lipid globules into a suspension of small lipid globules)

Answer 60

* Hollow, pear-shaped organ * Located in the depression on the posterior surface of the liver’s right lobe * Between meals, stores and concentrates bile secreted from the liver * Contraction of smooth muscle fibers eject contents of gall bladder into cystic duct

Answer 61

1. Left and right hepatic ducts collect bile from liver 2. L and R hepatic ducts unite forming common hepatic duct 3. Bile will then go to the common bile duct (to the duodemum) or the cystic duct (to gallbladder for storage) 4. common bile duct and pancreatic duct meet at hepatopancreateic ampulla 5. Enter the duodenum

Answer 62

* Located in the depression on the posterior surface of the liver’s right lobe * three regions: the fundus, the body, and the neck

Answer 63

* Liver produces about 1 L of bile per day * Unless hepatopancreatic sphincter is open, bile flows into the gallbladder for storage * Release of CCK by the duodenum triggers: * Dilation of the hepatopancreatic sphincter * Contraction of the gallbladder * Bile is ejected into the duodenum * Bile salts break apart lipid droplets through emulsification

Digestion Lecture 2 Flashcards

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