lecture 27: digestive system

Question 1

why do we have accessory organs

Answer 1

• secrete substances required for chemical digestion
• food does NOT actually pass through these organs

Question 2

quadrants

Answer 2

RUQ
RLQ
LUQ
LLQ

Question 3

regions

Answer 3

epigastric (L&R hypochondriac)
umbilical (L&R lumbar)
pubic (L&R inguinal)

Question 4

organs

Answer 4

liver
gallbladder
pancreas
stomach
spleen
duodenum
diaphragm
gallbladder

Question 5

pancreas

Answer 5

• LUQ/left hypochondriac and epigastric regions
• closely associated w spleen and stomach

structure:
- head, body, uncinate process, tail
- pancreatic duct, accessory pancreatic duct

Question 6

secretory structures

Answer 6

• minor duodenal papilla: the opening for the accessory pancreatic duct
• hepatopancreatic
• major duodenal papilla: rounded projection in the duodenum into which the common bile duct and pancreatic duct drain
• accessory pancreatic duct
• pancreatic duct:
  secretes digestive enzymes, ions, and water

Question 7

blood supply

Answer 7

• celiac trunk: short, arises from aorta, passes below the median arcuate ligament
• superior mesenteric artery (blood to head and uncinate process)
• splenic artery

Question 8

venous drainage

Answer 8

• portal vein
• superior mesenteric vein
• splenic vein: runs along the posterior border of the pancreas up to the neck, where it joins the superior mesenteric vein

Question 9

role in digestion (exocrine and endocrine)

Answer 9

exocrine functions: pancreatic juice secretion into duodenum
endocrine functions: hormone secretion into bloodstream
*key for blood glucose/sugar regulation

Question 10

Pancreatic Acini

Answer 10

Exocrine
- 99% of glandular epithelial cells
- secrete pancreatic juice: water, some salts, sodium bicarbonate (pH balance), pancreatic enzymes (digest macromolecules)

Question 11

Pancreatic Islets (of Langerhans)

Answer 11

Endocrine
- 1% of glandular epithelial cells
- secrete hormones: insulin (beta cells) lowers blood glucose, glucagon (alpha cells) high blood glucose), somatostatin, pancreatic polypeptide

Question 12

is the pancreas a endo or exocrine gland

Answer 12

both

Question 13

what’s in the RUQ

Answer 13

diaphragm, liver

Question 14

lobes of liver

Answer 14

• caudate lobe
• right lobe
• left lobe
• IVC
• quadrate lobe

Question 15

liver ligaments

Answer 15

• coronary ligament: liver to diaphragm
• falciform ligament: liver to anterior abdominal wall
• ligamentum teres: “round ligament”

Question 16

porta hepatis

Answer 16

• hepatic portal vein: receives blood from stomach, intestines, pancreas, and spleen, and carries it into liver through the porta hepatis
• proper hepatic artery: continuation of the common hepatic artery, a branch of the celiac trunk
• common hepatic duct: tube that carries bile from liver

Question 17

liver blood supply

Answer 17

blood supply:
- portal vein: deoxygenated blood containing nutrients (GI tract), deoxygenated blood containing nutrients (so it can filter toxins by going back to your heart). blood vessel that carries blood from GI, gallbladder, pancreas, and spleen to liver
- proper hepatic artery: oxygenated blood from the heart. continuation of the common hepatic artery, a branch of the celiac trunk
venous drainage:
- hepatic veins: drains low o2 blood into the IVC

Question 18

hepatic blood flow summary

Answer 18

hepatic blood flow is the blood flow to and from the liver, responsible for delivering oxygen and nutrients to the liver cells and removing waste products from the liver

1. oxygenated blood from hepatic artery or nutrient-rich deoxygenated blood from portal vein go into…
2. hepatic sinusoids
3. central vein
4. hepatic veins
5. IVC

Question 19

liver roles in digestion

Answer 19

• metabolic reg
• bile production
• detoxification
• storage

Question 20

the liver receives blood from the…

Answer 20

hepatic artery and portal vein

Question 21

RUQ

Answer 21

inferior surface of liver
gallbladder fossa

Question 22

gallbladder

Answer 22

function: stores and concentrates bile before release into the duodenum
- cystic duct
- neck
- body
- fundus

Question 23

biliary tree

Answer 23

series of ducts that transport bile from liver to small intestine, aids in digestion and absorption of fats

1. L and R hepatic ducts
2. common hepatic duct
3. cystic duct: bidirectional flow
4. bile duct
5. accessory pancreatic duct
6. pancreatic duct
7. hepatopancreatic ampulla

Question 24

what does bile do

Answer 24

• emulsifies fat breaks down fat into smaller molecules that can be absorbed during digestion
• bile is produced by the liver and stored in the gallbladder and released into the duodenum
• 3 organs associated with bile

Question 25

bile: for liver to duodenum

Answer 25

hepatocytes produce bile -> bile canaliculi -> small bile ducts -> right or left hepatic duct ->common hepatic duct -> cystic duct or bile duct -> if bile duct then to the -> hepatopancreatic ampulla -> duodenum

Question 26

the cystic duct and the ______ join to form the bile duct

Answer 26

common hepatic duct

Question 27

peritoneum

Answer 27

double-layered serous membrane: - parietal peritoneum: lines walls of the abdominopelvic cavity - visceral peritoneum: lines organs in the abdominopelvic cavity - space between parietal and visceral layers = peritoneal cavity

Question 28

organ classification

Answer 28

- intraperitoneal organs: completely covered by visceral peritoneum (JIGS CLS - jejunum, ileum, gallbladder, stomach, colon, liver, spleen) - retroperitoneal organs: covered anteriorly by parietal peritoneum (PAR DUCK - pancreas, rectum/anus, adrenal glands, duodenum, ureters, colon, kidneys) intraperitoneal organs are mobile, retroperitoneal organs are fixed to the posterior abdominal wall

Question 29

intraperitoneal organs

Answer 29

- colon (transverse, sigmoid) - spleen - stomach - jejunum - ileum - liver - gallbladder covered by visceral peritoneum

Question 30

retroperitoneal organs

Answer 30

- duodenum - pancreas - colon (ascending, descending) - rectum and anal canal - kidneys and adrenal glands - ureters covered by parietal peritoneum

Question 31

peritoneal folds

Answer 31

- greater omentum: attaches stomach to small intestine and transverse colon - lesser omentum: attaches stomach and duodenum to the liver - falciform ligament: attaches liver to anterior abdominal wall and diaphragm - mesentery: anchors jejunum and ileum to posterior abdominal wall - mesocolon: anchors transverse and sigmoid colon to posterior abdominal wall (double-fold of visceral peritoneum)

Question 32

which organs are retroperitoneal? a) spleen, rectum, kidney b) pancreas, rectum, kidney c) pancreas, spleen, kidney

Answer 32

b) pancreas, rectum, kidney

Question 33

structures

Answer 33

- mouth: saliva is secreted by the major salivary glands, which lubricates food. through mastication, food is mixed with saliva and shaped into a soft, flexible mass called a bolus - esophagus: is a collapsible, muscular tube that connects the pharynx to the stomach. it passes a bolus into the stomach by peristalsis. - stomach: connects the esophagus to the duodenum accessory organs small intestine: extends from the pyloric sphincter to the ileocecal junction. it is divided into three parts; duodenum, jejunum, and ileum. large intestine: extends from the ileocecal junction to the anus. its regions include the cecum, ascending, transverse, descending, sigmoid colon, rectum, and anal

Question 34

Function review

Answer 34

1. ingestion: involves taking foods and liquids into the mouth (eating) 2. secretion: cells within the walls of digestive canal and accessory digestive organs secrete water, acid, buffers, and enzymes into the lumen of the digestive canal 3. motility: alternating contraction and relaxation of smooth muscle in the walls of the digestive canal mix food and secretions and move them toward the anus 4. digestion: the breakdown down of ingested food by the teeth, stomach, and small intestine into small molecules for use by body cells 5. absorption: entrance of ingested and secreted fluids, and the products of digestion into the cells lining the lumen of the digestive canal. absorbed substances circulate throughout the body 6. defecation: wastes, indigestible substances, bacteria, cells sloughed from the lining of the digestive canal, and digested materials that were not absorbed leave the body through the anus as feces

Question 35

which major artery supplies blood to the head of the pancreas?

Answer 35

superior mesenteric artery

Question 36

what does the mesentery bind too

Answer 36

binds the jejunum and ileum to the posterior abdominal wall

Question 37

the portal vein carries...

Answer 37

deoxygenated, nutrient-rich blood from the GI tract