Digestive system 2

Question 1

3 parts of the pancreas

Answer 1

head, body and tail

Question 2

pancreas - 2 major ducts that secrete into the small intestine

Answer 2

the pancreatic duct (duct of Wirsung)

the accessory duct (duct of Santorini)

Question 3

composition of pancreatic juice?

Answer 3

Pancreatic juice is a clear, colourless liquid that contains water, some salts, sodium bicarbonate and several enzymes.
1.2–1.5L of pancreatic juice are produced every day

Question 4

what converts the stomach acid contents to a slightly alkaline pH (7.1–8.2), halting stomach pepsin activity and promoting activity of pancreatic enzymes?

Answer 4

the bicarbonate in pancreatic juice

Question 5

enzymes found in pancreatic juice?

Answer 5

Pancreatic amylase — digests starch

Pancreatic lipase — digests triglycerides

Proteases — digests proteins

• Trypsinogen — activated by enterokinase (a brush border enzyme)
• Chymotrypsinogen — activated by trypsin
• Procarboxypeptidase — activated by trypsin
• Proelastase — activated by trypsin
• Trypsin inhibitor — combines with any trypsin produced inside the pancreas

Ribonuclease and deoxyribonuclease — digests RNA and DNA

Question 6

what hormones secreted by the small intestine regulate pancreatic secretions?

Answer 6

Secretin
-Stimulates secretion of pancreatic juice that is rich in bicarbonate ions, promotes normal growth and maintenance of pancreas, enhances effects of CCK.

Glucose-dependent insulinotropic peptide (GIP)
-Stimulates pancreatic beta cells to release insulin.

Cholecystokinin (CCK)
-Stimulates secretion of pancreatic juice rich in digestive enzymes, promotes normal growth and maintenance of pancreas, enhances effects of secretin

Question 7

Key components of the liver

Answer 7

Right and left lobes
Falciform ligament
Quadrate lobe 
Caudate lobe
Ligamentum teres (round ligament)
Right and left coronary ligaments

Question 8

3 parts of the gallbladder

Answer 8

fundus, body and neck

Question 9

describe the differences in the hepatic artery and the hepatic portal vein?

Answer 9

The hepatic artery supplies oxygenated blood from the branch of the aorta, and the hepatic portal vein provides nutrient rich blood from the stomach, spleen and intestines. All blood eventually leaves the liver via the hepatic vein.

Question 10

decribe the blood flow to and from the liver, starting at the liver and finishing in the heart

Answer 10

Oxygenated blood from the hepatic artery OR nutrient-rich blood from the hepatic portal vein

Liver sinusoids

Central vein

Hepatic vein

Inferior vena cava

Right atrium of the heart

Question 11

where are CCK and secretin made?

Answer 11

in the small intestine

Question 12

components of bile

Answer 12

Water, cholesterol and several ions​

A phospholipid called lecithin​

Bile salts (Na and K salts of bile acids are a digestive product. These play a role in emulsification, the breakdown of large lipid globules into a suspension of small lipid globules.​ They also aid in the absorption of lipids following their digestion.)

Bile pigments (bilirubin from haemoglobin: excretory product)

Question 13

composition and function of bile

Answer 13

Bile is a yellow, brownish, or olive-green liquid secreted by hepatocytes at a rate of 800–1000 ml day. The pH of bile is 7.6-8.6.

Bile is transported by a duct system to the gallbladder for concentration and temporary storage. The excretory product contains components of worn-out red blood cells. This is digestive secretion.

Question 14

sequence of bile production

Answer 14

right and left hepatic ducts
common hepatic duct from liver
cystic duct from GB (some may be stored here)
common bile duct
pancreatic duct from pancreas
duodenum

Question 15

regulation of bile secretion

Answer 15

Parasympathetic impulses and vagus nerves

Cholecystokin (CCK): causes the gallbladder to contract and release stored bile

Secretin: causes the liver to increase its output of bile

Question 16

3 mechanisms through which carbohydrate metabolism maintains normal blood glucose levels

Answer 16

Glycogenolysis — breaks down glycogen to glucose and releases the glucose into the bloodstream.

Gluconeogenesis — converts certain amino acids, triglycerides and lactic acid to glucose.

Glycogenesis — converts glucose to glycogen and triglycerides for storage.

Question 17

lipid metabolism

Answer 17

Storage — hepatocytes store some triglycerides.

Lipolysis — breaks down fatty acids to generate ATP.

Lipogenesis — synthesises lipoproteins, which transport fatty acids, triglycerides, and cholesterol to and from body cells.

Cholesterol synthesis.

Synthesises bile salts from cholesterol.

Question 18

which organ stores and activates vitamin D?

Answer 18

the liver

Question 19

functions of the small intestine

Answer 19

Mix chyme with digestive juices and bring food into contact with mucosa for absorption

Completes digestion of carbohydrates, proteins, and lipids; begins and completes digestion of nucleic acids.​

Absorbs about 90% of nutrients and water that pass through digestive system.

Question 20

3 anatomical subdivisions of the small intestine

Answer 20

Duodenum
Jejunum
Ileum

The duodenum is retroperitoneal and the shortest of the regions. It starts at the pyloric sphincter of the stomach and is in the form of a c-shaped tube that extends about 25cm until it merges with the jejunum. Duodenum means “12” and this region got its name from being about as long as the width of 12 fingers.

The jejunum is about 1m long and extends to the ileum. Jejunum means “empty,” which is how it is found at death.

The ileum is the final and longest region of the small intestine at about 2m. It joins the large intestine at a smooth muscle sphincter called the ileocecal sphincter (valve).

Question 21

brush border enzymes (microvilli of small intestine)..?

Answer 21

Carbohydrate digesting enzymes — ɑ-dextrinase, maltase, sucrase, and lactase.

Protein-digesting enzymes — peptidases (aminopeptidase and dipeptidase).

Nucleotide-digesting enzymes — nucleosidases and phosphatases.

They provide:
Digestion at brush-border.
Digestion in the lumen of the small intestine.

Question 22

what is segmentation (in small int)?

Answer 22

localised mixing contractions that occur in portions of the intestine distended by a large volume of chyme. Thi brings food particles in contact with the mucosa for absorption.

Question 23

what is migrating motility complex (MMC)?

Answer 23

the type of peristalsis that occurs in the small intestine when distension of the small intestinal wall lessens. This propels chyme forward along short stretches of intestine at a time.

Question 24

what are enteric reflexes?

Answer 24

Enteric reflexes are reflexes that respond to the presence of chyme and work to increase intestinal motility (sympathetic impulses, on the other hand, decrease motility). There are two types of enteric reflexes — vasoactive intestinal polypeptide and segmentation.

VIP (vasoactive intestinal polypeptide) stimulates the production of intestinal juice.
Segmentation depends on distention which sends impulses to the enteric plexus and CNS.
distention produces more vigorous peristalsis.
10 cm per second.

Question 25

do sympathetic impulses increase or decrease motility?

Answer 25

increase

Question 26

what is chemical digestion in the small intestine?

Answer 26

Chemical digestion occurs via the pancreatic juice, bile and intestinal juice. These break down nutrients into absorbable forms such as carbohydrates, proteins and lipids.