Chapter 2. Gastrointestinal System

Question 1

• Tongue has what bony attachments?

- attached to the floor of the mouth by frenulum.

Answer 1

• (styloid process, hyoid bone)

- Frenulum

Question 2

• Mechanical breakdown, plus WHAT chemical secretion?

- does hydrolysis of starch and glycogen into maltose.

Answer 2

• ptyalin, enzyme in saliva

- Saliva amylase

Question 3

How long is the esophagus?

Food moves thru esophagus by?

Answer 3

10” long

Peristalsis

Question 4

• This guardes the stomach entrance from esophagus.
• Surface area increased by what, which serves as temporary store for food?
• These are recognised as distinct regions of the stomach?

Answer 4

• Cardioesophageal sphincter
• Rugae
• Fundus, body and pylorus

Question 5

• Lubricant, protects surface from acid.
• Vitamin B12 absorption (in small intestine ilium).
• Kills bacteria, breaks down food, converts pepsinogen.
• Broken down to pepsin (a protease)
• Stimulates acid secretion (in response protein)

Answer 5

Mucus- Mucus cell
Intrinsic factor- Parietal cell
Acid (H+)- parietal cell
Pepsinogen- Chief cell
Gastrin- G cell

Question 6

• Gastric acid secretion mechanism.
• The caudad region of stomach contract to propel food into the duodenum. The rate of gastric emptying time is fastest if gastric content is isotonic. Fat inhibits gastric emptying time (i.e. increase gastric emptying time

Answer 6

-IntheparietalcellsCO andHOareconvertedH+andHCO- 223
catalyzed by carbonic anhydrase. The parietal cells secrete HCl into the lumen and absorb HCO3- into the blood stream.
-Gastric emptying time.

Question 7

Gastric acid stimulations. Gastric acid production is stimulated by three mechanisms.

Answer 7

Vagal stimulation. V nerve innervates p. cells and stimz H+ secre.
Histamine release. H released from mast cells in gastric mucosa and diffuses to parietal cells, secrete H+
Gastrin release: response to eating (protein), stim. p. cells to sec. H+

Question 8

Small intestine parts and length

Answer 8

Duodenum: 1st part of s.i., C-shaped 10” (inch) long and curves around the head of pancreas and entry of common bile duct.
Jejunum: 8 to10 feet long.
Ileum: 12 feet long. Towards end of s.i.

Question 9

• Highest drug absorption
• A large glandular organ attached near the stomach and enz helps in carb digestion
• Bile secretions are?

Answer 9

Duodenum

• Pancreas- secretes intestinal enzymes (pancreatic lipase, amylase, protease),
• Bile secretions are bile salts, bilirubin, phospholipids, and cholesterol.

Question 10

The majority of food absorption takes place here. Define secretions.

Answer 10

Jejunum
• Secretin stim. pancreas to prod. watery fluid, high in bicarb conc
• Pancreozymin stim. pancreas to prod. a viscous fluid low in bicarb conc

Question 11

This is also known as the large intestines.

Consists of what bacteria and what vitamin does it produce?

Answer 11

• Colon consists of higher flora and fauna in GI tract 90 to 99% anaerobic bacteria. Example B.
fragilis and C. difficle anaerobic and aerobic E. coli.
• Vitamin K2 (menaquinone).

Question 12

What causes the ff:
-Oral thrush
• Gingivitis (gum inflammation)

Answer 12

• C albicans and moniliasis

- Fusobacterium sp

Question 13

This is reflux of gastric acid contents into esophagus, heartburn, or regurgitation. Common and extra esophageal symptoms?

Answer 13

Gastro esophageal reflux disease (GERD)
Extra esophageal symp: cough, laryngitis and asthmatic syndrome
Common: heartburn, regurgitation of acid or bile and hyper salivation

Question 14

What causes: Gastritis and peptic and duodenal ulcer

Answer 14

• Gastritis: NSAIDs, cigarette smoking, heavy alcohol

- PU/DU: Helicobacter pylori and NSAIDs

Question 15

Diseases of the stomach.

Answer 15

Gastritis (inflammation of gastric or stomach lining) and heavy alc.
• Gastroenteritis: Inflamm of entire GI tract
• Peptic ulcer

Question 16

Diseases of the small intestine.

Answer 16

• Duodenal ulcers
• Q.Zollinger Ellison syndrome- excess HCl secre.
• Celiac disease- sensitivity to gluten in cereals, inability of absorption of gluten (upper part of small intestine)

Question 17

Inflamm sites and drug tx for Ulcerative colitis and Crohn’s Disease.

Answer 17

UC: localized in colon, 5ASA.
10-20 liq. stools per day cont. blood and mucus (less for CD)
CD: esophageal to rectum, patches are present in entire GI tract. 5ASA or Oral prednisone.

Question 18

These are ulcers in tissues present in Crohn’s disease and give tx.

Answer 18

Fistula/ granulomas/ skip patches are treated by infliximab, adalimumab or metronidazo

Question 19

-Pseudo membranous colitis is overgrowth of what bacteria? Give tx.
• Amebic colitis is caused by?
• Cholera is caused by?

Answer 19

• Clostridium difficile tx by Metronidazole, Vancomycin PO
• Entamoeba histolytica
• Vibrio cholera

Question 20

Digestive enzymes are classified based on their target substrates
• Proteases and peptidases
• Lipases
• Carbohydrases
• Nucleases

Answer 20

• Proteases, peptidases split proteins into small peptides and a.a.
• Lipases split fat into 3 f.a. and a glycerol molecule.
• Carbohydrases split carbs, starch and sugars into simple sugars like glucose.
• Nucleases split n.a. into nucleotides.

Question 21

Carb digestion, conversions:
Amylase, Trahalase, Glucosidase and Lipase
Acarbose inhibits what?

Answer 21

Amylase: Hydrolyse starch and glycogen into maltose
Trehalase: deg. carb to gluc.
Glucosidase: bkdw suc. and starch to gluc.
Lipase: bkdw fat
-inhibits aloha glucosidase

Question 22

Carb digestion, conversions:

Maltase, Sucrase, Lactase

Answer 22

• Maltase: Converts maltose into glucose + glucose
• Sucrase: Converts sucrose into glucose + fructose.
• Lactase: Converts lactose (milk) into glucose + galactose.

Question 23

Disorder of carbohydrate absorption. Lactose intolerance results from what and non-absorbed lactose causes?
Milk intolerance can results from 2 reasons:

Answer 23

absence of brush border lactase = osmotic diarrhea

1) Lactose intolerance
2) milk protein allergies

Question 24

Absorption of Proteins: These are secreted by pancreas, which helps in digestion of proteins: also give coversions and enzymes involved

Answer 24

• Trypsin is sec. in the inact. trypsinogen= trypsin by enzyme enterokinase.
• Chymotrypsin is sec. in the inact. chymotrypsinogen= chymotrypsin
by trypsin.

Question 25

Absorption of Iron: It is absorbed as heme iron (iron bound to hemoglobin or myoglobin) or as free Fe2+ In intestinal cells, heme iron is degraded to Fe and released. The free Fe binds to apoferritin and is transported into the blood. Explain Transferrin

Answer 25

Transferrin: Free Fe2+ circulates binds transferring and transports it from small intestine to its storage sites in the liver and from the liver to the bone marrow for the synthesis of hemoglobin.

Question 26

• It is multi organ disease but it is mainly associated with pancreatic secretion. • It results from a defect in Cl- channels that are caused by a mutation in the transmembrane conductance regulator (CFTR) gene.

Answer 26

Cystic fibrosis - assoc. w/ def. pancreatic enz= malabsorption and stethorrhea

Question 27

Innervations of GI tract. Autonomic innervations. -It is usually excitatory on functions of GI tract. It is carried via the vagus and pelvic nerves. • It usually inhibitory on the functions of GI tract

Answer 27

• Vagus nerve innervates the esophagus, stomach, pancreases and upper large intestine • Pelvic nerve innervates the lower large intestine and rectum, and anus. Cholinergic- excitatory Adrenergic-inhibitory

Question 28

- Irritable bowel syndrome symptoms: | - However Inflammatory bowel disease symptoms are?

Answer 28

- IBS gives bloating, constipation, diarrhea, N&V | - IBD: Crohn's disease and UC may give bleeding and diarrhea

Question 29

Cystic fibrosis most common, fatal genetic disease affecting young Canadians, multi- organ disease affecting primarily the lungs and the digestive system. How?

Answer 29

In the lungs, CF causes severe breathing problems. A build-up of thick mucus makes it difficult to clear bacteria and leads to cycles of infection and inflamm. wc damages lung tiss. In the dig. tract, extreme diff. to digest and absorb nutrients from food

Question 30

- Polypeptides and caffeine stimulates secretion of? | - Proteins?

Answer 30

- Gastrin | - HCl