GI tract

Question 1

What are the four layers of the stomach/intestines, and what are their functions?

Answer 1

Mucosa - Simple columnar epithelium. Gastric glands. Mucous cells. Microvilli.
Submucosa - Connective tissue with blood and lymph supply.
Muscularis - Smooth muscle tissue.
Serosa - Areolar connective tissue.

Question 2

What are the four areas of the stomach, and where are they located?

Answer 2

Cardia - Opening from the esophagus, by the lower esophageal sphincter.
Fundus - Upper left corner.
Body - Large central portion.
Pylorus - Last part just before the pyloric sphincter.

Question 3

What is the esophagus?

What is the duodenum?

What is the pancreas?

What is the spleen?

Answer 3

Matstrupen

Tolvfingertarmen

Bukspottskörteln

Mjälte (OBS ej del av matsmältningssystemet, det är en lymfkörtel)

Question 4

Name of food through out the GI?

Answer 4

FOOD comes into mouth and get chewed into BOLUS. This is turned into CHYME after dissolved by the acid in the stomach.

Question 5

How is protein digested?

How is fat digested?

How are carbohydrates digested?

Answer 5

Pepsin enzyme (Pepsinogen + HCl) digests protein into peptides, which are small chains of amino acids, from chief cells. Protease enzyme from pancreatic juice.

Lipase enzyme from chief cells. Also bile from gallbladder.

Amylase enzyme. IS ONLY BROKEN DOWN IN THE SMALL INTESTINE APPARENTLY.

Question 6

Which of carbohydrates, proteins, and fats digest fastest in the stomach?

Answer 6

Carbo, then protein and last fats. When it all is out in the duodenum, it feedbacks inhibitory to the stomach (hormone secretin and CCK).

Question 7

How do you treat peptic ulcers?

Answer 7

Antacids (neutralization)
Mucosal protective agents
Acids secretion depressors (anticholinergics and PPI Losec/Nexium)
Surgery (vagotomy and resection BI/BII)

Question 8

What is helicobacter pylori?

Answer 8

Its the only bacteria that survives the gastric acid. Treat with Proton Pump Inhibitors (PPI) and antibiotics.

Question 9

How is peptic ulcers caused?

Answer 9

By imbalance between harmful agent like acid and protective/neutralizing mechanisms.

Question 10

Where is the pancreas located and what are its functions?

Answer 10

Location: Behind stomach.
In short: Produces pancreatic juice, insulin, and all digestive enzymes.

Produces pancreatic juice in acinar cells which passes into duodenum via pancreatic duct. Also produces sodiumbicarbonate (NaHCO3) that help digestion. Creates all digestive enzymes; lipase for fat, amylase for starch, and protease for protein. The latter is made in an inactive state which activates by enterokinase in the small intestine: chymotrypsinogen, trypsinogen, and carboxypeptidase.

Question 11

Describe bile production and its pathway.

Answer 11

Produced by hepatocytes (liver cells). Transported through canaliculi, bile ducts, and hepatic duct. It is then stored in the gallbladder. Secreted through cystic duct into the common bile duct and then into the duodenum.

Question 12

What is the functional unit of the liver, and how does it work?

Answer 12

Lobule, consists of hepatocytes in rows that radiate around central vein with sinusoids between the cells. The blood reaches liver lobules from hepatic artery (an artery branch of celiac) carrying O2 and from hepatic portal vein (no O2) carrying nutrients from GI.

Question 13

What are the functions of bile, and how is it connected to bilirubin?

Answer 13

Emulsification: breaking apart clusters of fats so they are more digestible.
The bile is combined with bilirubin (which comes from the heme group of erythrocytes when they are broken down).
When bile is digested it turns into stercobilin, which gives feces its brown color. The bile salts are reabsorbed into in the small intestine called ileum, and is then carried through the portal vein back to the liver.
Gallstones may form from bile and obstruct the bile ducts from the gallbladder, pain is included for free.

Question 14

What are the seven functions of the liver?

Answer 14

In short: metabolism, cleans blood, excretes bilirubin, and store vitamins.

1. Carbohydrate metabolism. Polysaccharide is stored in the liver as glycogen. It also converts glycogen, fructose, galactose, lactic acid, and amino acids into glucose to raise the blood sugar.
2. Lipid metabolism. Produces cholesterol, triglycerides and makes bile. It also makes lipoproteins for lipid transport.
3. Protein metabolism (and urine). Removes the amino group from amino acids, which turns into ammonia (NH3) and then urea. This is transported to the kidneys. Synthesize most common protein: albumin.
4. Removes many harmful substances from blood. Detoxifies alcohol, inactivates steroid and thyroid hormones, and eliminates some drugs e.g. penicillin into bile.
5. Excretion of bilirubin. From heme to bile to feces.
6. Stores fat-soluble vitamins (ADEK) and minerals (Fe, Cu)
7. Activates vitamin D.

Question 15

The duodemal glands produce alkaline mucus, why?

Answer 15

To help neutralize stomach acid.

Question 16

Why is there circular folds (rugae of mucosa) in the intestinal wall structure?

Answer 16

To create an increased surface area.

Question 17

What is villi?

Answer 17

Fingerlike projections of mucosa (outermost layer of the GI), which increases the surface area. Microvilli on absorptive cells further enhance absorption. Villi contain vessels that absorb nutrients.

Question 18

What happens in the small intestines?

Answer 18

Chyme enters small intestine carrying partially digested carbohydrates and proteins. Intestinal juice (composed of bile and pancreatic juice) completes digestion. 90% of absorption of products of digestion occurs in the small intestine. (Monosaccharides; amino acids. Fatty acids and monoglycerides. Phosphate sugar, and bases of DNA RNA).

Question 19

What are the four regions of the large intestine?

Answer 19

Cecum (Ileocecal sphincter, appendix attached)
Colons (ascending, transverse, descending and
sigmoid)
Rectum
Anal with sphincters

Question 20

Name some common GI disorders.

Answer 20

Gastritis (or dyspepsia = regurgitations)
Pancreatitis

Gall stones
Peptic ulcers

Cancer (stomach, pancreas, colon)
Liver cirrhosis = skrumplever

Allergies

Question 21

What is hernia?

Answer 21

Bråck - När tarmarna sticker ut framåt, man kan ibland se dem under huden.

Herniation of abdominal contents like intestines in defect or weak areas in the abdominal wall. Can be painful.

Question 22

Name some examination techniques of the GI tract.

Answer 22

• X-Ray
   – Plain films
   – contrast (passage/single/double)
   – CT
• Ultrasound
• MRI
• Endoscopies (+biopsy etc)
   – Gastroscopy
   – Procto/Rectoscopy
   – Sigmoideo/coloscopy
   – ERCP
• “Camera-capsule”

Question 23

Major hormones that control digestion.

Answer 23

Gastrin - Stimulate secretion of gastric juice, increase motility of GI tract, and relaxes pyloric sphincter.

Secretin - Inhibits secretion of gastric juice, stimulates secretion of pancreatic juice and bile.

Cholecystokinin (CCK) - Inhibits gastric emptying, stimulate sectreion of pancreatic juice and bile, and makes you feel full to satisfaction.

Question 24

Which functions of the human body helps the digestive system to provide energy and nutrients for the metabolism?

Answer 24

• Ingestion: eating
• Secretion: release of water, enzymes, buffers
• Mixing and propulsion: movement along GI tract
• Digestion: breakdown of foods
– Mechanically: by movements of digestive organs
– Chemically: by enzymes
• Absorption: moving products of digestion into the
body
• Defecation: dumping waste products

Question 25

What is the definition of the GI tract, and which body parts does it include?

What is the definition of accessory organs of the digestive system, and which body parts?

Answer 25

A tube through us humans of which foods passes and where digestion and absorption occur. Includes: mouth, pharynx, esophagus, stomach, small intestine, large intestine.

Organs that help in digestion but through which food never passes through. Includes: teeth, tongue, salivary glands, liver, gallbladder, and pancreas.

Question 26

What is the greater omentum?

Answer 26

(Del av bukhinna som är placerad framför tarmarna). Connective tissue sheet “laying on top” of the intestines.

It’s the anterior part of the peritoneum.

Question 27

The mouth cavity is formed by?

What’s the uvula?

Which tonsils are located at the base of the tongue?

Answer 27

Formed by:
– Cheeks and tongue
– Hard palate anteriorly, soft palate posteriorly

Uvula (gomspene) extension of soft palate posteriorly. During swallowing, uvula blocks entry of food or drink into nasal cavity.

Lingual tonsils.

Question 28

What are the three pairs of salivary glands?

These exocrine glands with ducts secrete saliva, which conists of what?

Answer 28

– Parotid (Largest; inferior and anterior to ears)
– Submandibular (In floor of mouth; medial and inferior to mandible)
– Sublingual (Inferior to tongue and superior to submandibular)

99.5% water (helps dissolving), salivary amylase (starts digestions of starches) and mucus.

Question 29

What are the three stages of swallowing?

Answer 29

1. Voluntary and active phase where bolus is put at the back of the oral cavity
2. Pharyngeal stage, soft palate moves up and epiglottis (struphuvud) moves down to prevent food from entering nasopharynx and larynx.
3. Esophageal phase, food comes down the esophagus by peristalsis (sammandragande muskelrörelser i matstrupen, you guessed it smoooth muscle cells)

Question 30

What is the stomach? (berätta om magsäcken specifikt)

Answer 30

• J-shaped enlargement of GI tract
• Mixing chamber and holding reservoir
• Very elastic and muscular
• Four regions

Question 31

What are the five different cells of the stomach?

Answer 31

Surface mucous cells - Secretes mucus
Mucous neck cells - Secretes mucus

Parietal cells - Secretes hydrochloric acid and intrinsic factor
Chief cells - Secretes pepsinogen and gastric lipase

G cells - Secretes the hormone gastrin (signaling the other cells that it is secretion time)

Question 32

What is diverticulosis/diverticulitis?

Answer 32

Diverticulosis is when there are no symptoms. If the diverticula become inflamed or infected, causing more severe symptoms, it’s called diverticulitis.

Pockets developing in end of large intestine, often due to age.

Question 33

What is bariatric surgery?

Answer 33

Surgical procedures performed on the stomach or intestines to induce weight loss.