Digestive System

Question 1

Functions of digestive system

Answer 1

• ingestion: taking food into mouth
• mixing & propulsion: through GI
• digestion: breakdown ingested food (mechanically & chemically)
• absorption: passage of nutrients into the blood
• metabolism: production of cellular energy (ATP)
• defecation

Question 2

Organs

Answer 2

2 main groups:
* alimentary canal or GI tract
-continous tube from mouth to anal canal
-5-7 meters
* acessory digestive
-teeth, tongue, salivary gland, liver, gallbladder & pancreas

Question 3

Peritoneal cavity: greater sac and omental bursa (lesser sac)

Answer 3

Subdivided into greater sac & omental bursa:
Greater sac
* accounts for most of the space in the peritoneal cavity
* begins at the diapgragm & continues into pelvic cavity

omental bursa (lesser sac)
* smaller subdivision of the peritoneal cavity
* located posterior to the stomach & liver
* continues with the great sac through omental foramen

Question 4

Intraperitoneal & retroperitoneal

Answer 4

Intraperitoneal
* completely surrounded by the peritoneum

Mesentary
* folding of the peritoneum from the mesentary

Retroperitoneal
* Only 1 surafce covered by the peritoneum

Question 5

Omenta

Answer 5

Greater omentum
* attaches to the greater curvature of the stomach & 1st part of duodenum & transverse colon
* contains arteries and accompanying veins. right and left gastro-omental vessels
* follows inflammation-can move

Lesser omentum
* expands from the lesser curvature of the stomach & 1st part of the duodenum to inferior surface of the liver
divided into:
* hepatoduodenal ligament: duodenum and liver
* hepatogastric ligament: stomach to liver

Question 6

Abdominal esophagus

Answer 6

Represents the short distal part of the esophagus located in the abdominal cavity
* emerges through right crus usually at T10

Associated with esophagus: (friends)
* anterior vagus trunk– anterior surface of esophagus
* posterior vagus trunk–posterior surface of esophagus

Question 7

Stomach

Answer 7

• most dialated part of GI tract
• positioned between the abdominal esophagus & small instestine
• located in the epigastric, umbilical, and left hypochondirum regions

Parts
1. cardia: surrounds the opening of the esophagus
2. fundus: area above the level of the cardial orifice (food reaches- we are full)
3. body: largest region
4. pyloric part: distal end, divided into pyloric antrum & pyloric canal

Question 8

Small intestine

Answer 8

The longest part of the gastrointestinal tract
* extends from the pyloric orifice to the ileocecal fold

Consists of:
duodenum: 25cm
* C-shaped structure adjacent to head of pancreas
* above level of umbilicus
* it is mostly retroperitoneal except in the beginning
* connected to liver by hepatoduodenal ligament
* suspensory muscle of duodenum/ligament of Trietz–lig contracts makes angle wider for food to pass
* 4 parts
1. superior part (intraperitoneal)
2. descending part (retrop)
3. inferior part (retrop)
4. ascending part (retrop)

jejunum: 2.5 m
* is mostly in the left upper quadrant of the abdomen, proximal 2/5
* slightly larger in diameter & has a thicker wall than ileum
* less prominent arterial arcades & longer vasta recta (straight arteries) compared to ileum

ileum: 3.5 m
* makes up the distal 3/5 of small intestine
* mostly right lower quadrant
* has thinner walls, shorter vasta recta, more mesentaric fat, & more arterial arcades

Question 9

ilial cecal fold

Answer 9

Opening into large intestine. 2 flaps projecting into lumen of large intestine.

Function
* preventing reflux from the cecum to ileum
* regulating the passage of contents from ileum to cecum

Question 10

Large Intestine/Colon

Answer 10

• extends from distal end of ileum to anal canal (1.5 m)
• function: absorbs fluids & salts from gut content
• parts:
  1. cecum (contact w/anterior abdominal wall)
  2. ascending colon (secondarily retrop.)
  3. right coloc flexure
  4. transverse colon (intraperitoneal)
  5. left colic flexure
  6. descending colon (secondarily retrop.)
  7. sigmoid colon (intraperitoneal)
  8. rectum (retroperitoneal structure)

Question 11

Liver (functions, surfaces, lobes)

Answer 11

largest visceral organ in body
* primarily located in R hypochondrium & epigastric regions

functions:
* produces bile (breaks fat)
* cholesterol metabolism
* urea cycle
* protein production (albumin)
* clotting factor production
* detoxification of blood

Surfaces include:
diaphragmatic surface in anterior, superior, and posterior directions
* lies against inferior surface of diaphragm
* subphrenic recess: seperates diaphragmatic surface of liver from diaphragm & divided into R and L areas by falciform ligament
* hepatorenal recess: part of peritoneal cavity on R side between liver and R kidney an R suprarenal gland

visceral surface in inferior direction
* covered with visceral peritoneum except in the fossa for the gallbladder & at the porta hepatis/triad

Lobes
* right lobe (bigger)
* left lobe
* caudate lobe (superior)
-bounded on L by ligametum venosum & on R by groove for inferior vena cava
* quadrate lobe (inferior)
-bounded on L by ligamentum teres and on R by fossa of gallbladder

Question 12

Gallbladder (location, parts & function)

Answer 12

is a pear shaped sac lying on visceral surface of R lobe of liver in a fossa between right and quadrate lobes

Consists of:
* a rounded end (fundus)
* a major part in the fossa (body)
* a narrow part (neck)

Function: recieves, concentrates, and stores bile from liver

Question 13

Pancreas (location, parts, function)

Answer 13

Located posterior to stomach
* extends from duodenum, on the right, to the spleen, on the left

Consists of:
* head
* neck
* tail

Function:
* digestion: produces and secretes enzymes (breaks fat and sugar)
* endocrine: produces and secretes hormones like insulin and glucagon