Digestive Tract

Question 1

Digestive Tract

Answer 1

• oral cavity
• pharynx
• esophagus
• stomach
• small intestine
• large intestine
• rectum/anus
• actual passageway through which food is going to travel

Question 2

Accessory organs

Answer 2

• secrete things into the digestive tract
• salivary glands
• liver
• gallbladder
• pancreas

Question 3

Ingestion

Answer 3

• take food into our mouth

Question 4

Secretion

Answer 4

• producing and releasing mucin (helps moisten food w/mucus) and fluids such as acid, bile, and enzymes

Question 5

Digestion

Answer 5

• breakdown of large food items into smaller structures and molecules -> so we can use the nutrients like Vit. D

Question 6

Absorption

Answer 6

• passive or active transport of electrolytes, digestion products, vitamins, and water across GI tract epithelium and into the GI tract blood and lymph vessels

Question 7

Elimination

Answer 7

• indigestible material is compacted into feces and then eliminated via defecation

Question 8

Mechanical digestion

Answer 8

• physically breaks down ingested material into smaller pieces
• Ex: teeth -> chewing food

Question 9

Chemical Digestion

Answer 9

• breaks down ingested material into smaller molecules using enzymes
• ex: secrete acid to raise pH to break down

Question 10

Peritoneum

Answer 10

• abdominal organs are supported by serous membranes that suspend organs from posterior abdominal wall and secrete lubricating fluid

Question 11

Parietal peritoneum

Answer 11

• lines body walls (external)

Question 12

Visceral peritoneum

Answer 12

• covers organs

Question 13

Peritoneal Cavity

Answer 13

• potential space where layers of peritoneum that face each other secrete lubricating fluid
• lies btw parietal peritoneum and the visceral peritoneum

Question 14

Mucosa

Answer 14

• inner layer
• divided into:
  > epithelium: layer of cells that help us absorb things
  > lamina propria
  > muscularis mucosa (deepest)

Question 15

Submucosa

Answer 15

• loose CT
• nerves, arteries, veins, and lymphatics travel through this layer

Question 16

Muscularis

Answer 16

• 2 or more layers of smooth muscle
• helps move food along the tract

Question 17

Adventitia/Serosa

Answer 17

• CT that either connects to another organ or is part of the peritoneum

Question 18

The Esophagus

Answer 18

• muscular, tubular passageway from the pharynx to stomach
• directs food from oral cavity to esophagus
• lift larynx so epiglottis folds over
• food passes through hold in diaphragm called esophageal hiatus to get to stomach

Question 19

Hiatal hernia

Answer 19

• stomach pops out of esophageal hiatus
• can cause heart burn
• can be serious or non-serious

Question 20

Cardia

Answer 20

• narrow superior entryway into stomach from esophagus
• passageway

Question 21

Fundus

Answer 21

• dome-shaped region lateral and superior to the esophageal connection

Question 22

Body

Answer 22

• largest region; inferior to cardiac orifice and fundus

Question 23

Pylorus

Answer 23

• narrow, medially directed region that forms termination of stomach
• where we squeeze everything in so we enter the small intestine

Question 24

Pyloric Sphincter

Answer 24

• leads to duodenum

Question 25

Mucus cells

Answer 25

• secretion: mucin
• functions: protection of epithelium from acidic secretions (acid can damage stomach lining)

Question 26

-parietal cells

Answer 26

• secretions: hydrochloric acid and intrinsic factors
• function: hydro: denature proteins (melts proteins apart from one another)
  > intrinsic: helps bind Vitamin B12

Question 27

Chief cells

Answer 27

• secretions: enzymes (help promote chem rxn)
• function: digestion

Question 28

Enteroendocrine cells

Answer 28

• secretion: gastrin (secreted into the bloodstream and then travel all over the body)
• function: hormone that stimulates secretion of other stomach cells
  > important for digestion and metabolic fxn

Question 29

Duodenum

Answer 29

• c-shaped region that arches around pancreas
• receives bile and pancreatic juices (from pancreas, liver, gallbladder)

Question 30

Jejunum

Answer 30

• middle region
• primary region of chemical digestion and absorption
• breaking things down and absorbing them into the bloodstream

Question 31

Ileum

Answer 31

• distal region
• terminates at ileocecal valve = sphincter that controls entrance into large intestine
• sphincter: helps us control the timing and the absorption of heat goes on in our digestive system

Question 32

Small intestine

Answer 32

• finishes chemical digestion -> introduce more enzymes
• absorbs up to 90% of the nutrients and water from GI tract
• blood supply is SMA

Question 33

Small Intestine: Histology

Answer 33

• circular folds (ridges in lining) form from mucosa and submucosa
• increase surface area (imp for absorption)
• slow down food
• villi project from the mucosa to increase surface area

Question 34

Large intestine

Answer 34

• absorbs most of the water from digested material to solidify material into feces
• “large” refers to diameter (width) in relation to small intestine
• how food passes

Question 35

Large intestine: all the parts

Answer 35

• veriform appendix: projects from cecum
• cecum: “blin pouch” located in the right. Lower abdominal quadrant
• ascending colon
• hepatic fixture: exists next to the liver
• transverse colon: going all the way across the abdominal cavity
• splenic flexure: next to spleen
• descending colon
• sigmoid colon

Question 36

Large intestine: blood supply

Answer 36

• superior mesenteric artery: supplies from cecum to first 2/3 of transverse colon
• inferior mesenteric artery: supplies from distal 1/3 of transverse colon to sigmoid colon

Question 37

Rectum and anal canal

Answer 37

• internal anal sphincter: involuntary control. Usually contracted until it’s not. Gives out when there’s too much poop
• external anal sphincter: voluntary control. Keeps you from pooping your pants