Digestive System

what's the difference between the GI tract and Accessory Organs

Food goes through the GI tract to be digested, while accessory organs assist digestion but food never goes through them

what are 2 other names for the Gastrointestinal Tract

GI Tract and Alimentary Canal

how does the length of the GI tract compare in a living person versus a cadaver

living: 16-23 ft, cadaver: 23-30 ft

list organs in the GI tract (in order of the pathway of food)

mouth, pharynx, esophagus, stomach, small intestine, large intestine, rectum, anus

what are the accessory organs

gallbladder, liver, pancreas, salivary glands, tongue, teeth

digestion definition

breaking down food using enzymes or force

defecation definition

unabsorbed materials are eliminated from the body

ingestion definition

eating

absorption definition

nutrients and other molecules pass into the bloodstream

secretion definition

accessory organs and GI tract create 7 liters of digestive fluid each day, includes saliva and mucus

propulsion definition

food is swallowed and pushed through the GI tract

mechanical digestion definition

digest food through force (ex. chewing, stomach churning)

chemical digestion definition

digest food using enzymes (ex. mouth producing saliva)

peristalsis definition

smooth muscle contractions that push food through the GI tract involuntarily

what organs/structures are capable of secretion

salivary glands, liver, gallbladder, pancreas

what organs/structures are capable of propulsion

pharynx, esophagus, stomach, large intestine, small intestine

what organs/structures are capable of digestion

stomach, large intestine, small intestine

what organs/structures are capable of absorption

stomach, large intestine, small intestine

where do nutrients go after being absorbed by the stomach and intestines

into the bloodstream

what are two other names for the mouth

oral cavity; buccal cavity

how do the lips and cheeks help eat

keep food between the teeth to chew

how many permanent teeth are there in a typical adult

32

what 2 substances makes up our teeth

dentin and enamel

enamel definition

substance found on the outside of the tooth

dentin definition

substance found on the inside of the tooth

crown definition

visible top part of the tooth

root definition

part that anchors the tooth to the gum

alveoli definition

socket that the tooth sits in

canine function

tearing and piercing food

premolars or molars function

grinding and crushing food

incisors function

biting off pieces of food

structural difference between the hard and soft palate

hard palate - made of bone; soft palate - made of skeletal muscle

hard palate purpose

tongue pushes against while chewing

soft palate purpose

blocks the nasopharynx; elevates when swallowing

what type of tissue is the tongue made of

skeletal muscle

tongue functions

move food between teeth while chewing; mixes food with saliva to form bolus; pushes to pharynx; helps with speech

bolus definition

partially digested food that is formed when the tongue mixes saliva with food and passes to the esophagus

papillae definition

peg-like projections that taste buds are found within

saliva functions

dissolve food chemicals to allow taste; moisten food to create bolus; digest starchy food

major salivary glands vs. minor salivary glands difference

major - found outside the mouth, activated by food; minor - inside the mouth, continually secretes saliva to keep mouth moist

how much saliva do the major salivary glands produce daily

1.5 L

what are the three major salivary glands

parotid gland, sublingual gland, sub-mandibular gland

what type of digestion happens in the mouth, how?

chemical - the salivary glands do chemical digestion by producing enzymes to help break down food; mechanical - the teeth and palates help with chewing food

another term for throat

pharynx

what type of tissue is the pharynx lined with, why?

stratified squamous epithelium; to protect from abrasions while swallowing

how many layers of muscle line the wall of the pharynx

3

pharynx wall muscles purpose

contract to propel food down the pharynx to the esophagus

how long is the esophagus

10 inches

esophagus function

to push food from the pharynx to the stomach using peristalsis

what does the esophagus look like when you are not eating

collapsed

upper esophageal sphincter function

opens to let food into the esophagus; keeps air out of the GI tract

lower esophageal sphincter function

opens to let food into the stomach; prevents food from regurgitating back into the esophagus

what happens if the lower esophageal sphincter fails

heartburn, acid reflux, GERD

what happens if the upper esophageal sphincter fails

air gets into your stomach and GI tract

stomach location

left side of the abdomen, beneath liver

stomach size

6-10 inches; varies based on amount of food

rugae definition

folds in the inner wall of the stomach

stomach functions

temporarily stores food; digests food chemically & mechanically, producing chyme; pushes chyme to small intestine; absorbs alcohol & aspirin

3 layers of stomach names

longitudinal (outer); circular (middle); oblique (inner)

stomach wall muscles function

they contract to digest and push food

mucosa definition

lining of the stomach

tissue type of lining of the stomach

epithelial tissue

2 special structures found in the lining of the stomach

mucus and gastric pits

production of mucus in the stomach importance

produces cells that secretes mucus that protects the stomach from digesting itself

what do gastric pits lead to

gastric glands

chief cells and parietal cells location

inside gastric glands

chief cells function

produces pepsinogen (inactive pepsin)

parietal cells function

secrete hydrochloric acid

what acid makes up stomach acid

hydrochloric acid

hydrochloric acid functions

makes stomach contents acidic; activates pepsin - which digests proteins; chemical digestion of food; kills bacteria in food

stomach acid pH

1.5-3.5 L

what does pancreatic juice produce

proteases, amylases, lipases, nucleases

largest internal organ

liver

liver weight

3 lbs

liver location

beneath diaphragm

how many lobes does the liver have

4

liver function (digestive system)

produce bile

liver function (in general)

process nutrient rich blood from the small intestine

where does the liver pass bile to

duodenum

bile appearance

yellow-green

bile function

break down fats so they're easier to digest

bile duct function

transporting bile from the liver into the gallbladder (and then the duodenum)

which accessory organ plays an important role in both the digestive and endocrine system

pancreas

what fluid does the pancreas produce

pancreatic juice

how much pancreatic juice is produced per day

~1.5 L

is pancreatic juice basic or acidic

basic

where does the pancreas pass pancreatic fluid to

duodenum

how does pancreatic fluid protect the duodenum

neutralizes chyme entering the duodenum from the stomach

what are the four enzymes found in pancreatic fluid

proteases, amylases, lipases, nucleases

what do proteases help digest

proteins

what do amylases help digest

starches

what do lipases help digest

fats

what do nucleases help digest

nucleic acids

why does the gallbladder appear green

because it stores bile

gallbladder location

in a crease in the liver

gallbladder function

stores additional bile

longest part of the human GI tract

small intestine

pyloric sphincter function

controls how much chyme is dumped into the small intestine from the stomach

where does most chemical digestion and absorption occur

small intestine

3 parts of small intestine in order

duodenum, jejunum, ileum