Digestive System

layer of the GI Tract

mucosa
submucosa
muscularis
serosa

regions of the oral cavity

vestibule
oral cavity proper

vestibule

area just inside the lips

oral cavity proper

teeth, tongue, and spit glans

hard palate

anterior 2/3 of the palate
palatine processes of maxillae bones and palatine bones

soft palate

posterior 1/3
muscular

uvula

extends posteriorly from the soft palate

function of uvula

prevents things from going up into the nasopharynx

lingual frenulum

attaches the tongue to the floor of the mouth

papillae

houses taste buds

salivary glands produce

saliva

three pairs of salivary glands

parotid glands
submandibular glands
sublingual glands

parotid glands

largest salivary glands
anterior and inferior to the ear

parotid duct location

runs parallel to the zygomatic arc
pierces buccinator before opening into the mouth near the upper 2nd molar

submandibular salivary glands location

inferior body of mandible

submandibular duct

opens in the floor of the mouth next to lingual frenulum

sublingual salivary glands

inferior to the tongue

sublingual ducts

open onto the inferior surface of the oral cavity

teeth

dentition

crown

part of teeth superficial to the gums

enamel

coating on the teeth
strongest substance in the body

neck

area where the tooth narrows

roots

part of the tooth anchored in the bone

gingiva

gums

dentin

substance that makes up most of the tooth

pulp cavity

opening in the tooth filled with arteries, veins, and nerves

root canal

canals in roots that allow for travel to pulp cavity

mesial surface

surface facing away from the back molar

distal surface

surface facing the back mola

buccal surface

surface facing the cheek

labial surface

surface facing the lips

lingual surface

surface facing the tongue

occlusal surface

chewing surface

incisors

most anterior
shaped like chisels for slicing

canines

posterolateral to incisors
pointed for puncturing and tearing

premolars

posterolateral to canines
have flat crowns with ridges for crushing and grinding

molars

thickest and most posterior teeth
adapted for crushing and grinding

esophagus

conducts ingested materials from pharynx to stomach.

superior esophageal sphincter

closes during inhalation preventing air from entering

inferior esophageal sphincter

prevents materials from regurgitating from stomach

peristalsis

rhythmic contraction of digestive tube

peristalsis begins

esophagus

muscles in the peristalsis

voluntary in the top 1/3
slightly voluntarily in middle 1/3
after completely involuntary

stomach location

upper left quadrant

3 layers of muscularis tunic in the stomach

longitudinal layer
circular layer
oblique layer

outer layer of stomach muscles

longitudinal layer

middle layer of stomach muscles

circular layer

inner layer of stomach muscules

oblique layer

gastric acid

hydrochloric acid (HCl)
pepsinogen

chyme

once bolus has mixed with gastric acid, a pasty and semisolid mixture (after 2-6 hours)

four regions of stomach muscles

cardiac
fundus
body
pyloris

greater curvature

lateral curve of the stomach

lesser curvatre

medial curve of the stomach

rungae

gastric folds on the internal surface of the stomach

greater omentum

extends inferiorly from the greater curvature of the stomach and covers most of the abdominal organ

lesser omentum

connects to lesser curvature of the stomach and the proximal end of the small intestine to the liver

heartburn

due to reflux

refulx

acid from the stomach moving into the esophagus, irritating the mucosa

common causes of heartburn

weakened lower esophageal sphincter- fats, alcohol or chocolate reacting with stomach acids
hiatal hernia
increased pressure- obesity, overfull stomach or lying down

hiatal hernia

weak spot in the diaphragm, allows the stomach to move upward

small intestine

finished chemical digestion
site for most nutrient absorption

3 segments of the small intestine

duodenum
jejunum
ileum

duodenum

originates at the pyloric sphincter
receives bile to emulsify fats
receives pancreatic secretion for digestion

jejunum

primary region for chemical digestion and nutrient absorption

ileum

distal end terminates at the ileocecal valve

ileocecal valve

sphincter that controls the entry of material into the large intestine

teniae coli

bundles of longitudinal muscle folds

haustra

sacs of contracted teniae coli

cecum

first part of the large intestinea

ascending colon

right lateral border of the abdomen

right colic flexure

near inferior border of the liver, making a 90 turn to the left

transverse colon

starts at the right colic flexure
approaches the spleen in the upper left abdominal quadrant

left colic flexture

90 turn in the transverse colon that turns inferiorly at the spleen

descending colon

starts at the left colic flexure

sigmoid colon

has a shape resembling an S

rectum

muscular tube that readily expands to store accumulated fecal material prior to defecation

anal canal

last few centimeters of the large intestine

internal and external anal sphincters

voluntary muscles

appendicitis

inflamation of the appendix

diarrhea

Large Intestine hasn't reclaimed a lot of water
way for the body to cleanse itself

constipation

LI reclaims to much water d

diverticulosis

development of diverticula along the length of the colon

diverticulitis

inflammation of diverticula

liver location

right quadrant of the abdomen

4 lobes of the liver

right lobe
left lobe
caudate lobe
quadrate lobe

right and left lobes

major lobes of the organ

falciform ligament

separate the right and left lobes

caudate and quadrate lobes

sometimes considered subdivision of the right lobe

hepatic portal vein

carries nutrient-rich blood from the GI tract capillaries, spleen, and pancreas to the liver

hepatic artery

carries oxygen- rich blood to the liver

hepatic veins

empty into the inferior vena cava

gallbladder

arises from inferior surface of the liver
stores bile

biliary apparatus

network of thin ducts that transport bile from the liver and gallbladder to the duodenum

cystic duct

from gallbladder

common hepatic duct

from liver

common bile duct

junction of cystic and common hepatic

jaundice

yellowing of skin, conjunctiva, and mucous membranes due to deposit of bilirubin

obstructive jaundice

bile ducts are obstructed so bile cannot drain out of the liver and overflows into the blood

hemolytic jaundice

from RBC's being broken down in large quantities

physiologic jaundice

immature liver cannot excrete the bilirubin as quickly as it is being formed