Digestive System Anatomy: Esophagus, Stomach, Intestines, Liver, and Innervation

esophagus

connects the pharynx to the stomach

the esophagus has

upper and lower sphicnters

Stomach regions

cardiac orifice - opening for the esophagus

pyloric orifice - beginning of duodenum

fundus

superior part above of the cardiac orifice

body

above the notch in the lesser curvature

pyloric region

junction with the duodenum

small intestines extend from

the pylorus of the stomach to the cecum

Duodenum

first part of the small intestine

superior, descending, and horizontal, and ascending portions

almsot ciricular

large intestine - colon

extends from ileum to anus

parts of the large intestine

ascending, transverse, descending

right and left colic flexures

at either corner of the transverse colon

the large instestine contains three bands of smooth muscle on the outside called

tenia coli

the tenia coli creates a ____ appearance known as ___

sacculated

haustra

Liver

largest gland in the body

highly vascularized

the liver is attachted by ligaments to

diaphragm, anterior wall of the abdomen, stomach, and duodenum

liver blood supply

portal vein (75)

hepatic artery (25%)

biliary tract

liver and glabladder

left and right hepatic ducts come together to form the

common hepatic duct

common hepatic duct joins the ______ from the gallbladder to form the_____

Cystic duct

common bile duct

common bile duct goes into the duodenum after being joined by the

pancreatic duct

What duct joins the common bile duct as it enters the duoduem

pancreatic dcut

peritoneum

pariteal and visceral

everything from the neck to the transverse colon receives innervation

parasympathetic from vagus nerve

what are the three main ganglia that supply sympathetic innervation to the GI tract

celiac ganglion

superior mesenteric

inferior mesenteric

GI system lining (deep to superficial)

mucosa

submucosa

muscularis

serosa

mucosa or mucous membranse

epithelium

lamina propria which contains small glands

muscularis mucosa - smooth muscle separating mucosa from the submucosa

submucosa

dense connective tissue with nerves and glands

Meissner's nerves! (plexus of autonomic nerves)

muscularis

thick layer of smooth muscle

internal sublayer of circular muscle

external sublayer of longitudinal smooth muscle

Myenteric Plexus

autonomic innervation to gastro intestintal tract

found between layers of in the muscularis

serosa

outermost layer

same as visceral peritoneum

mesothelium

Esophagus contains

non keratinized stratified squamous epithelium

esophageal glands

stomach contains

rugae - fold in mucosa and submucosa when stomach is empty

the stomach mucosa epithelium

surface mucus cells

deeply invaginating simple columnar eputherlim

secrete thick, adherent and highly viscous mucous layer

Gastric pits

form from tubular invaginations of epithelium

each with an opening to the lumen of the stomach

lead to long branching tubular glands

names of the cells of the mucus glands

mucus neck

parietal cell

chief cell

G cell

MUCOSA SMALL INTESTINES

small intestines absorption is achieved by

increasing the surface area

1. Plicae circularis (3x)

2. Villi (10x)

3. Microvilli on enterocytes (20x)

4. intestinal glands (crypts)

Plicae Circulares

circular or semilunar folds of the mucosa

evaginations of the mucosa and submucosa that projet into the lumen

villi

short mucosal outgrowth on plicae circualris

covered by a simple columnar epithelium (enterocutes) and goblet cells

ct tissuse from lamina propia

fenestrated capillaries and lacteals

enterocytes

tall simple columnar epithelium

striated or brush border of microvilli with a glycocalyx

absorptioN!

goblet cells

secrete mucin whihc is hydrated to mucous

lacteal

lympathic vessels in villi that absorb chylomicrons

SUBMUCOSA SMALL INTESTINES

Submucosa contains

duodenal glands (brunner's gland) - alkaline mucus to neutralize acid material from stomach

ileum has GALT in the lamina propia and submucosa

nodules in peyer's patches

The large intestines mucosa contains

flat! (no plicase circularis or villi)

intestinal glands - tubular invaginations

colonocytes - simple columnar cells with micro villu

LOTS OF Goblet Cells

GALT in lamina propria

LIVER

Hepatic lobules

hepatocytes that form hundreds of irregular anastomosing plates radiating toward a small central vein

peripherally each lobule has 3-6 portal areas of which contains

a portal triad and some lympahtic vessels and nerves

portal triad

venule of portal vein

arterliole of hepatic artery

small bile duct

between the anastosoming plates are

sinusoids

sinusoids

emerge from peripheral branches of the portal vein and hepatic artery

converge on central vein

venous and arterial blood mix

have thin discontinuous lining of fenestrated endothelia which allows for plasma to fill perisnusoidal space

when the fluid enters to sinusoids it will leak out into the

perisinusoidal space

perisinusoidal space

subendothelila space between hepatocyte and sinusoids

site of exchange of material between blood and hepatocytes

hepatic blood supply

hepatic artery (20-30%) carries well oxygenated blood from aorta

portal vein (70-80%) carriers poorly oxygenated but nutrient rich blood from GI tract and spleen to the sinusoids of the liver

both flow into CENTRAL VEIN

Blood flows from the _____ to the ____

periphery (portal triad)

central vein

hepatocytes can secerte plasma proteins into perisinusoidal space and is picked up bu the sinusoid

endocrine!

Bile flows

opposite of blood!

from central to the portal triad region

hepatocytes can also secrete bile into the bile duct

exocrine!