tissue,stomach,liver pancreas

Alimentary canal tissue ( inner to outer)

• mucosa

• Sub mucosa

• Muscularis externa

• Serra’s

Mucosa

Lines Lumen. 3 sublayers:

• epithelium- secrete mucus

• Lamina propria- capillaries for nourishment+absorption

• Muscularis mucosa

Functions of mucosa layer

Produce mucus, digestive enzymes, and hormones, absorb and products of digestion and protect against disease

sub mucosa

Areolar CT

Has Blood lymphatic vessels/ follicles, nerve plexus, elastic tissues to help organs, restore shape after storing food

Muscularis externa

For segmentation and peristalsis

Inner circular layer (thickens to form sphincters)

Outer longitudinal layer

Stomach has 3rd oblique layer

Serosa

Outermost layer made by visual peritoneum: Areolar CT covered by mesothelium.

Except an esophagus where it’s replaced by fibrous adventitia

Mesentery

Double layer of peritoneum fused together; root for blood vessels and nerves.

• greater omentum (inferior)

• Lesser omentum (superior)

Peritoneum

Serous membrane of abdominal cavity, visceral and parietal layer

Retroperitoneal organs

Pancreas

Duodenum

Large intestine

Define deglutition

Swallowing

Buccal phase of deglutition

Tongue presses against hard palate, bolus pushed into oropharynx

Pharyngeal-esophogeal phase of deglutition STARTS

Soft palate and uvula close off nasopharynx

Epilogttis blocks trachea

Upper esophogeal sphincter relaxes/opens

Pharyngeal-esophogeal phase of deglutition CONT

Constructor muscles of fair contract, forcing food down

Upper esophageal sphincter contracts/ close after food enters

Food entering stomach

Peristalsis moves

Gastroesophogeal sphincter surrounding cardial orrifice opens

liver functions

produces bile- emulsifies fats

makes transport proteins

lobes of liver 4

right

left

caudate

quadrate

Falciform ligament of liver

separates the right and left lobe

suspends the liver from the diaphragm/anterior abdominal wall

Round ligament of liver

remnant of fetal umbilical vein

Bile duct

union of common hepatic duct and cystic duct

Liver Lobules

Hexagonal structural/functional units of liver

plates of hepatocytes (liver cells) that filter and process nutrient-rich blood

Portal Triad

In the corner of each lobule contains:

hepatic artery (oxygen)

hepatic portal vein

bile duct

Liver Sinusoids

• Leaky capillaries found between hepatic plates

• Blood from hepatic portal vein and hepatic artery come from triad region through sinusoids into central
  vein

Stellate/hepatic Macrophages

in liver sinusoids – remove debris and old RBCs

Hepatocytes

Produce around 900 mL of bile each day

process bloodborne nutrients (stores glucose as glycogen and makes plasma proteins),process fat-soluble vitamins

performs detoxification (ex: converts ammonia to urea)

bile

alkaline solution Containing bile salts, cholesterol, triglycerides, phospholipids, electrolytes, bilirubin (broken down in intestine to stercobilin → brown color)

Enterohepatic circulation

recycling mechanism to conserve bile salts

• reaborbed into blood by ileum, then to liver as HP blood

gallbladder

Thin-walled muscular sac on ventral liver surface

Contains folds so it can expand

release bile into cystic duct then bile duct

Gall Stones

Caused from too much cholesterol or too few bile salts

can obstruct flow of bile from gallbladder

pancreas

Supplies most enzymes needed to digest chyme and bicarbonate to neutralize stomach acid; empties into duodenum

Posterior to the stomach

parts of pancreas

Acini

Ducts – secrete to duodenum via the main
pancreatic duct

Acini

clusters of secretory cells that produce zymogen granules containing proenzymes

pancreatic juice

Proteases-secreted in inactive form, activated in duodenum
cells

Amylase

Lipases

Nucleases

Step 1 of bile/pacreatic secretions

CCK and secretin are released by duodenal enteroendocrine cells step

Step 2 of bile/pacreatic secretions

CCK induce secretion by acinar cells

Secretin causes secretion by duct cells step

Step 3 of bile/pancreatic release

Bile scretion by liver, stim by bile salt return step

Step 4 pancreatic/bile secretion

Gallbladder contraction step : stim by CCK

Step 5 of pancreatic/bile secretion

Hepatopancreatic sphincter relaxation step

Enteropeptidase

Bound to plasm membrane of duodenum, Activates protease in pancreatic juice into active form

when does bile secretion increase

When enterohepatic circulation returns large amounts of bile salts
intestinal cells exposed to HCl and fatty chyme causes secretin release; stimulates gallbladder to release bile