LiverGallbladder

Common bile duct

Pancreas

Pancreatic duct

Duodenum

Biliary and Pancreatic Anatomy

Islet cellsecretinghormones

Cells secretingpancretic juice

Insulin and glucagon

Pancreticduct

Duodenum

Pancreas

Common bile duct

Blood

Pancreatic Anatomy

Pancreatic Secretions

• Acinar Enzymes Digestion

• Ductal HCO3 and Water Protection Digestion

Cell Type Component Function:

ATP

cAMP

Adenyl cyclase

?

?Ca2+

Ca2+

stores

Secretin

Ach

CCK

En

zymes

IP3

The Hormones also Modulate Enzyme Expression

Primary Stimulus

PANCREATIC ACINAR CELL

Ca2+ CCK

Pancreatic Duct Cell

Regulators of Pancreatic Secretion

• Acinar CCK / Ach Secretin

• Ductal Secretin CCK / Ach

Cell Type PrimaryActivator Potentiator

(Ca2+ )

(cAMP )

Cephalic and Gastric: Neural – Ach

Intestinal : Hormonal

Liver

HepaticDucts

Right

Left

Common BileDuct

Cystic Duct

GallbladderAmpulla

ofVater

DuodenalLumen

PancreaticDuct

Sphincterof Oddi

• Excretory Component - Bilirubin, Drug Metabolites.

• Secretory Component- Bile: Produced and Filtered by Hepatocytes

Primary Bile Acids: Cholic Acid, Chenodeoxycholic Acid

- Secondary Bile Acids - Formed by Bacteria in the Intestine

: Deoxycholic Acid, Lithocholic Acid

Bile AcidsPrimary bile acids Secondary bile acids

Cholesterol

Cholic acid Deoxycholic acid

Chenodeoxycholic acid

Lithocholic acid

Liver Intestine

Cholesterol 7-hydroxylase

80% 20%Fraction of Total

Amphipathic Carboxylic Acids

C

Have both Hydrophilic and Hydrophobic domains

Formation

of

Micelles

Co-Lipase

Bile Acids are Amphipathic

Centralvein

Hepatic cell plateBile canaliculus

Venous sinusoidTerminalbile duct

Kupffer cell

Portal venule

Aorta

(200)

Celiac(700)

PortalVein

Superior Mesenteric (700)

InferiorMesenteri

c (400)

LIVER

STOMACH

SPLEEN

PANCREAS

SMALLINTESTINE

COLON

To Systemic Circulation

(1800) mls/min

HEPATIC

Rates:

ml/min

Cholesterol 7-hydroxylase

Newly synthesizedbile acids(0.6 g/24 h)

Cholesterol

2 - 4 gbile-acid pool: circulated 6 - 10 times in 24 h

Excretedbile acids(0.6 g/24 h)

Liver

BileductsPortal

vein

ColonSmall intestine

Stomach

EnterohepaticCirculation

SECRETIONS of the INTESTINES

Information pertaining to the next 3

slides is found in the Lecture Notes for

the last Lecture

Blood vesselsLymph vesselsNervesSmooth muscleConnective tissuelymphocytesPlasma cellsEosinophiles

Villousepithelium

Undifferentiated

GobletMitoses

Endocrine cells

Cryptepithelium

Cryptlumen

Muscularismucosa

Absorp-tive cells

Gobletcells

Endocrine cells

Cell Loss

• Crypts of Lieberkuhn: Small and Large Intestine

- Contain Primarily Epithelial Cells, Mucus Goblet Cells, and Endocrine Cells.

- Water Secretion - VIP Activates Water Secretion by Elevating cAMP and Cl- conductance.

- Cell Growth and Differentiation: Cell Turnover at the Tip of a Villus is High (3-6 day Cycle).

Secretions of the Small Intestine (2000 ml/day)

Crypt Secretion

H2O2 Cl-

Na+ K+

PDtecAMP? Ca2+

Cl-

Cl-Na+

ATPADP + Pi

3 Na+

2 K+

Key Players:

cAMP Activated Cl- Channel

Na+ / K+ / Cl- Co-transport

Na-K ATPase

VIP – neurotransmitter Histamine also can activate