**The Pancreas, Liver, And Gall Bladder Flashcards
What are the gastrointestinal digestive organs?
- Pancreas
- Liver
- Gallbladder
What are the endocrine organs?
- Pancreas
- Liver
Describe Exocrine function
- Secretion onto a surface
- Epithelial cells
- Diverse secretion types
Describe Endocrine function
- secretion into the vasculature
- epithelial and non-epithelial cells
- Exocytosis
What are the 3 types of exocrine glands
- Merocrine Glands
- Holocrine Glands
- Apocrine Glands
What is the most common exocrine gland that releases products via exocytosis at the apical end of secretory cells? (I.e., salivary glands, pancreas)
Merocrine Glands
Describe Holocrine Glands
- Secretory cells disintegrate to form the secretion
- like Sebaceous Glands
How do Apocrine glands function?
- Secretion of membrane-enclosed apical cytoplasm containing proteins and lipids
- Examples: Mammary glands (these also have merocrine function)
What are the endocrine functions of the pancreas?
- Islets of Langerhans (insulin and glucagon)
- Protein and polypeptide hormones
What are the Exocrine elements of the Pancreas?
- Acinar Cells
- Releases digestive molecules into the duodenum
In the Pancreas, what do Acinar cells release via exocytosis And where do they release them to?
- Zymogen granules
- released into intercalated ducts
What are the molecularly diverse elements of Zymogen granules?
- Alpha-amylase
- Lipases
- Nucleases
- Proteases (zymogens
- Trypsinogen
- Chymotrypsinogen
- Elastase
What does Alpha-amylase do?
Hydrolyze long-chain carbs
What do Lipases do?
-Hydrolisis of lipids
What do Nucleases do?
-Hydrolisis of DNA and RNA
What does Trypsinogen get cleaved to and by what?
- Trypsin
- By enterokinase
What happens to Chymotrypsinogen ?
-cleaved to Chymotrypsin by trypsin
What activate see Elastase?
Trypsin
What two proteins induce Acinar and crontroacinar exocrine activity?
- Cholecystokinin (CCK)
- Secretin
CCK
Neuroleptic of the central and enteric nervous system; I cells
Secretin
S cells
What are the different types of cells in the Islets of Langerhans?
- Alpha cells
- Beta Cells
- Delta cells
- PP cells
What do Alpha cells do?
- Secrete glucagon
- make up 30% of Islet cells
What do Beta cells do?
- Secrete insulin
- 65% of Islet cells
What do delta cells do?
- Secret Somatostatin
- inhibits GI and pancreatric endocrine and exocrine secretion
-4% of Islet cells
What do PP cells do?
- Secrete pancreatic polypeptide
- Inhibits pancreatic exocrine secretion, GI motility, gastric acid secretion
-less than 1% of islet cells
Functions of the liver
- Blood reservoir (roughly 20% blood is at any given time passing through liver)
- Bile secretion
- Detoxification
- Metabolic Homeostasis
What are the elements of metabolic homeostasis that happen in the liver?
- Carb metabolism
- Lipid Metabolism
- Protein metabolism
- Storage
- Serum protein production
Describe the liver
- Largest organ in the body
- highly regenerative
- Dual blood supply (Hepatic artery and Portal Vein?), receives 30% of cardiac output
What are the major cell types of the liver?
- Hepatocytes
- Kupffer cells
- Sinusoidal Epithelial cells
Describe Hepatocytes and their function.
- Polarized epithelial cells
- Metabolism carbohydrates, proteins, and lipids
- Produces bile from Cholesterol
- Detoxifies endogenous and xenobiotic molecules
Describe Kupffer cells and their function
- Liver-specific macrophage
- removes pathogens and debris from the blood
- Prevent systemic blood wide infections
- Filter blood
- Clears colon and intestinal bacteria
Describe sinusoid all epithelial cells and their function
- Large Pores between cells (fenestrae)
- No basement membrane
Two major sources of blood to the liver
- Hepatic artery (30%)
2. Portal Vein (70%)
Normal blood volume of the liver
- 450 ml
- Expansion: .5-1 L
What are the 3 structure models of liver architecture?
- Classic Hepatic Lobule
- Portal Lobule
- Hepatic Acinus
How does the liver maintain Carbohydrate Metabolism Homeostasis?
- Glycogen Storage
- Guconeogenisis
- Normalizes blood glucose
How does the liver maintain Fatty Acid Metabolism homeostasis?
- Oxidizes Fatty Acids
- Produces Ketone Bodies
- Synthesizes fatty acids
- Synthesizes triglycerides, phospholipids, and cholesterol
- Forms lipoproteins to transport lipids and fatty acids
How does the liver maintain systemic protein metabolism homeostasis?
- Deaminates amino acids
- Forms urea to remove ammonia from the blood
- Synthesizes non-essential amino acids
Where are Vitamins, Fatty acids, and Iron stored?
The liver
What does the liver contribute to protein production?
- Acute phase proteins
- Clotting factors
- Albumin
- Apolipoproteins
What happens during phase 1 of hepatocyte xenobiotic (drug)/molecule elimination?
- Drugs/molecules converted to more polar compounds; oxidized
- Cytochrome p450 and microsomal oxidases
- Some drugs/molecules transported directly into the bile
- Output of phase one is called a Metabolite
What happens during phase 2 of hepatocyte xenobiotic (drug)/molecule elimination?
- Drugs/molecules/phase 1 metabolites conjugated to hydrophilic molecules
- transferases
How are metabolites eliminated in detoxification?
In the bile or urine
What is contained in Bile?
- bile salts
- cholesterol
- phospholipids
- bilirubins
- waste
What stimulates bile release And how?
CCK
- contracts gallbladder smooth muscle
- relaxes hepatoprancreatic sphincter
What stimulates HCO3- secretion into bile?
Secretin
Where are pancreatic zymogens activated?
In the duodenum to protect acinar cells
What is a Zymogen?
-inactive enzyme precursor
