CCK causes
gallbladder contraction, relaxation of sphincter of Oddi
Which organ has amazing regenerative abilities due to mitosis of hepatocytes?
liver -also the largest organ
Sinusoids
capillaries that separate hepatic plates
-very permeable
how are products of digestion delivered to the liver?
hepatic portal vein
-GI drains into portal vein → liver
Hepatic blood flow
25% of CO
Hepatic portal system
unique pattern of capillaries → veins → capillaries → veins
How does the liver detoxify blood?
Kupffer cells: phagocytosis
Chemical alternated (hormones or drugs)
Production of urea, uric acid
Excretion
Functions of the liver
detoxify blood; secrete bile; metabolize carbs, lipids, proteins
Bile is composed of:
bile pigment (bilirubin), bile salts, phospholipids (lecithin), cholesterol, inorganic ions
Bilirubin
produced in spleen, liver, and bone marrow
-product of Hgb breakdown
-conjugated vs unconjugated
Unconjugated (free) bilirubin
not very water soluble
carried attached to albumin
Conjugated bilirubin
some free bilirubin is conjugated with glucuronic acid to make it water soluble
Conjugated bilirubin uses
-bacteria turn into urobilin → feces brown
- used to make bile
-absorbed by intestine sent back to liver
-remains in blood to be filtered by kidneys → amber color to urine (beer brown)
Bile acids are derived from
cholesterol
T/F the liver helps balance blood glucose
T
glycogenesis
creates glycogen
lipogenesis
creates triglycerides
glycogenolysis
breaks down glycogen
gluconeogenesis
creates glucose from AA
ketogenesis
creates ketones
What stimulates the conversion of fatty acids into ketone bodies
Glucagon
Excessive catabolism of fat
ketoacidosis
Liver produces
plasma albumin, most plasma globulins, clotting factors, angiotensinogen
Albumin fx
provides oncotic pressure and transport
Globulins fx
provide transport and blood clotting
Clotting factors made
1 (fibrinogen, 2 (PT), 3, 5, 7, 9, 10, 11
Chemical alteration by hepatocytes to detoxify blood
**ammonia is converted to urea, porphyrins into bilirubin, purines into uric acid
-urea returns to blood to be filtered by kidneys
-steroids and xenobiotics are altered then secreted into bile
Gallbladder fx
stores and concentrates bile from the liver
What hormone tells the gallbladder what to do?
CCK
Fx of bile
aids in excretion of bilirubin
bile salts and IgA inhibit bacterial growth
neutralize gastric acid
aid in fat absorption
emulsify triglycerides and phospholipids
T/F pancreas has both endocrine and exocrine functions
T
Pancreas endocrine fx
Islets of Langerhans cells make insulin (beta cells) and glucagon (alpha cells)
-inner portion on pic
Pancreas exocrine fx
pancreatic juice (enzymes)
-get deliver to duodenum via pancreatic duct
Pancreatic Fx
secrete bicarb to neutralize chyme from stomach
Digestive enzymes
Digestive enzymes for proteins
trypsin, chymotrypsin, caboxypolypeptidase
Digestive enzymes for carbohydrates
pancreatic amylase
Digestive enzymes for lipids
Pancreatic lipase, cholesterol esterase
What hormones regulate pancreatic secretion?
Ach, CCK, Secretin
Ach effect on pancreas
stimulates enzyme release
CCK effect on pancreas
stimulates enzyme release
Secretin effect on pancreas
stimulates large amounts of water and bicarb
Secretion in 3 phases
Cephalic- PNS release of enzymes
Gastric- more release of enzymes
Intestinal- secretin stimulates release into duodenum
PNS division of pancreas
activated while eating and stimulates insulin release
SNS division of pancreas
inhibits insulin secretion and stimulates glucagon secretion
— produces stress hyperglycemia