DIGESTIVE SYSTEM 3: Liver, Gallbladder, & Pancreas Flashcards
Largest mass of glandular tissue in the body
The largest internal organ; weighing 1,500g (2.5%) of adult body weight
Liver
Location of the liver
Upper right & partially in the upper left quadrants of the abdominal cavity
Liver is enclosed in a capsule of fibrous CT
- a serous covering (visceral peritoneum) surrounds the capsule
Glisson’s capsule
The liver is anatomicallduvuded by deep groves into 2 large lobes _______&________; and 2 smaller lobes _______&_________
Large lobes : Right & Left lobes
Small lobes: Quadrate & Caudate lobes
In the embryo, the liver develops as an endodermal evagination from the wall of the foregut to form
Hepatic diverticulum
The diverticulum proliferates, giving rise to the ________
, which arranged in cellular cords, forming the parenchyma of the liver
Hepatocytes
The original stalk of the hepatic diverticulum becomes the :
Common bile duct
An outgrowth from the common bile duct forms the cystic diverticulum that gives rise to the:
Gallbladder & cystic duct
The liver produced and secreted
Circulating plasma proteins
Liver plays important roles in the uptake, storage, & distribution of both nutrients and vitamins from bloodstream. Also maintains the:
Blood glucose level & regulates circulating levels of VLDL
5 circulating plasma proteins produced by the liver:
Albumin - regulate plasma volume & tissue balance; maintaining plasma colloid pressure
Lipoproteins - particular VLDL; LDL & HDL
Glycoproteins - proteins involved in iron transport (transferrin, haptoglobin, hemopexin)
Prothrombin & Fibrinogen - components of the blood-clotting cascade
Nonimmune a-globulins & B-globulins - help maintain plasma colloid osmotic pressure; carrier proteins
Vitamins that taken up in bloodstream and stored or modified by liver:
Vitamin A - important in vision; released in the circulation in the form of retinol
Vitamin D (cholecalciferol) - important in calcium & phosphate metabolism ; not stored in the liver.
Sources: dietary vit. D3 & in the skin during UV light exposure
Vitamin K - important in hepatic prothrombin synthesis & other clotting factors; transport in liver with chylomicrons
Sources: dietary vit. K & synthesis in the small Intestine by bacterial flora
Related disorders to vitamin A deficiency
Night blindness & multiple skin disorders
Predominant form of circulating vitamin D
25-hydroxycholecalciferol
Disorders associated with deficiency of vit. D
Rickets & Bone mineralizations disorder
Disease associated with Vitamin K deficiency
Hypothrombinemia & bleeding disorders
Hepatocytes in the liver involved in the:
Degradation of drugs, toxins & xenobiotics
Liver converts drugs & toxins into more soluble forms in 2 phases:
Phase I (oxidation) - hydroxylation & carboxylation; involves biochemical reactions of cytochrome 450
Phase II (conjugation) - conjugation w/ glucuronic acid, glycine, or taurine; makes the product more water-soluble
Exocrine function of the liver
Bile production
Bile compositions:
- conjugated and waste products
Water - serves as solute
Phospholipids (lecithin) & cholesterol - precursors of membrane components & steroids
Bile salts (bile acids) - emulsifying agents; aid in the digestion and absorption of lipids from the gut
Bile pigments - detoxify bilirubin; end product of hemoglobin degradation
Electrolytes - maintain bile as an isotonic fluid
The bile is carried from the parenchyma of the liver by the bile ducts that fuse to form the
Hepatic duct
Liver modifies the action of hormones; liver’s endocrine-like actions involve:
Vitamin D - converted to 25-hydroxycholcalciferol
Thyroxine - secrete as T4 converted to T3
Growth Hormone (GH) - amplified by liver produced insulin-like vrowth factor 1 (IGF-1); inhibited by somatostatin
Insulin & glucagon - pancreatic hormones
