Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
36 Cards in this Set
- Front
- Back
|
What is the liver and what does it do?
|
•Largest mass of glandular tissue
•Second largest organ (after the skin) –>3 lbs. •Most versatile organ –Endocrine and exocrine function –Synthesizes and accumulates substances –Detoxifies –Transports •Develops as endodermal outpocketing of the gut |
|
|
What is the structure of the liver ?
|
•Reddish brown and soft
•Covered with a thin capsule: Glisson’s Capsule –Most of the surface covered with mesothelium •Strands of connective tissue enter the Hilum and subdivide into lobes and lobules –4 incompletely separated lobes •Entire liver is histologically identical |
|
|
What do these images show?
|
Structure of the liver!
|
|
|
What are the two types of tissue that make up the liver?
|
•Stroma
–Supporting tissue –Capsule and collagenous extensions from Hilum –Reticular fibers supports cells and keeps sinusoids open •Parenchyma –Hepatocytes –Lipid-Storing Cells |
|
|
What are hepatocytes?
|
•Principal cell type: 80% of all liver cells
•Performs nearly all functions associated with liver –Polyhedral shape –Lightly eosinophilic •2000 mitochondria per cell –Stores glycogen and lipid –Extensive RER and SER –Arranged in anastomosing cords –Surrounded by sinusoidal capillaries |
|
|
What does this image show?
|
Structural components of a hepatocyte
Notice lots of smooth ER and the cytoplasm is completely filled |
|
|
What does this image show?
|
Hepatocytes stained with H&E
Notice they are binucleated and have uneven cytoplasm |
|
|
What are portal areas?
|
•Triangular arrangement of connective tissue containing profiles of several structures
–Branch of Bile Duct –Branch of Portal Vein –Branch of Hepatic Artery –Lymphatic Vessel –Peripheral Nerves •Vessels may branch giving rise to more than 4 tubules in portal area |
|
|
What does this image show?
|
Portal Area
Find: Portal Vein, Lymphocytes and arterioles, and bile duct |
|
|
What does this image show
|
Portal Areas on a liver tissue
|
|
|
How does fluid move in the classic hepatic lobule, portal lobule and portal acinus?
|
In the classic hepatic lobule, blood flows into the center vein.
In the portal lobule, material moving from the 3 adjacent lobule drain to a center bile duct. In the portal acinus blood flows from adjacent portal areas into adjacent lobules. |
|
|
What are the three different liver lobules?
|
•Classical Lobule: Hexagonal
–Central Vein plus all hepatocytes that drain into it –Bounded by portal areas –Blood flows from periphery to center •Portal Lobule: Triangular –Bile flows to center •Portal Acinus: Diamond shaped –Based on oxygenated blood flow –Explains observed metabolic differences |
|
|
What does this image show?
|
Liver Lobule
|
|
|
Study this image
|
Shows the flow of blood and blie
|
|
|
What does this image show?
|
Liver Lobule
|
|
|
What are hepatic sinusoids?
|
•Line the plates of hepatocytes
•Every hepatocyte has at least one surface directly along a sinusoid •Arise at periphery of classic lobule and converge and anastomse toward central vein •Contain Kupffer Cells –Actively phagocytic •RBCs, iron, cellular debris –Monocyte–Macrophage derivative |
|
|
What does this image show?
|
Sinusoidal Endothelium
|
|
|
What does this image show?
|
Hepatocyte and Sinusoids
|
|
|
What is the perisinusoidal space?
|
•Space of Disse
•Contains projecting microvilli |
|
|
What is the bile canaliculi?
|
•Small, tubular spaces created where adjacent hepatocytes meet
–Tight Junctions and Desmosomes •Initial portion of exocrine duct system •Begin as blind tubules •Merge to form Canals of Hering, Bile Ducts, left and right Hepatic Ducts and then the Common Bile Duct |
|
|
Study this image and note where the Bile Canaliculus is
|
Bile Canaliculus
|
|
|
What does this image show?
|
Bile Canaliculi
|
|
|
What does this image show?
|
Bile Ductule
|
|
|
What does this image show?
|
Hepatic Circulation
|
|
|
What does this image show?
|
How a lobule is vascularized
|
|
|
Is the liver vascularized?
|
•Highly vascularized
•Functions intimately associated with blood system •Hepatocytes simultaneously bathed with both arterial and venous blood –Portal vein from intestines: 75% •High nutrients; Low O2 –Hepatic artery from aorta: 25% •Low nutrients; High O2 •Blood leaves liver through the Hepatic Vein |
|
|
What endocrine and exocrine functions is the liver involved in?
|
•Endocrine
–Synthesis of most blood plasma proteins –Synthesis of plasma lipoproteins •(LDL, VLDL, HDL) •Exocrine –Synthesis of Bile: Emulsifies lipids •500–1000 ml per day •90% recycled constituents; 10% synthesized de novo |
|
|
What is bile made of?
|
•Water
•Electrolytes •Bile acids •Phospholipids •Cholesterol •Lecithin •Bilirubin |
|
|
What are other metabolic functions of the liver?
|
•Glycogen synthesis and storage
•Destruction of aged RBCs and reclamation of products •Detoxification of metabolic wastes •Storage of lipids and lipid-soluble vitamins (A, D, and K) •Hemopoiesis in the fetus and in severe anemia |
|
|
What is unique about the liver?
|
•Extraordinary capacity for self renewal
–Up to 75% can be replaced in rat –Less but still significant in human –Controlled by unknown circulating factors –Subject of intense research |
|
|
What is the gallbladder and what does it do?
|
The Gallbladder
•Small, distensible, hollow, pear-shaped organ •Functions: –Stores bile –Concentrates bile –Releases bile –Does not make bile •Capacity of 100 ml |
|
|
What are the components of the gallbladder?
|
•Mucosa
–Simple columnar epithelium –No goblet cells –Cells have microvilli –Primary function is absorption, •Capable of secreting a little mucus –Lamina propria has no glands •Except right near Cystic Duct –Mucosa thrown into numerous nonpermanent folds •Rokitansky–Aschoff Sinuses •Muscle layer –Thin layer of smooth muscle arranged in oblique layer –Contraction aids in expelling lumenal contents –Not considered to be a muscularis mucosae •No submucosa •Most of organ covered by serosa; adventitia covers portion attached directly to liver |
|
|
What does this image show?
|
Gallbladder
|
|
|
What does this image show?
|
Gallbladder
|
|
|
What does the gallbladder do?
|
•Stores, concentrates, and releases bile
•Concentration is active process –Cells transport Na+ from lumen into lateral intercellular spaces –Water follows passively; taken up by vessels in lamina propria |
|
|
What controls the muscular layer of the gallbladder?
|
•Contraction of muscular layer controlled by Cholecystokinin (CCK)
•Presence of dietary lipid in lumen of small intestine stimulates I cells to release CCK |
