Mohammed Sanwar Hussain Taishan Medical University ,2011 Autumn Batch7th semesterRoll No:201121009

Topics that are going to be explained:

• Embryology• Gross Anatomy• Histology• Physiology• Pathology• Diagonistics

How can you love me if you don’t know me?

Everything you INGEST, INHALE and TOUCH goes through the liver.

Hepatic Embryology • During the third week of fetal life, the liver

primordium appears as an outgrowth of endodermal epithelium at the distal end of the foregut, known as the hepatic diverticulum or liver bud .

• Penetrate the septum transversum, which is the mesodermal plate.

• Connection between the hepatic diverticulum and the distal foregut narrows, thus forming the bile duct.

• Kupffer cells and connective tissue cells of the liver are derived from the mesoderm of the septum transversum.

EMBRYOLOGY

• Largest solid organ in the human body

• Weight - 1.2 to 1.4kg

• Span - 13 to 15.5cm .more than 15.5cm • considered as hepatomegaly

• Location - Right hypochondrium and part of • Epigastrium

• Surfaces of the liver Diaphragmatic surface Visceral surface

GROSS ANATOMY

Where is the Liver?

Anatomy of the Liver

• Consists of 2 lobes divided by falciform ligament

• There is no known difference between the lobes

The Anatomy of the Liver

Liver surfaces

• Divided into 2 anatomical regions:1.Diaphragmatic surface:Smooth and dome-shaped surfaceAnterior liver partInferior to diaphragmSeparated from diaphragm by subphrenic recess

and from posterior organs {kidney and suprarenal glands} by hepatorenal recess

Covered by peritoneum except

1.Diaphragmatic surface

2. Visceral surface

Covered by visceral peritoneum except porta hepatis and gall bladder bed.

• The visceral surface is related to: Right side of the stomach i.e. gastric and pyloric areas Superior part of the duodenum i.e. duodenal area Lesser omentum Gall bladder Right colic flexor and right transverse area ; colic area Right kidney and suprarenal gland; Renal area

Posterior liver view

Liver lobesRight and left lobeFunctionally independent i.e. each with own blood and nerve supply

Blood supply in by:Hepatic arteryPortal vein

Blood out through:Vein and biliary drainage

Liver lobes1.The Right lobeDemarcated by :

1. Gall bladder fossa

2. Inferior vena cava fossa

3. Imaginary line from fundus of gall bladder and inferior vena cava

Liver lobes2. Left lobe

Divided into:Medial and lateral segments

1.Medial superior – caudate lobe

2.Medial inferior - quadrate lobe

2. Left lobe cont… The lateral segment

is separated from the medial segments by:

On visceral surface: 1. fissure of

ligamentum teres (round ligament)

2. fissure of ligamentum venosum

On diaphragmatic surface:

1. Attachment of falciform ligament

Visceral surface 1. The round ligament(ligamentum

teres) – obliterated umbilical vein 2. The ligamentum venosum – fibrous

remnant of fetal ductus vein3. The Porta hepatis (hepatic potal;

portal fissure) - transverse fissure on the visceral surface of the liver.

– It gives passage to the:1. Portal vein2. Hepatic artery 3. Hepatic nerve plexus4. Hepatic ducts5. Lymphatic vessels

Peritoneal relations of the LiverThe Lesser omentum • Encloses the portal triad (bile duct, hepatic artery and portal vein

)• Passes from the liver to lesser curvature of the stomach + 2 cm of

duodenum• Thick free edge -- hepatoduodenal ligament• Sheet like remainder – hepatogastric ligament

Liver

• Vascular organ– Hepatic artery

• Supplies O2 rich blood from heart to liver

• Provides 20-30% of blood supply to liver

– Portal vein• Supplies nutrient rich

blood from the digestive tract

• Provides 70-80% of blood to liver

From Aorta

From GI tract

Histology of LiverLiver Lobule

• Liver lobule is a hexagonal-shaped structure and functional units of the liver: Composed of – Hepatocyte (liver cell) plates. – A central vein. – Liver sinusoids – enlarged, leaky capillaries

located between hepatic plates– Kupffer cells – hepatic macrophages found in liver

sinusoids– Portal triads: located at each of the six corners of

liver lobule. • Each lobule is separated from the other by

connective tissue.

Portal Triads

• Portal triads consist of: – A branch of bile duct; it drains the bile. – Hepatic artery; supply the liver with oxygenated blood. – Hepatic portal vein; supplies the liver with nutrient rich

blood from the small intestines.

Liver Lobule

Liver Lobule

Branch of hepatic artery

Histology of Liver• Functions of hepatocytes include:

– Production of bile– Processing blood borne nutrients– Storage of fat-soluble vitamins– Detoxification

• Secreted bile flows between hepatocytes toward the bile ducts in the portal triads

Liver Histology

Microscopic Anatomy of Liver

• Cell types – Hepatocytes

• 70% of volume of liver• Regenerative• Perform major functions

of liver

– Kupffer cells• Macrophages acting as

phagocytes

Hepatic Physiology

• Liver: • Largest solid organ in the body• Performs over 500 chemical processes• Produces over 160 different proteins• Makes clotting factors for the blood• Stores & releases sugar as glycogen• Metabolizes, detoxifies, synthesizes

Functions

• Bile production and secretion• Detoxification • Storage of glycogen• Protein synthesis• Production of heparin and bile pigments• Erythropoiesis (in fetus)• Immunologic

Excretory System

• Excretion of bile acids, cholesterol, bilirubin

• Begins at the bile canaliculi, enters hepatic ducts, then to common hepatic & bile duct

Excretion/Secretion

• Liver processes and excretes– Bile

• Water, electrolytes, phospholipids, bile salts or acids, bile pigments, cholesterol , heme waste products, and other substances from blood

• 3L produced/day• 1L excreted/day• Functions

• Bile acids needed for fat absorption• Mechanism to remove cholesterol and waste

• Bilirubin is the principal pigment in bile

Bilirubin Metabolism

Metabolism of Bilirubin

• Around 126 days, RBCs are phagocytized and hgb released

• Hgb broken down into:– Heme

• Converted to bilirubin– Globin

• Broken into amino acids and recycled– Iron

• Bound by transferrin and returned to iron stores in the liver or bone marrow

Metabolism of Bilirubin• Bilirubin

– Bound by albumin and taken to liver (unconjugated or indirect bilirubin)• Water insoluble• Can not be removed from body

• Once at the liver, unconjugated bilirubin flows into sinusoidal tissue and albumin releases it

• Ligandin, picks up the unconjugated bilirubin and presents it to glucuronic acid

• In the liver it becomes conjugated with the help of UDP-glucuronyl transferase– Water soluble– Combines with gallbladder secretions and expelled into intestines

Metabolism of Bilirubin

• Intestinal bacteria degrade conjugated bilirubin to form urobilinogen– 80% of urobilinogen formed is oxidized to stercobilin and

excreted in feces, giving stool the brown color– 20% of urobilinogen formed

• Absorbed by extrahepatic circulation to be recycled through liver and re-excreted

• Enters systemic circulation to be filtered by kidney and excreted in urine

Synthesis

• Synthesize many biological compounds– Carbohydrates

• Metabolism important– Uses glucose for its own cellular energy– Circulates glucose to peripheral tissue– Stores glucose as glycogen

• Major player in maintaining stable glucose concentration due to glycogenesis, glycogenolysis and gluconeogenesis

Synthesis

– Lipids• Liver gathers free fatty acids from diet and breaks them

down to Acetyl- CoA to form triglycerides, phospholipids or cholesterol

• Converts insoluble lipids to soluble forms• 70% of cholesterol produced by the liver

– Proteins• Almost all proteins made in the liver• Exceptions are immunoglobulins and hgb

Detoxification

• Liver serves as a gatekeeper between the circulation and absorbed substances– First pass: every substance absorbed in GI tract passes

through liver• Detoxification includes drugs and poisons, and metabolic

products like ammonia, alcohol, and bilirubin• 3 mechanisms

– Binds material reversibly to inactivate– Chemically modify compound for excretion– Drug metabolizer for detox of drugs and poisons

Storage

• Glycogen• Vitamins• Iron• Blood

Immunologic

• Phagocytosis of bacteria• IgA secretion

Normal Liver

Defining Terms

• Hepatitis: refers to any swelling, inflammation, or irritation of the liver

• Inflammation that lasts long enough will create fibrosis

• Extreme fibrosis is called cirrhosis• Cirrhosis can be either compensated or

decompensated

Cirrhotic Liver

Symptoms

• When your liver is sick there can be symptoms like:

• Fatigue• Nausea• Loss of appetite• Swollen abdomen• Itchy skin• Jaundice

Things I DON’T LIKE

• Viruses• Too many fatty

foods• Drugs /Medication• Alcohol

Hepatitis AGets into your body throughyour mouth

How to Prevent Hepatitis A• Wash your hands• Be careful not to

eatunwashed food

• Be careful not to drink unclean water

• Get vaccinated

Hepatitis B & C

Gets inside your body throughbreaks in the skin(the virus lives in your blood)

• Used Needles• Fighting• Tattoos• Body Piercings

Ways to Stop Hepatitis B & C • Don’t use needles that you’re

not supposed to

• If you find a needle don’t touch it

• Don’t share razors or toothbrushes

• Be careful with tattoos and body piercings

• Get vaccinated

What is a Vaccine?

Vaccine is likea winter coat –

Ready to protect you!!!!!

Liver “Function” Tests

• ALT: alanine aminotransferase (SGPT)

• AST: aspartate aminotransferase (SGOT)

• Alkaline Phosphatase & Bilirubin

• Known as LFT’s (but they’re really not)

Liver Synthetic Function

• Total Protein and serum albumin

• Total Bilirubin

• Prothrombin Time (PT / INR)

• These are “true” tests of liver function