Liver

Christopher Ramnanan, Ph.D.cramnana@uottawa.ca

Dept. of Cellular and Molecular Medicine

• Describe anatomy and innervation of the liver. • Describe the portal and vascular systems of the liver and

their integration one with another.

• Identify the surface and segmental anatomy of the liver.

• Describe the vascular anatomy of the liver:i: PortalIi: Systemic

The Liver-Foregut Structure

-Largest internal organ (~1.5 kg, high variance)

-Largest gland (up to 1 L/day)

-Primary source of endogenous glucose production

-Most prolific lymph producing organ (~25-50% of total lymph reaching thoracic duct)

-Filter for most ingested substances

-Anatomical location fits physiologic roles (processing nutrients, detoxification of ingested materials, responding to pancreatic hormones, etc.)

R. Hypo-chondriac

• Superiormost abdominal organ; plastered against underside of diaphragm, dominates right hypochondriac/epigastric regions (upper right quandrant)

• Attached to/moves with diaphragm in respiration• Largely protected by ribs

Right Upper

Right Lower

Left Upper

Left Lower

Location of Liver

Epigastric L. Hypo-chondriac

Clinical Anatomy: Liver Biopsies

• Percutaneous liver biopsies historically sampled b/w 9th and 10th rib

• Use of organ percussion or imaging (ultrasound) can help guide the procedure

• Modern day approaches also laparoscopic and transjugular routes

Peritoneal Relationships (Review)

Note: Lesser Omentum and its components (Hepatoduodenal and Hepatogastric Ligaments) derived from embyrological ventral mesentery

The Lesser Sac/Omental Bursa (Review)This wire is going through the Omental (Epiploic) Foramen to gain access to the Lesser Sac (Omental Bursa)

Lesser sac, Main anterior wall:Lesser OmentumStomach

Main posterior wall:Pancreas

Lesser Sac

Greater Sac

Peritoneal Relationships (New)

Falciform Lig. (remnant of ventral mesentery)

Free edge contains patent paraumbilical veins and Lig. Teres Hepatis (Round Ligament of the Liver; obliterated umbilical vein)

Right Triangular Ligament

Left Triangular Ligament

Coronary Lig.

Bare Area (exposed Glisson’s capsule)

-Glisson’s capsule (fibrous, unyielding) covers entire liver (diaphragmatic and visceral surfaces); Clinically: may restrict liver during acute venous congestion causing pain (‘runner’s stitch’)

-Visceral peritoneum (shiny) covers Glisson’s capsular surface except in one part: Bare area

-Liver is therefore intraperitoneal (covered with visceral peritoneum, tethered by mesentery-derived structures, degree of mobility)

-Note potential spaces: subphrenic and hepatorenal recesses of peritoneal cavity

Subphrenic

Falciform Lig.

Caudate Lobe

Anterior View,Diaphragmatic Surface

Posterior View,Visceral Surface

Left Lobe

Right Lobe Right Lobe

(4) Anatomical Lobes

Quadrate Lobe

All four lobes visible only posteriorly

H-Pattern on Visceral Surface

Left strut = left sagittal (umbilical) fissure

Fissure for lig. venosum(remnant of ductus venosus)+ Fissure for round ligament of liver

(remnant of umbilical vein)

Right strut = right sagittal fissure

Fossa for IVC+ Fossa for gall bladder

Cross-bar =

Cross-bar = porta hepatis (site where portal triad of structures access

the liver)

Pre-natal circulation: notePatent umbilical veinDuctus venosus

Post-natal circulation: noteLigamentum Teres Hepatis(Round ligament of liver)Ligamentum Venosum

Round ligament of liver (obl. umb. vein)

Ligamentum venosum(obl. ductus venosus)

IVC

Gallbladder

Porta hepatis

Physiological/Functional Liver Lobes

Inferior vena cava

Fundus ofgallbladder

Cantlie’s line

Right sagittalfissure

Rt.

Rt.

Lt.

Lt.

The imaginary line connecting the IVC and the gallbladder (Cantlie’s Line) helps divide the functional liver into right and left lobes

(8) Physiologic, Functional Lobes

-The 8 physiologic lobes are ‘created’ by the plane of the intrahepatic course of the left, central, and right hepatic veins-Lobe I is associated with anatomical caudate lobe (viewed posteriorly); all other lobes (II-VIII) do not approximate any particular anatomical lobe-Each lobe fed by independent branch of the portal triad set of structures and is therefore surgically resectable

II

III

V

VI

VIIVIII

IV

I

Arterial Supply of the Liver

Common Hepatic A.

Left Gastric A.

Celiac Trunk: Artery of the Foregut

Right Gastric A.

Proper Hepatic A.

Gastroduodenal A.

Splenic A.

R. And L. Hepatic A.

Cystic A.

Arterial Supply of the LiverSignificant Variations in Hepatic Arteries

Typical Source of Aberrant Right Hepatic

Artery: SMA

Typical Source of Aberrant Left Hepatic Artery: Left

Gastric Artery

Splenic V.Hepatic Portal V.

SMV

Hepatic V. IVC

IMV

GI organ (bowel, pancreas, stomach) cancers can metastasize to liver using portal venous route

Hepatic Portal Vein: ~70-80% of Liver Blood Supply; mixes with arterial blood to supply in liver sinusoids to feed liver cellsHepatic Vein: Drains Liver Blood Directly Into IVC

Portal Vein

PANCREAS

Hepatic Vein

INSULIN GLUCAGON

GlucoseProduction

DESIRABLE GLUCOSE LEVELS

LIVER

Anatomical Location, and Vascular Relationship, of Liver relative to Endocrine Pancreas is ideal for control of blood sugarFYI: Papers by Alan Cherrington, Vanderbilt University School of Medicine

1) Paraumbilical -to Body wall veins (Caval)-to Paraumbilical V. (Portal)

2) Esophageal-to Azygos System (Caval)-to Left Gastric V. (Portal)

3) Rectal-Mid/Inf Rect V. to Int. Iliac V.

(Caval)-Sup. Rect. V. to IMV (Portal)

4) Retroperitoneal (gut structures near body wall)-to lumbar veins (Caval)-to gut veins (Portal)

Portal-Caval Anastomoses

What anatomical principle allows for the backflow of blood from one system to another?

Clinically:Gut, Butt,Caput

Review:Distal esophageal veins can drain to either left gastric vein (portal drainage) or to the azygous system of veins (caval drainage)

Paraumbilical v.

Note: In cases of impaired liver or IVC venous drainage, blood can return to the SVC by traveling via thoracoepigastric veinaxillary vein. Distensions/varicosities-Caput Medusae

Thoracoepigastric v.

Lymphatic Drainage of Liver

• Diaphragmatic surface mainly drains to diaphragmatic/ant. mediastinal nodes (follows body wall lymph flow)

• Visceral surface drains to hepatic then to celiac nodes (follows GI tract lymph flowchyle cistern)

Innervation of the Liver (Conceptual)

• Foregut Structure• Parasympathetic fibers:

Vagus Nerve• Sympathetic Fibers:

Greater Splanchnic N. (T6-T9)

• Symp. fibers synapse at celiac ganglia; postsynaptic fibers hitch a ride with proper hepatic artery to liver tissue

• Pain fibers travel back to spinal cord corresponding to sympathetic supply (pain refers to T6-T9 dermatome)

Referred Liver Pain

• Foregut structure (pain refers to upper abdominal wall, epigastric/ right hypochondriac regions)

• Pain can also refer to shoulder (irritation of diaphragm)

Here is a rough estimate of the stations that will be on the Mid-Term Practical Exam for Unit II

 

Discipline                                Number of Station

•         Anatomy                                 6 (12 MCQs)

•         Histology                                4

•         Radiology (ENT+GI)             4

•         Pathology                               3

•         ENT                                         2

•         Embryology                            1

 

Info on the exam:

Practical exam includes mostly sessions covered on Wednesday BUT it can have questions from the rest of the week. For example an X-ray shown in CBL may end up on the radiology section.

Bell ringer, 1 point per station, 1 or 2 MCQs

2 min. per station

Total: +/- 20 Stations  + Rest

4 rotating groups, +/- 40 students per group, 50min per group

LAB 5 CHECKLIST – LIVER

ANATOMICAL LOBES AND STRUCTURES- Right lobe- Left lobe - Quadrate lobe - Caudate lobe - Left sagittal (umbilical)fissure

- Ligamentum venosum - Round lig. of liver

- Right sagittal fissure - Fossa for IVC- Fossa for gallbladder

- porta hepatis

PERITONEAUL RELATIONSHIPS- Lesser omentum

- Hepatogastric lig.- Hepatoduodenal lig.

- Right triangular lig.- Coronary lig. - Left triangular lig.- Falciform lig.- Ligamentum teres hepatis (Round

ligament of liver)- Bare Area - Glisson’s capsule- Diaphragmatic surface- Visceral surface- Subphrenic recess - Hepatorenal recess

ARTERIAL SUPPLY OF THE LIVER - Celiac trunk - Common hepatic a. - Proper hepatic a. - Right and Left hepatic a.

NB: Items italicized are conceptual, those denoted with a * are FYI

LYMPHATICS - Diaphragmatic surface: anterior mediastinal

nodes (superficial drainage)- Visceral surface: hepatic lymph nodes (deep

drainage)- Chyle cistern

VENOUS DRAINAGE- Inferior vena cava - Hepatic v.- Portal v.- Superior mesenteric v. - Inferior mesenteric v. - Splenic v. - Thoracoepigastric v. - Paraumbilical v.

INNERVATION- Vagus n. - Greater splanchnic n. (T6-T9)- Celiac ganglia

PHYSIOLOGIC LOBES- Cantlie’s line - 8 physiologic lobes

PORTAL-CAVAL ANASTOMOSES- Paraumbilical

- Body wall veins - Paraumbilical v.

- Esophageal - Azygos system - Left gastric v.

- Rectal - Superior rectal v. - Mid/Inf rectal v.

- Retroperitoneal - Lumbar veins - Gut veins