Metabolism And Excretion Lecture 1- The Gross Structure And Anatomical Relationships Of The Liver

Front 1

Function of the liver

Back 1

Largest gland in the body
Plays a role in digestion
Hematopoietic organ during embryonic/fetal developmen

Front 2

Metabolic conversions of the liver

Back 2

After absorption occurs in the gastrointestinal system, all products of digestion are transported in the portal system to hepatic cells
There they may be stored for further processed before entering general circulation

Front 3

Secretory function of the liver

Back 3

Produces bile which is stored in the gall bladder

Front 4

Excretory function of the liver

Back 4

Converts end products of protein catabolism to urea and uric acid for disposal in the kidneys

Front 5

Synthetic function of the liver

Back 5

Produces globulin, albumin, prothhrombin, and most other clotting factors
Also produces acute phase proteins, carrier proteins, etc.

Front 6

Storage function of the liver

Back 6

Serves to store starch and glycogen, fat and some protein

Front 7

Detoxifying function of the liver

Back 7

Extracts harmful substances from the blood

Front 8

Filtering blood function of the liver

Back 8

Removes foreign particulate matter including the breakdown products of blood cells which come from the spleen

Front 9

Position/Location of the Liver

Back 9

In adult it is located between the diaphragm cranially and the stomach and intestinal mass causally
Extends across medial plane
BULK IN ON THE RIGHT SIDE IN ALL SPECIES

Front 10

the liver is held in position by

Back 10

Pressure of the viscera
Close attachment to the diaphragm

Front 11

External Features of the Liver

Back 11

Reddish brown in color
Firm in consistency by friable
Size and weight varies

Front 12

percent body weight of the liver in
carnivores
omnivores
herbivores

Back 12

Carnivores 3-5% body weight
Omnivores 2-3% body weight
Herbivores 1-1.5% body weight

Front 13

the liver is covered in peritoneum except at the :

Back 13

Portal/hilus
Fossa for the gall bladder
Origins of various ligaments/peritoneal reflections

Front 14

Cranial (parietal) or diaphragmatic
surface of the liver

Back 14

Convex
Fits into the concavity of the diaphragm
Faces to the left and right sides dorsally

Front 15

Caudal or visceral surface of the liver

Back 15

Concave
In contact with visceral organs
Faces mainly caudoventrally and to the left
Contains the portal area (most indented area) - contains hepatic artery, nerves and lymphatic vessels; portal vein and the common bile ducts.

Front 16

Dorsal border of the liver

Back 16

Extended further caudally and dorsally on the right side by the caudate process which carries a deep impression for the cranial pole of the right kidney
Mid line- groove for caudal vena cava
To the left of this- notch for esophagus

Front 17

Ventral border of the liver

Back 17

Sharp edged, continues around the edge of the periphery of the organ, except dorsally.
Notch for the round ligament (ligamentum teres)

Front 18

what are the lobes of the liver

Back 18

The liver is divided into lobes by a series of deep fissures that extend inward from the central margin

Front 19

Left Lateral and Left medial lobes of the liver

Back 19

form 1/2 – 1/3 of liver mass

Front 20

The quadrate lobe of the liver

Back 20

deep wedge shaped that lies essentially on medial plane

Front 21

Right ____ and right ___ lobes of the liver

Back 21

medial and lateral

Front 22

The caudate (caudate/papillary process) lobe of the liver

Back 22

most caudal portion of the liver and is associated with the cranial half of the right kidney.
PAPILLARY PROCESS TENDS TO LIE IN THE LESSER CURVATURE OF THE STOMACH

Front 23

Back 23

Front 24

Back 24

Front 25

Back 25

Front 26

Back 26

Front 27

Coronary Ligaments of the liver

Back 27

As the falciform ligament passes up the diaphragmatic surface of the liver, the two layers of peritoneum that compose it separate when the caudal vena cava is reached.
The layers diverge to the left and right to become the left and right laminae of the coronary ligaments which FORM A CONNECTION BETWEEN THE LIVER AND THE IMMEDIATELY ADJOINING PART OF THE DIAHPRAM.

Front 28

Falciform Ligament of the liver

Back 28

Forms a fat filled fold in the dog, but it starts out as a narrow sickle shaped band with a free edge that begins on the VENTRAL WALL OF THE ABDOMEN NEAR THE AMBILICUS.
It passes forward from the abdominal wall TO the diaphragm, gradually increasing in width till it reaches the LIVER where its free border disappears into the UBLIMICAL FISSURE.

Front 29

Right and left triangular ligaments
of the liver

Back 29

Laterally the coronary ligaments are continuous with the left and right triangular ligaments and ATTACH THE LIVER FIRMLY TO THE LEFT AND RIGHT TENDINOUS REGIONS OF THE DIAPHRAM.

Front 30

Hepatorenal ligament of the liver

Back 30

Passes from the CAUDATE PROCESS TO THE VENTRAL SURFACE OF THE RIGHT KIDNEY (and the cecum).
It develops as an offshoot from the right triangular ligament

Front 31

Round (ligamenum teres) of the Liver

Back 31

Is a slight THICKENING OF THE CAUDAL FREE EDGE OF THE FALCIFORM LIGAMENT.
It is the vestige of the UMBILICAL VEIN

Front 32

Lesser omentum of the liver.

Back 32

Passes from the VISCERAL SURFACE OF THE LIVER TO THE STOMACH (HEPATO-GASTRIC) AND DUODENUM (HEPATO-DUODENAL)

Front 33

Gall Bladder

Back 33

Pear shaped organ
Partly fused to liver ( in the fossa of the gall bladder)- one part of neck and part of body
Where it is not fused it has peritoneal covering
STORES BILE DURING PERIOD OF DIGESTIVE REST

Front 34

the gallbladder generally lies between

Back 34

THE QUADRATE LOBE MEDIALLY AND THE MEDIAL LOBE LATERALLY

Front 35

The opening of the bile duct into the duodenum is guarded by .

Back 35

the SPHINCTER OF ODDI, closed except for mealtimes

Front 36

the gallbladder receives bile via

Back 36

the cystic duct, thus BILE CAN FLOW THOUGH THE CYSTIC DUCT BOTH WAYS.

Front 37

Histology of gallbladder

Back 37

Simple columnar epithelium
Mucosal crypts
Muscularis mucosa
Loose connective tissue lamina propria/submucosa
Muscularis externa- bundles of muscle fibers random orientation
Tunica serosa

Front 38

Bile duct system begins

Back 38

with microscopic canaliculi within the lobules of the liver parenchyma.

Front 39

canaliculi open into

Back 39

larger ductules that by successive unions within the connective tissue between lobules ultimately form A FEW LARGE HEPATIC DUCTS.

Front 40

Before or shortly after leaving the liver at the porta these combine to form a

Back 40

single trunk known as the COMMON HEPATIC DUCT.

Front 41

A tortuous side branch

Back 41

THE CYSTIC DUCT- arises from the common trunk and leads to the pear shaped gall bladde

Front 42

THE BILE DUCT OR COMMON BILE DUCT-

Back 42

part of the COMMON TRUNK that is DISTRAL TO THE ORIGION OF THE CYSTIC DUCT.

Front 43

bile duct or common bile duct eventually runs to

Back 43

the duodenum, entering the dorsal or mesenteric border on the MAJOR DOUDENAL PAPILLA.

Front 44

Blood supply to the liver

Back 44

Receives blood from the HEPATIC ARTERY( BRANCH OF THE CELIAC ARTERY-3/5 O2 supply to organ) and the PORTAL VEIN- 4/5 total blood supply

Front 45

THE INTRAHEPATIC ARTERIES RUN IN COMPANY WITH THE

Back 45

BRANCHES OF THE PORAL VEIN and the hepatic duct and supply the connective tissue structures before opening into the hepatic sinusoids along with the branches of the portal vein

Front 46

THE PORTAL VEIN is formed by the union of

Back 46

the tributaries of the digestive tract, pancreas and spleen

Front 47

ALL BLOOD DELIVERED TO THE LIVER IS COLLECTED BY A SINGLE SET OF VEINS

Back 47

central veins of the hepatic lobules

Front 48

central veins of the hepatic lobules form a

Back 48

few large hepatic veins that DRAIN INTO THE CAUDAL VENA CAVA as it tunnels through the liver substance.

Front 49

forms the ventral surface of the fore-gut at the junction of the stomach/duodenum

Back 49

The HEPATIC DIVERTICULUM

Front 50

GROWS though the mesenteric mesenchymal cells INTO

Back 50

the mesoderm of the SEPTUM TRANSVERSUM.

Front 51

The ENDODERMAL CELLS OF THE HEPATIC DIVERTICULUM differentiate into

Back 51

Hepatocytes (liver cells) of the bile duct system and gall bladder
MESODERMAL CELLS of the SEPTUM TRANSVERSUM contribute to BLOOD VESSELS

Front 52

Blood stem cells from the

Back 52

yolk sac migrate to the liver to form blood islands, which form blood cells- thus at an early stage the liver is hematopoietic.

Front 53

Comparative aspects – DOG
Liver

Back 53

Relatively large- 3-4% body weight
Almost entirely within costal area
Parietal surface extremely convex
Ventral border palpable
DEEPLY DIVIDED INTO FIVE CHIEF LOBES BY FISSURES extending from the ventral margin
Centrally located papillary process, which protrudes from the dorsal part, most prominent feature on visceral surface

Front 54

Comparative aspects – DOG Gall Bladder

Back 54

Sunk deep between quadrate and right medial lobes
To right of medial plane
Appears at visceral surface
Common bile duct opens INTO THE DUODENUM about 5-8 CM DISTAL TO PYLORUS, usually in conjunction WITH OR at last NEAR the smaller PEANCREATIC DUCT on the MAJOR DUODENAL PAPILLA.
The discharge of bile depends on the duodenum.

Front 55

Comparative aspect- HORSE
Liver

Back 55

Smaller than carnivore – 1-1.5% body weight
Long axis oblique- highest point is at level of right kidney and lowest point is on the left side
Asymmetrical- 2/3 lies on the right side of median plane
Visceral surface lies against the stomach, the duodenum, dorsal diaphragmatic flexure of the colon and the caecal base.
Dorsal fixed border of the liver extends between the left and right triangular ligaments and is very irregular-the long free margin (left, ventral and right border) is sharper and is indented by a number of fissures: usually talk of left, quadrate and caudate lobes in the horse-
Right lobe is the largest-irregularly quadrilateral in form on the sternal part of the caudate lobe and process.
Quadrate lobe is located between the right lobe and the falciform ligament which separates it from the left lobe.
Left lobe consists of medial and lateral portion, lateral part id oval in outline and thickest centrally.

Front 56

Comparative aspect- HORSE Bile duct system

Back 56

NO GALLBALDDER
Bile duct opens into the cranial duodenum ON THE PAPILLA SHARED WITH HE MAJOT PEANCREATIC DUCT, ABOUT 13-15 CM DISTAL TO THE PYLORUS. Known as the HEPATOPANCREATIC AMPULLA.

Front 57

Comparative aspect- COW
Liver

Back 57

NO DISTINCT PATTERN OF LIVER LOBULATION
CAN BE PALPATED IN CRANIAL RIGHT PARALUMBER FOSSA
Lies in contact with right abdominal wall, from the ventral end of seventh rib to the last rib
Lies almost entirely in the medial plane
Rotated 90 degrees from its position in embryo and most other mammals- THE RIGHT LOBE IS DORSAL AND THE LEFT LOBE IS VENTRAL
Displacement due to development of compound stomach on left side of the abdomen
Diaphragmatic surface faces dorsally cranially and to the right
Falciform ligament is attached along a line from the esophageal impression to the notch for the round ligament
Long triangular area on the dorsal surface does not have serous covering due to being in contact with the diaphragm

Front 58

Comparative aspect- COW
Liver visceral surface relates to

Back 58

Reticulum
Ruminal atrium
Omasum
Dudouneum
Gall bladder
Pancreas

Front 59

Comparative aspect- COW Gall bladder and Bile duct system

Back 59

Gallbladder projects beyond the lateral margin of the right lobe
BILE (COMMON BILE) DUCT TERMINATES IN THE SEOCND BEND OF THE SIGMOIND FLEXTURE OF THE DUENUM ABOUT 60 NM FROM THE PYLORUS

Front 60

Comparative aspect- SHEEP AND GOATS
Liver

Back 60

Generally resembles that of cow but smaller
Lobes more distinct
Deeper fissure for round ligament
Narrower and less blunt shaped caudate process

Front 61

Comparative aspect- SHEEP AND GOATS Gallbladder and bile duct system

Back 61

Elongated gallbladder
Gallbladder fossa more distinct
Pancreatic duct joins the bile duct before the reaches the duodenum and no dilatation (ampulla) is present in duodenal wall

Front 62

Comparative aspect- PIG
Liver

Back 62

Relatively large and resembles dog in lobation and position

Left lateral lobe usually largest
On dorsal part of right lateral lobe is the caudate lobe, clearly marked by a fissure
The caudate process does not make contact with right kidney- no renal impression
NO PAPILLARY PROCESS
Short quadrate lobe is present centrally and lies in the central portal fissure
HIGH CONTENT OF INTERLOBULAR FIBROUS TISSUE OUTLINES MINUTE LIVER LOBULES-speckled appearance

Front 63

Comparative aspect- PIG
Liver
Three deep fissures that divide it into FOUR PRINCIPLE LOBES-

Back 63

LEFT LATERL AND MEDIAL
RIGHT LATERAL AND MEDIAL

Front 64

Comparative aspect- PIG
Gallbladder and bile duct system

Back 64

Fundus of gallbladder foes not reach central border of liver
COMMON BILE DUCT OPENS ATH THE DUODENAL PAPILLA ABOUT .5-5 CM FROM PYLORUS

Front 65

Comparative aspect- BIRDS
Liver

Back 65

Dark brown
Right and left lobes connected cranially by bridge dorsal to the heart
Since no diaphragm lobes of liver embrace the caudal part of heart
Larger right lobe carries gallbladder in visceral surface and is perforated by caudal vena cava
Left lobe is divided by fissure into caudoventral and caudodorsal parts
Most parietal surface is convex and lies against sterna ribs and sternum and is in contact with air sacs
Cranioventral part makes contact with spleen, proventriculus, gizzard, duodenum, jejunum and ovary

Front 66

Comparative aspect- BIRDS
Gallbladder and bile duct system

Back 66

Two bile ducts one from each lobe enter distal end of duodenum close to pancreatic ducts
Only duct from right liver lobe is connected to gallbladder
Some species lack gallbladder
Pigeon
Budgie
Some parrots