Digestive System: Intestines, Liver & Pancreas

Overview of Digestive System

• The digestive system comprises, small and large intestines (Intestinum tenue et crassum), the liver (Hepar), and the pancreas (Pancreas).

Small and Large Intestine

• The small and large intestines together are known as the Intestinum tenue et crassum.
• The intestines' length exceeds that of the animal's body, with the ratio varying across species:
  • Approximately 5 times the body length in cats.
  • Around 15 times in pigs
  • Roughly 10 in horses
  • Nearly 25 in ruminants
• The mesentery supports the intestinal tract from the roof of the abdominal cavity via serosal folds.
• The dorsal attachment of the mesentery forms the root of the mesentery (Radix mesenterii).

Small Intestine: Duodenum

• The duodenum is the first segment of the small intestine, with Gll. duodenales submucosae present.
• It originates at the pylorus and extends to the start of the jejunum.
• Its length varies among species:
  • 90-120 cm in cattle.
  • 1-1.50 m in horses
  • 40-95 cm in swine
  • 20-60 cm in goats
  • 10 cm in cats
• The duodenum is supported through:
  • The mesoduodenum, which suspends most of its length.
  • The hepatoduodenale ligament attaches its cranial part to the liver.
  • The plica duodenocolica connects it to the descending colon at junctures

Duodenum Segments

• Pars cranialis is the cranial segment.
• Flexura duodeni cranialis constitutes the cranial flexure (1).
• Ansa sigmoidea (Ru, eq, su,) :is a sigmoid loop (s-shaped flexure).
• Pars descendens descends as the duodenum (2).
• Pars transversa marks the transverse part (3).
• Flexura duodeni caudalis represents the caudal flexure, seen with diverticulum duodeni in horses.
• Pars ascendens ascends as the duodenum (4).
• Flexura duodenojejunalis forms the duodenojejunal flexure (5).

Small Intestine: Jejunum

• The jejunum is the longest part of the small intestine, located between the duodenum and ileum.
• It is characterized by loops or ansa
• Jejunum length across species:
  • Up to 40 meters observed for ruminants
  • 30 meters for sheep
  • 14-22, up to 28 meters for horses
  • Approximately 15 meters in pigs
  • Around 1 meter in cats
• The mesojejunum is long and its most mobile and free part is the entire alimentary canal.

Small Intestine: Ileum

• The ileum is the short, terminal section of the small intestine.
• The ostium ileale (7) marks the ileal orifice at the junction of the cecum and ascending colon.
• The plica ileocecalis (18) fold connects the ileum's antimesenterial surface to the cecum.
• The mesoileum suspends the ileum.

Large Intestine: General Features

• The large intestine is composed of the cecum, colon, and rectum.
• Villi intestinales are absent in the large intestine, but pll. intestinales are present.

Large Intestine: Cecum

• The cecum is a dead-end sac, with length varying across species from shortest in cats to largest in horses.
• The abdomen holds the cecum, on the right side for carnivores, ruminants and horses, but on the left in pigs.
• Its parts comprise:
  • Body
  • Apex, which extends towards the pelvic inlet

Cecum Attachment and Opening

• The cecum opens into the colon via the cecocolicum orifice, -ostium cecocolicum,
• It is secured by the plica ileocecalis and mesocecum.

Cecum in Carnivores (ca)

• The cecum in carnivores are found with the following features:
  • Irregularly twisted or S-shaped tube with a length of 20 cm
  • comma-shaped tubes length only 2-4 cm
• Located right on the median plane within the right latero-ventral region.
• related:
  • Dorsally to the right kidney.
  • Ventrally to the ileum and jejunum
  • Laterally to descending duodenum and right lobe of the pancreas
• Joined to the ileum and ascending colon through peritoneal folds

Cecum in Ruminants

• Occupies the dorsal third of the right abdomen, running starting ventral to the vertebrae in the 3rd and 4th lumbar region
• Apex reaches to the pelvic inlet,
• Has a cylindrical shape with a length:
  • 30-70cm in cattle
  • 25-42 cm in sheep.

Cecum in Pigs and Horses

• It has longitudinal muscle concentrated into the bands
• exhibits haustra, or sacculations, which ruffle the wall.
• It has bands dorsalis, ventralis, medialis, and lateralis
• Has haustra for added storage and absorption.

Cecum in Pigs

• The cecum located on the left side of the abdomen's, ventral and caudal end to, and with the left kidney.
• Directed towards the caudoventral side.
• Measurements are 25-30 cm in length, with volume, 1,5-2,2
• Features 3 Teniae ceci, also containing+3 rows of Haustra ceci

Cecum in Horses

• Primarily on the right side of the median plane
• It stretches from the right iliac region through the sublumbar regions
• This reaches down to just before the xiphoid cartilage
• The cecum has a length 80-130
• A volume measure of 30

Horse Cecum Structures

• The horse cecum exhibits:
  • Plica cecocolica for connection on the cecum
  • Falciform ileocecalis of the internal location
  • Contains a mescolon

Cecum in Horses (eq)

• It contains four taeniae ceci rows in addition to the four rows
• Also features, dorsalis, ventralis, medialis, lateralis

Horse Cecum Regions

• The parts comprise :
  • Basis ceci, a base → fossa paralumbalis. It is the dorsal part due to greater and lesser curvature
  • Corpus ceci, or body → towards the right portion of the abdominal wall
  • Apex ceci, the apex to the xiphoid cartilage region

Colon Segments

• It starts at the cecocolic orifice and ends at the rectum's.
• The region also has great mesocolon

Colon's Segments

Ascending

• From the cecum, in the pig (colon crassum)

Transversum

• Across the other location, middle

Descendens

• Towards where fecal matter leaves, which happens at the tenuae, smaller point
• Small colon
• Features connecting to, colon itself for all

Colon in Dogs (ca)

• The ascending colon begins at the cecum on the right and travels cranially to the right colic flexure.
• The transverse colon moves from right to left cranially towards the root of the mesentery.
• The descending colon runs to the pelvic inlet, continuous where the rectum is.

Colon in Ruminants (Ru)

• The Colon has 3 connecting regions:
  • Ansa proximalis towards, in, and close-shaped disc
  • Gyri centripetales, or centripetal with turns are for in, or input gyri
  • Flexura centralis to enable bending or flexibility for the central core.
  • Gyri centrifugal, turns move to outgoing
  • Ansa Distalis, is its own region from the prior
  • The final segments, transversum with a, Descendens, is part of sigmoidenm

Colon in Pigs (su)

• Ansa spiralis which then creates gyri and bands, with flexura centralis
• These gyri also allow turns to be made outward
• The right section travels transversely
• This part is also part of the discendens section of the colon

Colon Regions in Horse (eq)

• These regions feature:

Large Colon

• Known as crassum, consists of E1 - E1.5

Transverse Section

• The middle region, which E2

Small Colon and Tenue region

• The external and ending part; E3

Large Colon with Connections

• It is shaped like the letter, U doubled and to for horses
• Runs around 3-4mm, has 80 Liters of volume, a great amount
• Ventrale Dextrum can connect
• About 4 bands and 4 rows connect.

Sternali

• Bends or flexing
• Flexura, or having flexibility with in between
• It is the last ventral

Pelvina

• Bends with the pelvic

Sinistrum

• To and from bending.
• And at the start at around

Dorsale

• Connects or to bending

Horse Internal Regions

Tenue

• Moving to around the lefts as a transversum
• Measures, length, to 2.5-4, with also rows

Rectum Characteristics

• The straight portion of the alimentary canal in the pelvic cavity
• It extends from the pelvic inlet forming continuing around the portion of the region
• Features, as well, Ampulla recti that very large for enlaement
• Ends that short path to the anal canal
• Has, Plcae Trasvertices, and also, Columnae Rectales

Regions of the Anus

• Also known as the: Canalis Analis
• It is the shortest point from the anus to where it connects
• The intestinal glands with the anus region
• Forms with enlarged tunica muscularis
• Also, the ability to keep the opening closed at all times

The External Regions

• In Latin; cannalis with annular, featuring zones of
  • Junctio with internal
  • Mediates with Anocutanea for junctions
  • Zone Sinus for zones

Glands and Alimentary

• There are two glands in the canal:
  • Large, liver-like regions known as Hepar
  • Pancreas small areas that allow for insulin

Liver (Hepar) in General

• Largest, as a red gland
• Ends caudial also through the diaphragm with mass
• Each region has a size that may variablize depending on breeding/age
• This means it is connected to the stomach, as well and the kidney
• Consists of faces the diaphragmatea

Liver: Visceral Face

• Esophage, and areas to be connected
• Gasctica that are to be connected to the stomach
• Reticularis with reticulum areas
• Duodenals connecting to and from the intestines
• Connects to the caudatus, and the adrenal region

The Liver Borders

• Has around four borders
  • One dorsal, ventral and sinistial
  • The last with a notch can have division

Liver Ligaments

• It will connect to the diagram from around the region with area
• These connections ensure it
• • The triangular as it attaches
• A faliform has a cut, notch that ends the cycle
• The omentuum connects which forms smaller sections or cycles
• Is a region without the internal in the pig

Liver in Ruminants

• On the left around to a portion of the diaphragm also at rib scale
• About 4 lobes

Liver in Horses

• The gallbladder is non-existent
• It allows closer positioning for wall regions
• 5 main sections/ lobes

Liver in Carnivores

• Ends at the abdominals wall
• The lobes at 6

Liver in Pigs

• At about 6

Gall Bladder

• Sits at around quadrate with a surface connection
• Pear type shape that makes is the end

Vein Connections

The blood flows form the :

• Connective
• Hepatic
• and cystic cycles

Pancreas

This organ

• is located in the dorsal section
• Notched the same that it is in the descendent

Pancreas Properties

• Features two surfaces facing the ventralis and dorsales sides.
• Is with major with accessorius
• This feature then with then close off with other means

The regions and Pancreas

• It forms an "L"
• Is located along the lobe
• That also has 2 duct openings

Pig Liver Sections

• Known as "S"
• It circles around rings.
• Has two connections for the duct

Bird Alimentary

• Features "U" like sections
• And the internal walling as as loop
• The area where the rectum, colon or vent is very small

Bird Sections

• Features coprodeum, urodeum, and proctoduem
• That will open with a tail called ventosa
• Has the lip with a part that is at the bottom
• Ends with, ventia

Overview of the digestive system including the small and large intestines, liver, and pancreas. Focus on the intestines' length relative to body size across species. Includes duodenum anatomy.