Digestive System: Intestines

Digestive System Overview

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

Small And Large Intestine (Intestinum Tenue Et Crassum)

• It is longer than the length of the body: ca x5 in cats, su x15 in pigs, eq x10 in horses, and Ru x25 in ruminants (longest).
• Mesenterium refers to serosal folds suspending the intestinal tract from the roof of the abdominal cavity.
• Radix mesenterii is the mesentery's dorsal attachment.

Small Intestine: Duodenum (Intestinum Tenuе)

• The duodenum begins from the pylorus and extends to the start of the jejunum.
• Gll. duodenales submucosae are present.
• Length varies by species: bo (cattle): 90-120 cm, eq (horse): 1-1.50 m, su (pig): 40-95 cm, ca (cat): 20-60 cm, fe (ferret): 10 cm.
• Mesoduodenum suspends most of the duodenum, short except in dogs.
• Lig. hepatoduodenale attaches the cranial part to the liver.
• Plica duodenocolica attaches the duodenojejunal flexure to the descending colon via the duodenocolic fold.
• Pars cranialis is the cranial part.
• Flexura duodeni cranialis is the cranial flexure, labeled as (1).
• Ansa sigmoidea, a sigmoid loop (s-shaped flexure), is present in ruminants, horses, and pigs.
• Pars descendens is the descending duodenum (2).
• Pars transversa is the transverse part (3).
• Flexura duodeni caudalis is the caudal flexure, with duodeni in horses, plus diverticulum duodeni. is the caudal flexure.
• Pars ascendens refers to the ascending duodenum (4).
• Flexura duodenojejunalis is the duodenojejunal flexure (5).

Small Intestine: Jejunum

• The jejunum forms the longest segment of the small intestine, located between the duodenum and ileum with loops (ansa).
• Lengths vary across species: Ru: bo (cattle) is up to 40 m, ov;cap (sheep and goat) equals 30 m; eq (horse) is 14-22 (up to 28) m; su (pig) is 15 m; ca (cat) is 1 m.
• Mesojejunum is long.
• The jejunum is the most mobile and free section of the alimentary canal.

Small Intestine: Ileum

• The ileum is the short terminal part of the small intestine
• Ostium ileale is the ileal orifice at the junction of the cecum and ascending colon.
• Plica ileocecalis (fold 18) attaches the antimesenterial surface of the ileum to the cecum.
• It is suspended by the Mesoileum

Large Intestine (Intestinum Crassum)

• Consists of the cecum (caecum), colon, and rectum.
• Villi intestinales are absent, but pll. intestinales are present.
• In horses and pigs, part of the large intestine wall contains bands (teniae [taeniae]) and sacculations (haustrae).

Cecum

• A blind sac.
• Least long in cats, becoming longer in pigs, then ruminants, and is longest/largest in horses.
• It's located in the abdominal cavity on the right side in carnivores, ruminants, and horses, but on the left in pigs.
• The Corpus ceci (caeci) represents the cecum's body.
• The Apex ceci (caeci) refers to the apex, directed towards the pelvic inlet, except in horses.
• It opens freely into the colon at the cecocolicum orifice or Ostium cecocolicum (саесо-).
• The cecum gets set by the Plica ileocecalis [-caecalis] and Mesocecum.

Cecum in Carnivores

• In cats, the cecum is an irregularly twisted or S-shaped blind tube, 20 cm long;
• In ferrets, the cecum is comma-shaped, 2-4 cm long.
• It is located to the right on the medial plane, VL 2-4.
• It is related dorsally to the right kidney, ventrally to the ileum and jejunum, and laterally to the descending duodenum and the right lobe of the pancreas.
• The ileum and ascending colon are connected by short peritoneal folds.

Cecum in Ruminants

• It occupies the dorsal third of the right abdomen, beginning ventrally to VL 3-4,.
• The Apex ceci points towards the pelvic inlet.
• It exhibits a cylindrical shape
• Length in cattle: 30-70 cm, in sheep/goats: 25-42cm.

Cecum in Horses and Pigs

• Contains TENIAE ceci (caeci): longitudinal muscular. layer concentrated in bands that include dorsal, ventral, medial, and lateral band
• HAUSTRA ceci (caeci): The wall is ruffled into sacculations

Cecum in Pigs

• Location is to the left side abdominal cavity: begins - ventral to caudal end of the left kidney.
• The apex ceci points caudoventrally.
• Dimensions: Length: 25-30 cm and Volume:1.5-2.2.
• Features 3 Teniae ceci plus 3 rows of haustra ceci.

Cecum in Horses

• Lies chiefly to the right of the median plane.
• It extends from the right iliac and sublumbar regions to the abdominal floor, caudal to the xiphoid cartilage.
• Length 80-130 cm and Volume: 30 L.
• Plica cecocolica (caeco-): cecocolic fold
• Plica ileocecalis (caecalis): ileocecal fold
• Mesocolon

Cecum in horses, eq, continued

• 4 Teniae ceci +4 rows of Haustra ceci
• tenia [taenia] dorsalis
• tenia [taenia] ventralis
• medial (tenia [taenia] medialis,
• tenia [taenia] lateralis
• Comma-shaped.
• 1» Basis ceci: base → fossa paralumbalis dextr.; is the most dorsal strongly curved with its and its greater curvature dorsally and its lesser curvature ventrally.
• 2» Corpus ceci – body → right abdominal wall .
• 3» Арех сесі - an apex → to the xiphoid cartilage XIII-XVI intercostal space

Colon

• Originates at the cecocolic orifice and terminates at the rectum at the pelvic rim.
• Consists of three parts:
  • Colon ascendens (ascending colon) is the eq and has the Colon crassum (ascending). great colon
  • Colon transversum is the transverse colon
  • Colon descendens is the descending colon and is the eq and has the Colon tenue (descending) small colon.
• Mesocolon's include:
  • Mesocolon ascendens attached to colon ascendens
  • Mesocolon transversum. attached to colon transversum
  • Mesocolon descendens attached to colon descendens

Colon in dogs

• The ascending colon begins at the cecum on the right of the mesentery's root, coursing cranially to join the transverse colon at the right colic flexure.
• The transverse colon then runs from right to left cranial to the mesentery's root.
• The descending colon joins at the left colic flexure, extending to the pelvic inlet where it becomes the rectum.

Colon in Ruminants

• Colon ascendens or ascending colon is located for Ansa proximalis that connect disc sharped coiled, including, the, Ansa spiralis, Gyri centripetales - centripetal turns, Flexura centralis, and Gyri centrifugales that connect the disc shape
• Ansa distalis
• Colon transversum and Colon descendens plus Colon sigmoideum (bo)

Colon in Pigs

• (1) Colon ascendens is the ascending colon forms a cone-shaped coil.
  • Ansa spiralis: Gyri centripetales (+2 bands - teniae; & +2 rows of sacculations – haustra): Flexura centralis and Gyri centrifugales Ansa spiralis and distalis (2) connects Column transversum to the right (3) Column Descendens

Large Colon in horses

• The large colon (Colon crassum) is "U" shaped, doubled on itself twice, and forms a "horse shoe-shaped loop"
• Measure 3-4 m long, with a volume of 80 L.
• Anatomical Considerations:
• Colon ventrale dextrum (right ventral colon): Has four bands and four rows of sacculations. Contains Fexura sternalis (sternal flexure)
• Colon ventrale sinistrum (left ventral colon). flexura pelvina (pelvic flexure )
• Colon dorsale sinistrum (left dorsal colon) with a flexura diaphragmatica.
• Colon dorsale dextrum- ight dorsal colon with 3 bands.

Small Colon

• Colon tenue – descending (small) colon [H], the Length is 2,5-4 m, and has 2 bands ir with 2 rows of sacculations)
• Colon transversum – that is Transverse colon [G] to left

Rectum

• Refers to the straight, terminal part of the alimentary canal within the pelvic cavity.
• It starts at the pelvic inlet, continuing from the desending colon.
• It has the Ampulla recti (enlarged, prominent in horses, absent in ferrets. sheep and goat)
• Terminates at the short anal canal
• Plicae transversales recti transverse rectal folds in ruminants.
• Has the Columnae rectales in ruminants

Anal Canal

• The anal canal is the short terminal portion of the alimentary canal with absence of intestinal glands.
• Anus is the orifice it surrounds
• Presence of an enormously enlarged tunica muscularis, forming the anal sphincter; keeps the opening closed.
• M. sphincter ani internus et externus

Anal canal parts in carnivores

• Mucosa of the anal canal.3 annular zones:
• Zona Columnaris ani: Junctio anorectalis
• Zona Intermedia: Juncio anocutanea
• Zona Cutanea. Sinus paranalis (Car)

Accessory Digestive Glands

• Two glands are closely associated with the alimentary canal: the liver (Hepar) and pancreas (Pancreas).

Liver

• It is the largest gland of the body that is located caudal to the diaphragm.
• It's situated inside the abdominal cavity and has most of its mass to the right of the median plane.
• The size depends on breed, animal species and age, with a reddish-brown color.
• Two surfaces: diaphragmatic and visceral

Liver surfaces

• Facies diaphragmatica is the diaphragmatic surface, which is convex and touches the abdominal side of the diaphragm.
• Facies visceralis is irregularly concave and makes contact with the stomach. Related with the duodenum, colon, jejunum, the right kidney, and the adrenal gland. These structures cause impressions on the liver

Liver Visceral Surface Impressions

• esophagea -Impressio esophagea – esophageal impression, on Margo dorsalis
• gastric -Impressio gastrica – gastric impression, on left lobe of monogastrics; Also evident of ruminants:
• Impressio reticularis – impresion of reticulum on left lobe;
• omalis -Impressio omasica occupies most of the visceral surface.
• duodenalis Impressio duodenalis – duodenal impression, to the ventral to right of the porta.
• colica Impressio colica colic impression, made by duodenal and diaphragmatic flexures of ascending colon, seen on right ventral area on horse of visceral surfaca — cecalis found in horse.
• Impressio cecalis – cecal impression,on the right obe;
• renalis found: Process that is related to the right, large in kidneylobe.
• Impressio renalis – renal impression,right kidney found. -adrenalis -Impressio adrenalis impression is found from Processus right and has large caudate lobe of adrenal gland.

Liver borders

• Contains four borders the dorsal, ventral, right, and left borders – margo dorsalis, ventralis, dexter et sinister.
• The dorsal border is thick and rounded, with the rest of the borders sharp and thin.
• The ventral border and deep interlobar notches (incisurae are what divide the liver into interlobares) divide the liver into lobes.

Liver Ligaments

• Lig. coronarium hepatis attaches the liver to the diaphragm.
• Lig. triangulare dextrum and Lig. triangulare sinistrum are right/left triangular ligaments connecting lobes to the diaphragm.
• Lig. falciforme hepatis attaches to the sternal part of the diaphragm originating ventral to the round ligament.
• Lig. teres a ligament that runs among free borders of the falciform ligament.
• The ligament (absent in the pig) that attaches connect the cudate the liver is what the Lesser
• hepatogastricum that connects the stomach (Lessersurvature) to the liver hepatoduodenale:The part connecting the Liver to the Duodeum
• hepatorenale or ligament that is the the kidney.

Liver of ruminants

• Left border-7 the rib
• the large is the right one with 4 and a caudate popcess large
• Shallow Interlobar notches are divided into lobes in Interlobares
• gall bladder large 5:52/9:17 https://www.youtube.com/watch?v=O5wYc5V7-zI

lobes I lobus hepatis sinister left II lobushepatis dexter right side lobusquadratus4 lobus caudatus5: caudate6 proccess

Liver of Horse

• Lies close to the right of on walland ontop of diaphram
• weighs 4. 5 and 3 and a half KILOS The right is the left.

Horse liver lobes: I Lobus hepatis sinistra lateralis small and left II Lobus hepatis sinistra medialis III large.lobus hepatis dextra large and quadrate lobus

Overview of the digestive system focusing on the small and large intestines, liver, and pancreas. Includes details on duodenum length in various species. Also covers mesenterium and its role in suspending the intestinal tract.