Digestive System Anatomy

General Anatomy of the Digestive System

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

Intestines

• The intestines are longer than the body in domestic animals, with varying ratios:
  • ca (cat): x5
  • su (pig): x15
  • eq (horse): x10
  • Ru (ruminants): x25
• The mesentery is serosal folds suspending the intestinal tract from the abdominal cavity roof.
• The root of the mesentery, or radix mesenterii, is the dorsal attachment.

Small Intestine

• The duodenum is the first part of the small intestine, beginning at the pylorus and extending to the jejunum.
• The Gll. duodenales submucosae are present.
• Duodenum lengths vary:
  • 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
• The mesoduodenum suspends most of the duodenum, being short except in dogs.
• Lig. hepatoduodenale attaches the cranial part to the liver.
• The plica duodenocolica at the duodenojejunal flexure attaches to the descending colon via the duodenocolic fold.

Duodenum Specifics

• Pars cranialis is the cranial part of the duodenum. ` - Flexura duodeni cranialis is the cranial flexure (1).
• Ansa sigmoidea (Ru, eq, su) is a sigmoid loop or s-shaped flexure.
• Pars descendens is the descending duodenum (2).
• Pars transversa is the transverse part of the duodenum (3).
• Flexura duodeni caudalis is the caudal flexure, present in eq with the diverticulum duodeni.
• Pars ascendens is the ascending duodenum (4).
• Flexura duodenojejunalis is the duodenojejunal flexure (5).

Jejunum

• The jejunum comprises the longest part of the small intestine, located between the duodenum and ileum.
• The jejunum has loops (ansa)
• The jejunum has a length
  • Ru: bo – up to 40 m; ov/cap ↔ 30 m
  • eq ↔ 14-22 (28) m
  • su → 15 m
  • ca ↔ 1 m
• Mesojejunum is the long mesentery
• The jejunum is the most mobile and free part of the alimentary canal.

Ileum

• The ileum is the short terminal part of the small intestine.
• The ostium ileale (7) is the ileal orifice joining the cecum and ascending colon.
• The plica ileocecalis (18) attaches the antimesenterial surface of the ileum to the cecum.
• The ileum is suspended by the mesoileum.

Large Intestine

• Intestinum crassum includes the cecum, colon, and rectum.
• It lacks villi intestinales, but pll. intestinales are present.

Cecum

• The cecum refers to a blind sac.
• Cecum length increases from cat to horse: cat → pig → ruminant → horse.
• The location is the abdominal cavity, on the right side in most animals, but on the left in the pig.
• The corpus ceci (caeci) is the body of the cecum.
• The apex ceci (caeci) is directed towards the pelvic inlet, except in the horse.
• The cecum opens freely into the colon at the cecocolicum orifice, or ostium cecocolicum (caeco-).
• Fixation occurs via the plica ileocecalis and mesocecum.

Cecum of Carnivores (Car)

• In carnivores, the cecum is an irregularly twisted or S-shaped blind tube, 20 cm long in ca.
• The fe cecum is comma-shaped and only 2-4 cm long.
• The cecum is located to the right on the median plane.
• The cecum's relations are 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 cecum connects to the ileum and ascending colon via short peritoneal folds.

Cecum of Ruminants

• The cecum is in the dorsal third of the right abdomen, ventral to VL 3-4.
• Apex ceci faces the pelvic inlet.
• The cecum takes a cylindrical shape.
• The length of the livestock cecum has a length
  • 30-70 cm (bo)
  • 25-42 cm (cap, ov)

Cecum of Horse and Pig

TENIAE ceci (caeci), or longitudinal muscular layer, is concentrated in bands. -dorsal band – tenia dorsalis -ventral band – tenia ventralis -medial band – tenia medialis -lateral band – tenia lateralis HAUSTRA ceci (caeci) are sacculations that ruffle the wall

Cecum of pigs

• Location is on the left abdominal side, beginning ventrally to the caudal end of the left kidney.
• Apex ceci-pointed towards the caudoventral side. -Length: 25-30 cm -Volume: 1.5 - 2.2 -bands and sacculations: 3 Teniae ceci +3 rows of Haustra ceci

Cecum of Horses

• Mainly on the median plane right side
• Extends from Right iliac and sublumbar regions to the abomden floor (distal to xiphoid cartilage)
• 80-130cm Length and 30L volume
• eq = Plica cecocolica (caeco-) is a cecolic fold
• Plica ileocecalis (caecalis) is a ileocecal fold Mescolom -

Cecum features specifically for Horses

• 4rows tenia ceci with 4 rows of haustra ceci

Cecum - general

1. The basis ceci – base to fossa paralumbalis dextr, is the most dorsal part strongly curvy ,w/ greater curvy.
2. The corpus ceci - body to the right abdominal wall
3. The apex ceci an apex to the xiphoid cartilage

Colon

• The colon starts at the cecocolic orifice and ends at the rectum at the pelvic inlet.
• Consisting of three parts: -The colon ascendens or ascending colon -The Colon transversum, or transverse colon -The Colon descendens, the descending colon.
• Mesocolon parts include Mesocolon ascendens which is attached to colon ascendens , Mesocolon transversum attached to colon transversum, and Mesocolon descendens then attaches to colon descendens.

Colon of dogs

• The ascending colon starts at the cecum on the right of the mesentery root. Courses cranially to mix w/ the transfer colon in the right colic flexure.
• Then The transverse colon courses from right/left to the root of the mesentery
• Joins the decending colon in the left colic flexure; descending colon expands into the pelvic inlet, and later is mixed with the rectum

Colon of Ruminants

• 1: the Colon ascendens- the ascending colon : Ansa proximalis disc-like coils -Gyri centripetales inward turns
  • Flexura centralis the central flexure
  • Gyri centrifugales turns outward.

Colon of Pigs

• One: The colon Ascendens: cone-shaped coil with Gyri centripetales wide turns
• 2 bands/ teniae and 2 rows sacculations +Flexura centralis: is the central flexure

• Gyri centrifugales goingout

Large Colon of Horses

• The Colon crassum is doubled to form a horse shape -3-4m length and 80L volume

• Colon ventrale dextrum faces right and has 4 sacculatons. o +Flexura sternalis is the breastplate colon +Flexura pelvina is the pelvis Then the Colon dorsale sinistrum to the right =3bands

Smaller Colon of the horse

Small colon - the descending - is about 2.5-4m. with 2 bands

Rectum

• straight terminal part of the ali canal to the pelvic cavity begins by the pelvis and mixes with descending colon The Ampulla recti enlaged is promin in the cap, fe etc Termin in the short canal

Anal Canal (Canalis analis)

• short, the end for the alimentary channel Absence = intestinal Anus= the surrounding canal

Associated Glands

• Two glands associated with the alimentary canal are the liver (Hepar) and the pancreas (Pancreas).
• The Liver is known as Hepar

Liver Anatomy

-Largest abdominal gland

• The liver lays by the diaphragm; cranial abdo cavity
• Most lays at the middle plane _ The Liver has the surface and dimensions/ size
• Reddish brown surface

Liver aspects

• 2 Surfaces diagphragm+ visc

  --Facies diaphrag convex near abdominal

Visc is is irregular Causes Impressions on the Liver Esophea-Imp Margo. Imp is from gas; Rumi and mono gastric from the left lobe Reticular is left. Imp duod ventral side.Imp Coloca +Visc surfaces - Vesca foe gall

• Ports of river - 4 borders to the river - vent / dorsa

Ligaments of the Liver

• attaches by the Lig coraroum - caval foreman and is the coronary ligament.
• Right and left ends make cont.

The cord has - falciforme hepalic Lig falciforme, notch with the round ligaments

• Lig Hepatorenal in (pigs)

Liver (Ruminants)

• The rib cages lay near the right 4 sections The sinster the left right side quad caudeae Processus Large and papal process

Liver of Horses

gall bald missing

-near diaphragm has L lobes

• 5kg sinstral + med +Lat +Quadr +caude

The Liver (Carn)

• Big the the diaphragm -124- 1350 gr Has 6 lobes Sin the side -mid lathe right caud quard

Liver of Swines

• the hepalic
  ++ the process, but no papal

Gall Bladder

A Vesca located on the quad lobe -The body then

• • colum directed
  • funded as a ending spot. membrane = tunicae

Pancreas

Location body is by the duodenum the other sides

+The ducks in close wby the sphincter Minor + major V shapes. -ducts 5 then 10 cm +++ the acce.

The Glands (equ)

Tri shape with Yellowish

• in the upper abdomen +the V1-3 Anulus btween to lobed and around port valc

+the duos near major ++ the acssess minor

Pancreas-

The quad is 40-50 cm or .13% Ventral. Notched. Can be accesory

Special Notes on Poultry

-The intestines have a descending doude and the mesentary surrounds and surr the pancreas. +jeunym forms =coils and illuem

+reculum = +10cm to cloaca the cloaca is the diget (sot separated bursa) separated as well -external

The Ventus is external - Labio venti