Digestive System: Intestines, Liver, Pancreas

• The digestive system consists of the small and large intestines, liver (Hepar), and pancreas (Pancreas)

Intestinum Tenu et Crassum

• The small and large intestines' combined length is longer than the body's length
• In cattle, the combined length is 5x the body length
• In pigs, it is 15x
• In horses, 10x
• In sheep and goats, 25x and longest

Mesenterium

• Mesenterium: serosal folds that suspend the intestinal tract from the abdominal roof
• Radix mesenterii: the mesentery's root, is the dorsal attachment

Intestinum Tenu

• The Duodenum is the first part of the small intestine
• It starts at the pylorus and extends to the jejunum's beginning
• Gll. duodenales submucosae can be found here
• Duodenum length in cattle is 90-120 cm
• Duodenum length in horse is 1-1.5meters
• Duodenum length in pigs is 40-95 cm
• Duodenum length in rabbits is 20-60 cm
• Doudenum length in felines is 10 cm

Mesoduodenum

• The mesoduodenum suspends most of the duodenum, short except in dogs
• The cranial part of the duodenum attaches to the liver via the Lig. hepatoduodenale
• The Plica duodenocolica attaches the duodenojejunal flexure to the descending colon

Duodenum Parts

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

Jejunum

• It is the longest part of the small intestine, located between the duodenum and ileum
• Loops (ansa) are present
• Length in ruminants is up to 40 meters
• Length in sheep and goats is 30meters
• Length in equine is 14 - 22 (28) meters
• Length in swine is 15 meters
• Length in rabbits and hares is 1 meter
• The mesojejunum is long
• Jejunum: the alimentary canal's most mobile and free part

Ileum

• Ileum: the small intestine's short, terminal part
• Ostium ileale (7): ileal orifice at the cecum and ascending colon junction
• Plica ileocecalis fold (18) attaches the ileum's antimesenterial surface to the cecum
• It is suspended by the Mesoileum

Intestinum Crassum

• Characteristics of the large intestine: CECUM, COLON, RECTUM
• Villi intestinales are absent
• pll. intestinales are present
• In equine and swine some parts contain bands (teniae [taeniae]) and sacculations (haustrae)

Cecum Characteristics

• Cecum: a blind sac
• Cecum length increases from cat → pig → sheep/goat → equine
• Location is in the abdominal cavity
• It is on the right side in carnivores, ruminants, and horses
• In pigs, it is on the left side

Cecum Parts

• Corpus ceci (caeci): body
• Apex ceci (caeci): apex, directed to the pelvic inlet, except in equine
• Ostium cecocolicum(caeco-): free opening into the colon at the cecocolicum orifice
• Plica ileocecalis [-caecalis]: fixing to the cecum
• Mesocecum provides further fixation

Carnivore Cecum

• Irregularly twisted or S-shaped blind tube is 20 cm long
• Comma-shaped and only 2-4 cm long

Cecum location in all carnivores

• Located to the right on the median plane at VL 2-4
• Related dorsally to the right kidney
• Related ventrally to the ileum and jejunum
• Related laterally to the descending duodenum and pancreas' right lobe
• Connected to the ileum and ascending colon via short peritoneal folds

Ruminant Cecum

• In the dorsal third of the right abdomen, beginning ventral to VL (vertebrae lumbales) 3-4
• Apex ceci is directed to pelvic inlet
• Cylindrical shape
• Length ranges from 30-70 cm in cattle
• Length ranges from 25-42 cm in sheep and goats

Swine and Equine Cecum

• Teniae ceci (caeci) longitudinal muscular layer is concentrated in bands
• HAUSTRA ceci (caeci): ruffled wall into sacculations
• Dorsal band – tenia dorsalis
• Ventral band – tenia ventralis
• Medial band – tenia medialis
• Lateral band – tenia lateralis

Swine Cecum

• Location on the left side of the abdominal cavity begins ventral to the caudal end of the left kidney
• Apex ceci points towards the caudoventral side
• Length: 25-30 cm
• Volume: 1.5 - 2.2
• Bands and sacculations: 3 Teniae ceci +3 rows of Haustra ceci

Equine Cecum

• Located chiefly to the median plane's right
• Extends from the right iliac and sublumbar regions and caudad to the xiphoid cartilage
• 80-130 cm long
• Volume: 30L
• Plica cecocolica (caeco-): cecocolic fold
• Plica ileocecalis (caecalis): ileocecal fold
• Mesocolon

Teniae Ceci

• 4 bands and 4 rows of Haustra ceci
• Tenia [taenia] dorsalis -Tenia [taenia] ventralis
• Medial (tenia [taenia] medialis
• Tenia [taenia] lateralis
• It has a comma-shape

Cecum (Parts)

• Basis ceci – base → fossa paralumbalis dextr.; most dorsal part that is strongly curved with greater curvature dorsally and lesser curvature ventrally
• Corpus ceci body → right abdominal wall;
• Apex ceci – an apex → to the xiphoid cartilage XIII-XVI intercostal space

Colon

• Begins at the cecocolic orifice
• Terminates at the rectum at the pelvic inlet

Mesocolon

• Mesocolon ascendens: attached to colon ascendens
• Mesocolon transversum: attached to colon transversum
• Mesocolon descendens: attached to colon descendens
• Colon ascendens: ascending colon
• Colon transversum: transverse colon
• Colon descendens: descending colon ✓ eq * Colon crassum (ascending) great colon, ✓ eq * Colon tenue (descending) small colon.

Canine Colon

• Ascending colon begins at the cecum, courses cranially & joins the transverse colon at the right colic flexure
• Transverse colon courses from right to left cranial to the mesentery's root
• Joins the descending colon at the left colic flexure
• Descending colon extends to the pelvic inlet

Ruminant Colon

• Ansa proximalis → to disc-shaped coil Gyri centripetales ← centripetal turns (in-going coils) Flexura centralis – central flexure Gyri centrifugales → centrifugal turns (out-going coils)
• Ansa distalis
• Colon transversum

• Colon sigmoideum (bo)

• Colon descendens

Suine Colon

• Colon ascendens
• Cone-shaped coil: Gyri centripetales – centripetal turns (in-going coils, wider): +2 bands - teniae; +2 rows of sacculations – haustra Flexura centralis – central flexure Gyri centrifugales → centrifugal turns (out-going coils)
• Ansa distalis -Colon transversum →to-the right Colon descendens

Equine Colon

Large colon [(E1-E1.5] - (crassum) -Transverse colon [E2] Transversum Small colon [E3]. Tenue

• Large Colon: "U" shaped, doubled on itself twice forming a horse shoe-shaped loop
• Length: 3-4 m and a volume of 80L Colon ventrale dextrum: right ventral colon ; - 4 bands and 4 rows sacculations - Flexura sternalis sternal flexure [12’]

Colon ventrale sinistrum: right ventral colon - Flexura pelvina- pelvic flexure Colon dorsale sinistrum : Left dorsal colon Colon dorsale Dextrum: Right dorsal colon with 3 bands; .014 [14] Transverse Common/small Colon et tenue has 2 bands ir 2rows of sacculations

Rectum

• The straight, terminal part of the alimentary canal in the pelvic cavity - Continuous with the descending colon
  • Enlaged (very prominent in eq; absent – fe,ov,cap)
  • Terminates at the short "anal canal"

Anal Canal - Canalis

Absent intestinal glands

• Anus: the orifice it surrounds
• Very enlarged tunica muscularis which makes up the anal sphincter

Anal Canal (Mucosa)

• 3 annular zones:
  • Zona columnaris ani Junctio anorectalis
    • Zona intermedia Juncio anocutanea Zona cutanea Sinus paranalis Car Glands associated with the alimentary canal: the liver (Hepar), and the pancreas (Pancreas)

Hepar

• The body's largest gland and is located caudal to the diaphragm, in the abdominal cavity's cranial part
• Mass is on the median plane's right
• The size varies, depending on the species, breed, and age
• Reddish-brown

Liver Surfaces

• Diaphragmatica & Visceral

Facies diaphragmatica

• Is convex
• In contact with the diaphragm's abdominal surface

Liver Characteristics

• Esophageal impression, on Margo dorsalis Gastric impression, on left lobe of monogastrics and ruminants Impresion of reticulum on left lobe;
  • Impression on left lobe/visceral surface Impression ventral and to the right of the porta
• Colic impression, on the right ventral part of visceral surface
• Made by duodenal (only in equine) made dternal and diaphragmatic flexures and hepaticof ascending colon;
• Cecal impression - right lobe of the body
• Renal Right and caudate lobe (Absent in su ):

Impressions on the liver:↓

Equine liver

has four borders:

• Dorsal
• Ventral
• Right BOrder
• Left Border

Equine Liver (Structure)

The dorsal is thick and rounded with sharp , thin edges with deep interlobar notches (incisurae interlobares)

Ligaments of the liver:

Attached by the ligament-Lig. oronarium hepatis around the area of the caval foramen The right and left ends of the coronary ligaments contious and connected by the right and left triangular ligament- Lig. triangulare sinistrum, which are attached to the diaphragm The right/ sternal attaches to the sternal through the diaphragm The lesser attaches lig- hepatic duodenale (cranial liver)

• Hepatorenale- ligament (not in pigs) located between caudate process and right kidney

Equine Liver - Ligaments

Lig. coronarium hepatis, ligaments Lig. triangulare sinistrum - left triangular Lig. falciforme hepatis Coronarium ligament

Ruminant Liver Lobes

• (a) Lobus hepatis sinister left lobe
• (b) Lobus hepatis dexter right lobe
• (c ) Lobus quadratus -Quadrate lobe
• Lobus caudatus Caudate Lobe+ with Incisurae interlobares is shallow (

gall bladder

Ox Bile Facets

• Facies and vesica (a) Lobus Sinister - sin-left lateral; (b) dexter right Quadratus -Quadrate (p) processus biliaris

Equine Liver Characteristics

• The horse liver has 5 lobes (a) ventral (a') medial
• In the old: 2.5-3.5cmg and 5 kg
  • (b) ventral,absent in horse absent ! hepaticus communis

Canidae Liver Lobes

• lateral- left
• lateral b medialis- quadratus 5% in mass in dogs only no gallbladder There are 6
• sinistre is lateralis (c) Caudatus

• -Vesica fellean-( gallbladder only) 249 in Mass. (feless)-No -

S.I

• Gall bladder sits between and is on .
• Pear-S

Ligaments of the liver-

(In pigs are on the dorsal- caudal face.

Pig Liever absent

Absent process

(d) dorsalis,. Accessorius Pancreatide

Gall Bladder- - (fellas and vesta)

.and

•

(ducts

gall bladder absent

panrearis:

• ductus pancreaticus (1) Accessorius minor; accessorius •

Pancreas

. () 8-10cm-

• is

• . ..

Poultry Digestive Tract

• Duodenum descending and ascending (U) where loops are around the pancreas mesentery
• Coils go through the lumen and into the
• ceca at the end of the small intestine
• ceca bend towards and face towards the coloa

Poultry Liver and Gallbladder

The birds' liver has 2 parts with no

• .
• has* 2 parts.

Avian Cloaca

3 parts a b c to colaca .

Overview of the digestive system including the small and large intestines, liver, and pancreas. Includes details on the duodenum and mesoduodenum. Also provides comparative intestinal lengths in livestock.