Dig Sys 2

• The alimentary canal is a long tube composed of segments with varying diameters
• Most organs are hollow, tubular, and in the abdominal cavity
• The esophagus travels from the neck and thorax to the abdomen
• The rectum is located in the pelvic cavity

Esophagus

• Alternative spellings include "Esophagus, oesophagus"
• The tunica mucosa has deep longitudinal folds and esophageal glands
  • ca extends over the entire length
  • su extends to the cranial half
  • Ru, eq, fe are only at the pharyngo-esophageal junction
• The tunica muscularis has two layers
  • Circular muscle layer (stratum circulare)
  • Longitudinal muscle layer (stratum longitudinale)
• The tunica adventitia is the outer coat
  • Tunica adventitia is present in the cervical portion
  • Tunica serosa is present in the thoracic (pleura) and abdominal (peritoneum) portions
• There are 3 parts
  • Cervical part (Pars cervicalis): from pharynx to 1st rib
  • Thoracic part (Pars thoracica): from 1st rib to diaphragm
  • Abdominal part (Pars abdominalis): from diaphragm to stomach
• In cattle, the esophagus length is 90–95 cm
  • Cervical part is 42-44 cm
  • Thoracic part is 48-49 cm
  • Abdominal part is 2 cm
  • Its diameter reduces at the thoracic inlet and cranial to the diaphragm's esophageal hiatus
  • The last part increases in diameter caudally and joins the rumen's atrium at a right angle
  • Esophageal glands are present only at the pharyngoesophageal junction
• In pigs, the esophagus is short and wide with a thin muscular layer
• The beginning and end diameters are approximately the same, and esophageal glands are only in the cervical part
• In horses, the esophagus is about 1.5 m in length
  • The muscular layer is 4–5 mm thick proximally, gradually increasing to 1.2-1.5 cm towards the cardia
  • It joins the stomach at an acute angle, and the sphincter (m. sphincter cardiae) is extremely strong
  • Esophageal glands are only at the pharyngoesophageal junction
• In carnivores, the pharyngoesophageal limen (limen pharyngoesophageum [oesophageum]) is an annular constriction of mucosa
  • It marks the division between the laryngopharynx and the esophagus

Stomach

• Alternative name: Ventriculus s. gaster
• A dilated part of the alimentary canal between the esophagus and duodenum
• Location is in the abdominal cavity:
  • Caudal to the liver
  • Against the left abdominal wall
• The wall is made of three layers
  • Tunica mucosa + glandulae gastricae
  • Tunica muscularis
  • Peritoneum
• Stomachs are divided into two types based on compartmentation
  • Simple stomach: a single chamber (monogastric) [Car, su, eq]
  • Complex stomach: several chambers (polygastric) [Ru]
• Stomachs are divided based on the composition of their lining
  • Glandular stomach is lined by exclusively glandular mucosa with a simple columnar epithelium [Car]
  • Composite stomach a glandular part (pars glandularis) and a non-glandular part (pars nonglandularis)
    • Non-glandular mucosa with a stratified squamous epithelium with varying degrees of keratinization [Ru, su, eq]
• Parts
  • Cardiac part or cardia (pars cardiaca or cardia): area around cardiac opening
  • Fundus (fundus ventriculi): the left extremity of the cardiac part
  • Cardiac notch (incisura cardiaca) is between the esophagus and fundus
  • Body (corpus ventriculi) is between the fundus and pylorus
  • The pyloric part (pars pylorica)
  • The pyloric opening (Ostium pyloricum) is between the stomach and duodenum
• The pyloric part is a narrowed part of the stomach opposite the cardia
• It contains
  • pyloric antrum (antrum pyloricum): the first wider part
  • pyloric canal (canalis pyloricus): the second, short, narrow part towards the duodenum
• Pylorus is the distal constriction containing the pylorus sphincter (m.spincter pylori)
• Ostium pyloricum lies between the stomach and duodenum
• It has two surfaces:
  • Parietal (Facies parietalis) which is against the diaphragm and liver
  • Visceral (Facies visceralis) which is in contact with abdominal organs caudal to it.
• It as two borders:
  • Dorsal concave border (lesser curvature; Curvatura ventriculi minor): attaches to the lesser omentum
  • Angular notch (incisura angularis) lies between the corpus and pyloric part
  • Ventral convex border (greater curvature; Curvatura ventriculi major): attaches to the greater omentum is much longer
• Wall Structure
• Outside layer (stratum longitudinale)
  • Fibre longitudinales
  • Fibre oblique externae
  • Fibre oblique internae
• Inner circular layer (stratum circulare)
  • m. sphincter cardiae
  • m. sphincter pylori
• Ligaments loosely attach it to neighboring organs
  • The greater omentum connects the stomach to the diaphragm via the gastrophrenic ligament (lig. gastrophrenicum)
  • To the spleen via the gastrolienal ligament (lig. gastrolienale)
  • The lesser omentum connects to the liver via the hepatogastric ligament (lig. hepatogastricum)

Dog stomach

• Dog stomach (ca) is a simple glandular stomach
• Size, shape, and position are degree-of-fullness dependent
  • Capacity is 0.5 - 6 L (~ 2.5 L)
  • Empty weight is 65 to 270 g
  • Shape is elongated "U"
  • Mucosa is "wrinkled" (plicae gastricae)
• Entire stomach (pars cardiaca, fundus, corpus, pars pylorica) lies in the intrathoracic part
  • Pars cardiaca is opposite the IX intercostal space
  • Fundus and corpus are on the left side in a median plane
• Contact with the diaphragm and liver is in the abdominal cavity
  • Pars pylorica is ventral to the right, against the liver
• A moderately full stomach enlarges cranialy to the IX-XII rib
  • Caudaly to the 1st–2nd lumbar vertebrae (VL I-II)
  • The ventral part of the body and parts of the pyloric atrium make contact with the abdominal floor

Cat stomach

• (fe) is simple glandular
• "C"-shaped
• Deep angular notch (incisura angularis)
• Capacity is ~ 250 ml

Horse stomach

• (eq) is simple composite
• Relatively small with a capacity of 6–15 L
• In the left cranial abdominal region
• Sharp-bent elongated bag shape
• The cardial notch (incisura cardica) is sharp so that the cardia and pylorus are close
• Pronounced fundus projects as a blind sac (saccus cecus [caecus] ventriculi)
• Non-glandular part extends from the cardia (including the blind sac) a short distance into the body
  • The non-glandular part of the gastric mucosa is thick, pale and extends from the cardia
  • The plicate border (margo plicatus) is a raised ridge between non-glandular and glandular parts
• Glandular part color of mucose from reddish brown to yellowish pink

Pig stomach

• (su) is of the simple-composite type
• It lies on the left side of the abdominal cavity
  • Parietal surface lies in the gastric impression of the liver
  • Against the left dorsal part of the diaphragm
  • The cardia is at the level of the 11th–12th thoracic vertebra
• Capacity ranges from 1 to 6 L
• The fundus presents a flattened conical pouch with ventricular diverticulum (diverticulum ventriculi)
  • It points to the right and caudally
• Deep Incisura angularis
• Protuberantia in pylorus forms the torus pyloricus with circular muscle, fat, and mucose

Ruminant stomach

• This stomach is a complex composite
• Pars nonglandularis: forestomach (proventriculus) of 3 compartments:
  • Rumen (100-145 L)
  • Reticulum (~12 L )
  • Omasum (7-18 L)
• Pars glandular: true stomach
  • Abomasum (~ 20 L)
• The rumen communicates with reticulum through the ruminoreticular opening (ostium ruminoreticulare)
• The reticulum communicates with the omasum through the reticuloomasal opening (ostium reticuloomasicum)
• The omasum communicates with the abomasum through the omasoabomasal opening (ostium omasoabomasicum)

Rumen

• 1st compartment: Rumen (pars nonglandularis)
• laterrally compressed, huge (volume 100-145 L)
  • on the left side, from diaphragm to pelvic inlet
• Two surfaces:
  • The parietal (facies parietalis) faces the left and is related to the diaphragm, the left abdominal wall, and the floor of the abdomen
  • The visceral (facies visceralis) faces the right and is related to the intestines, liver, omasum, and abomasum.
• Ends
  • The cranial (extremitas cranialis)
  • The caudal (extremitas caudalis)
• External Structures
  • Cranial groove (sulcus cranialis) is at the cranial end
  • Caudal groove (sulcus caudalis) is at the caudal end
  • Longitudinal groove (sulcus longitudinalis dexter [c;c‘] et sinister) is on appropriate sides of the rumen
  • Dorsal sac (saccus dorsalis)
  • Ventral sac (saccus ventralis)
  • Dorsal coronary groove (sulcus coronarius dorsalis)
  • Ventral coronary groove (sulcus coronarius ventralis)
  • Caudodorsal blind sac (saccus caecus caudodorsalis)
  • Caudoventral blind sac (saccus caecus caudoventralis)
  • Dorsal curvature (curvatura dorsalis)
  • Ventral curvature (curvatura ventralis)
  • Ruminoreticular groove (sulcus ruminoreticularis)
  • Oesophagus (esophagus [oesophagus])
  • Atrium (atrium ruminis) also known as Cranial ruminal sac (saccus cranialis)
• Pillars (Pila)
  • cranial, (Pila cranialis)
  • caudal, (Pila caudalis)
  • right longitudinal, (Pila longitudinalis dextra)
  • left longitudinal, (Pila longitudinalis sinistra)
  • right accessoty, (Pila accessoria dextra)
  • left accessoty, (Pila accessoria sinistra)
  • dorsal coronary, (Pila coronaria dorsalis)
  • ventral coronary (Pila coronaria ventralis)
• Plica ruminoreticularis* is a ruminoreticular fold.
• Rumen lining is stratified squamous epithelium with millions of ruminal papillae -Projections up to 1 cm long -The ruminal mucosa of inflections (pillar/plica) is lighter and nonpapillary.

Reticulum

• 2nd compartment (pars nonglandularis) Crainial compartment between the diaphragm and rumen

• On ventral abdominal wall at the 6th–9th intercostal space

• The reticulum of cattle is spherical, about 12 L of capacity

• Two surfaces:

• facies diaphragmatica* (convex and in contact with the diaphragm)

• facies visceralis* lies against the rumen

• Related to the left lobe of the liver, omasum, and abomasum on the right

• Occasionally in contact with the ventral end of the spleen on the left

• Two curves: greater curvature (curvatura major) courses the left side ventrally

• lesser curvature (curvatura minor) faces to the right and caudally and is connected to the omasum

• Honey comb shaped lining via 8-12mm high crests criss crossing

Omasum

• 3rd compartment (pars nonglandularis)
• abdominal side vventrally in intrathoracic part of abdominal cavity
• regio hypochondrica dextra ventral to VII-X intercostal spaces.
• Ox Volum:7-18 L The parietal and visceral surface relate to the liver and abdomen Omasal curvature (Curvatura omasi)

Omasum Internal

• The Omasal laminae - Laminae omasi are parallels
  • Highest on the Dorsal Omasum
  • Lowest on the Parietal Omasum
  • Absent in Fundus Omasi
  • Covered with Pillaie Omassi 5 mm in length
  • Short Stubby and Rough
  • 90-130 total
  • 12-15 Highest

Abomasum

• 4th Complex composite stomach
• True stomach where enzymes work
• ↔Ostium omasoabomasium
• Right costal arch, on ventral part of abdomen,Opposite to the 7th - 11th
• Is permanent Sprial Holds of mucosa: number 12-16

Gastric groove.

Gastric groove - (sulculus Verticuli) Ru

• Well developed, Throught all Proven Truculus to the obomassum
  • 3segments (1Retichulargroore, masso groove, masso groove)
• edges made up of high Mucosal fold with its floor
• *Labiumd extremitities with floor side by side

Differences for small ruminants

Peculiarities in the stomach of small ruminants

• Rumen 12-25L
• Saccus ceasus cado Ventralis
• Longer saccus ceasus caudodorsalis
• Reticulum-1-2 L
• Illipsoidal Shape
• Omassu- 0,3-0,9L

Overview of the anatomy of the esophagus. Includes the tunica mucosa, tunica muscularis and tunica adventitia. Also includes discussion of the cervical, thoracic, and abdominal parts.