Animal anatomy, histology, pathological anatomy

Anatomical and physiological characteristics of ruminants.
They developed in the process of their evolution, domestication and breeding.
Skin and its derivatives.Cattle have thick skin, with a characteristic fold - the dewlap. Leather derivatives include hooves, pulp and horns. Uneven growth of horns associated with pregnancy is accompanied by the formation of horny rings and interceptions, which make it possible to determine the age of the animal.
Mammary gland(udders) in cows consist of four lobes, in sheep and goats the udder is bipartite.
Digestive organs.Cattle and small cattle have eight incisor teeth on the lower jaw, four on each side. The thickened gums of the upper jaw form the dental plate. The tongue is relatively thick and coarse in structure, the papillae of the back of the tongue are large and facing the pharynx. The pharynx is short and wide. The esophagus is wider than that of a horse.
The stomach of ruminants consists of four chambers: the rumen, the mesh, the book, and the abomasum. A camel has three stomach chambers (no book).
In dairy calves, the abomasum is relatively largest in size. From the entrance of the esophagus into the scar, along the right wall of the scar and the mesh to the hole between the mesh and the book, the esophageal groove stretches, opening into the stomach. The mucous membrane of the abomasum is smooth, with long spiral folds, and contains numerous glands.
In calves aged 15–20 days, the rumen and other chambers of the stomach increase due to the ability to digest rough plant feed. The first three sections of the stomach do not have glands. Their mucous membrane forms peculiar folds and papillae for each section.
In a calf aged 3 months. The capacity of the rumen is 10–15 liters, at the age of one year – 68 liters, and in an adult animal – from 100 to 200 liters, and the rumen and mesh account for 84% of the total contents of the stomach (up to 235 liters), the abomasum holds 10–20 liters, the book – 7– 18l.
In sheep and goats, depending on the breed and size, the capacity of the rumen ranges from 13–23 l, the mesh – 1–2, the book – 0.30.9, the rennet – 1.75–3.3 l.
Thus, the stomach of ruminants occupies most of the abdominal cavity. The scar almost completely occupies the left half of the abdominal cavity and partially extends behind and below to the right half. The mesh serves as a continuation forward and downward of the vestibule of the dorsal sac of the scar, located in the region of the xiphoid cartilage, with its anterior part adjacent to the diaphragm; the book is located in the right hypochondrium; abomasum - in the area of ​​the xiphoid cartilage under the book and in the right hypochondrium.
Small intestineruminants are distinguished by their long length and relatively narrow lumen; the mucous membrane has circular folds. It is located in the right hypochondrium, iliac and groin. In a cow, the length of the duodenum is 90–120 cm, in a sheep – 95–110 cm; in a cow, the length of the jejunum and ileum together with the duodenum is 27–49 m, in a sheep – 25 m. The mucous membrane of the ileum forms a circular valve at the junction with the cecum.
Colonruminants do not have shadows or pockets. Its length in cattle is from 6.4 to 10 m. and more; in sheep 4– bm. It lies in the right half of the abdominal cavity, the rectum with a number of ring-shaped constrictions is located in the pelvic cavity. The colon creates a significant disc-shaped labyrinth.
Liverlocated in the right hypochondrium, directly behind the diaphragm. Its weight in large ruminants is from 3.4 to 9.2 kg, in small ruminants – from 0.63 to 0.95 kg. The liver has a flattened convex-concave shape and a weakly expressed lobular-lamellar structure. On the posterior surface of the right lobe of the liver in ruminants (with the exception of reindeer and camels) there is a gallbladder with a cystic duct, which, merging with the hepatic duct, forms a bile duct that flows into the duodenum at a distance of 50–70 cm from the pylorus and 30–40 cm from the pancreatic duct. In sheep, the mouth of both ducts is located at a distance of 30–35 cm behind the pylorus.
PancreasIt has a head and right and left lobes in the area of ​​the liver and the S-shaped bend of the duodenum, lying from the 12th rib to the 2nd–4th lumbar vertebra. Its mass in a cow is 420 g.
Rib cageconsists of 13 pairs of ribs. 6 lumbar vertebrae.
Heartlocated between the 3rd and 6th ribs, 5/7 on the left side of the chest. In the area of ​​the coronary and longitudinal grooves there is usually a lot of subepicardial fatty tissue. Heart weight from 2.23 kg in cows to 3.01 kg in bulls; in sheep – 0.23–0.24 kg.
Lungs(left and right) have cranial, middle and caudal lobes, and the right one also has an accessory lobe. The surface of the lungs has a characteristic lobular pattern, caused by highly developed connective tissue layers between the lobules. Lung weight in cattle is 2.99–3.93 kg, in sheep and goats 0.22–0.39 kg.
Spleenlocated in the left hypochondrium, connecting to the scar with loose fiber. Its length is 40–50 cm, width 10–15, thickness 2–3 cm. Weight in cattle is 0.5–1 kg, in sheep 0.12–0.16 kg.
Kidneysin cattle, the grooved multipapillary type with a pronounced lobular structure; in small ruminants they are smooth, single-papillary, and bean-shaped. The mass of the kidneys in large animals is 720–1940.
Adrenal glandsin cattle the shape resembles: the right one is a heart, and the left one is a kidney; in sheep it is a large bean.
Reproductive organs.The ovaries of cows are ellipsoidal, while those of sheep and goats are round. The uterus is bicornuate. Its mucous membrane has caruncles with crypts, which serve as junctions between the fetal membranes and the uterus.
Thyroidin cattle it is located near the larynx; it is dicotyledonous, lobed in structure, with a relatively strongly pronounced isthmus; length 6–7 cm, width 5–6, thickness – 1.5 cm. There are two pairs of parathyroid glands, the outer body is located cranial to the thyroid gland, the inner body is on its medial surface.
Thymusin young calves it is relatively large, has an unpaired left thoracic lobe and paired cervical parts protruding along the trachea to the larynx. In adult animals, only traces of it remain in the chest cavity.