Skeletal, Digestive and Circulatory system of Rat

Skeletal system

The skeleton of rat has 223 bones that are distributed into the axial skeleton and the appendicular skeleton. The axial skeleton consists of skull, vertebral column, sternum, ribs and ear ossicles. The appendicular skeleton is represented by girdles and limb bones.

Skeletal System

Digestive system

A well developed digestive system which can take care of the energy requirements of the animal is present. It consists of an alimentary canal and associated structures.

The buccal cavity contains teeth, which are of three different types : incisors, premolars and molars. Canines are absent. The long self sharpening chisel shaped incisors grow throughout the life of a rat.

Salivary glands in the buccal cavity, gastric glands in the stomach, intestinal glands in the small intestine, liver and pancreas situated outside the alimentary canal, are the associated structures. Liver is not only the largest gland in the body, but is also a versatile gland involved in a large number and variety of functions. Pancreas serves both as an exocrine and an endocrine gland. As an exocrine gland it produces digestive juices and as an endocrine gland it produces the hormone insulin.

Digestive System

Circulatory system

The circulatory system is well developed. It is represented by a heart, blood vessels and blood. Heart is four chambered, with a clear separation of deoxygenated and oxygenated blood. Its functioning is described as double circulation. It consists of a pulmonary circulation and a systemic circulation. Blood is red in colour, Hemoglobin is present in RBC. The RBC are biconcave and enucleate.