CLASSIFICATION OF MUSCLES

Muscles are classified based on various factors, including the presence or absence of cross-striations and the mode of control exerted over them.

7.2.1 Striated or Non-Striated

Figure 7.2 shows striated muscles, which encompass skeletal and cardiac muscles, are distinguished by cross-striations, while non-striated muscles, known as smooth muscles, are identified by the absence of cross-striations and are pre­dominantly situated in the walls of visceral organs.

7.2.2 Control on Muscle

Control-wise, muscles fall into two types: voluntary and involuntary. Skeletal muscles, which are voluntary, can be consciously controlled and are innervated by somatic nerves. On the other hand, smooth and cardiac muscles are involuntary and cannot be controlled consciously. Autonomic nerves innervate them.

7.2.3 Muscle Movement

Skeletal muscles are also categorised based on the type of movement they induce and their strategic positions con­cerning the structures they affect. Flexors and extensors facilitate joint movement in different directions; adductors and abductors draw a limb toward or away from the median plane, respectively, while sphincters, arranged circularly, constrict body openings. Due to the high prevalence of movement abnormalities in veterinary patients with neu­romuscular system disease, it is crucial to understand how skeletal muscle functions and is controlled by the nervous system. Abnormalities of cardiac muscle and smooth mus­cle also feature prominently in many other clinical disor­ders, and such muscle is often the target of pharmacological clinical intervention.

7.3