Muscular System in Vertebrates (Comparative) .pptx

Muscular System in Vertebrates (Comparative) .pptx

1. Muscular System in Vertebrates Dr Showkat Ahmad wani

2. Introduction The muscular system is responsible for movement, posture, circulation, digestion, and locomotion in vertebrates. It consists mainly of three types of muscles : Skeletal (striated, voluntary) – locomotion and posture. Smooth (non-striated, involuntary) – visceral functions. Cardiac (striated, involuntary) – heart function. While these types are common across vertebrates , their arrangement, specialization, and degree of development vary among fishes, amphibians, reptiles, birds, and mammals .

3. Types of Muscles in Vertebrates Skeletal muscles – attached to bones; responsible for voluntary movements. Visceral muscles (smooth) – control gut, blood vessels, and internal organs. Cardiac muscles – form the myocardium of the heart.

4. Comparative Study Across Vertebrates 1. Fishes Trunk muscles are the most prominent, arranged into myotomes (zig-zag blocks separated by myosepta). Locomotion is mostly by lateral undulations of the trunk and tail. Fins are moved by specialized appendicular muscles . Jaw and pharyngeal muscles are well-developed for feeding and respiration .

5. 2. Amphibians Show transition from aquatic to terrestrial locomotion . Trunk muscles are less segmented than in fishes. Development of limb muscles (forelimbs & hindlimbs) for jumping and walking. Jaw and tongue muscles modified for prey capture (sticky tongue in frogs) . Smooth muscles in skin assist in cutaneous respiration .

6. 3. Reptiles Stronger axial and appendicular musculature than amphibians. Trunk muscles provide support for crawling and some bipedal locomotion. Rib-associated muscles (intercostals) aid in breathing (thoracic respiration). Jaw muscles (e.g., adductor mandibulae ) are very strong for biting. Tail muscles are used in swimming, defense, or fat storage in some species.

7. 4. Birds Muscular system is highly specialized for flight . Pectoralis major – large, powerful flight muscle for the downstroke. Supracoracoideus – responsible for upstroke by a pulley-like tendon. Reduction in trunk muscles; limb muscles dominate . Leg muscles strong for perching, walking, or swimming . Smooth muscles control gizzard (food grinding).

8. 5. Mammals Most complex and highly differentiated muscular system. Axial muscles less important for locomotion, more for posture. Appendicular muscles highly specialized (running, climbing, swimming). Facial muscles (unique to mammals) for expressions, suckling, and communication. Diaphragm – a muscular partition aiding in efficient respiration. Cardiac and smooth muscles more advanced and efficient.

9. Comparative Highlights Feature Fishes Amphibians Reptiles Birds Mammals Trunk muscles Segmented myotomes Less segmented Strong, support crawling Reduced, flight muscles dominate Reduced, posture-oriented Limb muscles Weak (fins only) Well-developed Strong, for crawling/climbing Highly specialized for wings Highly specialized for varied locomotion Jaw muscles Feeding & respiration Feeding + tongue movement Very strong (biting) Adapted for beak movement Highly varied, mastication Special features Tail muscles dominate Tongue muscles (frogs) Intercostals for breathing Pectoralis & supracoracoideus Diaphragm, facial muscles

10. Conclusion The muscular system in vertebrates shows a progressive shift from simple segmental myotomes in fishes to highly specialized muscles in mammals . The trend reflects adaptation to environment and mode of locomotion : Aquatic undulations (fishes) → limb-based movement (amphibians & reptiles) → aerial locomotion (birds) → highly diverse locomotion (mammals) .

11. Thank you