Dr Praveen Kumar Agrawal is teaching live on Unacademy Plus
Course: Locomotion and Movement -2 Lesson -4:A Comparison of Different types of muscles DR. P. K. AGRAWAL M.Sc, PH.D., CSIR NET (JRF), SRF, GATE, FIAZ 20 Years of Pre-medical teaching experience Ex Faculty, Allen Career Institute, Kota Watch my Live Classes on Unacademy Plus
Skeletal muscles Smooth muscles Cardiac mucles Cylindrical Fibres unbranched Multinucleate Light and dark bands clearly visible Light and dark bands not visible Intercalated discs absent Nerve supply from central nervous Nerve supply from autonomic nervous Nerve supply from autonomic nervous Spindle shaped Fibres unbranched Uninucleate Cylindrical Fibres branched Uninucleate Light dark bands faint in appearance Intercalated discs present Intercalated discs absent system Voluntary in nature Soon undergo fatigue Possess high degree of contractility Possess low degree of contractility sss high degree of contractility Present in limbs, body walls, tongue, Present in internal visceral organs, iris, Present in the wall of heart chambers system Involuntary in nature Rarely undergo fatigue system and brain. Involuntary in nature Never undergo fatigue etc. blood vessels, dermis etc.
Important terms related to muscles 1. Cyclosis: The streaming movement of cytoplasm in a cell is called cyclosis. It is clearly exhibited in some protozoan like paramecium 2. Sarcomere Sarcomere represents the structural and functional unit of a myofibril. It is the unit of contraction. In a striated muscle fibre, the portion between two successive Z lines is called sarcomere. 3. Rigor mortis : Usually, some hours after the death of an individual, its muscles are stiffened. This muscular stiffening, after death, is called rigor mortis. This phenomenon is important in medical jurisprudence as this helps fixation of hours of death after a murder and thus helps to track the criminal . 4. Myoglobin Similar to haemoglobin, myoglobin is also an iron containing red coloured pigment. But it is found only in muscles. A myoglobin molecule consists of one heme and one polypeptide chain. It can carry one molecule of oxygen (but haemoglobin can carry 4 O2 molecules) .5. Red muscle fibres : These are dark red coloured muscles, having a very high amount of myoglobin These are rich in mitochondria and having a high rate of metabolism. These cells generate a powerful, sustained but slow contraction movement. These generally do not undergo fatigue. These are associated with posture maintaining muscles (such as neck muscles) 6. White muscle fibres These are faintly red in colour and have low amount of myoglobin. These also have a poor number of mitochondria. These cells contract very fast and soon undergo fatique. These are found in upper limbs, where high contractility is required for short duration
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