Muscular system overview
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This document provides an overview of the muscular system. It discusses the three types of muscles - skeletal, cardiac, and smooth muscles. Skeletal muscles are voluntary and striated, found attached to bones, and enable movement. Cardiac muscle is exclusively found in the heart and contracts involuntarily. Smooth muscles are not striated, act involuntarily, and are located in organs like the intestines. The document also examines muscle structure, types of contractions, energy sources, exercise effects, and attachments. Examples of major skeletal muscles and their functions are outlined.
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Muscular system overview
- 1. Presented by: Mr.Vijay Salvekar Associate Professor Dept. of Pharmacology GRY Institute of Pharmacy , Borawan Muscular System
- 2. Did you know that ? - more than 50% of body weight is muscle ! - And muscle is made up of proteins and water
- 4. The Muscular System • Muscles are responsible for all movement of the body • There are three basic types of muscle – Skeletal – Cardiac – Smooth
- 5. Info About Muscles • Only body tissue able to contract • create movement by flexing and extending joints • Body energy converters (many muscle cells contain many mitochondria)
- 6. 3 Types of Muscles
- 7. Three types of muscle Skeletal Cardiac Smooth
- 8. Classification of Muscle Skeletal- found in limbs Cardiac- found in heart Smooth- Found in viscera Striated, multi- nucleated Striated, 1 nucleus Not striated, 1 nucleus voluntary involuntary involuntary
- 9. Characteristics of Muscle • Skeletal and smooth muscle are elongated • Muscle cell = muscle fiber • Contraction of a muscle is due to movement of microfilaments (protein fibers) • All muscles share some terminology – Prefixes myo and mys refer to muscle – Prefix sarco refers to flesh
- 10. Shapes of Muscles • Triangular- shoulder, neck • Spindle- arms, legs • Flat- diaphragm, forehead • Circular- mouth, anus
- 11. Skeletal Muscle • Most are attached by tendons to bones • Cells have more than one nucleus (multinucleated) • Striated- have stripes, banding • Voluntary- subject to conscious control • Tendons are mostly made of collagen fibers • Found in the limbs • Produce movement, maintain posture, generate heat, stabilize joints
- 12. Structure of skeletal muscle • Each cell (fibre) is long and cylindrical • Muscle fibres are multi-nucleated • Typically 50-60mm in diameter, and up to 10cm long • The contractile elements of skeletal muscle cells are myofibrils
- 13. Skeletal muscle - Summary • Voluntary movement of skeletal parts • Spans joints and attached to skeleton • Multi-nucleated, striated, cylindrical fibres
- 14. Smooth Muscle • No striations • Spindle shaped • Single nucleus • Involuntary- no conscious control • Found mainly in the walls of hollow organs
- 15. Smooth muscle • Lines walls of viscera • Found in longitudinal or circular arrangement • Alternate contraction of circular & longitudinal muscle in the intestine leads to peristalsis
- 16. Structure of smooth muscle • Spindle shaped uni-nucleated cells • Striations not observed • Actin and myosin filaments are present( protein fibers)
- 17. Smooth muscle - Summary • Found in walls of hollow internal organs • Involuntary movement of internal organs • Elongated, spindle shaped fibre with single nucleus
- 18. Cardiac Muscle • Striations • Branching cells • Involuntary • Found only in the heart • Usually has a single nucleus, but can have more than one
- 19. Cardiac muscle • Main muscle of heart • Pumping mass of heart • Critical in humans • Heart muscle cells behave as one unit • Heart always contracts to it’s full extent
- 20. Structure of cardiac muscle • Cardiac muscle cells (fibres) are short, branched and interconnected • Cells are striated & usually have 1 nucleus • Adjacent cardiac cells are joined via electrical synapses (gap junctions) • These gap junctions appear as dark lines and are called intercalated discs
- 21. Cardiac muscle - Summary • Found in the heart • Involuntary rhythmic contraction • Branched, striated fibre with single nucleus and intercalated discs
- 22. Muscle Control Type of muscle Nervous control Type of control Example Skeletal Skeletal Controlled by CNS Voluntary Lifting a glass Cardiac Regulated by ANS Involuntary Heart beating Smooth Controlled by ANS Involuntary Peristalsis
- 23. Types of Responses • Twitch- – A single brief contraction – Not a normal muscle function • Tetanus – One contraction immediately followed by another – Muscle never completely returns to a relaxed state – Effects are compounded
- 24. Where Does the Energy Come From? • Energy is stored in the muscles in the form of ATP • ATP comes from the breakdown of glucose during Cellular Respiration • This all happens in the Mitochondria of the cell • When a muscle is fatigued (tired) it is unable to contract because of lack of Oxygen
- 25. Exercise and Muscles • Isotonic- muscles shorten and movement occurs ( most normal exercise) • Isometric- tension in muscles increases, no movement occurs (pushing one hand against the other)
- 26. How are Muscles Attached to Bone? • Origin-attachment to a movable bone • Insertion- attachment to an immovable bone • Muscles are always attached to at least 2 points • Movement is attained due to a muscle moving an attached bone
- 28. The Skeletal Muscles There are about 650 muscles in the human body. They enable us to move, maintain posture and generate heat. In this section we will only study a sample of the major muscles.
- 31. Temporalis Elevate & Retract Mandible
- 32. Trapezius Extend Head, Adduct, Elevate or Depress Scapula
- 33. Latissimus Dorsi Extend, Adduct & Rotate Arm Medially
- 34. Deltoid Abduct, Flex & Extend Arm
- 35. Pectoralis Major Flexes, adducts & rotates arm medially
- 36. Biceps Brachii Flexes Elbow Joint
- 37. Triceps Brachii Extend Elbow Joint
- 43. Forearm Muscles • Flexor carpi—Flexes wrist • Extensor carpi—Extends wrist • Flexor digitorum—Flexes fingers • Extensor digitorum—Extends fingers • Pronator—Pronates • Supinator—Supinates
- 44. Gluteus Maximus Extends & Rotates Thigh Laterally
- 45. Rectus Femoris Flexes Thigh, Extends Lower Leg
- 46. Gracilis Adducts and Flexes Thigh
- 47. Sartorius Flexes Thigh, & Rotates Thigh Laterally
- 48. Biceps Femoris Extends Thigh & Flexes Lower Leg
- 49. Gastrocnemius Plantar Flexes Foot & Flex Lower Leg
- 50. Tibialis Anterior Dorsiflexes and Inverts Foot