1. Muscles Dr. Sama ul Haque

2. Objectives Define a muscle. Define a muscle. Classify muscles according to their structure and functions. Classify muscles according to their structure and functions. Differentiate the types of muscles, on the basis of structural peculiarities and functions. Differentiate the types of muscles, on the basis of structural peculiarities and functions. Understand terms related to muscles. Understand terms related to muscles. Know how the muscles are named. Know how the muscles are named.

3. Types of the muscle Skeletal: Striated and voluntary. Skeletal: Striated and voluntary. Smooth: Non-striated and involuntary. Smooth: Non-striated and involuntary. Cardiac: Striated and involuntary. Cardiac: Striated and involuntary.

5. Are effectors which enable movement to be carried out. Muscles

6. Types of connective tissues wrappings of skeletal muscle

7. Endomysium : a delicate connective tissue sheath surrounds muscle fiber. Endomysium : a delicate connective tissue sheath surrounds muscle fiber. Perimysium : a coarser fibrous membrane surrounds several sheathed muscle fibers to form bundle of fibers called a fascicle. Perimysium : a coarser fibrous membrane surrounds several sheathed muscle fibers to form bundle of fibers called a fascicle. Epimysium : a tougher overcoat of connective tissue surrounds many fascicles. Epimysium : a tougher overcoat of connective tissue surrounds many fascicles.

9. The Epimysium blend into the strong, cord- like tendons, or into sheet-like Aponeurosis. The Epimysium blend into the strong, cord- like tendons, or into sheet-like Aponeurosis. Function: attaching the muscle to bone…. Function: attaching the muscle to bone…. Providing durability Providing durability Conserving space Conserving space

10. Muscles & the Skeleton Skeletal muscles cause the skeleton to move at joints Skeletal muscles cause the skeleton to move at joints They are attached to skeleton by tendons. They are attached to skeleton by tendons. Tendons transmit muscle force to the bone. Tendons transmit muscle force to the bone. Tendons are made of collagen fibres & are very strong & stiff Tendons are made of collagen fibres & are very strong & stiff

11. Muscle function Providing movement Providing movement Maintaining posture Maintaining posture Stabilizing joint Stabilizing joint Generating heat Generating heat

12. Skeletal Muscle Functions of Skeletal Muscle –Produce Movement –Maintain posture –Stabilize joints –Generate Heat Sites of Muscle Attachment –Bones –Cartilage –Connective tissue coverings Muscle Fibers blend into a connective tissue attachment –Tendon—cordlike structure –Aponeurosis—sheet-like structure Properties of Muscle –Irritability – ability to receive and respond to a stimulus –Contractibility – ability to shorten when an adequate stimulus is received –Extensibility – ability to lengthen when an adequate stimulus is received –Elasticity – ability to return to normal shape

14. Origin : is the point where the muscle is attached to immovable or less movable bone. Origin : is the point where the muscle is attached to immovable or less movable bone. Insertion : is the point where the muscle attached to movable bone. Insertion : is the point where the muscle attached to movable bone.

15. Prime mover : the muscle that has the major responsibility for causing a movement. Prime mover : the muscle that has the major responsibility for causing a movement. Antagonist : the muscle that reverse a movement. Antagonist : the muscle that reverse a movement.

16. Antagonistic Muscle Action Muscles are either contracted or relaxed Muscles are either contracted or relaxed When contracted the muscle exerts a pulling force, causing it to shorten When contracted the muscle exerts a pulling force, causing it to shorten Since muscles can only pull (not push), they work in pairs called antagonistic muscles Since muscles can only pull (not push), they work in pairs called antagonistic muscles The muscle that bends the joint is called the flexor muscle The muscle that bends the joint is called the flexor muscle The muscle that straightens the joint is called the extensor muscle The muscle that straightens the joint is called the extensor muscle

17. Elbow Joint The best known example of antagonistic muscles are the biceps & triceps muscles The best known example of antagonistic muscles are the biceps & triceps muscles

18. Naming Skeletal muscles Direction of the muscle fibers: Orbicularis oris (close and protrude lips), Occuli (close the eyelids) Direction of the muscle fibers: Orbicularis oris (close and protrude lips), Occuli (close the eyelids) Relative size of the muscle: Gluteus Maximus, Medius, Minimus Relative size of the muscle: Gluteus Maximus, Medius, Minimus Location of the muscle: Obturator Internus (Abduct and rotates laterally thigh) Location of the muscle: Obturator Internus (Abduct and rotates laterally thigh) Number of the origin: Biceps, Triceps Number of the origin: Biceps, Triceps Location of the muscle’s origin and insertion: Occipito-frontalis Location of the muscle’s origin and insertion: Occipito-frontalis Shape of the muscle: Deltoid Shape of the muscle: Deltoid Action of the muscle: Pronator Quadratus Action of the muscle: Pronator Quadratus

19. Shape and Fiber Architecture of Skeletal muscle

20. Terms related to Muscle: Terms related to Muscle: –Belly (Fleshy part, Contractile) –Tendon (C.T, Non-Contractile) –Aponeurosis (Flattened tendon) –Ligament

21. Thank you