MusclesMuscles

Dr. Sama ul Haque

ObjectivesObjectives

Define a muscle.Define a muscle. Classify muscles according to their Classify muscles according to their

structure and functions.structure and functions. Differentiate the types of muscles, on the Differentiate the types of muscles, on the

basis of structural peculiarities and basis of structural peculiarities and functions.functions.

Understand terms related to muscles.Understand terms related to muscles. Know how the muscles are named.Know how the muscles are named.

Types of the muscleTypes 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.

Are effectors which enable movement to be carried out.

MusclesMuscles

Types of connective tissues Types of connective tissues wrappings of skeletal musclewrappings of skeletal muscle

Endomysium Endomysium : a delicate connective tissue : a delicate connective tissue sheath surrounds muscle fiber.sheath surrounds muscle fiber.

PerimysiumPerimysium : a coarser fibrous membrane : a coarser fibrous membrane surrounds several sheathed muscle fibers to surrounds several sheathed muscle fibers to form bundle of fibers called a fascicle.form bundle of fibers called a fascicle.

Epimysium Epimysium : a tougher overcoat of : a tougher overcoat of connective tissue surrounds many fascicles.connective tissue surrounds many fascicles.

The Epimysium blend into the strong, cord- The Epimysium blend into the strong, cord- like tendons, or into sheet-like like tendons, or into sheet-like AponeurosisAponeurosis..

FunctionFunction: attaching the muscle to bone….: attaching the muscle to bone….

Providing durability Providing durability

Conserving space Conserving space

Muscles & the SkeletonMuscles & the Skeleton

Skeletal muscles cause the skeleton to move Skeletal muscles cause the skeleton to move at jointsat joints

They are attached to skeleton by tendons.They are attached to skeleton by tendons. Tendons Tendons transmittransmit muscle force to the bone. muscle force to the bone. Tendons are made of collagen fibres & are Tendons are made of collagen fibres & are

very strong & stiffvery strong & stiff

Muscle functionMuscle function

Providing movementProviding movement Maintaining postureMaintaining posture Stabilizing joint Stabilizing joint Generating heatGenerating heat

Skeletal MuscleSkeletal Muscle Functions of Skeletal Functions of Skeletal

MuscleMuscle– Produce MovementProduce Movement– Maintain postureMaintain posture– Stabilize jointsStabilize joints– Generate HeatGenerate Heat

Sites of Muscle Sites of Muscle AttachmentAttachment– BonesBones– CartilageCartilage– Connective tissue Connective tissue

coveringscoverings

Muscle Fibers blend into a Muscle Fibers blend into a connective tissue attachmentconnective tissue attachment– Tendon—cordlike structureTendon—cordlike structure– Aponeurosis—sheet-like Aponeurosis—sheet-like

structurestructure Properties of MuscleProperties of Muscle

– Irritability – ability to Irritability – ability to receive and respond to a receive and respond to a stimulusstimulus

– Contractibility – ability to Contractibility – ability to shorten when an adequate shorten when an adequate stimulus is receivedstimulus is received

– Extensibility – ability to Extensibility – ability to lengthen when an adequate lengthen when an adequate stimulus is receivedstimulus is received

– Elasticity – ability to return Elasticity – ability to return to normal shapeto normal shape

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

InsertionInsertion : is the point where the muscle : is the point where the muscle attached to movable bone.attached to movable bone.

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

AntagonistAntagonist : the muscle that reverse a : the muscle that reverse a movement.movement.

Antagonistic Muscle ActionAntagonistic Muscle Action

Muscles are either contracted or relaxedMuscles are either contracted or relaxed When contracted the muscle exerts a When contracted the muscle exerts a

pulling force, causing it to shortenpulling force, causing it to shorten Since muscles can only pull (not push), they Since muscles can only pull (not push), they

work in pairs called work in pairs called antagonistic musclesantagonistic muscles The muscle that bends the joint is called the The muscle that bends the joint is called the

flexorflexor muscle muscle The muscle that straightens the joint is The muscle that straightens the joint is

called the called the extensorextensor muscle muscle

Elbow JointElbow Joint The best known example of antagonistic The best known example of antagonistic

muscles are the biceps & triceps musclesmuscles are the biceps & triceps musclesElbow joint flexed

Flexor m uscles contractedExtensor muscles re laxed

Elbow joint extendedExtensor muscles contracted

Flexor m uscles relaxed

biceps

triceps

Section through arm

Flexorm uscles

Extensor m uscles

Hum erusBone

Naming Skeletal musclesNaming Skeletal muscles DirectionDirection of the muscle fibers: Orbicularis oris of the muscle fibers: Orbicularis oris

(close and protrude lips), Occuli (close the eyelids)(close and protrude lips), Occuli (close the eyelids) Relative Relative sizesize of the muscle: Gluteus Maximus, of the muscle: Gluteus Maximus,

Medius, MinimusMedius, Minimus LocationLocation of the muscle: Obturator Internus (Abduct of the muscle: Obturator Internus (Abduct

and rotates laterally thigh)and rotates laterally thigh) NumberNumber of the origin: Biceps, Triceps of the origin: Biceps, Triceps Location of the muscleLocation of the muscle’’s s originorigin and and insertioninsertion: :

Occipito-frontalisOccipito-frontalis ShapeShape of the muscle: Deltoidof the muscle: Deltoid ActionAction of the muscle: Pronator Quadratus of the muscle: Pronator Quadratus

Shape and Fiber Architecture of Skeletal muscle Shape and Fiber Architecture of Skeletal muscle

Terms related to Muscle: Terms related to Muscle:

– Belly (Fleshy part, Contractile)Belly (Fleshy part, Contractile)

– Tendon (C.T, Non-Contractile) Tendon (C.T, Non-Contractile)

– Aponeurosis (Flattened tendon)Aponeurosis (Flattened tendon)

– LigamentLigament

Thank youThank you