Muscular TissueMuscular TissueMuscular TissueMuscular Tissue

Functions of MuscleFunctions of Muscle

Movement:Movement: skeletal,skeletal, cardiac, and smooth cardiac, and smooth musclesmuscles

Stability:Stability: skeletal muscleskeletal muscle

Communication:Communication: skeletal muscleskeletal muscleCommunication:Communication: skeletal muscleskeletal muscle

Control of body openings and passages:Control of body openings and passages:skeletal and smooth musclesskeletal and smooth muscles

Heat production:Heat production: skeletal musclesskeletal muscles

Functions of MuscleFunctions of Muscle

cardiac, and smooth cardiac, and smooth

skeletal muscleskeletal muscle

skeletal muscleskeletal muscleskeletal muscleskeletal muscle

Control of body openings and passages:Control of body openings and passages:skeletal and smooth musclesskeletal and smooth muscles

skeletal musclesskeletal muscles

Properties of MusclesProperties of Muscles

ExcitabilityExcitability ((responsiveness)responsiveness)chemical, mechanical or electrical stimuli.chemical, mechanical or electrical stimuli.

ConductivityConductivity initiate events that lead to initiate events that lead to contraction.contraction.

ContractilityContractility ability to shorten substantiallyability to shorten substantially

ExtensibilityExtensibility able to stretch between able to stretch between contractions.contractions.

ElasticityElasticity ability to return to original length ability to return to original length after stretching.after stretching.

Properties of MusclesProperties of Muscles

responsiveness)responsiveness) respond to respond to chemical, mechanical or electrical stimuli.chemical, mechanical or electrical stimuli.

initiate events that lead to initiate events that lead to

ability to shorten substantiallyability to shorten substantially

able to stretch between able to stretch between

ability to return to original length ability to return to original length

Muscle TissueMuscle TissueThere are There are 3 3 types of muscle tissue:types of muscle tissue: skeletalskeletal smoothsmooth cardiaccardiac

Muscle TissueMuscle Tissuetypes of muscle tissue:types of muscle tissue:

Classification of Muscle CellsClassification of Muscle Cells

Striated vs. Nonstriated Striated vs. Nonstriated

striated have a banded appearance (stripes)striated have a banded appearance (stripes)

Single nucleus or multinucleated cellsSingle nucleus or multinucleated cells

Muscle cells can be controlled Muscle cells can be controlled Muscle cells can be controlled Muscle cells can be controlled

voluntarily (consciously)voluntarily (consciously)

oror

involuntarilyinvoluntarily ((automatically)automatically)

Classification of Muscle CellsClassification of Muscle Cells

Striated vs. Nonstriated Striated vs. Nonstriated

striated have a banded appearance (stripes)striated have a banded appearance (stripes)

Single nucleus or multinucleated cellsSingle nucleus or multinucleated cells

Muscle cells can be controlled Muscle cells can be controlled Muscle cells can be controlled Muscle cells can be controlled

voluntarily (consciously)voluntarily (consciously)

automatically)automatically)

Skeletal MuscleSkeletal Muscle

Cells are long and cylindrical in shapeCells are long and cylindrical in shape

Cells are multiCells are multi--nucleatednucleated

CrossCross--striations presentstriations present

Under voluntary controlUnder voluntary control

Contractile proteins:Contractile proteins: actin, myosin and tinin.actin, myosin and tinin.Contractile proteins:Contractile proteins: actin, myosin and tinin.actin, myosin and tinin.

Regulatory proteins:Regulatory proteins: troponin and tropomyosin.troponin and tropomyosin.

Sarcomere is contractile unit of skeletal muscle; Sarcomere is contractile unit of skeletal muscle; defined as the distance between defined as the distance between

Skeletal MuscleSkeletal Muscle

Cells are long and cylindrical in shapeCells are long and cylindrical in shape

nucleatednucleated

striations presentstriations present

Under voluntary controlUnder voluntary control

actin, myosin and tinin.actin, myosin and tinin.actin, myosin and tinin.actin, myosin and tinin.

troponin and tropomyosin.troponin and tropomyosin.

Sarcomere is contractile unit of skeletal muscle; Sarcomere is contractile unit of skeletal muscle; defined as the distance between defined as the distance between 2 2 “Z” discs.“Z” discs.

Skeletal MuscleSkeletal MuscleWhole muscle Single muscle fiber

Skeletal MuscleSkeletal MuscleSingle muscle fiber

Skeletal Muscle Structure/ OrganizationSkeletal Muscle Structure/ OrganizationSkeletal Muscle Structure/ OrganizationSkeletal Muscle Structure/ Organization

Skeletal Muscle CellsSkeletal Muscle Cells

Striated, voluntary,Striated, voluntary, and multinucleatedand multinucleated

are long,are long, thin and cylindrical; they are thin and cylindrical; they are attached to bones and move our skeletonattached to bones and move our skeleton

are usually called “are usually called “muscle fibersmuscle fibers are usually called “are usually called “muscle fibersmuscle fibers

do not divide to create new cellsdo not divide to create new cells

new fibers are produced by stem cellsnew fibers are produced by stem cells

Striations Striations ---- cross stripes (bands) run cross stripes (bands) run perpendicular to the cellsperpendicular to the cells

Skeletal Muscle CellsSkeletal Muscle Cells

and multinucleatedand multinucleated

thin and cylindrical; they are thin and cylindrical; they are attached to bones and move our skeletonattached to bones and move our skeleton

muscle fibersmuscle fibers””muscle fibersmuscle fibers””

do not divide to create new cellsdo not divide to create new cells

new fibers are produced by stem cellsnew fibers are produced by stem cells

cross stripes (bands) run cross stripes (bands) run perpendicular to the cellsperpendicular to the cells

Skeletal Muscle TissueSkeletal Muscle TissueSkeletal Muscle TissueSkeletal Muscle Tissue

Neuromuscular controlNeuromuscular control

Skeletal muscle contraction is controlled by a nerve Skeletal muscle contraction is controlled by a nerve impulse (action potential) transmitted by the motor impulse (action potential) transmitted by the motor nerve from the brain or spinal cord.nerve from the brain or spinal cord.

motor unitmotor unit consists of all the muscle fibers controlled consists of all the muscle fibers controlled by a single motor neuron.by a single motor neuron.by a single motor neuron.by a single motor neuron.

Fine control muscles (i.e. eyelid muscles) have fewer Fine control muscles (i.e. eyelid muscles) have fewer muscle fibers/ nerve (muscle fibers/ nerve (22::11).).

A contraction is initiated by an action potential (nerve A contraction is initiated by an action potential (nerve impulse) and followed by the release a chemical impulse) and followed by the release a chemical neurotransmitter at the neuromuscular junction (NMJ). neurotransmitter at the neuromuscular junction (NMJ).

Neurotransmitter for skeletal muscle is acetylcholine.Neurotransmitter for skeletal muscle is acetylcholine.

Neuromuscular controlNeuromuscular control

Skeletal muscle contraction is controlled by a nerve Skeletal muscle contraction is controlled by a nerve impulse (action potential) transmitted by the motor impulse (action potential) transmitted by the motor nerve from the brain or spinal cord.nerve from the brain or spinal cord.

consists of all the muscle fibers controlled consists of all the muscle fibers controlled

Fine control muscles (i.e. eyelid muscles) have fewer Fine control muscles (i.e. eyelid muscles) have fewer

A contraction is initiated by an action potential (nerve A contraction is initiated by an action potential (nerve impulse) and followed by the release a chemical impulse) and followed by the release a chemical neurotransmitter at the neuromuscular junction (NMJ). neurotransmitter at the neuromuscular junction (NMJ).

Neurotransmitter for skeletal muscle is acetylcholine.Neurotransmitter for skeletal muscle is acetylcholine.

Neuromuscular controlNeuromuscular control

Each muscle fiber is innervated by a single Each muscle fiber is innervated by a single motor neuronmotor neuron

Contractions may be graded or full due to the Contractions may be graded or full due to the number of muscle fibers that respond to the number of muscle fibers that respond to the stimulus. The more fibers, the greater the stimulus. The more fibers, the greater the stimulus. The more fibers, the greater the stimulus. The more fibers, the greater the muscle contractionmuscle contraction

Synapse Synapse –– functional connection between a functional connection between a nerve fiber and its target cell.nerve fiber and its target cell.

Neuromuscular junctionNeuromuscular junctionmotor nerve and a muscle fiber.motor nerve and a muscle fiber.

Neuromuscular controlNeuromuscular control

Each muscle fiber is innervated by a single Each muscle fiber is innervated by a single

Contractions may be graded or full due to the Contractions may be graded or full due to the number of muscle fibers that respond to the number of muscle fibers that respond to the stimulus. The more fibers, the greater the stimulus. The more fibers, the greater the stimulus. The more fibers, the greater the stimulus. The more fibers, the greater the

functional connection between a functional connection between a nerve fiber and its target cell.nerve fiber and its target cell.

Neuromuscular junctionNeuromuscular junction –– synapse between a synapse between a motor nerve and a muscle fiber.motor nerve and a muscle fiber.

Every muscle contraction is preceded by a nerve impulse from Every muscle contraction is preceded by a nerve impulse from

the CNS.the CNS.

Motor nerve

Muscle fibersinnervated by innervated by single motorneuron

Neuromuscularjunctions

Every muscle contraction is preceded by a nerve impulse from Every muscle contraction is preceded by a nerve impulse from

Cardiac muscleCardiac muscle

Characterized by:Characterized by:

-- crosscross--

-- intercalated discsintercalated discs

-- uniuni--nucleate cellsnucleate cells-- uniuni--nucleate cellsnucleate cells

-- automaticityautomaticity

Composed of the same contractile proteins as Composed of the same contractile proteins as skeletal muscle.skeletal muscle.

Cardiac muscleCardiac muscle

Characterized by:Characterized by:

--striationsstriations

intercalated discsintercalated discs

nucleate cellsnucleate cellsnucleate cellsnucleate cells

automaticityautomaticity

Composed of the same contractile proteins as Composed of the same contractile proteins as skeletal muscle.skeletal muscle.

Cardiac Muscle CellsCardiac Muscle Cells

are called “are called “cardiocytescardiocytesheart wallsheart walls

branching cells connect at branching cells connect at disks disks which allow contractions to occur which allow contractions to occur fasterfaster

are regulated by pacemaker cells which are regulated by pacemaker cells which control contraction of the heart musclescontrol contraction of the heart muscles

striated, involuntary,striated, involuntary,

Cardiac Muscle CellsCardiac Muscle Cells

cardiocytescardiocytes” ” and found in and found in

branching cells connect at branching cells connect at intercalated intercalated which allow contractions to occur which allow contractions to occur

are regulated by pacemaker cells which are regulated by pacemaker cells which control contraction of the heart musclescontrol contraction of the heart muscles

striated, involuntary,striated, involuntary, and single nucleusand single nucleus

Cardiac muscleCardiac muscle

Characterized by:Characterized by:

-- crosscross--

-- intercalated discsintercalated discs

-- uniuni--nucleate cellsnucleate cells-- uniuni--nucleate cellsnucleate cells

-- automaticityautomaticity

Composed of the same contractile proteins as Composed of the same contractile proteins as skeletal muscle.skeletal muscle.

Cardiac muscleCardiac muscle

Characterized by:Characterized by:

--striationsstriations

intercalated discsintercalated discs

nucleate cellsnucleate cellsnucleate cellsnucleate cells

automaticityautomaticity

Composed of the same contractile proteins as Composed of the same contractile proteins as skeletal muscle.skeletal muscle.

Cardiac Muscle TissueCardiac Muscle TissueCardiac Muscle TissueCardiac Muscle Tissue

Smooth muscleSmooth muscle

Characterized by:Characterized by:

Spindle shaped cellsSpindle shaped cells

UniUni--nucleate cellsnucleate cells

Involuntary controlInvoluntary control Involuntary controlInvoluntary control

Found in walls of hollow organs, blood Found in walls of hollow organs, blood vessels and glandsvessels and glands

Smooth muscleSmooth muscle

Characterized by:Characterized by:

Spindle shaped cellsSpindle shaped cells

nucleate cellsnucleate cells

Involuntary controlInvoluntary controlInvoluntary controlInvoluntary control

Found in walls of hollow organs, blood Found in walls of hollow organs, blood vessels and glandsvessels and glands

Smooth Muscle CellsSmooth Muscle Cells are small and pointed at their endsare small and pointed at their ends

can divide and regenerate new cellscan divide and regenerate new cells

nonnon--striated, involuntary,striated, involuntary,

found in hollow organs like the intestine, found in hollow organs like the intestine, bladder, lungs, and blood vesselsbladder, lungs, and blood vesselsbladder, lungs, and blood vesselsbladder, lungs, and blood vessels

move substances through hollow opening move substances through hollow opening by contracting slowly; they squeeze things by contracting slowly; they squeeze things through like a tube of toothpastethrough like a tube of toothpaste

Smooth Muscle CellsSmooth Muscle Cellsare small and pointed at their endsare small and pointed at their ends

can divide and regenerate new cellscan divide and regenerate new cells

striated, involuntary,striated, involuntary, and single nucleusand single nucleus

found in hollow organs like the intestine, found in hollow organs like the intestine, bladder, lungs, and blood vesselsbladder, lungs, and blood vesselsbladder, lungs, and blood vesselsbladder, lungs, and blood vessels

move substances through hollow opening move substances through hollow opening by contracting slowly; they squeeze things by contracting slowly; they squeeze things through like a tube of toothpastethrough like a tube of toothpaste

Smooth Muscle TissueSmooth Muscle TissueSmooth Muscle TissueSmooth Muscle Tissue