human muscular system svhs adv, biology biology unit #6 2011-12

Human Human Muscular Muscular SystemSystem

SVHS Adv, Biology BiologySVHS Adv, Biology Biology

Unit #6Unit #6

2011-122011-12

Normal Normal or or

Not???Not???

Muscular Muscular SystemSystem

• Study of Study of muscle is muscle is known as known as myologymyology..

• 40-50% of 40-50% of body weight body weight is muscle.is muscle.

Tortora pages Tortora pages 154154

Muscle Muscle Tissue Tissue TypesTypes

• SmoothSmooth– Involved in Involved in internal internal processes.processes.

– Makes up Makes up the walls the walls of hollow of hollow internal internal structures.structures.

– InvoluntaryInvoluntary


• CardiacCardiac– Forms wall Forms wall of the of the heart and heart and major major vessels vessels leading leading from the from the heartheart



• SkeletalSkeletal– Attached Attached to to skeleton.skeleton.

– ResponsiblResponsible for e for skeletal skeletal movement.movement.



Functions of Functions of Muscle Muscle TissueTissue

• Producing body Producing body movementmovement

• Movement of Movement of substances in body.substances in body.

• Stabilizing body Stabilizing body position.position.

• Regulating organ Regulating organ volume.volume.

• Heat production.Heat production.


Striated Muscle Striated Muscle Connective Connective Tissue.Tissue.

• Connective Connective tissuestissues– Superficial faciaSuperficial facia

• Contains fat and is Contains fat and is just below the just below the skin.skin.

– Deep faciaDeep facia• Connective tissueConnective tissue• Holds muscles Holds muscles together.together.

• Separates muscle Separates muscle bundlesbundles

• Extends to form Extends to form tendonstendons

Tortora pages Tortora pages 154-155154-155


• The entire The entire muscle is muscle is wrapped in the wrapped in the epimysiumepimysium



• Muscle bundles fasicles are surrounded by facia called perimysium



• Each muscle Each muscle fiber (cell) is fiber (cell) is covered by covered by facia called facia called endomysium.endomysium.


Striated Striated MuscleMuscle

• Blood supplyBlood supply– Muscle Muscle contraction contraction requires large requires large amounts of amounts of energy and so energy and so requires large requires large amounts of amounts of nutrients and nutrients and oxygen.oxygen.


Striated Muscle Striated Muscle Nervous TissueNervous Tissue

Nerve tissueNerve tissue• Motor neuronMotor neuron

– Motor unitsMotor units

• Muscle must Muscle must receive a receive a stimulus in stimulus in order to order to contract.contract.

• Role of muscle Role of muscle action action potential.potential.


Homework Quiz - Activity AHomework Quiz - Activity A

1- T or F1- T or F Smooth muscle is voluntary and Smooth muscle is voluntary and found in the found in the walls of blood walls of blood vessels.vessels.

2- T or F2- T or F Cardiac muscle is not under Cardiac muscle is not under conscious control.conscious control.

3- T or F3- T or F Striated muscle is voluntary and Striated muscle is voluntary and is also called is also called

skeletal muscle.skeletal muscle.4- Which of the following is not a function of 4- Which of the following is not a function of

the muscular system?the muscular system?– A) Creating motionA) Creating motion– B) Moving substances in the in the body.B) Moving substances in the in the body.– C) Creating body heat.C) Creating body heat.– D) Sustaining the body’s posture.D) Sustaining the body’s posture.– E) Producing hormones for growth.E) Producing hormones for growth.

5- Which of the following is not a 5- Which of the following is not a characteristic of muscle tissue?characteristic of muscle tissue?

A) Ability to return to it’s original A) Ability to return to it’s original shape.shape.

B) Ability to respond to a stimuli.B) Ability to respond to a stimuli.

C) Ability to push bones to create C) Ability to push bones to create movement.movement.

D) Ability to shorten.D) Ability to shorten.

E) Ability to stretch.E) Ability to stretch.

6-6- The ability of muscle to stretch is The ability of muscle to stretch is referred to as ?referred to as ?

7-7- Muscle making up the wall of the heart is Muscle making up the wall of the heart is known as ?known as ?

8- 8- Muscle making up the walls of the Muscle making up the walls of the intestine is known as ?intestine is known as ?

AnswersAnswers

1) True1) True

2) True2) True

3) True3) True

4) E (producing hormones for growth)4) E (producing hormones for growth)

5) C (ability to push bones)5) C (ability to push bones)

6) Extensibility (ability to stretch)6) Extensibility (ability to stretch)

7) Cardiac (makes up wall of heart)7) Cardiac (makes up wall of heart)

8) Smooth (makes up wall of intestines)8) Smooth (makes up wall of intestines)

Muscles + Bones Muscles + Bones = Lever Systems= Lever Systems

• Class I leverClass I lever– fulcrum between fulcrum between resistance and resistance and energy.energy.

• Class II leverClass II lever– Resistance Resistance between energy between energy and fulcrum.and fulcrum.

• Class III leverClass III lever• Energy is between Energy is between fulcrum and fulcrum and resistance.resistance.

Skeletal Muscle Skeletal Muscle StructureStructure

Each Each muscle muscle fiber or fiber or cell is cell is composed composed of of subunits subunits called called myofibrilmyofibrilss


Striated Muscle Structure

• Structure of Structure of striated muscle striated muscle cell.cell.

– Sarcolemma– Sarcoplasm– Sarcoplasmic reticulum

– Transverse tubules

Tortora pages 156-Tortora pages 156-157157

Striated Muscle Striated Muscle StructureStructure

• Proteins of Proteins of muscle are called muscle are called myofilaments.myofilaments.

– Thin protein Thin protein filament is filament is composed of:composed of:• ActinActin• Tropomyosin.Tropomyosin.

– Thick protein Thick protein myofilament is myofilament is myosin.myosin.• Myosin has Myosin has cross bridges.cross bridges.


Striated Striated Muscle Muscle

StructureStructure• ActinActin

– Contains myosin Contains myosin binding site.binding site.

– Site is covered by Site is covered by tropomyosin.tropomyosin.

• MyosinMyosin– Contains actin Contains actin binding site.binding site.

– Contains a binding Contains a binding site for ATP.site for ATP.


Striated Muscle Striated Muscle StructureStructure

• Sarcomeres are Sarcomeres are contracting contracting units in muscle.units in muscle.

• Each fiber has Each fiber has many myofibrils.many myofibrils.

• Each myofibril Each myofibril is composed of is composed of many sarcomeres.many sarcomeres.– Z linesZ lines– A bandA band– I bandI band– H zoneH zone


C & D Quiz1. Which lever type is a distance

multiplier?2. Which lever type has the force exerting

between the fulcrum and the load?3. A muscle that decreases the angle of a

joint.4. A muscle that moves a bone away from the

midline of the body.5. A muscle that decreases the size of an

opening.6. A muscle that produces a downward

movement.7. A muscle that turns the palm downward or

posteriorly.

Striated Striated Muscle Muscle

StructureStructure• Motor unitsMotor units

– Motor neuronMotor neuron– Muscle cellMuscle cell– 10-500 10-500 fibers per fibers per motor motor neuron.neuron.

•Neuromuscular Neuromuscular junctions junctions

–Motor end Motor end plate.plate.–Synaptic Synaptic cleft.cleft.–SarcolemmaSarcolemma

Neuromuscular Junctions

• Starting a Starting a muscle muscle contraction.contraction.1)1) Nerve impulse Nerve impulse

reaches axon reaches axon terminal.terminal.

2)2) Ca++ enters the Ca++ enters the synaptic end synaptic end bulb.bulb.

3)3) Vesicles move to Vesicles move to and fuse with and fuse with membrane.membrane.

4)4) Vesicle releases Vesicle releases ACH into the ACH into the synaptic cleft.synaptic cleft.

Neuromuscular Neuromuscular JunctionsJunctions

• 5) ACH diffuses 5) ACH diffuses across cleft and across cleft and binds to ACH binds to ACH receptors in receptors in sarcolemma.sarcolemma.

• 6) Muscle action 6) Muscle action potential is potential is created.created.

• 7) Within 1/500 7) Within 1/500 of a second ACHe of a second ACHe inactivates ACH.inactivates ACH.

• 8) Muscle 8) Muscle prepares for next prepares for next muscle action muscle action potential.potential.

Physiology of Physiology of ContractionContraction

• Muscle action Muscle action potential potential spreads across spreads across sarcolemma.sarcolemma.– Reaches into Reaches into the transverse the transverse tubules.tubules.

– Spreads to the Spreads to the sarcoplasmic sarcoplasmic reticulum.reticulum.

– Sarcoplasmic Sarcoplasmic reticulum reticulum releases Ca++releases Ca++

Physiology of Physiology of ContractionContraction

• Calcium binds Calcium binds to tropomyosin, to tropomyosin, changing its changing its shape.shape.

• Myosin and Myosin and actin bind.actin bind.

• ATP is broken ATP is broken down to ADP .down to ADP .

• Powerstroke Powerstroke occurs.occurs.

Striated Striated Muscle & Muscle & RelaxationRelaxation

• Two changes cause Two changes cause relaxation.relaxation.– ACh broken down by ACh broken down by Ache.Ache.

– Results in no Results in no muscle action muscle action potential.potential.

– Ca++ is rapidly Ca++ is rapidly removed from the removed from the sarcoplasm.sarcoplasm.

– Results in Results in tropomyosin tropomyosin covering the covering the myosin binding myosin binding sites on the sites on the actin.actin.

Striated Striated Muscle & and Muscle & and

EnergyEnergy

Tortora Tortora

Pages 160, 162-Pages 160, 162-163163

• ATP is needed as ATP is needed as energy source for energy source for muscle muscle contraction.contraction.

• ATP attaches to ATP attaches to ATP binding site ATP binding site on myosin head.on myosin head.

• ATP is broken ATP is broken down to ADP + P.down to ADP + P.

• Myosin cross Myosin cross bridge is bridge is energized.energized.

Striated Striated Muscle & and Muscle & and

EnergyEnergy

Tortora Tortora

Pages 160, 162-Pages 160, 162-163163

• Ca++ removes Ca++ removes tropomyosin.tropomyosin.

• Actin & myosin engage.Actin & myosin engage.• Cross bridge changes Cross bridge changes

shape. (Powerstroke)shape. (Powerstroke)• ADP is released.ADP is released.• ATP again attaches to ATP again attaches to

binding site causing binding site causing actin & myosin to actin & myosin to disengage.disengage.

• ATP is broken down ATP is broken down causing myosin head to causing myosin head to return to normal return to normal position.position.

• Powerstroke repeated.Powerstroke repeated.

Energy for Muscle

Contraction• Contraction is powered initially by ATP stored in the muscle.

•5 second supply.

•40 yards into 400 meter race.

Tortora Tortora

Pages 160, 162-Pages 160, 162-163163

Energy for Muscle

Contraction

• Creatine Phosphate– Energy is released from CP.

– Used to make more ATP from ADP and Pi.

– Supplies 15 seconds worth of energy.

– 22 seconds or 220 yards into race.

Tortora Tortora

Pages 160, 162-Pages 160, 162-163163

Energy for Muscle

Contraction• GlycolysisGlycolysis

– Glucose is broken down to Glucose is broken down to pyruvic acid.pyruvic acid.

– Occurs in sarcoplasm.Occurs in sarcoplasm.– Anaerobic (does not require Anaerobic (does not require oxygen)oxygen)

– Results in lactic acid if no Results in lactic acid if no oxygen available.oxygen available.

– Lactic acid causes fatigue Lactic acid causes fatigue feeling.feeling.

– Provides 30 seconds worth of Provides 30 seconds worth of muscle contraction.muscle contraction.

– You are now 300 yards into You are now 300 yards into race.race.

Tortora Tortora

Pages 160, 162-Pages 160, 162-163163

Energy for Energy for Muscle Muscle

ContractionContraction• Aerobic respiration.

– Occurs in mitochondria.– Breaks down pyruvic acid.

– Requires oxygen.

– Results in H2O and CO2 as wastes.

– Makes 36 ATP molecules.– Now you can run a marathon!!

Tortora Tortora

Pages 160, 162-Pages 160, 162-163163

Energy for Muscle Contraction

• Greg LeMond’s Greg LeMond’s career ended career ended due to a due to a mitochondrial mitochondrial condition.condition.

• What is he What is he doing today?doing today?

Tortora Tortora

Pages 160, 162-Pages 160, 162-163163

Still Still Racing!!Racing!!

Tortora Tortora

Pages 160, 162-Pages 160, 162-163163

Oxygen DebtOxygen Debt

• Occurs when Occurs when oxygen does not oxygen does not get to muscles.get to muscles.

• Glycolysis Glycolysis results in L.A.results in L.A.

• Must acquire Must acquire oxygen to pay oxygen to pay back debt.back debt.

• Heavy breathing Heavy breathing after exercise!after exercise!

TortoraTortora

Pages 160, 162-163Pages 160, 162-163

All-or-All-or-None None

PrinciplePrinciple• Any given motor unit Any given motor unit

will be fully will be fully contracted or not at contracted or not at all.all.

• Threshold stimulus Threshold stimulus causes contraction.causes contraction.

• Subthreshold will not Subthreshold will not create a contraction.create a contraction.

• Some motor units are Some motor units are contracted while contracted while others are not.others are not.

TortoraTortoraPage 163-Page 163-

164164

HomeostasisHomeostasis

• Oxygen DebtOxygen Debt– Due to lactic Due to lactic acid.acid.

– Paid back with Paid back with oxygen.oxygen.

• Muscle FatigueMuscle Fatigue– Due to L.A.Due to L.A.– Decrease in pH.Decrease in pH.

• Heat productionHeat production– 85% of energy is 85% of energy is released in form released in form of heat.of heat.

TortoraTortoraPage 164Page 164

Types of Types of ContractionContraction

• Different types Different types of contractions of contractions depending on how depending on how often stimulation often stimulation occurs.occurs.

• A muscle twitch A muscle twitch is a brief is a brief contraction of contraction of all muscle fibers all muscle fibers in a motor unit in a motor unit due to a single due to a single nerve impulse.nerve impulse.



• Phases of a Phases of a muscle twitchmuscle twitch– Latent phaseLatent phase

•Action Action potential potential spreads spreads across across sarcolemmasarcolemma

•Ca++ Ca++ released.released.



• Contraction Contraction phasephase– Power Power stroke.stroke.

– Actin and Actin and myosin myosin slide slide over one over one another.another.

– Muscle Muscle becomes becomes shorter.shorter.



• Relaxation Relaxation phasephase– Actin & Myosin Actin & Myosin disengage.disengage.

– Ca++ is Ca++ is actively actively pumped back pumped back into the into the sarcoplasmic sarcoplasmic reticulum.reticulum.



• Refactory Refactory phasephase

• Sarcolemma Sarcolemma not not responsive responsive to a to a stimulusstimulus



• Wave SummationWave Summation– Successive Successive stimuli prior stimuli prior to completion to completion of relaxation of relaxation phase.phase.

– Each Each contraction is contraction is stronger than stronger than the previousthe previous


Types of Types of ContractionContraction• Incomplete Incomplete TetanusTetanus– 20 to 30 stimuli 20 to 30 stimuli per second.per second.

– Partial Partial relaxationrelaxation

• Complete TetanusComplete Tetanus– 80-100 stimuli 80-100 stimuli per secondper seconds.

– No relaxation.No relaxation.



• IsotonicIsotonic– Contraction Contraction and movementand movement

• IsometricIsometric– Contraction Contraction without without movementmovement


Skeletal Muscle Tissue

Characteristics

• Muscle tone.Muscle tone.• A muscle in A muscle in partial partial contraction.contraction.

• A few fibers A few fibers are contracting are contracting at all times. at all times. (recruitment)(recruitment)

Skeletal Muscle Tissue

Characteristics

• Muscular Atrophy– Don’t use it and you lose it!

• Muscular Hypertrophy

• Muscle getting bigger due to work?

Thursday 12/4Thursday 12/4Page 163-164Page 163-164

Cardiac Muscle Tissue Cardiac Muscle Tissue CharacteristicsCharacteristics

Smooth Muscle Tissue Characteristics

How Skeletal Muscles Produce Movement

• Origin• Insertion

How Skeletal Muscles Produce Movement

• Group actions– Prime mover– Antago– Synergists– fixators

Naming Muscles

• Direction of Muscle fibers

Naming Muscles (cont)

• Location


• Number of origins


• Shape


• Origin and insertion


• Action


• Size

4 Characteristics of Muscle 4 Characteristics of Muscle TissueTissue

• Excitability:Excitability: – Ability of tissue to receive and Ability of tissue to receive and respond to stimuli.respond to stimuli.

• Contractility:Contractility:– Ability to shorten and thicken.Ability to shorten and thicken.

• ExtensibilityExtensibility– Ability of muscle tissue to stretch.Ability of muscle tissue to stretch.

• ElasticityElasticity– Ability of muscle tissue to return Ability of muscle tissue to return to its original shape after to its original shape after contraction or extension.contraction or extension.


human muscular system svhs adv, biology biology unit #6 2011-12

Documents

ability of muscle

entire muscle

fcardiac muscle

fsmooth muscle

fstriated muscle

muscle fiber cell

muscular systemstudy

muscle bundles fasicles