Applied Exercise Applied Exercise PhysiologyPhysiology

Section 5: Body Section 5: Body SystemsSystems

Topic 1: Muscular SystemTopic 1: Muscular System

Prepared byPrepared by

Mr. CernyMr. Cerny

Niagara Wheatfield Senior High SchoolNiagara Wheatfield Senior High School

Types of MuscleTypes of Muscle• CardiacCardiac

HeartHeart

• SmoothSmooth Organ liningOrgan lining

• SkeletalSkeletal MovementMovement 40% of total body mass40% of total body mass

Types of Muscle (con’t)Types of Muscle (con’t)

Cardiac

Smooth

Skeletal

Skeletal Skeletal Muscle Muscle • How many How many

different different muscles can muscles can there be? there be?

• ~660~660

Skeletal Muscle StructureSkeletal Muscle Structure• Cylindrical fibers bunched togetherCylindrical fibers bunched together

Cable wire c.s.

MacrostructureMacrostructure

• It is the number of muscle It is the number of muscle fibers packed into a given fibers packed into a given muscle cross-sectional area muscle cross-sectional area that determine overall that determine overall force-generating capacityforce-generating capacity

Skeletal muscle c.s. 40x

MicrostructureMicrostructureSarcomere:Sarcomere:• basic functional basic functional

unit of muscleunit of muscle• Striated (light Striated (light

& dark bands)& dark bands)• Contains Contains ACTINACTIN

& & MYOSIN MYOSIN filaments that filaments that are responsible are responsible for contractionfor contraction

ActinActin & & MyosinMyosin

Where did the CaWhere did the Ca++++ come come from?from?

• CaCa++++ is stored and released from the is stored and released from the sarcoplasmic reticulum (SR)sarcoplasmic reticulum (SR)

• SR is a network of tubules within the SR is a network of tubules within the muscle fibermuscle fiber

Sarcoplasmic ReticulumSarcoplasmic Reticulum

Excitation-Contraction Excitation-Contraction CouplingCoupling

1.1. Action potential travels along neuron by the temporary Action potential travels along neuron by the temporary changing of chargeschanging of charges

2.2. Nerve impulse causes the release of acetylcholine (ACh).Nerve impulse causes the release of acetylcholine (ACh).3.3. ACh travels across neuromuscular junction, binding to muscle ACh travels across neuromuscular junction, binding to muscle

cell membrane.cell membrane.4.4. ACh binding initiates an electrical impulse which travels across ACh binding initiates an electrical impulse which travels across

membrane and into T tubules.membrane and into T tubules.5.5. Impulse stimulates release of CaImpulse stimulates release of Ca+2+2 from SR. from SR.6.6. CaCa+2+2 binds with t-t complex of the actin filaments, shifting it's binds with t-t complex of the actin filaments, shifting it's

position, exposing myosin binding sites.position, exposing myosin binding sites.7.7. Myosin binds to actin; CaMyosin binds to actin; Ca+2+2 presence also causes enzymatic presence also causes enzymatic

actions of myosin to breakdown ATP into ADP + P + energy.actions of myosin to breakdown ATP into ADP + P + energy.8.8. Energy of ATP degradation causes shape change of myosin Energy of ATP degradation causes shape change of myosin

head, pulling actin molecule toward center of sacromere.head, pulling actin molecule toward center of sacromere.9.9. After sliding, a new ATP binds to myosin, breaking the myosin-After sliding, a new ATP binds to myosin, breaking the myosin-

actin bond, releasing the myosin head.actin bond, releasing the myosin head.10.10. If CaIf Ca+2+2 is still present, the process repeats itself until is still present, the process repeats itself until

sacromere has shortened completely.sacromere has shortened completely.11.11. If a nerve impulse ceases, the CaIf a nerve impulse ceases, the Ca+2+2 is reabsorbed by the SR is reabsorbed by the SR

and the muscle relaxes. and the muscle relaxes.

Muscle Fatigue Muscle Fatigue 11

What causes it?What causes it?• 1) Reduction in ATP1) Reduction in ATP

Under high stress, ATP utilization reduced Under high stress, ATP utilization reduced faster than ATP productionfaster than ATP production

• 2) Peripheral metabolic bi-products2) Peripheral metabolic bi-products Lactic acidLactic acid H (and other free radicals)H (and other free radicals)

Muscle FatigueMuscle Fatigue• 3) Dehydration3) Dehydration

Increases temp = decreases contractile Increases temp = decreases contractile propertiesproperties

• 4) Decrease nerve signals/action 4) Decrease nerve signals/action potentialspotentials

• 5) Reduction of Ca 5) Reduction of Ca ““leakage” 1leakage” 1 From decrease nerve connectionFrom decrease nerve connection

Muscle TypesMuscle Types

ForceForce SpeedSpeed # mit.# mit. Resistance Resistance to fatigueto fatigue

ActivityActivity # # capillariescapillaries

Oxidative / Oxidative / nonoxidativnonoxidativ

ee

Slow Slow twitchtwitch

(I)(I)SameSame

(slightly (slightly less)less)

SlowSlow ManyMany YesYes EndurancEndurancee

ManyMany OxidativeOxidative

Fast Fast twitchtwitch

(II)(II)SameSame

(slightly (slightly more)more)

FastFast FewFew NoNo Sprinting Sprinting /bursts/bursts

FewFew nonoxidativnonoxidativee

Muscle StrengthMuscle Strength““Bigger” muscles:Bigger” muscles:

Usually NOT increase in muscle cells (hyperplasia)Usually NOT increase in muscle cells (hyperplasia) Usually an increase in existing tissue size Usually an increase in existing tissue size

(hypertrophy)(hypertrophy)

Factors contributing:Factors contributing:• GeneticsGenetics• ExerciseExercise• NutritionNutrition• EndocrineEndocrine• EnvironmentalEnvironmental• Nervous Nervous

The Muscular The Muscular SystemSystem

11.0 Describe Animal Health Needs11.0 Describe Animal Health Needs

11.3 Describe the musculoskeletal system 11.3 Describe the musculoskeletal system

Function of the muscular Function of the muscular systemsystem

• Provides movement in Provides movement in conjunction with the conjunction with the skeletal systemskeletal system

• Important in life supportImportant in life support

• Used by humans and Used by humans and other animals for foodother animals for food

ClassificationsClassifications of Muscles of Muscles

• VoluntaryVoluntary: Movement of the muscle : Movement of the muscle is under the control of the animalis under the control of the animal

• InvoluntaryInvoluntary: Movement of the : Movement of the muscle is not controlled by the muscle is not controlled by the animalanimal

Types of MusclesTypes of Muscles• Smooth Smooth

MusclesMuscles: : Involuntary Involuntary muscles, muscles, found in the found in the walls of walls of internal internal organs and organs and the blood the blood vessels.vessels.

SmoothSmooth Muscles Muscles

• Are not under voluntary controlAre not under voluntary control

• Are spindle shaped and are not Are spindle shaped and are not striated. striated.

• Interlace to form Sheets of Interlace to form Sheets of smooth muscle tissue. smooth muscle tissue.

• Are found in many internal Are found in many internal organs: Stomach, Intestines, organs: Stomach, Intestines, Blood Vessel wallsBlood Vessel walls

Types of MusclesTypes of Muscles

• Cardiac Cardiac MusclesMuscles: : Muscles that Muscles that form a form a network to network to make up the make up the heart. Not heart. Not under active under active brain controllbrain controll

Cardiac MusclesCardiac Muscles

• Only found in the HeartOnly found in the Heart• Are StriatedAre Striated• Are NOT under Voluntary Are NOT under Voluntary

Control Control • Contract Without Direct Contract Without Direct

stimulation by the stimulation by the Nervous System Nervous System

Types of MusclesTypes of Muscles

• Skeletal MusclesSkeletal Muscles: : Have a striped Have a striped appearance, appearance, include voluntary include voluntary and involuntary, and involuntary, attached to and attached to and moves your moves your bones. This is a bones. This is a majority of the majority of the muscle tissue in muscle tissue in your body.your body.

Skeletal MusclesSkeletal Muscles

• Are made of Elongated Are made of Elongated Cells called Cells called MUSCLE MUSCLE FIBERSFIBERS

• Are grouped into dense Are grouped into dense bundles called bundles called FASCICLESFASCICLES

• Are LARGE and have MORE Are LARGE and have MORE than ONE NUCLEUS than ONE NUCLEUS

• Most are VoluntaryMost are Voluntary