MUSCULAR SYSTEM

Stephen Springer Nolan Wool

FunctionsMovement

Posture

Fluid Propulsion

Generate Heart Beat

Structure of Skeletal Muscle

Skeletal Muscle Tissue

Nervous Tissue

Blood Connective Tissue

Structure of a Muscle Fiber Cylindrical Sarcolemma

covering Sarcoplasm

cytoplasm Myofibrils Myosin Actin

Relationship:Neuromuscular Junction

Stimulus travels from: Brain Neuron Neuron Motor

Muscle Axon End Plate

Myosin and Actin

Thick Heads/Cross

bridges

Thin Binding Sites

Myosin Actin

Sliding Filament Theory

1. Heads of myosin attach to binding sites of actin

2. Myosin heads swivel3. ATP releases myosin heads4. Muscle relaxes

Muscle Contraction

Calcium binds to troponin Tropomyosin pulls aside Binding sites on actin

exposed

Calcium released from sarcoplasmic reticulum exposes the binding sites

Muscle Contraction (Cont.)

Myosin heads bind to actin Power stroke occurs (swivel of

heads) Muscle contraction occurs

Muscle Contraction (Cont.)

ATP binds to myosin Linkage is released

ATP splits into ADP and Phosphorous Causes the myosin head to cock back

Cycle continues* *If there are ATP & Calcium Ions

Energy and Oxygen

Energy: Glycolysis

anaerobic Cellular Respiration aerobic

ATP

Contraction

Fatigue

Glycolysis Fast-twitch muscle Oxygen Debt

Lactic acid build up +2 ATP

Cellular Respiration

Slow-twitch muscle Includes the process of

Glycolysis +34 ATP

Definition: When a muscle is exercised strenuously for a prolonged period and loses its ability to contract.

Cause: Low pH Accumulation of Lactic Acid

Cramping

Definition: A painful condition in which a muscle undergoes a sustained involuntary contraction

Causes: Lack of ATP Changes in extracellular fluid Uncontrolled stimulation

Superficial MusclesZygomaticus

Sternocleidomastoid

Rectus AbdominusExternal Oblique

Frontalis

Trapezius

Deltiod

Pectoralis Major

Biceps Bracii

Gracilis

Adductor Longus

Sartorius

Rectus Femoris

Vastus Lateralis

Gastrocnemius

Soleus

Fibularis Longus

Extensor Digitorum Longus

Tibialis Anterior

Expeliarmis*Harry Potter

Posterior Superficial Muscles

OccipitalisSternocleidomast

oidTrapezius

Infraspinatud

Deltoid

Teres MajorRhomboideus

Latissimus Dorsi

Gluteus Medius

Gluteus Maximus

Adductor Magnus

Semitendinosus

Semimembranosus

Biceps Femorous

Calcaneal Tendon

Fibularis Longus

Gostrocnemius

Soleus

Gluteus Maximus

Nobody Cares

Triceps Bracii

Brachialis

Origin & Insertion

Origin:The immovable end of a muscle

Insertion:The moveable end of a muscle

Prime Movers, Synergists, & Antagonists

Antagonists: Resist prime

mover

Prime Mover (agonist): Mainly responsible for

movement

Synergists: Helper muscles

Recruitment and Muscle Tone

Muscle Tone: Nerve impulses

continuously sent from spinal cord

Recruitment: Increases number

of active muscle fibers Summation or Tetanic

Increase of weight

Summation and Sustained Contraction

Summation: Combined individual

twitches Eventual relaxation

Sustained Contraction (tetanic): Combined individual

twitches Doesn’t relax Rigor mortis

DiseasesMyotonic Dystrophy—An Expanding Gene: Stronger and more threatening with each

generation RNA too large to leave nucleas, gets copied,

passed to next generation continuously Weakness of limbs

Hereditary Idiopathic Dilated Cardiomyopathy: Actin not anchored to

z-line properly Causes the heart

chambers to enlarge and eventually fail