Muscular System
Maria Chuc Garcia
P.1

Major Functions of
Muscular System

Disorders

3 Types of Muscles
& Functions

Sarcomere

All Skeletal Muscles
& Facial Muscles

Neuromuscular junction

Sliding Filaments Theory
of Muscle Contraction

Muscle Coverings

Action Potential in Muscle Fibers

  1. Cardiac
  • Propels blood into circulation, involuntary control, and at the walls of the heart
  • Epimysium; Dense irregular C.T surrounding ENTIRE muscle
  • Perimysium; Fibrous C.T surrounding fascicles
  • Endomysium; fine areolar C.T surrounding each muscle fiber

Resting sarcolemma is polarized

  • Action potential caused by changes in electrical changes
  1. Endplate Potential
  • ACh is released from a motor neuron which binds to the receptor
  1. Depolarization
  • Generation of action potential(AP)
  1. Repolarization
  • Restoration of resting conditions

Smallest unit of muscle fiber

  • Contains A band ( dark region)
  • I bands( Lighter regions)
    -Z line of proteins on midline of light I band
  • Arrangement of actin and myosin myofilaments within
    image

Tricep Brachii

FOUR major functions

  1. Produce movement ( Responsible for all locomotion and manipulation
  2. Maintain posture and body position
  3. Stabilize Joints
  4. Generate heat as they contract
  1. AP arrives at the axon terminal
  2. Voltage channels open, calcium enters the motor neuron
  3. Release of ACh neurotransmitter into the synaptic cleft
  4. ACh diffuses across to ACh receptors (on sarcolemma)
  5. ACh binding receptors, open gates, allowing NA+ enter resulting in endplate potential
  6. ACETYLCHOLINESTERASE( enzyme) degrades ACh

Duchenne Muscular Dystrophy(DMD)

  • Form of muscular dystrophies, destroys muscle, appears at young age
  • Inherited, caused by defective gene for dystrophin, sacrolemma tears easily
  1. Smooth
  • Propels substances along internal passageways; mostly in the walls of hollow organs
  1. Skeletal
  • Attached to bones which allows movement
  • Manipulation of environment

Extensor carpi Rad

Deltoid

Exensor Aigtourum

Sternoclepidomastoid

Trapezius

Fibularis Longus

Infraspinatus

Semimembranosus

Teres Major

Semitendinosus

Rhomlbold Major

Gluteus Maximus

Biceps Brachii

Brachionardialis

Latissimus Dorsi

Bicep Femoris

Calcaneal(Achilles) tendon

Gastrocnemius

Soleus

External Oblique

Rectus Abdominis

Iliopsoas

Pectoralis Major

Deltoid

Flexor Carpi Radialis

Palmaris Longus

Satorius

Adauctor

Vastus

Tibrialis Anterior

Rectus Temoris

Gracilils

Vostus Mediallis

Etensor Digitorum Logus

Oribicularis Oculi ( Closes eyes; blinking/winking

Masseter ( Mover of jaw closure/elevates mandible)

Platysma ( Tenses skin of neck)

Frontalis ( Raises eyebrows)

Orbicularis Oris ( Closes lip/purses; kissing & whistling)

Zygomaticus ( SMILING MUSCLE)

Temporalis ( Closes jaw; ret position of mandible

In sarcomere, are units of muscles fibers that have a molecular mechanism contraction( muscle).

  • there is a process in which energy is exchanged and the creation of a contraction

-.ATP is split due to Myosin head

  • The heads link (think and thin filaments) forming CROSS BRIDGE
  • POWERSTROKE
    -Myosin head bind ATP, cross bring detached

1-Diagram-of-the-neuromuscular-junction-Top-A-nerve-action-potential-AP-arrives-at

sliding-filimang-theory

0199210896.action-potential.1

Rigor Mortis

  • After death (3-4 hours)
  • Calcium levels increase since ATP is no longer synthesized
  • ATP needed for CROSS BRIDGE DETACHMENT