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
- 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
- Endplate Potential
- ACh is released from a motor neuron which binds to the receptor
- Depolarization
- Generation of action potential(AP)
- 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
Tricep Brachii
FOUR major functions
- Produce movement ( Responsible for all locomotion and manipulation
- Maintain posture and body position
- Stabilize Joints
- Generate heat as they contract
- AP arrives at the axon terminal
- Voltage channels open, calcium enters the motor neuron
- Release of ACh neurotransmitter into the synaptic cleft
- ACh diffuses across to ACh receptors (on sarcolemma)
- ACh binding receptors, open gates, allowing NA+ enter resulting in endplate potential
- 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
- Smooth
- Propels substances along internal passageways; mostly in the walls of hollow organs
- 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
Rigor Mortis
- After death (3-4 hours)
- Calcium levels increase since ATP is no longer synthesized
- ATP needed for CROSS BRIDGE DETACHMENT