msd for pspd 2015
TRANSCRIPT
MUSCLE CONTRACTIONTRIGGER OF MOVEMENT
I Putu Gede ADIATMIKADept. of Physiology Faculty of Medicine – Udayana University
TEXT BOOK
TEXTBOOK OF MEDICAL PHYSIOLOGY
A.C. GUYTON
Musculoskeletal disorders
ATROPHYHIPERTROPHYCRAMPSEIZUREPARALIZEETC
HUMANMOVEMENT ?
What is the contribution of
Bone and joint
muscles
nerves
Human Movement ?
All of the systems must be in good condition
Stimulated by a stimulus from external or internal environment
Transferred as action potential by the nerves
Action potential is forwarded to the muscles through neuromuscular junction
Action potential within the muscles excite muscle contraction
Human movementRESPONSE TO ENVIRONMENT CHANGES
MOVEMEN
TSOMATIC
AUTONOMI
C
REFLEX
SYSTEM
NERVES
NEUROMUSCU
LAR JUNCTI
ON
MUSCLES
Action potential pathway
1. Central nerve system (CNS)
2. Peripheral nerve system (PNS)
Axon – skeletal muscles Somatic motor
neurons axon Neuromuscular
junction Muscle :
Skeletal muscles
Smooth muscles
Cardiac muscles
axon
Somatic neuron
neuromuscular junction
muscles
MEMBRANE POTENTIAL AND ACTION POTENTIAL
Cases If someone get an order to lift the upper
limb, what happen in the neuromuscular ?
Your hand touch the hot iron, what happen to your hand ? Why did happen ?
Neuron
Functional unit of nerves Surrounded by extracellular fluid Neuron has intracellular fluid
Membrane cell separated extra and intra cellular fluid membrane is permeable for ion Extra and intra cellular ion can pass the
membrane through the specific way
Neuron
Important ion for membrane potential : Sodium (Na) Potassium (K) Chloride (Cl)
Cause : a different electric potential between extra and intra cellular
Distribution of ION
IonIntra
cellular
Extra cellula
rResting condition
SodiumPotassiu
mChloride
121553,8
1454
120
- Permeability of K+ > Na+
- Resting membrane potential (-85 mV)
Bioelectric of extra and intra cellular Extra cellular : positive ( +++++++++++ ) Intra cellular : negative ( ----------------- )
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Ion movement
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Ion channel
Action Potential Cycle
duration : 2 – 4 msec. Action potential cycle consist of :
Depolarization Repolarization Hyperpolarization Refracter period: no response to stimulus
▪ Absolute refracter no action potential anymore▪ Relative refracter action potential occurred by
more adequate stimulus
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Action potential
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All or Nothing Principle
Action potential will occur if got optimum stimulation and will not occur if the stimulation is not enough MEMBRANE THRESHOLD
Action potential depend on : Stimulation intensity Point of membrane threshold Ion concentration
Which one is the action potential occurred ? WHY ?
Action potential conduction
Conduction on axon
Depend on type of axon : With myelin sheath Without myelin sheath
Axon surrounded by myelin sheath : Thicker than axon insulator Have node of Ranvier Wrapped by Schwann cells multiple
layer spingomyelin
Myelin sheath
- Increasing action potential conduction
- Conduction was done by jump at node of Ranvier (saltatory conduction)
Action potential conduction on axon
Without myelin sheath : Spread Slow
With myelin sheath : Jump within node of Ranvier saltatory
conduction Faster ( 50 x )
Benefits of saltatory conduction : Faster Save energy save space Suitable for high frequency impulse
SKELETAL MUSCLES CONTRACTION
Cases If someone get an order to lift the upper
limb, what process it occur within skeletal muscles ?
Two student sit on a different chair and in the some posture. On the next 30 minutes, one of them will change their posture cause of pain. Explain what did cause it ?
Cases
After run for marathon race, one runner felt down and scream that his leg cramped. Explain, why did happen ?
Muscle contraction
Initiated by action potential from terminal axon
MUSCLE TWITCH consist of : Contraction Relaxation
MUSCLE TWITCH
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Skeletal Muscle
SarcolemmaSarcoplasmic
Reticulum▪ T-tubule▪ Terminal
cisternaeMyofilament▪ Actin▪ Myosin
Mitochondria
Components of muscle contraction
Actin Myosin Calcium Ion Troponin Tropomiosin ATP
Muscle contraction process
Calcium released from
cisternae
Calcium attach to TROPONIN
TROPOMYOSIN detach
from ACTINMyosin attach
to Actins
POWER STROKE of
MYOSIN
SLIDING MECHANISM (Contraction)
Calcium pumped back to Cisternae
Myosin actins detached
Actin back to initial position (Relaxation)
The role of Troponin Tropomyosin Complex
To regulate contraction and relaxation regularly
In turn with myosin when attach to actins
TYPE OF MUSCLES CONTRACTION
Based on endurance : Rapid muscles CEPAT (FAST TWITCH) Slow muscle (SLOW TWITCH)
Based on change of length : Isometric Isotonic
Muscle endurance
Muscle type affect to its endurance Red muscles – SLOW TWITCH
Slow contraction Long time Longer endurance Important for body posture
White muscles – FAST TWITCH Rapid contraction Short time Easy to fatigue – shorter endurance Important for trained movement
TYPE of MUSCLE CONTRACTION
Isotonic muscle shortening, muscle tone constant Ex : lifting
Isometric muscle length constant, muscle tone increased Ex : push the wall
Muscle change
ATROPHY : no action potential from the nerve Break of axon No activity of muscle : DISUSE ATROPHY
HYPERTROPHY : regular activity with maximal load (in sport) : Muscle cell getting bigger more ACTIN and
MYOSIN Circulation increased oxygen and food supply
increased
Staircase phenomenon
Repetitive and faster stimulation can change the contraction relaxation type
Type of contraction relaxation : Treppe Summation Incomplete tetanus Complete tetanus
Cause : Muscle temperature increased warming up Cumulative of metabolism waste product
STAIRCASE PHENOMENON
Energy resources
Energy resources 1st : PHOSPHOCREATINE 2nd : GLYCOGEN 3rd : OXYDATIVE METABOLISM
Waste product of metabolism 1st and 2nd : LACTIC ACID 3rd :▪ Carbondioxyde▪ Water
ENERGY METABOLISMFood substances
Oxygen (+) Oxygen (-)
Carbonic acid
Lactic acid
CO2 and H2O
ATP
AEROBIC ANAEROBIC
EXCITATION CONTRACTION OF SKELETAL MUSCLES
Cases
After got fever, the child couldn’t move the lower limb. He suspect to suffer from poliomyelitis. Where did the source of damage ? Why ?
MOTOR UNIT
UNIT OF SKELETAL MUSCLES AND ITS NERVES Important for excitation contraction
process Number of motor unit is depend on the
load of each muscles Affect to muscle tones
Motor unit
NEUROMUSCULAR JUNCTION
Axon terminal Vesicle
acetylcholine Synaptic cleft
Acetylcholine esterase
Motor end plate ACh receptor
ACTION POTENTION IN SKELETAL MUSCLE
Similar to nerve process
Result : release of Ca++ into myofibrils
Effect : muscle contraction
MOTOR END PLATE
SARKOLEMA
T – TUBULE
TERMINAL CISTERNAE
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EXCITATION CONTRACTION
EXCITATION CONTRACTION OF SMOOTH MUSCLES
Action potential of smooth muscles
Easy to spread within muscles Cause : muscle interaction is very
thigh
Ion calcium movement into the cell is easier than sodium
Smoot muscle contraction process
Theory : Irregular actin myosin arrangement Extra cell and intracellular fibers contraction
Activator : Ca++ extra cell (caveola) and ATP Characteristic of contraction TONIC
CONTRACTION Longer and slower Dragging effect
STRONG CONTRACTION WITH MINIMAL ENERGY REQUIREMENT
SLIDING FILAMENT OF SMOTH MUSCLES
COMPARISON BETWEEN SKELETAL MUSCLES AND SMOOTH MUSCLES
1. Cross bridge cycle is slower2. Energy requirement to maintain
contraction is minimum3. Slower of initial contraction and
relaxation4. Strength of contraction is stronger5. Latch mechanism6. Stress-relaxation
Type of smooth muscles contraction
Cross sliding mechanism
Contraction cause change of cell to globular type
Drugs that affect to NEUROMUSCULAR JUNCTION
ACh-like action Drugs act as some as ACh Can’t be destroyed by ACh-esterase Cause local depolarization muscle spasm
Exp : Metacholine Carbachol Nicotine
Drug that affect to NEUROMUSCULAR JUNCTION
Inhibited ACh-esterase ACh can’t be separated
accumulation continued stimulation muscle spasm
Exp : Neostigmine Physostigmine Diisopropyl fluorophosphates
FATIGUE
Continued excitation can cause fatigue Classification :
Peripheral (Muscles) oxygen and energy decreased
Central (Nerve) impulse disturbation within CNS
Caused : activity Location :
Neuromuscular junction Nerve cell at cerebral cortex
Benefits : as body defense mechanism
FATIGUE
Prevention: Heavy workload short time Long time mild workload Avoid unnecessary movement Sufficient foodstuffs and oxygen
resources Sufficient rest Avoid to use drugs
THANK YOU