NEUROMUSCULAR JUNCTION CONSISTS OF: 1. THE AXONAL TERMINAL OF A SOMATIC MOTOR NEURON. 2. SYNAPTIC CLEFT 3. THE MOTOR END PLATE.

NEUROMUSCULAR JUNCTION

NEUROMUSCULAR JUNCTION

NEUROMUSCULAR JUNCTION

NEUROMUSCULAR JUNCTION FOR MORE INFORMATION SEE MODULE NUMBER 2 OF THE MUSCULAR CD ROM.

SLIDING FILAMENT THEORY

SLIDING FILAMENT THEORY

SLIDING FILAMENT THEORY

SLIDING FILAMENT THEORY

SLIDING FILAMENT THEORY

SLIDING FILAMENT THEORY

SLIDING FILAMENT THEORY FOR MORE INFORMATION SEE MODULE NUMBER 3 OF THE MUSCULAR CD ROM.

MOTOR UNIT A MOTOR UNIT IS A SOMATIC MOTOR NEURON AND ALL OF THE MUSCULE CELLS IT INNERVATES. THE NUMBER OF MUSCLE FIBERS PER MOTOR UNIT MAY BE AS HIGH AS SEVERAL HUNDRED OR A FEW AS FOUR.

MOTOR UNIT AS A RESULT, STIMULATION OF A SINGLE MOTOR UNIT CAUSES A WEAK CONTRACTION OF THE ENTIRE MUSCLE, OR A NUMBER OF MOTOR UNITS MAY CAUSE A STRONG CONTRACTION OF THE ENTIRE MUSCLE.

MUSCLE TWITCH THE RESPONSE, A CONTRACTION FOLLOWED BY RELAXATION, OF A MUSCLE TO A SINGLE BRIEF THRESHOLD STIMULUS.

THERE ARE THREE PHASES: MUSCLE CONTRACTION THERE ARE THREE PHASES: 1. LATENT PERIOD 2. PERIOD OF CONTRACTION 3. PERIOD OF RELAXATION

LATENT PERIOD THE PERIOD TIME, USUALLY A FEW MILLISECONDS, AFTER THE DECISION TO CONTRACT A SKELETAL MUSCLE AS BEEN MADE AND THE ACTUAL SHORTING OF THE MUSCLE HAS OCCURRED.

PERIOD OF CONTRACTION THE PERIOD OF CONTRACTION IS WHEN CROSS BRIDGES ARE ACTIVE, FROM THE ONSET TO THE PEAK OF TENSION DEVELOPMENT, AND THE MYOGRAM TRACING RISES TO A PEAK.

PERIOD OF CONTRACTION IF THE TENSION BECOMES GREAT ENOUGH TO OVERCOME THE RESISTANCE (WEIGHT BEING MOVED),THE MUSCLE SHORTENS.

PERIOD OF RELAXATION THE PERIOD OF RELAXATION FOLLOWS THE PERIOD OF CONTRACTION, AND IS THE RESULT OF Ca2+ ION CONCENTRATION RETURNING TO NORMAL LEVELS.

PERIOD OF RELAXATION THE MUSCLE TENSION DECREASES TO ZERO AND THE TRACING RETURNS TO THE BASELINE. IF THE MUSCLE HAS SHORTENED DURING CONTRACTION, IT NOW RETURNS TO ITS INITIAL LENGTH.

THREE PHASES OF MUSCLE CONTRACTION

GRADED MUSCLE RESPONSES MUSCLE CONTRACTION CAN BE GRADED IN TWO WAYS: 1. BY CHANGING THE SPEED OF STIMULATION. 2. BY CHANGING THE STRENGTH OF THE STIMULUS.

GRADED MUSCLE RESPONSES MUSCLE RESPONSES TO AN INCREASE IN THE NUMBER OF STIMULI: 1. TREPPE 2. TEMPORAL (WAVE) SUMMATION 3. INCOMPLETE TETANI 4. COMPLETE TETANI

TREPPE A MUSCLE MUST HAVE BEEN AT REST FOR A PERIOD OF TIME.

TREPPE ALL PHASES OF MUSCLE CONTRACTION ARE PRESENT AND HAVE NOT BEEN ALTERED.

TREPPE THE STIMULI ARE EQUIDISTANCE APART.

TREPPE THE AMOUNT OF TENSION IS INCREASING DUE TO WARMING OF THE MUSCLE. THE INCREASE IN TEMPERATURE CAUSES ENZYMES TO BE MORE EFFECTIVE.

TREPPE THE AMOUNT OF TENSION DEVELOPED, WITH THE SAME STRENGTH OF STIMULUS, INCREASES AND THEN REMAINS THE SAME.

MYOGRAMS

MUSCLE IS STIMULATED AT AN INCOMPLETE TETANI IF THE STIMULUS STRENGTH IS HELD CONSTANT AND THE MUSCLE IS STIMULATED AT AN INCREASINGLY FASTER RATE, INCOMPLETE TETANI RESULTS.

INCOMPLETE TETANI ALL PHASE OF MUSCLE CONTRACTION ARE PRESENT. HOWEVER, THE PERIOD OF RELAXATION IS SHORTED.

INCOMPLETE TETANI THE STIMULI ARE OF THE SAME STRENGTH, HOWEVER, THEY ARE BECOMING CLOSER TOGETHER.

INCOMPLETE TETANI THE AMOUNT OF TENSION IS INCREASING DUE TO AN INCREASE IN THE NUMBER OF Ca2+.

COMPLETE TETANUS WHEN ALL EVIDENCE OF MUSCLE RELAXATION DISAPPEARS AND THE CONTRACTIONS FUSE INTO A SMOOTH, SUSTAINED CONTRACTION, COMPLETE TETANUS RESULTS.

COMPLETE TETANUS NOTICE THAT THE PERIOD OF RELAXATION HAS COMPLETELY DISAPPEARED.

COMPLETE TETANUS THE STIMULI ARE BEING DELIEVED ONE AFTER ANOTHER, WITH NO TIME ELAPSED.

COMPLETE TETANUS THE TENSION HAS PLATEAUED, BECAUSE ALL OF THE MYOFILAMENTS ARE FORMING BONDS. THERE IS A MAXIMUM OF Ca2+ IN THE MYOFIBRIL.

MUSCLE TONE MUSCLE TONE KEEPS THE MUSCLES OF THE BODY FIRM, HEALTHY, AND READY TO RESPOND TO STIMULI. IN ADDITION, MUSCLE TONE HELPS STABLIZE JOINTS AND MAINTAIN POSTURE.

MUSCLE TONE MUSCLE TONE IS THE RESULT OF ASYNCHRONOUS MUSCLE MOTOR UNIT CONTRACTION.

ENERGY FOR CONTRACTION 1. ATP 2. CREATINE PHOSPHATE 3. GLYCOLYSIS 4. AEROBIC CELLULAR RESPIRATION

MUSCLE FATIGUE TRUE MUSCLE FATIGUE IS THE RESULT OF BUILD UP OF ACIDIC COMPOUNDS, MAINLY LACTIC ACID, A REDUCTION IN THE AMOUNT OF ATP, AND ELECTROLYTE IMBALANCES.