Contraction of Skeletal Muscles MUSCLE TWITCH AND SUMMATION

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Contraction of Skeletal Muscles

Contraction of Skeletal Muscles

MUSCLE TWITCH AND SUMMATION Electric shocks were used to stimulate a frog muscle, and

MUSCLE TWITCH AND SUMMATION Electric shocks were used to stimulate a frog muscle, and then the movements of the muscle were changed into an electrical current, displayed on the right. These studies showed: 1) a single electric shock results in a twitch. An action potential is produced, leading to a contraction. 2) If a second electric shock is delivered prior to the muscle relaxing, the second twitch will “ride piggyback” on the first. This is called summation. This leads to a stronger contraction

INCOMPLETE AND COMPLETE TETANUS

INCOMPLETE AND COMPLETE TETANUS

FORCE-VELOCITY CURVE This graph shows the inverse relationship between the force opposing a muscle

FORCE-VELOCITY CURVE This graph shows the inverse relationship between the force opposing a muscle contraction (load) and the velocity of muscle shortening. In other words, this lighter the load, the faster the muscle will shorten (duh). For very heavy loads (bottom of the curve) the muscle will reach a point where the contraction is isometric (the muscle does not actually move). Muscle contraction resulting in shortening is called isotonic.

TYPES OF ISOTONIC CONTRACTION: 1)Concentric contraction: A muscle fiber shortens when force is greater

TYPES OF ISOTONIC CONTRACTION: 1)Concentric contraction: A muscle fiber shortens when force is greater than load. 2)Eccentric contraction: A muscle may actually lengthen, despite contraction, if the load is too great. a)Allows you to lower a

Series Elastic Component • the series-elastic component refers to the elastic composition of the

Series Elastic Component • the series-elastic component refers to the elastic composition of the muscle (PARALLEL) and its associated structures (SEC), which must be stretched tight before the tension exerted by the muscle can cause

THE LENGTH-TENSION RELATIONSHIP IN SKELETAL MUSCLE CELLS

THE LENGTH-TENSION RELATIONSHIP IN SKELETAL MUSCLE CELLS

Skeletal Muscles Anatomy of Skeletal Muscle Skeletal muscleSkeletal Muscles Anatomy of Skeletal Muscle Skeletal muscle
MUSCLE CONTRACTION Muscle Contraction Muscle contractions begin withMUSCLE CONTRACTION Muscle Contraction Muscle contractions begin with
Muscle Physiology Twitch Contraction of muscle in responseMuscle Physiology Twitch Contraction of muscle in response
Slow Twitch and Fast Twitch Muscle Fibres DidSlow Twitch and Fast Twitch Muscle Fibres Did
Muscle Fibres K PEREIRA SLOW TWITCH FAST TWITCHMuscle Fibres K PEREIRA SLOW TWITCH FAST TWITCH
Skeletal Muscle Fibers Skeletal Muscle Contraction Sliding filamentSkeletal Muscle Fibers Skeletal Muscle Contraction Sliding filament
Muscle Physiology Muscles Skeletal Muscle Cardiac Muscle SmoothMuscle Physiology Muscles Skeletal Muscle Cardiac Muscle Smooth
Contraction of skeletal muscles Energy Needed for ContractionContraction of skeletal muscles Energy Needed for Contraction