Lecture 17b Flashcards
Contraction in the absence of adequate oxygen produces ________ which contributes to muecle soreness
Lactic acid
Heavy/ laboured breathing after excesise occurs to make up for ____
Oxygen debt
Fatigue is
The continued metabolic effort required to remove excess lactic acid that can accumulate during long periods of exercise
Repeated muscular contraction depletes cellular ______ store and outstrips the abilty to replenish ____ and _____ to make more
ATP
oxygen and nutrients
The byproduct of skeletal muscle contraction is
Heat
Breaking ATP bond results in ____ AND _____
Energy and heat
Motor neurons are
Specialized nerve fibre that transmits an impulse to a muscle, causing a contraction
Neuromuscular junction is what
Specialized point of contact between a nerve ending and the muscle fiber it innervates
A motor unit = ______ + ________
A motor neuron + muscle cells it innervates
The fewer number of fibres in a motor unit the more ______ the available movements are
Precise
The greater the number pf fibres in a motor unit the more ____
Powerful the contraction available
5 types of muscle contraction
Twitch Tetanic Tonic Isotonic Isometric
Myography is
Method of graphing the changing tension of a muscle as it contracts
Twitch contraction is what type of movement
Quick, jerky response
Twitch contractions are not generally
Related to normal muscle activity
Twitch contractions are seen in wahat fibre
Isolated muscle fibres
Twitch contractions are single contraction of muscle fibres caused
By a single threshold stimulus
Tetanic contraction are
Sustained, steady muscle contractions
Tetanic contractions are caused by a series of_____
Stimuli bombarding a muscle in rapid succession this series of stimuli join forces to produce a sustained/ prolonged contraction refered to as tetanus
Tetanic contractions are ______ dependant
Calcium
Tonic contractions are
Continual, partial contraction of a muscle
Flaccid
Muscles have less tone than normal
Spastic
Muscles have more tone than normal
Muscle tone it maintained by
Negative mechanisms
A few muscle fibers are always
Contracting to form a bit of tension
What is graded strength principle
Skeletal muscles contract with varying degrees of strength
What 4 things is graded strength principle
- Metabolic condition of individual fibres
- # of fibres contracting at the same time
- The # of motor units involved
- The intensity and frequency of the stimulation
Length tension relationship (part of graded strength principle)
A muscles maximum strength is directly dependent on the initial length of its fibres (the longer, the more they can contract)
If sacromeres are compressed,
It reduces the muscles contractile potential
If the sarcromeres are overstretched,
Actin and myosin are too far apart to bind
The strongest muscle contraction occurs when the
Muscle is stretched to its optimal length
Stretch reflex (graded strength principle) is
The load a muscle is exposed to influenses the strength of its contraction
The body tries to maintain constant muscle length in response to an increased load… up to a point
