topic 4 test Flashcards
role of acetylcholine
When the nervous system signal reaches the neuromuscular junction a chemical message is released by the motoneuron
role of cholinesterase
family of enzymes that catalyzes the hydrolysis of the neurotransmitter acetylcholine (ACh) into choline and acetic acid, a reaction necessary to allow a cholinergic neuron to return to its resting state after activation.
type I twitch fibers
slow twitch muscle fibers, low nerve transmission speeds and small muscle force. Can maintain for a long time. Slow-twitch fibers are designed for aerobic endurance activities that require long-term, repeated contractions, like maintaining posture or running a long distance.
type IIa twitch fibers
Fast twitch muscle fibers, fast neural transmission times and stronger contractions force, resistant to fatigue.These fast-twitch muscle fibers are also known as intermediate fast-twitch fibers. They can use both aerobic and anaerobic metabolism almost equally to create energy.
type IIb fibers
Fastest contraction times, larges force, fatigue quickly. These fast-twitch fibers use anaerobic metabolism to create energy and are the classic fast-twitch muscle fibers that excel at producing quick, powerful bursts of speed. This muscle fiber has the highest rate of contraction (rapid firing) of all the muscle fiber types, but it also has a faster rate of fatigue and can’t last as long before it needs rest.
flexion
a bending movement around a joint in a limb (as the knee or elbow) that decreases the angle between the bones of the limb at the joint
extension
a physical position that increases the angle between the bones of the limb at a joint
abduction
any motion of the limbs or other body parts that pulls away from the midline of the body
adduction
the movement of a body part toward the body’s midline
medial rotation
the movement of a limb or muscle group toward the center of the body
lateral rotation
the movement of a body part or muscle group away from the center of the body and around the longitudinal axis of a bone
pronation
a rotational movement of the forearm that results in the palm facing posteriorly
supinatin
rotation of the forearm and hand so that the palm faces forward or upward
elevation
movement in a superior direction
rotation
circular movement of a joint or muscle that allows body to move in circular manner
depression
movement in a downward direction
circumduction
multiple active muscles performing different synchronous ranges of motion
dorsi flexion
backward bending and contracting
plantar flexion
extension of ankle so that foot points away
eversion
the movement of the sole of the foot away from the median plane
inversion
movement in which the plantar surface (sole) of the foot rotates towards the mid-line of the body
isotonic
constant tension/constant movement, holding weight at the max amount possible
isometric
(static) muscle does not move, the muscle is static/stationary, contracted with no movement
isokinetic
constant speed and movement, repeated movement at a constant speed
concentric
muscle shortens as it is generating force
eccentric
muscle lengthens as it is generating force
agonist
prime movers generates the movement, arm down = tricep flexing
antagonist
muscle that contracts eccentrically, arm up = tricep is strecthing
doms result
Eccentric muscle action and muscle damage. Overstrecthing and overtraining
doms prevention
Reducing the eccentric component of muscle actions during early training. Starting at a lower intensity and gradually increasing
force definition
mechanical interaction that goes on between two objects or bodies (push/pull) (force = mass x acceleration)
speed definition
change in displacement
velocity definition
The speed of something within a certain direction (v=distance/time)
acceleration definition
The increase of speed within a subject (acceleration = change in velocity/time)
displacement definition
The movement of an object from its stationary place/position
momentum definition
The amount of movement a moving subject has created because of its mass and velocity
impulse definition
The effect of force acting over time to change the momentum of an object
center of mass
Mathematical point around which the mass of a body or object is evenly distributed
a change in body position during sporting activities can
change the position of the center of mass
first-class lever definition
effort and resistance are on opposite sides of the fulcrum
second class lever definition
effort and resistance are on the same side of the fulcrum but the effort arm is longer/greater than the resistance, it is the most uncommon
third class lever definition
effort and resistance are on the same side of the fulcrum but the effort arm is shorter/less than the resistance arm, it is the most common
anatomical first-class lever
the tricep-elbow joint
anatomical second-class lever
calf-ankle joint
anatomical third-class lever
bicep-elbow joint
first law of motion definition
Inertia - states that every object will stay stationary until an external force is acted upon it
second law of motion
It is when the force applied to an object becomes the mass of the object multiplied by the acceleration of the object
third law of motion
States that for every action, an equal and opposite reaction also presents
first law example
The soccer ball will stay at rest until a player comes and kicks it
second law example
The acceleration of a hockey puck depends on how heavy the puck is and how hard the player hits it
third law example
When a basketball player bounces a basketball, the force has an opposite reaction which brings the ball back up
angular momentum
Angular momentum is the measure of the amount of (or potential for) rotation. Angular Momentum = Moment of Inertia x Angular Velocity
moment of inertia
Moment of Inertia is how difficult a body or object is to rotate about an axis. It depends on the mass of the body and the mass distribution around the axis.
angular velocity
Angular velocity is the rate at which an object rotates or revolves about an axis.
angular momentum in sports
A figure skater starts a spin by pulling in his arms to lessen his Moment of Inertia.
Bernoulli’s principle
principle of the conservation of energy, faster-moving air has low air pressure and slower-moving air has high air pressure
