motoneurons, sliding filament, biomechanics

Question 1

what is a motor unit

Answer 1

a single motoneuron and the muscle fibers that it innervates. The number of muscle fibers per motoneuron ranges between 2000 and 10. A large number of muscle fibers allows a single motoneuron to cause the muscle to generate large forces. A small number of muscle fibers per motoneuron gives small force but great precision.

Question 2

innervation ratio

Answer 2

muscle fibers to motorneuron

Question 3

type 1

Answer 3

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.

Question 4

type IIa

Answer 4

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.

Question 5

type IIb

Answer 5

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.

Question 6

sliding filament theory

Answer 6

the sliding of actin past myosin generates muscle tension

Question 7

motoneurons

Answer 7

nerves that carry info from CNS to muscle and signal them to contract / relax

Question 8

neurotransmitters

Answer 8

A chemical substance that is released at the end of a nerve fiber by the arrival of a nerve impulse and, by diffusing across the synapse or junction, causes the transfer of the impulse to another nerve fiber, a muscle fiber, or some other structure.

Question 9

skeletal muscle tissue is composed of cells called

Answer 9

muscle fibers

Question 10

chemical message released by motoneuron is called

Answer 10

acetylcholine

Question 11

cholinesterase

Answer 11

family of enzymes that catalyzes the hydrolysis of the neurotransmitter acetylcholine (ACh) into choline and acetic acid,

Question 12

force

Answer 12

mechanical interaction that goes on between two objects or bodies (push/pull) (force = mass x acceleration)

Question 13

speed

Answer 13

Change in displacement

Question 14

vector

Answer 14

An object that has both magnitude and a direction

Question 15

scalar

Answer 15

Having only magnitude and not direction

Question 16

velocity

Answer 16

The speed of something within a certain direction (v=distance/time)

Question 17

displacement

Answer 17

The movement of an object from its stationary place/position

Question 18

acceleration

Answer 18

The increase of speed within a subject (acceleration = change in velocity/time)

Question 19

momentum

Answer 19

The amount of movement a moving subject has created because of its mass and velocity

Question 20

impulse

Answer 20

The effect of force acting over time to change the momentum of an object

Question 21

center of mass

Answer 21

Mathematical point around which the mass of a body or object is evenly distributed