Strengthology 101a - Master Set

Nerve fibers within the muscle spindle function to:

1. Monitor extent of stretch within extrafusal (ordinary) muscle fibers. 2. Initiate a rapid reflex response to overstretching by way of extrafusal fiber contraction. 3. Reestablish proper spindle length through contraction of intrafusal fibers.

The # of slow-twitch fibers per motor unit:

10-190

The # of fast-twitch fibers per motor unit:

200-800

Which band is darker, the A band or the I band?

A Band

What comprises a motor unit?

A motor neuron and all the muscle fibers it controls (or innervates).

What is the process by which ATP is broken down for muscle contraction?

ATPase activity - this process is greater in FAST TWITCH muscles.

Myofilaments consist primarily of two contractile proteins. Name them.

Actin (thin) Myosin (thick)

Slow-Twitch fibers are used in performance of activities requiring ______, or _______ metabolism of energy.

Aerobic or Oxidative

The _________ states that when a motor neuron stimulates a muscle fiber, a minimal quantity of stimulus, named the threshold is necessary to produce contraction. If the stimulus falls below the threshold, no muscle contraction occurs.

All-or-None Law

What percentage of total body weight is comprised of muscle tissue?

Approximately 40-50% of total body weight is composed of muscle tissue.

What is the name of the nerve fiber that conducts the stimulus away from the nerve cell?

Axon

The A band is comprised of which type of myofilaments?

Both Thick and thin

How does the Golgi Tendon Organ (GTO) sense the degree and extent of muscle tension.

By monitoring tendon length.

A motor signal originating from __________ the stimulates skeletal muscle to contract.

Central Nervous System (CNS)

Proprioceptors provide rapid feedback stimuli to which the ______ responds.

Central Nervous System (CNS)

What is found within the sarcoplasm?

Contractile proteins, Enzymes, Fat Glycogen, and nuclei.

The protruding Myosin heads are typically referred to as _________.

Cross Bridges

The application of proper strength training is believed to _______ the _______.

Decrease the CNS inhibition process

Which levels of fascia extend beyond the muscle and join to form tendons?

Endomysium

The relatively thick, outer layer of protective fascia, which surrounds each muscle organ is called the ___________.

Epimysium

Ordinary muscle fibers are known as ________ (in comparison to the Muscle Spindle).

Extrafusal

True or False. There can be different muscle fibers types assigned to the same motor neuron.

FALSE

Connective tissues divide muscles into their, smaller, working divisions. Each division is wrapped in a supporting connective tissue called ________.

Fascia From Latin for "band" or "bundle". Also, think of fascia board in construction. It separates differing layers by a "band" of wood.

The first division of muscles occurs at the ________.

Fascicle Latin for "little bundle"

This type of muscle fiber is used in performance of maximal force muscle contractions.

Fast-Twitch

Slow-Twitch fibers are resistant to ___________.

Fatigue

A person's fiber types are determined ________.

Genetically

Specialized nerves that protect against excessive force by inhibiting muscle contraction.

Golgi Tendon Organs (GTO)

This CNS response determines the number and type of motor units recruited, as well as the number of times they discharge, or fire, enabling appropriate responses, relative to the degree(s) of muscle force required.

Graduation of Response a.k.a. The Motor Unit Recruitment Pattern (MURP)

_________ is the neuromuscular process by which motor units are regulated and recruited to properly meet varied and graduated demands for muscle force.

Graduation of Response; a.k.a. The Motor Unit Recruitment Pattern (MURP)

What are the results of a decrease in the CNS inhibition process (brought on by initial adaption to strength training)?

Greater motor unit recruitment Improved patterns of firing

The Muscle Spindle is formed by these types of fibers:

Intrafusal

Bands or sheets of connective tissue that connect one bone to another

Ligaments

Anatomical names are frequently derived from:

Location, Size, Shape, Action, Points of origin/insertion, or Muscle fiber direction

Any stimulus (sent to the motor unity) that is equal or greater than the threshold produces ________ contraction in the muscle fiber.

Maximal

Slow-Twitch muscles contain more and larger _______ and related _______, as well as more blood _____ and intercellular ______.

Mitochondria and related Enzymes Capillaries and intercellular Fat

The neurons responsible for transmitting motor signals to muscle tissue are known as __________.

Motor Neurons

When necessary, the GTO reacts by inhibiting further muscle contraction by reducing:

Motor unit recruitment and firing

Stimuli of long duration can will cause sustained _________.

Muscle Contraction

Specialized nerve fibers found within the muscle that lie parallel to the regular muscle fibers:

Muscle Spindle

Muscle fibers are made up of small, thread-like strands known as ____________.

Myofibrils

Myofribrils are formed of smaller structures called ___________.

Myofilaments

What is the name of the red-pigmented protein involved in oxygen transport and utilization?

Myoglobin

Fast-Twitch fibers are low in _______, and therefore, are more _______ in color.

Myoglobin, White in color.

Nervous system reflexes designed to prevent injury from extreme force or overuse.

Neuromuscular Inhibitors

The marked gains in strength regularly observed during the early phases of a resistance training program are attributed to overall improvement of __________ functioning, rather than muscle ___________.

Neuromuscular functioning, rather than muscle hypertrophy.

Stimuli are transmitted from the CNS by nerve cells in the spinal cord called ________.

Neurons

What happens if the stimulus (sent to the motor unit) falls below the threshold?

Nothing. No muscle contraction occurs.

Although fiber transformation (e.g. fast to slow) has not been proven, the _________ of Fast-Twitch fibers can be significantly altered.

Oxidative

The connective tissue sheath, which penetrates the muscle and encloses the fascicle, is called the _________.

Perimysium

The muscle end attached to the most movable bone, furthest from the midline of the body is referred to as the _____ __ ______.

Point of Insertion

The muscle end attached to the least movable bone, nearest to the midline of the body, is referred to as the _____ __ _____.

Point of Origin

Name of the protective sensory receptors within the nerve endings of muscles, tendons, and ligaments (joints).

Proprioceptors

A term used to describe the protective response designed to prevent overload injury to working muscle, connective tissue, and joint.

Reflex inhibition

Beneath the endomysium is the _________, a thin membrane that surrounds the semifluid ___________ of the muscle cells.

Sarcolemma and Sarcoplasm Sarco - Greek for flesh; Lemma - Greek for sheath; Plasma - Greek for a thing molded or formed

Myofilaments do not extend the entire length of the muscle, but form repeating units called _______.

Sarcomeres

Fast-Twitch muscle fibers have faster ______.

Shortening Speeds (contraction)

Muscle fibers termed slow-twitch have slower _______.

Shortening Speeds (contraction)

________ states that selection of motor neuron size and its associated muscle fiber type follows an order of efficiency, i.e., smallest to largest.

Size Principle of Recruitment

Skeletal muscle composition (in %)

Skeletal muscle is composed mainly of water (75%). The remainder consists of about 20% protein and about 5% enzymes, fats, carbohydrates, pigments, and inorganic salts.

The __________ states that myosin heads vibrate internally against actin filaments causing a simultaneous contraction on both sides of the sarcomere with overall shorten of muscle fiber.

Sliding Filament Theory

Slow and Fast: Color

Slow = Red Fast = White

Slow and Fast: Fiber Size

Slow = Smaller Fast = Larger

Myoglobin gives ________ its red appearance.

Slow twitch

In general, which motor units are activated first?

Slow twitch muscle fibers (Type I)

Two major categories of muscle fiber:

Slow-Twitch (Type I) and Fast-Twitch (Type II). *The fast-twitch fibers are further divided into sub-types, i.e., Type IIa and Type IIb.

Motor units are recruited in the order of:

Smallest to Largest

Fiber types are distinguished from each other according to:

Speed of contraction, level of force production, rate of fatigue, and source of energy (oxygen, oxygen/glycogen, or glycogen, respectively).

Sprinting and long distance running. Which fibers for each activity?

Sprinting = Fast Twitch Long Distance = Slow Twitch

This provides the CNS with sensory information important for the control of body movement, balance, and posture.

Stretch Reflex

True or False. All muscles in a motor unit contract and relax simultaneously.

TRUE

True or False. Everyone has both types of muscle fiber.

TRUE

True or False. Most people have an equal split between Type I and Type II fibers.

TRUE

True or false, tendons will thicken as a result of strength training.

TRUE

What is the purpose of a tendon?

Tendons attach skeletal muscle to bone.

Proprioceptors function primarily to monitor these forces within the musculoskeletal structures.

Tension, stretch, and pressure

The center of an uncontracted muscle is known as ______.

The H Zone

Another name for the Graduation of Response

The Motor Unit Recruitment Pattern (MURP)

What determines the number of motor units recruited?

The amount of force required

The A band runs the length of which type of filament?

The thick filament

In general, which motor units are recruited secondarily?

The two levels of fast-twitch fibers (Type IIa and IIb)

The only filament type in the H Zone is thick or thin?

Thick

What is the phrase for the minimum amount of stimulus required to produce muscle contraction?

Threshold

What bonds the myofibrils into a unified cross section of the muscle fiber?

Z Disc

Each sarcomere is distinguished from its neighboring sarcomere by ___________.

Z Disc, or Z Line