muscular system part 2

Muscle fatigue

the physiological inability of a muscle to contract when stimulated

Not fully known

Causes to muscle fatigue are \_______

Imbalances of calcium and potassium ions and problems At neuromuscular junction

Suspected causes of muscle fatigue

Oxygen deficit

Major factor to muscle fatigue

Oxygen deficit

Not total lack of oxygen, person cannot take in oxygen fast enough to keep the muscles supplied with oxygen they need

Blood supply

Work that a muscle can do and how long it can work without being fatigued depends on how good it's \_______ is

Lactic acid, anaerobic pathway

When muscles lack sufficient oxygen for aerobic respiration, \______ begins to accumulate in the muscle via \_________

Burning

What happens when lactic acid builds up?

Lactic acid and ATP supply running low causing ionic imbalance

Two causes of muscle contracting less and less effectively and stopping eventually

No

Is completely muscle fatigue common?

Marathon runners collapsing

Example of true muscle fatigue

Get rid of lactic acid and replenish ATP and CP reserves

Why do people breathe deeply and rapidly when recovering from muscle fatigue?

No

Do muscles always shorten when they contract?

Isotonic contraction

the myofilaments are successful in their sliding movements, the muscle shortens, and movement occurs

isometric contraction

Muscle contracts but there is no movement, muscle stays the same length, tension increases, myofilaments try to slide

Muscle tone

continuous state of partial contraction

Different motor units scattered through muscle being stimulated by nervous system in systematic way. "On duty" Incase required

What is muscle tone the result of?

Flaccid

soft, flabby muscle because nerve supply to muscle destroyed so not stimulated

Atrophy

Muscle does this when nerve supply destroyed

flaccid paralysis

defective (flabby) or absent muscle control caused by a nerve lesion

spastic paralysis

stiff and awkward muscle control caused by a central nervous system disorder

Yes

Does the amount of work a muscle does change the muscle?

aerobic exercise (endurance)

Results in stronger and more flexible muscles because blood supply increases and fibers from more mitochondria for oxygen storage, helps us reach steady rate of ATP production and improves efficiency of aerobic respiration

Yes

Does aerobic exercise help other muscles too?

No

Does aerobic exercise cause muscles to grow in size?

resistance exercise (isometric)

increases muscle size and strength, pit muscles against immovable object

Enlargement of fibers and amount of connective tissue reinforcing muscle

Why do muscles grow?\#

Muscle fatigue

the physiological inability of a muscle to contract when stimulated

Not fully known

Causes to muscle fatigue are \_______

Imbalances of calcium and potassium ions and problems At neuromuscular junction

Suspected causes of muscle fatigue

Oxygen deficit

Major factor to muscle fatigue

Oxygen deficit

Not total lack of oxygen, person cannot take in oxygen fast enough to keep the muscles supplied with oxygen they need

Blood supply

Work that a muscle can do and how long it can work without being fatigued depends on how good it's \_______ is

Lactic acid, anaerobic pathway

When muscles lack sufficient oxygen for aerobic respiration, \______ begins to accumulate in the muscle via \_________

Burning

What happens when lactic acid builds up?

Lactic acid and ATP supply running low causing ionic imbalance

Two causes of muscle contracting less and less effectively and stopping eventually

No

Is completely muscle fatigue common?

Marathon runners collapsing

Example of true muscle fatigue

Get rid of lactic acid and replenish ATP and CP reserves

Why do people breathe deeply and rapidly when recovering from muscle fatigue?

No

Do muscles always shorten when they contract?

Isotonic contraction

the myofilaments are successful in their sliding movements, the muscle shortens, and movement occurs

isometric contraction

Muscle contracts but there is no movement, muscle stays the same length, tension increases, myofilaments try to slide

Muscle tone

continuous state of partial contraction

Different motor units scattered through muscle being stimulated by nervous system in systematic way. "On duty" Incase required

What is muscle tone the result of?

Flaccid

soft, flabby muscle because nerve supply to muscle destroyed so not stimulated

Atrophy

Muscle does this when nerve supply destroyed

flaccid paralysis

defective (flabby) or absent muscle control caused by a nerve lesion

spastic paralysis

stiff and awkward muscle control caused by a central nervous system disorder

Yes

Does the amount of work a muscle does change the muscle?

aerobic exercise (endurance)

Results in stronger and more flexible muscles because blood supply increases and fibers from more mitochondria for oxygen storage, helps us reach steady rate of ATP production and improves efficiency of aerobic respiration

Yes

Does aerobic exercise help other muscles too?

No

Does aerobic exercise cause muscles to grow in size?

resistance exercise (isometric)

increases muscle size and strength, pit muscles against immovable object

Enlargement of fibers and amount of connective tissue reinforcing muscle

Why do muscles grow?

Muscle fatigue

the physiological inability of a muscle to contract when stimulated

Not fully known

Causes to muscle fatigue are \_______

Imbalances of calcium and potassium ions and problems At neuromuscular junction

Suspected causes of muscle fatigue

Oxygen deficit

Major factor to muscle fatigue

Oxygen deficit

Not total lack of oxygen, person cannot take in oxygen fast enough to keep the muscles supplied with oxygen they need

Blood supply

Work that a muscle can do and how long it can work without being fatigued depends on how good it's \_______ is

Lactic acid, anaerobic pathway

When muscles lack sufficient oxygen for aerobic respiration, \______ begins to accumulate in the muscle via \_________

Burning

What happens when lactic acid builds up?

Lactic acid and ATP supply running low causing ionic imbalance

Two causes of muscle contracting less and less effectively and stopping eventually

No

Is completely muscle fatigue common?

Marathon runners collapsing

Example of true muscle fatigue

Get rid of lactic acid and replenish ATP and CP reserves

Why do people breathe deeply and rapidly when recovering from muscle fatigue?

No

Do muscles always shorten when they contract?

Isotonic contraction

the myofilaments are successful in their sliding movements, the muscle shortens, and movement occurs

isometric contraction

Muscle contracts but there is no movement, muscle stays the same length, tension increases, myofilaments try to slide

Muscle tone

continuous state of partial contraction

Different motor units scattered through muscle being stimulated by nervous system in systematic way. "On duty" Incase required

What is muscle tone the result of?

Flaccid

soft, flabby muscle because nerve supply to muscle destroyed so not stimulated

Atrophy

Muscle does this when nerve supply destroyed

flaccid paralysis

defective (flabby) or absent muscle control caused by a nerve lesion

spastic paralysis

stiff and awkward muscle control caused by a central nervous system disorder

Yes

Does the amount of work a muscle does change the muscle?

aerobic exercise (endurance)

Results in stronger and more flexible muscles because blood supply increases and fibers from more mitochondria for oxygen storage, helps us reach steady rate of ATP production and improves efficiency of aerobic respiration

Yes

Does aerobic exercise help other muscles too?

No

Does aerobic exercise cause muscles to grow in size?

resistance exercise (isometric)

increases muscle size and strength, pit muscles against immovable object

Enlargement of fibers and amount of connective tissue reinforcing muscle

Why do muscles grow?

Sliding Filament Mechanism

The process by which skeletal muscle shortens during contraction because the thick and thin filaments slide past one another.

Skeletal Muscle

A skeletal muscle is an organ made up of fascicles that contain muscle fibers (cells), blood vessels, and nerves. The skeletal muscle is wrapped in epimysium.

Fascicle

A fascicle is a bundle of muscle fibers wrapped in perimysium.

Muscle Fiber

(CELL) - Long cylindrical cell covered by a vascular endomysium. The cell membrane, the sarcolemma, surrounds the sarcoplasm with its myofibrils, many peripherally located nuclei, mitochondria, transverse tubules, sarcoplasmic reticulum, and terminal cisterns. The fiber has a striated appearance in skeletal muscle.

Myofibril

Threadlike contractile elements within the sarcoplasm of a muscle fiber that extend the entire length of the fiber; composed of filaments.

Filaments

(Microfilaments) - Contractile proteins within myofibrils that are of two types: thick filaments composed of myosin and thin filaments composed of actin, tropomyosin, and troponin; the sliding of the thin filaments past the thick filaments produces muscle shortening.

What neurons are used to stimulate skeletal muscle fibers to contact?

Somatic Motor Neurons.

Where do muscle action potentials arise from?

The Neuromuscular Junction (NMJ) - The synapse between a somatic motor neuron and a skeletal muscle fiber.

What is a Synapse?

It is a region where communication occurs between two neurons, or between a neuron and a target cell.

What is a Synaptic Cleft?

This is a small gap which separates a neuron and it's receptor.

What is a Neurotransmitter?

It is a chemical that neurons use to communicate with their receptive cell. This chemical travels from the first cell across the Synaptic Cleft to the second cell.

What is a Axon Terminal?

It is located at the end of a motor neuron of a Neuromuscular Junction.

Synaptic End Bulbs

Found at end of axon terminal & contain synaptic vesicles that are filled with neurotransmitters.

Synaptic Vesicle

Membrane enclosed sacs which contain molecules of Acetylcholine (ACh).

Acetylcholine

The neurotransmitter which is released at the NMJ.

Motor End Plate

The region of the sarcolemma opposite to the synaptic end bulbs. This is the muscular part of the NMJ.

Acetylcholine Receptors

Located on the motor end plate, these are integral transmembrane proteins that bind specifically to ACh.

Junctional Folds

Ridge like part of muscle fibers sarcolemma; provide a large surface area for millions of ACh receptors located here.

Motor Unit

A somatic motor neuron plus all the skeletal muscle fibers it stimulates.