CPPS 302 Muscular System (Review)

What is the primary function of the muscular system

Turn chemical into mechanical energy which can produce

• equilibrium

• force

• work

• transport

What is Force in muscular system

Changes in velocity of muscle shortening

• F = ma

  • F = force

  • m = mass: the mass being moved

  • a = acceleration: the rate at which velocity changes

Define Work

Displacement in the direction of force

• W = Fs

  • W = work

  • F = force

  • s = displacement

What is transport in the muscular system?

The movement of substances throughout the body through muscle contractions, such as pumping blood (circulation), and moving food thorugh the digestive tract (digestion).

Despite all the three types of muscles geenrating the same tension, order the three types of muscles from its duration to go form contraction to relaxation

Which of the three muslces is attached by a tendon and is used for locomation and to maintain balance

Skeletal muscle

True or False: Skeletal muscle is mainly used for voluntary control

Mainly used for voluntary control yes but some unconscious and involuntary

Which type of muscle is attached to blood vessels only and is contraction is involuntary

Cardiac muscle

Which muscle types are controled by ANS and hormones

Smooth and Cardiac Muscles

Which muscle is attached to the wall of organ and blood vessels and its ocntraction is involuntary

Smooth muscles

Which muscle is responsible for blood pressure, digestion, bladder control, and air flow

Smooth muscle

What are the three general properties of the muscular system

1. Nucleated cells

2. Contraction can be involuntary or voluntayr

3. Pacemaker capacity for some

Which muscle type is multinucleated?

Skeletal muscle

Which muscle type is uninucleated?

Smooth and Cardiac muscle

Compare and Contrast muscle cell vs muscle fiber

They’re the same

Smooth muslce & cardiac muscle contain pace-making capacities which are modulated, skeletal muscle lacks pace-making capacity, so what does does skeletal muscle contraction only respond to

Signals from the somatic motor neuron

• ANS normally has no influence on the contraction of skeletal muscle

What are the special properties of muscular tissues

1. Excitability

2. Contractibility

3. Extensibility

4. Elasticity

5. Adaptability

“Every Couple Enjoys Eating Ass”

What is muscle excitability and what is the stimulus that excites cardiac, smooth, and skeletal muscle

Excitability = response to stimuli by producing action potentials

• Cardiac and Smooth muscle = electrical (APs imitated by the pacemaker cells)

• Skeletal = chemical (at neuromuscular junction)

What is the rate of muscle shortening known as

Velocity

What is the relationship between muscle shortening (velocity) of muscle fiber and its contraction

Greater the change in the velocity of muscle fiber shortening, greater the force of contraciton

Define extensibility

Extensibility: Ability for muscular tissues to stretch without being damaged

• 1/5 SPECIAL properties of muscular tissues

What limits muscle extensibility and keeps it within its functional physiological contractile range?

Connective tissues

Define Elasticity

• Ability for muscle to return back to its original length and sahpe after contraction or extension

What accessory protein provides muscle elasticity and stabilizes myosin?

Titin, which spans from Z disk to the neighbouring M line

What is adaptability in muscular tissues

Adaptability = ability of muscle tissues to undergo hypertrophy (increase in size) or atrophy (decrease in size).

What does it mean that adult muscle fibers are post-mitotic

They generally do not divide and have very little cell turnover

Exercis is known to produce muscle hypertrophy NOT hyperplasia, what is the difference

Hypertrophy = Increase in muscle cell size

Hyperplasia = increase in the number of cells

What properties of skeletal muscle demonstrate plasticity?

• Force of contraction

• contraction speed

• endurance

• Oxidative/glycolytic capacity

What is oxidative/glycolytic capacity in skeletal muscle

The ability of muscle cells to produce ATP (energy) through aerobic (Oxidative) or anaerobic (glycolytic) metabolism to support contraction

What changes can occur in skeletal muscle due to its oxidative/glycolytic plasticity

• Amount of energy stored

• Rate of energy consumption + production

• Muscle size

• Velocity of muscle shortening

Compare twitch durations across Type 1, IIa, IIx, IIb muscle fibers

Compare muscle shortening velocity across Type 1, IIa, IIx, IIb fibers

Slowest → Fastest

Type 1 → IIa → IIx → IIb

Compare cross sectional area across Type 1, IIa, IIx, IIb fibers

Smallest → largest

Type 1 → IIa → IIx → IIb

Compare metabolism across Type 1, IIa, IIx, IIb fibers

Type 1 = oxidative

Type IIa = predominantly oxidative

Type IIx = Intermediate, more glycolytic

Type IIb = predominantly glycolytic

Compare endurance across Type 1, IIa, IIx, IIb fibers

Highest → lowest

Type 1 → IIa → IIx → IIb

Compare energy efficiency across Type 1, IIa, IIx, IIb fibers

Highest → lowest

Type 1 → IIa → IIx → IIb

Why do type 1 muscle fibers contract slwoly and generate weaker force

They have slower rate of breaking down ATP, resulting in slower muscle shortening

What features support aerobic ATP production in Type 1 muscle fibers

Abundant myoglobin, mitochondria, oxidative enzymes, and high capillary density

“My Mouth Opens, Harder Daddy”

Why are type 1 muscle fibers highly resistant to fatigue?

Aerobic respiration provides a sustained supply of ATP, allowing prolonged contractions

Why do Type IIa muscle fibers contract faster and generate stornger force than Type 1?

They have faster rate of ATP hydrolysis, resulting in quicker muscle shortening (velocity)

How do type IIa fibers compare with Type 1 in myoglobin, mitochondria, and glycogen

Similar myoglobin content, but higher mitochondiral density and more glyocgen

Why do type IIa muscle fibers have high capillary density (muscle fibre is surrounded by many tiny blood capillaries)?

To provide sufficint oxygen for aerobic ATP production

Why do type IIa fibers require abundunt mitochondria and glycogen

To generate enough ATP to compensate for their faster rate of ATP hydrolysis

What is the role of creatine phosphate in Type IIa muscle fibers

It stores high-energy phosphate during rest and rapidly regenerate ATP during contraction

Why do Type IIb muscle fibers contract rapidly and generate very strong force?

They have the fastest rate of ATP hydrolysis and muscle shortening

What characteristics allow Type IIb fibers to rely mainly on anaerobic metbaolism

Low mitochondria, myoglobin, oxidative enzymes, and capillary density,, but high glycolytic enzyme activity and creatine phosphate

Why do type IIb muscle fibers fatigue quickly?

They rely mainly on anaerobic ATP production and cannot sustain prolonged contraction through oxidative metabolism