Biology · General Awareness

Muscle Biology

836 Questions

Muscle biology covers the structures, functions, and contraction mechanisms of skeletal, cardiac, and smooth muscles. Test questions target filaments, stimuli, and specific muscle roles. A clear understanding helps secure marks in biology sections.

Skeletal muscle controlCardiac muscle propertiesMuscle contraction mechanismActin and myosin filamentsMuscle functions

Muscle Biology Questions

Multiple choice biology control and co-ordination in plants and animals voluntary and involuntary movements impulse and its transmission coordination in human beings- nervous control

The dark bands (Black bands) (A-bands) of a skeletal
muscle are known as

  1. Isotropic bands

  2. Anisotropic bands

  3. Intercalated disc

  4. Cross bridges
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Each myofibril shows dark and light bands' The dark bands of the myofibril are termed as A-bands or anisotropic bands.

Multiple choice biology control and co-ordination in plants and animals voluntary and involuntary movements impulse and its transmission coordination in human beings- nervous control

The muscle fatigue occurs due to accumulation of

  1. Pyruvic acid

  2. ATP

  3. Lactic acid
  4. Eroman $CO _{2}$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

During muscle fatigue due to deposition of lactic acid, cytoplasm becomes acidic thereby enzyme activity stops and food is not oxidised and as the energy is not available, muscular contraction stops.

Multiple choice zoology skeleton and movements features of a muscle muscle features muscle contraction and its effects

All or none law is not applicable for

  1. Single skeletal muscle fibre

  2. Whole skeletal muscle

  3. Single smooth muscle fibre

  4. Whole cardiac muscle
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
  • The all-or-none law is the principle that the strength by which a nerve or muscle fibre responds to a stimulus is independent of the strength of the stimulus. If that stimulus exceeds the threshold potential, the nerve or muscle fibre will give a complete response; otherwise, there is no response.
  • Hence All or none law is not applicable for whole skeletal muscle.
  • So, the correct answer is 'Whole skeletal muscle'.
Multiple choice zoology skeleton and movements features of a muscle muscle features muscle contraction and its effects

All or none law is associated with

  1. Muscle fibre

  2. Neuron

  3. Uriniferous tubule

  4. Both A and B
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
  • The all-or-none law is a principle that states that the strength of a response of a nerve cell(neuron) or muscle fibre is not dependent upon the strength of the stimulus. If a stimulus is above a certain threshold, a nerve or muscle fibre will fire.
  • Hence All or none law is associated with muscle fibre and neuron.
  • So, the correct answer is 'Both A and B'.
Multiple choice zoology skeleton and movements features of a muscle muscle features muscle contraction and its effects

Muscle fibres that show, presence of well developed sarcoplasmic reticulum and are easily fatigued during exercise are likely to be in close association with

  1. Limb bones

  2. Wall of intenstine

  3. Heart

  4. Wall of fallopian tube
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Skeletal muscles show muscle fibres having well developed sarcoplasmic reticulum these muscles are easily fatigued during exercise. Skeletal muscles show voluntary movements.  These can be found in close association with limb bones.

So, the correct answer is 'Limb bones'.

Multiple choice zoology skeleton and movements features of a muscle muscle features muscle contraction and its effects

Muscles, which are immune to fatigue, are

  1. Striped muscles

  2. Cardiac muscles

  3. Jaw muscles

  4. Skeleton muscles
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The internal movements are performed by the involuntary muscles. The involuntary muscles function on their own and cannot be controlled willingly. The cardiac muscles are the involuntary muscles which are responsible for the pumping of the heart. The heart pumps and supplies the oxygenated blood to the different tissues in the body. The smooth muscles are responsible for carrying out peristalsis in the tube like structures of the alimentary canal.

Thus, the correct answer is option B. 

Multiple choice zoology skeleton and movements features of a muscle muscle features muscle contraction and its effects

Which of the following type of muscles are not fatigued soon?

  1. Cardiac muscle

  2. Smooth muscle

  3. Voluntary muscle

  4. Both A and B
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The correct option is D.

Cardiac and smooth muscle are not fatigued soon. Muscle fatigue is a symptom that decreases our muscles ability to perform overtime. 
Cardiac muscles, In smooth muscle myosin, the rate of ATPase activity is 10 to 100 slower than in skeletal muscle myosin. 

It must also be noted that nerve stimulation can cause a excitation or inhibition of the muscle cell.

Multiple choice zoology skeleton and movements features of a muscle muscle features muscle contraction and its effects

Substance that accumulates in a fatigued muscle is

  1. Pyruvic acid

  2. Lactic acid
  3. CO$ _2$

  4. ADP
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
Generally, the glucose undergoes metabolism in the presence of oxygen to form ATP(adenosine triphosphate) which is essential for the muscle contraction but during vigorous exercise, the body cannot meet the oxygen demand and the glucose undergoes metabolism in the absence of oxygen which results in the formation and accumulation of lactic acid. Hence Substance that accumulates in a fatigued muscle is lactic acid.
So, the correct answer is 'Lactic acid'.
Multiple choice zoology skeleton and movements features of a muscle muscle features muscle contraction and its effects

All or none law is not applicable for

  1. Whole skeletal muscle

  2. Single skeletal muscle

  3. Whole cardiac muscle

  4. Single smooth muscle fibre
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

All or none law is the principle that states that the strength by which a muscle fiber responds to a stimulus is independent of the strength of the stimulus. If that stimulus exceeds the threshold potential, the muscle fiber will give a complete response, otherwise, there is no response. 

Each muscle fiber is innervated by each nerve terminal or a nerve terminal innervates 2 or 3 muscle fibers. So their response is not related to others. The all or none law is seen is single fibers of skeletal muscles and smooth muscles but not the whole fiber. Whereas the cardiac muscle innervation is continuous and the whole muscle act as a single unit. So the whole cardiac muscle is applicable to all or none law. 
So the correct option is A.

Multiple choice zoology skeleton and movements features of a muscle muscle features muscle contraction and its effects

Prolonged activation of striated muscle causes it to fatigue. What is the reason?

  1. Breakdown of glycogen into lactic acid in muscle during aerobic respiration

  2. Breakdown of lactic acid in muscle during anaerobic respiration

  3. Breakdown of lactic acid into glycogen during anaerobic respiration

  4. Produce ethanol in muscle
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
  • Generally, the glucose undergoes metabolism in the presence of oxygen to form ATP (adenosine triphosphate) which is essential for the muscle contraction but during vigorous exercise, the body cannot meet the oxygen demand and the glucose undergoes metabolism in the absence of oxygen (anaerobic respiration)which results in the formation and accumulation of lactic acid. The breakdown of lactic acid in muscle causes the muscle to fatigue.
  • Hence prolonged activation of striated muscle causes it to fatigue because of breakdown of lactic acid in muscle during anaerobic respiration.
  • So, the correct answer is 'Breakdown of lactic acid in muscle during anaerobic respiration'.
Multiple choice zoology skeleton and movements features of a muscle muscle features muscle contraction and its effects

Lactic acid causes fatigue in muscles due to

  1. Sensitivity of neuromuscular junction

  2. Acidity

  3. Binding of muscle calcium

  4. Causing expulsion of cations
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

  • Lactic acid is formed and accumulated in the muscle under conditions of high energy demand, rapid fluctuations of the energy requirement and insufficient supply of O2.
  •  During exercise, there is a progressive reduction in the ability to produce muscle forces processes within the nervous system, as well as within the muscles contribute to this fatigue. 
  •  Finally, the small-diameter muscle afferents that increase firing with exercise and fatigue. Hence, Lactic acid causes fatigue in muscles due to the Sensitivity of neuromuscular junction.
 So, the correct answer is 'Sensitivity of neuromuscular junction'.

Multiple choice zoology skeleton and movements features of a muscle muscle features muscle contraction and its effects

When a threshold stimulus is applied to a muscle, the muscle fibres will contract fully or will not contract at all. This is known as:

  1. Sliding filament theory

  2. All or none principle

  3. Maximal oxygen uptake

  4. Contraction period
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
The all or none law states that the strength by which a nerve or muscle fiber responds to a stimulus that is independent of the strength of the stimulus. If that stimulus exceeds the threshold potential, the nerve or muscle fiber will give a complete response, otherwise, there is no response.
So, the correct option is 'All or none principle'.
Multiple choice zoology skeleton and movements features of a muscle muscle features muscle contraction and its effects
Though vertebrates are aerobes, their .....(i)..... show anaerobic respiration during ......(ii)..... During this, ......(iii)...... of skeletal muscle fibers is broken down to release lactic acid and energy. Lactic acid, if accumulates causes muscle fatigue.
Fill up the blanks in the above paragraph and select the correct option.

  1. i- Skeletal muscles ; ii-heavy exercise ; iii-glucose

  2. i- Skeletal muscles ; ii-mild exercise ; iii-glycogen

  3. i- Skeletal muscles; ii-heavy exercise ; iii-glycogen

  4. i- Cardiac muscles; ii-heavy exercise ; iii-glycogen
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Muscle fatigue is the reduction in force of contraction of a muscle after prolonged stimulation. In the absence of oxygen, skeletal muscle of human beings can contract for a short time, but it gets fatigued soon. This is due to the fact that in the absence of oxygen, products of glycolysis mainly lactic acid is not disposed of and accumulates in the muscles. This leads to muscle fatigue and pain in the muscles. A muscle gets fatigued sooner after a strenuous exercise than after a mild exercise. Faster breathing for sometime after a strenuous exercise supplies extra oxygen disposes off excess lactic acid and muscle fatigue disappears.

So the correct option is 'i-Skeletal muscles ; ii-heavy exercise ; iii-glucose'.

Multiple choice zoology skeleton and movements features of a muscle muscle features muscle contraction and its effects

The main cause for muscle fatigue 

  1. Acetic acid

  2. Water

  3. Lactic acid

  4. Hydro chloric acid
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Intracellular acidosis due mainly to lactic acid accumulation has been regarded as the most important cause of skeletal muscle fatigue. Inorganic phosphate, which increases during fatigue due to the breakdown of creatine phosphate appears to be a major cause of muscle fatigue.

So, the correct option is 'Lactic acid'.

Multiple choice zoology skeleton and movements features of a muscle muscle features muscle contraction and its effects

Which of the following is not true about rigor mortis?

  1. It is irreversible.

  2. It is not a permanent contraction.

  3. ATP increases in muscles.

  4. Time of onset is not same in all muscles.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Rigor mortis is the state of rigidity that develops in the muscles after death. It is used to determine or estimate the time of death. This refers to the stiffening of the body after death due to loss of Adenosine Triphosphate (ATP) from the body's muscles. ATP provides the energy to the muscles which help them to work and without this, the muscles become stiff and inflexible.