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

Ligaments and tendons are

  1. Epithelial tissues

  2. Muscular tissues

  3. Connective tissues

  4. Skeletal tissues
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Ligaments and tendons are a part of the musculoskeletal system, with ligaments attaching bones to bones and tendons muscles to bones. They both are connective tissue.

Multiple choice

Which of the following is a primary inspiratory muscle?

  1. Sternocleidomastoid muscle

  2. Scaleni

  3. Abdominal muscle

  4. External intercostal

  5. Anterior serratus
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The muscles extend from the tubercles of the ribs behind, to the cartilages of the ribs in front, where they end in thin membranes. These muscles work in unison during inhalation. The internal intercostal muscles relax while the external muscles contract, causing the expansion of the chest cavity and an influx of air into the lungs.

Multiple choice

The action potential in contractile muscle fibers of the heart is similar to that in skeletal muscles of the body. Among the following statements, select the incorrect statement regarding the action potential of human heart?

  1. Within the cell, Ca 2+ binds to troponin.

  2. Rapid depolarization occurs when fast‐opening Na + channels in the sarcolemma open.

  3. A plateau phase occurs during which K+ enters the cytosol of the muscle cell.

  4. Repolarization occurs as K + channels open and K + diffuses out of the cell.

  5. The refractory period of cardiac muscle is dramatically longer than that of the skeletal muscle.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

A plateau phase occurs, during which Ca2+ enters the cytosol of the muscle cell. Ca2+ enters from the sarcoplasmic reticulum within the cell and also from outside the cell through slow‐opening Ca2+ channels in the sarcolemma. 

Multiple choice

Why does heavy exercise cause muscle cramps?

  1. Due to the formation of ethanol

  2. Due to the formation of lactic acid

  3. Due to the evolution of CO2

  4. Due to the absence of oxygen
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

During heavy exercise, when there is a lack of oxygen in our muscle cells, pyruvate is converted into lactic acid. 

Multiple choice

The binding of acetylcholine to a cell triggers all the following processes except

  1. inducing or inhibiting the muscle contraction

  2. triggering exocytosis of enzymes

  3. triggering striated muscle contraction

  4. slowing down the rate of contraction

  5. triggering the synthesis of cyclic AMP (cAMP) in the liver cells
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

This is not true because synthesis of cyclic AMP occurs when the epinephrine and glucagon receptors present on the liver cells are triggered by the binding of the hormones epinephrine and glucagon.

Multiple choice

The intrinsic laryngeal muscles are responsible for maintaining sound production in humans. The movement of which of the following muscles causes abducted vocal folds?

  1. Posterior cricoarytenoid

  2. Lateral cricoarytenoid

  3. Transverse arytenoid

  4. Oblique arytenoid

  5. Cricothyroid
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Posterior cricoarytenoid is the ligament that passes downward from the posterior border of the arytenoid cartilage to the lamina of the cricoid cartilage. Posterior cricoarytenoid muscles abduct and externally rotate the arytenoid cartilages resulting in abducted vocal folds.

Multiple choice

Muscle fatigue is caused by the accumulation of

  1. pyruvic acid

  2. lactic acid

  3. oxalacetic acid

  4. uric acid
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Muscle fatigue during intense exercise is caused by the accumulation of lactic acid in muscle tissues. When oxygen supply is insufficient for aerobic respiration, muscles switch to anaerobic glycolysis, producing lactic acid as a byproduct. This buildup interferes with muscle contraction and causes the sensation of fatigue.

Multiple choice

In which of the following autoimmune disorders, muscles of the limbs become weak?

  1. Lambert-Eaton myasthenic syndrome

  2. Cutaneous small-vessel vasculitis

  3. Lichen planus

  4. Lichen sclerosus

Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Lambert-Eaton myasthenic syndrome is a rare autoimmune disorder that is characterised by muscle weakness of the limbs. It is the result of an autoimmune reaction, where antibodies are formed against voltage-gated calcium channels in the neuromuscular junction .

Multiple choice

The substance found in tendons and ligaments is

  1. collagenous fibres

  2. elastic fibres

  3. fibrous connective tissue

  4. reticular fibres

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Another type of connective tissue is  Fibrous Connective Tissue,. It is composed of large amounts of closely packed collagenous fibres.