Muscular tissue l General histology MCQs for dental students

Muscular system l General histology MCQs for dental students

MCQ on muscular system for general histology and biology in dentistry

Q1. Contraction In all types of muscles requires Ca++ lons, which of the following muscle components can bind Ca?

 (A) Rough endoplasmic reticulum

(B) Tropomyosin

(C) Troponin

(D) Active sites on actin

02. The thin filament protein Involved In the calcium regulation of contraction In striated muscle Is

 (A) Actin and myosin

(B) Troponin and tropomyosin

(C) Myosin and tropomyosin

(D) Actin and troponin

Q3. The endomysium is a C.T. that surrounds

 (A) Individual muscle fibers

(B) Muscle fascicles

(C) An entire muscle

(D) Small bundles of muscle fibers

Q4. In the sarcomere, the ATPase required for contraction is localized In the

 (A) Sarcoplasmic reticulum

(B) Thin filaments

(C) Both thick and thin filament

(D) Myosin heads

Q5. Which of the following statements concerning triads in mammalian skeletal muscle is true?

 (A) They can be observed by the light microscope

(B) They are characterized by a T-tubule that sequesters Ca" ion

(C) They consist of two terminal cistenae of the sarcoplasmic reticulum separated by a T-tubule

(D) They are located in the Z-disc

Q6. Smooth muscle cells (fibers) have the following characters EXCEPT

 (A) Are in cell to cell contact by means of nexus

(B) Require calcium ions as activators of myosin-actin interaction

(C) Striated and fusiform in shape

(D) They can synthesize and produce collagen

Q7. Which structural features would allow you to distinguish skeletal from cardiac and smooth muscle

 (A) Presence of apparent striation

(B) Shape and site of the nuclei

(C) Presence of triads

(D) All of the above

Q8. Atrial cardiac muscle cells characterized by the following EXCEPT

 (A) Have fewer T-tubules

(B) Small in size the ventricular muscle cells

(C) Contain many granules that cause Na+ diuresis and reduction in blood pressure

(D) They have a triad at the Z-line

Q9. All the smooth muscle fibers are mesodermal in origin EXCEPT those of

 (A) Vascular system

(B) Digestive system

(C) Reproductive system

(D) Iris

Q10. During muscle contraction

 (A) The A band decrease in length

(B) The I band remains in the same length

(C) The sarcomere decrease in length

(D) The H-band remains the same length

Q11. In which of the following z disk is present ?

 (A) The I band

(B) The A band

(C) The H band

(D) None of the above

Q12. Each smooth muscle

 (A) Has triad associated with its contraction

(B) Has diad associated with its contraction

(C) Possesses a single, centrally located nucleus

(D) Is characterized by the absence of sarcolemmal vesicles

Q13. Thick filaments are anchored to Z-disks by

 (A) C-protein

(B) Myomesin

(C) a-actinin

(D) Titin

(E) Nebulin

14. Which one of the following statements concerning cardiac muscle cell is true?

A. They are spindle-shaped

B. They require external stimulus to undergo contraction

C. They are multinuclear cells

D. They are joined together by intercalated disks

E. E They possess numerous cavedae

Q15. H-zone

A. Formed of actin only

B. Formed of myosin only

C. Formed of both actin and myosin

D. In res in iength during muscle contraction

Concerning muscle fibers, the following is true:

a. Muscle cells are termed muscle band.

b. Muscle fibers represent structural and functional unit.

c. Special organelles are the myoglobin.

d. Cell membrane is termed sarcomere.

As regards muscle fibers, one is true:

a. Originate from endoderm.

b. Stretching of the fibers lead to contraction.

c. Main organelle responsible for contraction is mitochondria.

d. Sarcoplasmic inclusions include glycogen, fat and myoglobin.

The origin of skeletal muscle fibers is:

a. Fusion of mononucleated undifferentiated ectodermal cells.

b. Fusion of mononucleated mesodermal cells (myoblasts).

c. Division of mononucleated mesodermal cells (myoblasts).

d. Division of mononucleated undifferentiated endodermal cells.

Skeletal muscle fibers can be found in the following site:

a. Myocardium.

b. Tongue or pharynx

c. The wall of blood vessels.

d. Wall of respiratory tract.

Myofibrils of skeletal muscle have the following characters except:

a- are of two types of filaments actin & myosin

b- are parallel to each other

c- are the main organelles of muscle cells

d- in between the myofibrils there is fine connective tissue

The H zone is light because it has only one type of myofilament

a- the thin filament (Actin).

b- the thick filament (Myosin).

c- The intermediate filaments (desmine & vimentin)

d- none of the above

The H zone is

a- present in middle of I band

b- present in middle of A band

c- it is dark region

d- Z line is present in its center

When skeletal muscle contracts

a- the A band decreases in length

b- the I band remains the same length

c- the H band remains the same length

a- d-the sarcomere decreases in length

The contraction of myofibrils in skeletal muscle takes place

a- at the H band

b- at the M band

c- at the I band

d- between two I bands

e- between two Z bands

- The dark bands of skeletal muscle

a- has a central Z-line

b- has a central H-line

c- it is formed of myosin only

d- it is formed of actin only

e- has both actin and myosin

Transverse tubules:

a- are not present in smooth muscle

b- are extensions of the sarcolemma

c- serve to transmit signals to myofibrils deep within the cell.

d- form part of the diads found in cardiac muscle

e- All of the above