Medical Quiz

Cell and Muscle Histology Quiz


Which characteristic is unique to cardiac muscles?

A. Contain centrally located nuclei

B. Striated

C. Often branched

D. Multinucleated

E. Lack T-tubule

Which feature typifies T-tubules?

A. Evaginations of the sarcoplasmic reticulum

B. Sequester calcium during muscle relaxation, releasing it during contraction

C. Carry depolarization to the muscle fiber interior

D. Overlie the A-I junction in cardiac muscle cells

E. Rich supply of acetylcholine receptors

All of these are thin filaments except for:

A. Myosin

B. Actin

C. Tropomyosin

D. Troponin

The basal lamina of a muscle fiber is part of which structure?

A. Perimysium

B. Epimysium

C. Fascia

D. Endomysium

E. Sarcoplasmic reticulum

What do you call #3?

A. A-band

B. I-band

C. M-line

D. Z-disc

E. H-zone

What is the sarcolemma?

A. Cytoplasm of muscle cells

B. Smooth ER of the muscle cells

C. Membrane and external lamina of muscle cells

D. Repetitive functional unit of muscles

What muscle is also known as visceral muscle?

A. Smooth muscle

B. Skeletal muscle

C. Cardiac muscle

What do you call #1?

A. A-band

B. I-band

C. M-line

D. Z-disc

E. H-zone

What specialized junction is an anchoring site for actin?

A. Intercalated disc

B. Fasciae adherents

C. Gap junctions

D. Desmosomes

Muscle cells are _______ origin.

A. Mesodermal

B. Endodermal

C. Ectodermal

What type of muscle is found in the walls of the organs?

A. Smooth muscle

B. Cardiac muscle

C. Smooth and cardiac muscles

D. Skeletal muscles

E. Smooth and skeletal muscles

With the transmission electron microscope skeletal muscle fibers can be seen to contain structures called triads. What do the two lateral components of a triad represent?

A. Attachment sites for thick myofilaments

B. Sites for calcium sequestration and release

C. Sites for impulse conduction into the fiber

D. Sites for ATP production

E. Sites for synthesis of proteins to be secreted outside the cell

What do you call #2?

A. A-band

B. I-band

C. M-line

D. Z-disc

E. H-zone

It is responsible for initiating muscle contraction in skeletal muscles.

A. Sarcoplasmic reticulum

B. Sarcolemma

C. Sarcomere

D. Sarcoplasm

Which characteristic is unique to smooth muscle?

A. T-tubules lie across Z lines

B. Cells have centrally located nuclei

C. Each thick filament is surrounded by six thin filaments

D. Thin filaments attach to dense bodies

E. Cells are multinucleated

What proteins are absent in smooth muscles?

A. Tropomyosin and troponin

B. Troponin and myosin

C. Tropomyosin and myosin

D. Troponin and actin

Myelinated motor nerves innervate the muscle via

A. Acetylcholine

B. Norepinephrine


D. Epinephrine

In smooth muscle, calcium released by the smooth ER initiates contraction by binding to what protein?

A. Actin

B. Calmodulin

C. Desmin

D. Myosin light chain kinase

E. Tropomyosin

What is the functional unit of a muscle?

A. Epithelial cell

B. Mesenchymal cell

C. Myoblast

D. Sarcomere

Which of the protein pairs are found in thick and thin filaments respectively?

A. Actin-myosin

B. Troponin-tropomyosin

C. Desmin-vimentin

D. Myosin-actin


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