Smooth muscle vs Cardiac and skeletal muscle
How to tell Smooth muscle and Cardiac and skeletal muscle apart when a board question makes them look alike.
Smooth is nonstriated visceral spindle; cardiac is striated branching intercalated discs; skeletal is striated voluntary multinucleated peripheral nuclei.
Side by side
Smooth muscle is nonstriated, involuntary, spindle-shaped, single central nucleus, dense bodies, and autonomic/visceral control.
Cardiac muscle is striated involuntary branching with intercalated discs; skeletal muscle is striated voluntary multinucleated fibers with peripheral nuclei.
Smooth muscle is nonstriated, involuntary, spindle-shaped, single central nucleus, dense bodies, and autonomic/visceral control.
Cardiac muscle is striated involuntary branching with intercalated discs; skeletal muscle is striated voluntary multinucleated fibers with peripheral nuclei.
The repair move
Before naming the answer, force the stem through the separator: Smooth is nonstriated visceral spindle; cardiac is striated branching intercalated discs; skeletal is striated voluntary multinucleated peripheral nuclei.
Try a free question
CoreA histology slide shows nonstriated, spindle-shaped cells with single central nuclei, arranged in fascicles in the muscular layer of the small intestine. These cells contract slowly and rhythmically under autonomic control. Which muscle type is this?
Show answer and explanation
Answer: A. Smooth muscle. Smooth muscle is nonstriated, involuntary, spindle-shaped with single central nucleus, has dense bodies (instead of Z-discs), uses Ca2+/calmodulin/MLCK for contraction, and is under autonomic and hormonal control. Found in GI tract, blood vessels, airways, bladder, uterus.
Why the other choices are tempting
- B. Cardiac muscle is STRIATED, involuntary, branching with intercalated discs, single central nucleus.
- C. Skeletal muscle is STRIATED, voluntary, multinucleated with peripheral nuclei, parallel fibers.
- D. Myoepithelial cells are contractile cells around glandular acini but are epithelial in origin.
- E. Cardiac conduction system cells (Purkinje, SA node) are modified cardiac myocytes.
Flashcards
Tap a card to flip it.
What clue supports Smooth muscle?
Choose Smooth muscle when the stem gives this pattern: Smooth muscle is nonstriated, involuntary, spindle-shaped, single central nucleus, dense bodies, and autonomic/visceral control.
What clue supports Cardiac and skeletal muscle?
Choose Cardiac and skeletal muscle when the stem gives this contrasting pattern: Cardiac muscle is striated involuntary branching with intercalated discs; skeletal muscle is striated voluntary multinucleated fibers with peripheral nuclei.
Quick answers
What is the fastest way to tell Smooth muscle from Cardiac and skeletal muscle?
Smooth is nonstriated visceral spindle; cardiac is striated branching intercalated discs; skeletal is striated voluntary multinucleated peripheral nuclei.
What is the key clue for Smooth muscle?
Smooth muscle is nonstriated, involuntary, spindle-shaped, single central nucleus, dense bodies, and autonomic/visceral control.
What is the key clue for Cardiac and skeletal muscle?
Cardiac muscle is striated involuntary branching with intercalated discs; skeletal muscle is striated voluntary multinucleated fibers with peripheral nuclei.