30 Questions
Smooth muscle cells have different physical dimensions in order to
adapt to different organs
Smooth muscle cells are organized into bundles or sheets to
enable coordinated contractions
Smooth muscle cells respond to different stimuli, including
neural, hormonal, and local factors
Smooth muscle cells receive nerve signals from the
autonomic nervous system
Smooth muscle cells adjust their physical dimensions to
fit the specific organs they are in
The organization of smooth muscle cells into bundles or sheets allows for
coordinated contractions
Smooth muscle cells can respond to a variety of stimuli, including
neural, hormonal, and local factors
Smooth muscle cells receive nerve signals from the
autonomic nervous system
Smooth muscle cells adjust their physical dimensions to
fit the specific organs they are in
The organization of smooth muscle cells into bundles or sheets allows for
coordinated contractions
Smooth muscle is found in which of the following organs?
Uterus
Which type of smooth muscle contracts as a single unit?
Single-unit smooth muscle
Which type of smooth muscle has discrete, separate muscle fibers?
Multi-unit smooth muscle
Which type of smooth muscle is found in the ciliary muscles of the eyes?
Multi-unit smooth muscle
What is the arrangement of actin and myosin filaments in smooth muscle?
Random arrangement
What is the major source of Ca2+ for smooth muscle contraction?
Extra cellular fluid
How much can smooth muscle contract compared to skeletal muscle?
80% of its length
What is the energy requirement to maintain the contraction of smooth muscle compared to skeletal muscle?
1/10 to 1/300
Which of the following is a location where single-unit smooth muscle is found?
Uterus
What is the function of smooth muscle in the body?
All of the above
Which of the following is true about smooth muscle fibers?
Some larger smooth muscle cells have caveolae near the cell membrane.
What is the role of caveolae in smooth muscle fibers?
They excite calcium release from the sarcoplasmic reticulum (SR).
How does smooth muscle contraction differ from skeletal muscle contraction?
Smooth muscle uses calmodulin as a calcium-binding protein.
What is the role of activated calmodulin in smooth muscle contraction?
It activates myosin light chain kinase (MLCK).
What happens when myosin is phosphorylated in smooth muscle contraction?
It binds to actin, forming a cross-bridge.
What is the role of myosin phosphatase in smooth muscle relaxation?
It removes phosphate from the myosin light chain.
Which factor determines the rate of contraction in smooth muscle fibers?
The extent of the sarcoplasmic reticulum (SR).
What is the role of calmodulin in smooth muscle contraction?
It phosphorylates myosin.
Which protein is responsible for phosphorylating myosin in smooth muscle contraction?
Myosin light chain kinase (MLCK)
What is the effect of reducing calcium ion concentration in smooth muscle?
It causes muscle relaxation.
Test your knowledge on the distinctive characteristics of smooth muscle. Learn about its physical dimensions, organization, response to stimuli, and nerve signaling.
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