Question

In what three ways is contraction in smooth muscle like contraction in skeletal muscle?

Answer 1

Smooth and skeletal muscle contractions are similar in that both use actin-myosin interactions, require ATP for energy in contractions, and depend on intracellular calcium to initiate contraction. There are, however, significant differences in how they are controlled and their structural properties.

Step-by-step explanation:

Contraction in smooth muscle and skeletal muscle shares several similarities. Here are three ways in which their contraction processes are alike:

1. Both types of muscles employ the movement of actin against myosin to create contraction. This is a fundamental mechanism of muscle contraction in which myosin heads pull on actin filaments, causing the muscle to shorten.
2. The energy for this contraction is provided by ATP, which powers the cross-bridge cycle allowing myosin to attach, pivot, and detach from actin filaments repeatedly. ATP’s role is crucial in muscle physiology, providing the chemical energy necessary for muscle movement.
3. Both smooth muscle and skeletal muscle require an increase in intracellular calcium concentration to initiate contraction. In skeletal muscles, excitation-contraction coupling involves the neurotransmitter acetylcholine and leads to calcium release, while in smooth muscle cells, calcium entry is often triggered by various stimuli, including hormonal or neural signals.

Despite these similarities, there are also significant differences between the two muscle types, such as control mechanisms and structural characteristics. Skeletal muscle contractions are typically under voluntary control, while smooth muscle movements are involuntary, controlling functions such as peristalsis and blood vessel constriction.