Question

What are involuntary muscles? Where are they found?

Answer 1

Hint: Muscle is a soft tissue found in most animal bodies.
Main purpose is to help us to move our body parts. Voluntary muscles are the type of muscles that are under conscious control and we can choose when to use them. They are also known as skeletal muscles that are attached to bones.

Complete answer:
Muscles: It is a tissue found in most of the animals. Muscle cells contain protein filaments of actin and myosin that slide past on one another and produce a contraction that changes both the length and the shape of the cell. Its function is to produce force and motion. They are primarily responsible for maintaining and changing posture of the body, helping in locomotion as well as movement of internal organs, such as the contraction of the heart and digestion.

There are mainly three types of muscle found in the body.
1. Skeletal muscle or voluntary muscle.
2. Smooth muscle or involuntary muscle.
3. Cardiac muscle.

Involuntary muscle: It is also known as white or smooth muscles.
- They are those types of muscles in the human body whose contraction is controlled by the autonomic nervous system.
- It includes all muscles whose activity is independent.
- They are mainly located within the body like lungs, and intestinal urinary bladder etc.
- They help you in breathing, in propelling food along the gut but you don’t have to think about using them or make them move. They just do it naturally even though you can stop them or make them go.
- Cardiac muscles found only in the heart are also an involuntary muscle as the nervous system does not control their activity directly.

Note: According to the sliding filament theory, the myosin filaments of muscle fibers slide past the actin filaments during muscle contraction. During muscle contraction the actin filaments slide over the myosin filament.
Step 1: Myosin head attaches to actin.
Step 2: myosin head pivots pulling the actin filament toward the center.