Muscles and nerve fibers allow us to move our bodies. It allows our internal organs to work. The human body contains more than 600 muscles, which represent about 40 percent of body weight.
All muscles are made of a type of elastic tissue.
Each muscle consists of thousands or tens of thousands of small muscle fibers. Each muscle fiber is approximately 40 mm long. It consists of small fiber threads.
Each muscle fiber is driven by a nerve, which causes it to shrink. Muscle strength depends mainly on the number of fibers present.
To nourish the muscle, the body metabolizes food to produce adenosine triphosphate, converting ATP muscle cells into mechanical energy.
Types of muscle
Humans and other vertebrates have skeletal, smooth and cardiac muscles.
Skeletal muscles move the external parts of the body and limbs. Skeletal muscles cover the bones and shape our bodies.
For every skeletal muscle in the human body there is one identical on the other side.
There are about 320 pairs of identical muscles. When one muscle contracts, the other expands, allowing movement.
The muscles are attached to strong tendons, and the tendons are attached to the bones or directly connected to them. Tendons extend over the joints, and this helps keep the joints stable. We consciously control the muscle and skeleton.
Most of the movements that we can see occur when skeletal muscles contract. These include moving our eyes, head, arms, fingers, running, walking and talking.
Skeletal muscles control facial expressions, such as smiles, frown, mouth and tongue.
Skeletal muscles make small adjustments to maintain position. They keep the person’s back straight or keep the head in one position. The bones must remain in the correct position so that the joints do not separate. Skeletal muscles and tendons do this.
Skeletal muscles also generate heat when they contract and release. This helps maintain body temperature. About 85 percent of the heat generated by the body is due to muscle contraction.
Types of skeletal muscle
Skeletal muscles are divided into different types
The first type: Red or slow muscles: these are dense and capillary. It is rich in myoglobin and mitochondria. This gives them red color. This type of muscle can contract for a long time without making too much effort. Type 1 muscles can maintain aerobic activity using carbohydrates and fats as fuel.
The second type: These muscles can contract quickly and with great force. Deflation is strong but short-lived. This type of muscle is responsible for most of our muscle strength, and our group increases after periods of weight training. It is the least dense in myoglobin and mitochondria.
Skeletal muscles are striated muscles. It consists of thousands of sarcomeros, or muscular units. Smooth muscles are not scratched.
Striped muscles appear striated under a microscope, because each muscle division consists of parallel ranges of different materials.
When the gangs in the sarcomas relax or contract, the entire muscles stretch or relax.
Different teams interact within each muscle, which allows the muscle to move hard and smoothly.
The muscles of the heart are responsible for the heartbeat. It is only present in the heart.
The heart muscles work nonstop, day and night. It works automatically, but is similar in structure to skeletal muscles. Sometimes they are classified as striated muscles.
It causes the heart to contract so that it can press our blood and release it until the heart is filled with blood again.
Smooth muscles are responsible for movements in the stomach, intestines, heart, arteries and hollow organs. The smooth muscles of the intestine are also called visceral muscles.
These muscles are activated automatically. We are not aware that we are using it. Unlike skeletal muscles, they do not depend on conscious thinking.
The smooth muscles in the walls of the intestine contract and push the food forward. During childbirth, smooth muscles contract in a woman’s uterus. Our students shrink and expand, depending on the amount of light there is. These movements depend on the movements of smooth muscles.
Smooth muscles are also found within the walls of the bladder, bronchial tubes and erect penis on the skin, leaving hair upright.