[Biology Class Notes] on Muscular System Pdf for Exam

Muscular system is an organ structure that assists in the motion of a human frame. A human muscular system comprises numerous fibres that ensure posture maintenance and blood circulation.

 

Approximately, there are around 700 muscles in a body that accounts for half of a person’s weight. Each of them is a distinct organ made up of blood vessels, tendons, skeletal tissues, etc. These tissues are also found inside various organs such as the stomach, blood vessels, etc.

 

Therefore, muscular system organs are accountable for the movement of the skeleton structure. Its contraction enables proper blood flow in human beings. However, there are various sorts of muscles resulting in the functioning of a physique.

 

Types of Muscular System

The human muscular system consists of various tissues that help in maintaining a stable bodily posture. These include –

 

1. Visceral: The muscles are available in organs such as intestines, stomach and blood vessels. Since these smooth muscles get controlled by the nervous system of a body, they are involuntary. The primary function of these tissues is to contract to make things move through an organ.

 

2. Cardiac: These tissues are found only in the heart of a human being, and they pump blood throughout the body. They are not in control of the conscious state of mind, and these cells of cardiac tissues are striated. When the brain signals these muscles, they tend to contract, resulting in a movement of the heart. Unlike smooth muscles, cardiac tissues are firm, and they appear to comprise light  and dark stripes when one places them under a light microscope. The colour of bands results due to the positioning of protein fibres within the cells. These cells are in a branched format of X or Y- shape connected firmly at specific joints known as intercalated disks. These disks consist of projections similar to a finger that ensures to maintain intense bondage between these cells. Both the branched format and disks help cells to prevent high blood pressure throughout life.

 

3. Skeletal Muscle: These muscular system parts are only voluntary tissues in the entire human frame. For every action that a person performs requires the functioning of these muscles, such as eating, dancing, jumping, etc. Their contraction allows movement in all parts of a body.

 

They move to create a pull in the tendons, shortening the tissue length, and nearing bones close to each other. Most of them attach with the bones via durable bands of connective tissue known as tendons.

 

Functions of Muscular System

The human muscular system helps to perform various types of activities and allows several daily functions. Some of these are listed below –

 

1. Maintain Posture: Another vital activity of the muscles is to keep the human frame in the correct position. They help a person to balance their physique and accurately perform all movements.

 

2. Movement: The primary muscular system function is the motion of body parts. When they contract, it results in various activities such as walking, eating, running, etc. Tiny skeletal muscles are accountable for the finest movements, such as writing, speaking, etc.

 

3. Blood Circulation: The muscles present in the heart ensure proper flow of blood to various portions of the body.

 

4. Respiration: For breathing purposes, there is a necessity of the diaphragm muscle. It relaxes pushing air from the lungs.

 

5. Digestion: Smooth muscles present in the stomach and intestines ensure proper digestion in a person.

 

6. Regulation of Temperature: The muscular system is also accountable for maintaining stable body temperature.

 

The muscular system is a group of tissues that make up the human body and are responsible for the movement of the bones. Tendons attach the bones to muscles. Muscles work in pairs, one muscle contracting while the other relaxes. This facilitates movement in all directions.

 

Types of muscle tissue

Three types of muscle tissue are currently known: skeletal, cardiac, and smooth.

1. Skeletal muscles are voluntary muscles that we use to move our arms and legs. They are attached to the skeleton and controlled by the brain. Here are some Examples related to skeletal muscles: biceps, triceps, quadriceps

2. Smooth muscle is found in organs such as the stomach and intestines and is also involuntary. It contracts and relaxes to push food through the digestive system.

3. Cardiac muscle is found in the heart and is also involuntary. It contracts and relaxes to pump blood around the body.

 

There are also two types of fibres within each type of muscle tissue: slow-twitch and fast-twitch. Slow-twitch fibres contract for a long time and produce low levels of force, while fast-twitch fibres contract quickly but fatigue quickly. This is why marathon runners have a higher percentage of slow-twitch fibres than sprinters.

 

Functions of different type of muscles

1. Functions of Skeletal muscles are:

• To move the bones by pulling on the tendons, to maintain posture, and to produce heat.

• Skeletal muscles are attached to the skeleton and controlled by the brain.

• There are three primary functions of skeletal muscle tissue: locomotion, posture maintenance, and heat production.

• The ability to move from one place to another is called locomoti
  on.

• Posture maintenance is keeping our bodies in correct positions, for example sitting up straight.

• Heat production is generating heat energy which helps keep our internal temperature stable.

 

2. Functions of Smooth muscles are:

• Smooth muscles are found in organs such as the stomach and intestines and are also involuntary.

• Smooth muscles perform contraction and relaxation in order to move food through the digestive system.

• The functions of smooth muscles are related to movement, secretion, absorption, vasoconstriction or vasodilation (relaxing blood vessel walls), filtration, peristalsis (muscular contractions that move substances along a tube) motion of material within body cavities.

 

3. Functions of Cardiac muscles are:

• Cardiac muscles are found in the heart.

• It contracts and relaxes to pump blood around the body.

• The functions of cardiac muscle are related to movement, specifically pumping blood throughout our bodies.