Types of muscles

Types of muscles

type	work
Smooth muscles:
These muscles have a very smooth, uniform appearance when observed under a microscope.	Smooth muscles are involuntary as we cannot control their movement. These muscles perform actions without us thinking about them. They contract and relax to allow digestion and excretion.
Skeletal muscles:
Skeletal muscles work with our bones to give us strength. Skeletal muscles are attached to bones by tendons. Tendons are thin, flexible strings made up of tough tissues.	Skeletal muscles are voluntary in action as we can control their movements. Our leg would not Bend to kick the football unless we want it to.

Heart/cardiac muscle:

The heart or cardiac muscle makes up the heart.

Cardiac muscles contracts and relaxes to pump blood out of and into the heart. It is also involuntary as it works our help.

We have more than 6000 muscles in our body, which together account for about 40 percent of our weight. They do everything from pumping blood throughout our body to helping us lift heavy objects.

Our heart is made up of cardiac muscle. The heart is an important component of the circulatory system.

Circulatory system:

Our body system is composed of the heart, blood and vessels that carry blood.

Blood:

It is a flood that moves through blood vessels. Our blood consist of plasma, blood cells and platelets.

· Plasma is a liquid component of blood. It contains proteins, nutrients and wastes.

· Red blood cells carry oxygen and carbon dioxide.

· White blood cells fight against disease causing microorganisms. They are helpful in improving our internal defense mechanism.

· Platelets help to clot blood when you get injured.

Blood composition in %:

White blood cells: 1%

Plasma: 52-62%

Red blood cells: 38-48%

Platelets: 1%

Blood is of no use if it is not pumped throughout the body this important function is performed by our heart.

Heart the muscular pump:

The heart is an important organ in the circulatory system. It is hallow, muscular pump that circulates blood throughout the body.

Structure of heart:

The human heart has four chambers. The upper chamber are the right and left atriums. The lower two chambers are the right and left ventricles. The size of and adults heart is about the closed fist.

Dual circulatory system:

Our heart performs two circulations: one from the heart to the lungs and the other from the heart to all other body parts.

Circulation of deoxygenated blood:

Deoxygenated blood from the body enters the heart through the right atrium. It is then pumped into the right ventricle. It is known as tricuspid valve, as it has three flaps. The function of heart’s valves is to control the flow blood. The right ventricle contracts and blood is pumped into the lungs to take oxygen.

Circulation of oxygenated blood:

After getting oxygenated, blood enters the left atrium. The left atrium pumps this blood into the left ventricle. The valve present between the left atrium and left ventricle is called bicuspid or mitral valve, as it has two flaps. The left ventricle pumps blood to the aorta and to the rest of the body.