The Human Circulatory system

The circulatory system is a network consisting of blood, blood vessels, and the heart. This network supplies tissues in the body with oxygen and other nutrients, transports hormones, and removes unnecessary waste products.

This system is a complex network consisting of arteries, veins, capillaries and the heart. Its primary role is to supply essential nutrients, minerals and other important components such as hormones to various parts of the body. Alternatively, the circulatory system is also responsible for collecting metabolic waste and toxins from the cells and tissues to be purified or expelled from the body.

Features of the Human Circulatory System

Human Circulatory System consists of blood that transports, nutrients, gases, wastes and hormones.

The heart consists of two pumps:
one to pump deoxygenated blood (blue vessels) to the lungs and the other to pump oxygenated blood (red vessels) to different organs and tissues.

Human Circulatory System consists of a system of blood vessels to circulate blood throughout the body.

It consists of organs like lungs and intestines that add materials to the blood and lungs and kidneys that remove wastes from the blood.

The Heart

The heart is a muscular organ about the size of a clenched fist. The heart is located towards the front of the cheast on the left side. The human heart is divided into four chambers – two upper chambers(left & right atria) and two lower chambers (left and right ventricles) which are filled with blood.

Blood enters the heart via veins that drain into the atria. The blood then moves into the ventricles and exits the heart via the arteries.

The role of the heart is to squeeze the blood in the two arteries for transport the blood in the two ventricles sufficiently for it to rush out of the heart and into the arteries for transport around the body

Blood Components

Blood, by definition, is a fluid that moves through the vessels of the circulatory system. In humans, it includes plasma (the liquid portion), blood cells (which come in both red and white varieties), and cell fragments called platelets.

  • Plasma is the main component of blood and consists mostly of water, with proteins, ions, nutrients, and wastes mixed in.
  • Red blood cells are responsible for carrying oxygen and carbon dioxide.
  • Platelets are responsible for blood clotting.
  • White blood cells are part of the immune system and function in immune response.

Cells and platelets make up about 45% of human blood, while plasma makes up the other 55%.

Blood Vessels

The major arteries are vessels that carry blood away from the heart, while the major veins carry blood towards the heart. Veins hold about tow third of all the human body. Veins are less muscular than arteries and are usually closer to the skin. Some arteries are close enough to the skin for a person to feel the pulse of the blood, such as the radial artery at the wrist.