Human Lungs

The human lungs are the organs of respiration in humans. Humans have two lungs, with the left being divided into two lobes and the right into three lobes. Together, the lungs contain approximately the same length as 1500 miles (2,400 km) of airways and 300 to 500 million alveoli, having a total surface area of about 70 m2 in adults — roughly the same area as one side of a tennis court.

Function: Their principal function is to transport oxygen from the atmosphere into the bloodstream, and to release carbon dioxide from the bloodstream into the atmosphere.

How it work: In order to completely explain the anatomy of the lungs, it is necessary to discuss the passage of air through the mouth to the alveoli. Once air progresses through the mouth or nose, it travels through the oropharynx, nasopharynx, the larynx, the trachea, and a progressively subdividing system of bronchi and bronchioles until it finally reaches the alveoli where the gas exchange of carbon dioxide and oxygen takes place.

Circulatory System

The circulatory system is an organ system that passes nutrients, gases, hormones, blood cells, etc. to and from cells in the body to help fight diseases and help stabilize body temperature and pH to maintain homeostasis.
The human circulatory system is responsible for delivering food, oxygen, and other needed substances to all cells in all parts of the body while taking away waste products

Circulatory system is divided into two types. They are systemic circulation and Coronary circulation.These are the explanation ;

A. SYSTEMIC CIRCULATION
Systemic circulation is the portion of the cardiovascular system which carries oxygenated blood away from the heart, to the body, and returns deoxygenated blood back to the heart.

B. CORONARY CIRCULATION
Coronary circulation is the circulation of blood in the blood vessels of the heart muscle.

There is also the most important organ for circulatory system. That is heart. Heart is responsible for pumping blood throughout the blood vessels by repeated, rhythmic contractions.The vertebrate heart is composed of cardiac muscle, which is an involuntary striated muscle tissue found only within this organ.