Transport In Mammals - Session 1

We have studied about transport in plants. We know that the xylem and the phloem undertake a vital role in the transport of nutrients and minerals in plants. Have you ever wondered how the transport of nutrients and minerals takes place in animals? The mammalian circulatory system is responsible for the transport in mammals.

The mammalian circulatory system is a complex network of organs and vessels. It is responsible for transporting blood, oxygen, nutrients, and waste products throughout the body. It is also known as the cardiovascular system. This system ensures that all cells receive the necessary nutrients and oxygen while removing metabolic waste products.

There are various components of the circulatory system. The heart is the central organ of the circulatory system. It is a muscular, cone-shaped organ situated in the chest-cavity. It contracts rhythmically to propel blood throughout the body.

The blood vessels carry the blood in the body. There are three types of blood vessels. These are arteries, veins and capillaries. The arteries are thick walled blood vessels. They carry oxygenated blood away from the heart.

The largest artery is called the aorta. It branches into smaller arteries that progressively divide into smaller arterioles. The arteries have strong and muscular walls. These strong walls allow them to withstand the high pressure generated by the heart's contractions. They can constrict or dilate to control blood flow to different body parts.

The veins return deoxygenated blood from the body to the heart. The smallest veins are called the venules. The venules merge into larger veins and eventually into the superior and inferior vena cava. The veins often have one way valves to prevent the backflow of blood. This valve is especially seen in the legs where blood must flow against gravity to return to the heart.

The capillaries are the smallest and thinnest blood vessels in the body. They connect the arteries to the veins. They form an extensive network throughout tissues. The capillaries are the primary site of nutrient and gas exchange between the blood and surrounding cells. Oxygen and nutrients diffuse out of capillaries into tissues. The waste products like carbon dioxide diffuse into capillaries for transport away.

The human heart has four chambers. These are two upper chambers and two lower chambers. The upper chambers of the heart are called the atria. Atria receives the blood. There are two atria, the left-atrium, and the right-atrium.

The heart also contains two ventricles. These are the left-ventricle, and the right-ventricle. The ventricles are the lower chambers. They are responsible for pumping blood out of the heart.

The heart is divided into left-side and right-side by a thick muscular wall called the septum. This division ensures that oxygenated blood from the left-side does not mix with deoxygenated blood from the right-side. The oxygen rich blood is called the oxygenated blood. The oxygen poor blood is called the deoxygenated blood.

The heart has four valves that regulate the blood flow. The tricuspid valve is on the right-side. The bicuspid valve is on the left-side. These two valves are called the atrioventricular valves. These valves are located between the atria and the ventricles. These valves prevent backflow of the blood from the ventricles into the atria.

The other two valves are the pulmonary valve and the aortic valve. These valves are called the semilunar valves. These valves are located between the ventricles and the major arteries leaving the heart. The pulmonary valve is on the right-side. The aortic valve is on the left-side. They prevent backflow of blood from the arteries into the ventricles.

The heart has its own network of blood vessels called the coronary arteries. These arteries supply the heart muscle with oxygen and nutrients. The left coronary artery and the right coronary artery branch off from the aorta and wrap around the heart.

The pulmonary artery is one of the two main arteries that originate from the heart. The other major artery originating from the heart is the aorta. The pulmonary artery begins at the base of the right ventricle of the heart. It consists of two main branches. These are the left pulmonary artery and the right pulmonary artery.

The left pulmonary artery travels to the left-lung. The right pulmonary artery goes to the right-lung. Inside the lungs, the pulmonary artery branches into smaller arterioles, eventually leading to smaller capillaries in the lung tissue.