Rivers, blood and transportation networks

Blood is pumped by the heart into the aorta, the largest artery in the body, and then into increasingly smaller arteries, arterioles, and capillaries. The velocity of blood flow decreases with increased cross-sectional blood vessel area. As blood returns to the heart through venules and veins, its velocity increases. The movement of blood is encouraged by smooth muscle in the vessel walls, the movement of skeletal muscle surrounding the vessels, and one-way valves that prevent backflow.

Blood and lymph are fluid connective tissues. They contain cells, also known as formed elements, circulating in a liquid extracellular matrix, the plasma. The formed elements are derived from hematopoietic stem cells in the bone marrow. Blood and lymph connect all vital parts and carry nutrients, oxygen, and other essential molecules like antibodies.
Blood
The blood flows through blood vessels— arteries, capillaries, and veins. Blood plasma is primarily made of proteins, solutes, and water.

The cardiovascular system is a vital transportation system in the body. It comprises the heart and blood vessels and facilitates the exchange of gases, nutrients, and waste products.
Heart
The heart is the central pump of the cardiovascular system that circulates blood throughout the body. It comprises two atria receiving the blood and two ventricles pumping blood out of the heart. Their rhythmic contractions, called heartbeats, ensure that blood flow remains continuous.
Blood Vessels
Blood...

Blood is specialized connective tissue comprising about 8% of the body mass. It has a thick, liquid extracellular matrix that contains cells, dissolved proteins, and electrolytes, making it five times more viscous than water. Blood is warm, around 38°C, and has an alkaline pH ranging from 7.35 to 7.45.
The primary function of blood is to transport oxygen and carbon dioxide between tissues and the lungs. Oxygenated blood is bright red, while oxygen-depleted blood is darker. It also carries...

Blood is circulated throughout the human body through a network of blood vessels called the circulatory system. This system includes arteries that transport blood from the heart to various body parts. These arterial pathways divide into smaller vessels until they reach the arterioles, which further split into capillaries. It is within these minuscule capillaries that the exchange of nutrients and waste products takes place. After this exchange, the blood is collected by venules, which fuse to...

The vascular system, an integral part of the circulatory system, comprises various blood vessels that play crucial roles in maintaining the body's homeostasis. These blood vessels form a complex and efficient circulatory network. The three primary categories of blood vessels are the arteries, veins, and capillaries.
Arteries
Arteries circulate oxygenated blood from the heart, except the pulmonary artery, which transports deoxygenated blood to the lungs. Large arteries, such as the aorta, have...