Why do animals have blood?

Oxygen Delivery: The primary function of blood is to transport oxygen from the lungs to the body's tissues and organs. Oxygen is absorbed in the lungs, and hemoglobin, an oxygen-carrying protein in red blood cells, binds to oxygen molecules. The oxygen-rich blood is then pumped throughout the body by the heart, ensuring a continuous supply of oxygen to all cells.

Carbon Dioxide Removal: Blood also plays a crucial role in removing carbon dioxide, a waste product of cellular metabolism, from the body. Carbon dioxide is carried back to the lungs by the blood, where it is released during the exhalation process.

Nutrient Distribution: Blood transports essential nutrients like amino acids, glucose, fatty acids, and vitamins from the digestive system to various parts of the body. These nutrients are necessary for growth, repair, and energy production.

Hormone Transport: Hormones are chemical messengers produced by glands and transported to target cells through the bloodstream. Blood helps in the distribution of these hormones, allowing them to regulate various physiological processes, including growth, reproduction, and metabolism.

Regulation of Body Temperature: Blood also contributes to maintaining body temperature within a relatively narrow range. When the body temperature rises, blood vessels near the skin dilate, increasing blood flow and promoting heat loss. Conversely, when the temperature drops, blood vessels constrict, reducing heat dissipation and conserving body warmth.

Waste Transport: Blood carries metabolic waste products from tissues and cells to the kidneys and liver for processing and elimination. The kidneys filter waste substances and excess water from the blood to produce urine, while the liver detoxifies and breaks down various harmful substances.

Protection: Blood contains specialized proteins and cells, such as antibodies and white blood cells, that play a vital role in the immune system and protection against pathogens and diseases.

Communication: Blood carries biochemical signals and signaling molecules throughout the body, enabling communication and coordination between different organs and systems.

Storage and Transport of Reserves: Blood plasma, the fluid component of blood, helps in storing and transporting essential ions, proteins, and molecules like glucose for quick access and utilization by the cells.

In summary, animals have blood to facilitate oxygen transport, carbon dioxide removal, nutrient delivery, hormone distribution, body temperature regulation, waste removal, protection, communication, and storage and transport of essential substances. Blood is a vital fluid that supports the overall functioning and survival of animals.