Category: 1. Human Body

The lymphatic system is involved in the removal of interstitial fluid from tissues, the transport of absorbed fats after digestion, and in protection. Immune cells and substances travel via the lymphatic system, sampling lymph for any potential invaders and mounting an immune response if needed.

There are a lot of systems, so let’s quickly summarize them. The integumentary system covers the entire body, protecting it from damage and regulating body temperature. The scaffold is provided by the skeletal system onto which the muscles act, ultimately facilitating movement. The nervous and endocrine systems are the main regulators, controlling the activity of almost everything via nerves and hormones, respectively.

The respiratory and circulatory systems keep us alive by facilitating breathing and pumping blood around the body, while the digestive systems permits feeding. The resulting wastes are removed and excreted from the body by the urinary system. Last but not least, the reproductive system prevents humanity from going extinct, while the lymphatic system transports lymph and plays a role in the protection from microorganisms.

The main responsibility of the reproductive system is to facilitate the generation of new offspring and to pass on our genes. The female system produces the eggs and nourishes the developing fetus until birth, while the male system synthesizes sperm and delivers it towards the egg to aid fertilization.

The urinary (excretory) system is the major filtering unit of the human body, being responsible for purifying the blood and eliminating wastes. The entire blood is continuously passed through the kidneys and the resulting unwanted or toxic substances are passed to the bladder, ultimately being eliminated via the urethra.

The digestive system is essentially a hollow system with two openings consisting of several organs. Food is ingested via the mouth, it is processed and absorbed inside the system, and the resulting solid wastes called feces are eliminated via the anus.

The main function of the respiratory system is to keep us alive via the inhalation of oxygen and elimination of carbon dioxide. The lungs and alveoli represent the site of gas exchange, which involve a series of convoluted air passages and membranes.

The circulatory system is responsible for keeping us alive by providing oxygenated, arterial blood, to every part of the human body. The key player is the heart, an organ that pumps oxygenated blood into arteries, which then returns back to the heart via veins as deoxygenated blood.

The endocrine system consists of glands that release substances called hormones into the bloodstream. These hormones allow chemical communication between anatomical structures, inducing various regulatory effects upon reaching their targets.

Nerves are responsible for transporting electrical impulses, which permit communication between the brain, spinal cord, our senses, and every peripherical anatomical structure. This communication allows humans to interact with their environment, sense, feel emotions, think, and perform many other complex cognitive tasks.

The 200 bones of the human body act as a scaffold, providing support, protection, facilitating locomotion, and even storing various cells and substances. The bones are the pulley systems onto which muscles act, the latter being capable of contracting and relaxing, ultimately producing movement.

The integumentary system consists of the skin and its associated appendages, such as hair follicles, nails, sweat glands, and sebaceous glands. It is involved in a variety of functions, including protection, tactile and thermal sensation, as well as temperature regulation through sweating.