Human Body Systems – Concept and characteristics

We explain what the systems of the human body are, what are their various functions and their main characteristics.

Human body systems
The correct functioning of the systems keeps the human being alive.

What are the systems of the human body?

When we talk about the systems of the human body we refer to the different sets of organs that compose it, collaborating in each case with the fulfillment of some specific type of functions. Seen this way, our body can be understood precisely as a simultaneous and juxtaposed set of systems, whose correct functioning keeps us alive.

Each of these human body systems involves various (and sometimes the same) organs, as well as various ducts, tissues, and glands, all coordinated by endocrine substances and nerve impulses, in order to operate more or less autonomously as the case may be.

This systemic understanding of the human body is particularly useful for medicine, which often consists of specialized branches in each of these systems: cardiology, endocrinology, gastroenterology, etc.

Nervous system

Central Nervous System
The central nervous system is made up of the brain, cerebellum, and telencephalon.

The nervous system is the main control system of the human body, which involves a very extensive network of nerves, made up of thousands of nerve cells (neurons and gliomas, mainly). This system fulfills the function of voluntary movement and decision-making, as well as conscience; but also with the internal and passive control of the organism, such as the regulation of involuntary movements, reflexes and other forms of nervous information transmission, such as the senses, pain, pleasure, etc.

The nervous system can be classified into the Central Nervous System, which make up the brain, cerebellum and telencephalon, located within the skull, as well as the spinal cord within the spinal column, to which a vast network of nerves is connected. of different size and importance that make up the Peripheral Nervous System.

Endocrine system

Endocrine System - Glands
Hormones are produced by the glands of the body and released into the blood.

This is the name of a complex system of internal regulation, which uses biochemical compounds called hormones to start, regulate or stop various body processes. These hormones are produced by the glands of the body and released into the blood, through which they travel to their destination. Thanks to hormones, metabolic, sexual and growth aspects of the body can be regulated, and even thermoregulation.

Respiratory system

Respiratory system
Breathing is a semi-reflex movement.

It is the one that involves oxygenation of the blood and the expulsion of carbon dioxide, essential processes for cellular respiration and energy metabolism. The lungs, bronchi and the entire airway from outside the body to them are involved in this apparatus: the trachea, pharynx, larynx, nose and the muscle that allows the inflation and deflation of the lungs: the diaphragm.

Breathing is a semi-reflex movement, which can be controlled but not prevented voluntarily, and that occurs by expanding the rib cage so that the air enters through the nostrils, where it is filtered by the nasal hairs, and descends to the lungs and in the bronchi, oxygen permeates into the blood. At the same time, the carbon dioxide accumulated in it is retained and exhaled in the opposite direction through the same ducts.

Circulatory system

Circulatory system
The heart operates like a pump, sucking in the blood and pushing it back.

Blood is the vehicle for oxygen that enters the lungs and must be distributed throughout the body. To do this, the blood encompasses a huge network of arteries and capillaries that they carry oxygenated blood to every corner, and from veins that collects the blood loaded with carbon dioxide and makes the journey back to the lungs, to start the circuit again.

The engine of this movement It is a muscle that constantly beats in our chest and is called the heart. This works like a pump, sucking the blood and pushing it back through a system of independent cavities that prevents the arterial and venous blood from mixing. This role is essential in the body and any defect that reduces the capacity of the heart has effects on general health.

Digestive system

Digestive system
Nutrient absorption occurs in the small and large intestines.

This is the necessary system for nutrition and food, that is, the assimilation of organic matter from outside the body. The circuit of this system begins with the mouth, tongue and teeth, as well as the salivary glands. There the food is cut, crushed, moistened and prepared (since then called “food bolus”) for its descent through the esophagus until it reaches the stomach, a kind of cauldron of gastric acids that disintegrate food and reduce it to its most basic elements. .

In said process the liver and pancreas are also involved, whose hormones and substances prepare everything for the absorption of nutrients, which occurs in the intestine (small first and large later), thanks to a series of villi that connect with blood capillaries.

Once the nutrients are retained, the rest of the organic matter ingested continues its course towards the large intestine and its final parts: cecum, colon and rectum, where they are stored until the moment of their expulsion through the anus, in defecation.

Follow in: Digestive system

Excretory system

Excretory system
Urine is expelled through the urethra out of the body.

Also called the urinary system, it is the system in charge of ridding the body of harmful metabolic substances and waste, whose accumulation in the body is risky. For this, it has two types of expulsion routes:

  • The sweat glands. Which are found along the skin and expel sweat, a saline liquid in which we get rid of many harmful substances and pathogenic microorganisms.
  • The urinary system. Composed of the kidneys, blood filters in which the metabolic waste substances (such as urea) are deposited and become urine, then stored in the bladder, where it arrives through the ureters after various processes of reabsorption and filtering of usable substances. When the urine is enough (around 400 cc) it is expelled through the urethra out of the body, in what is known as urination.

Reproductive system

Female reproductive system
In the uterus, the sperm and the ovum unite to give rise to a zygote.

This is the system that guarantees the human body its ability to procreation, that is, to generate new individuals of the species. Since our reproduction is always sexual, this device is substantially distinguished between men and women, as follows:

  • Male reproductive system. It is composed primarily of the penis, a highly sensitive organ that forms the corpora cavernosa that can fill with blood during sexual arousal, thus generating an erection and hardening of it, ready to penetrate the female genital tract. Then there are the man‘s external sex glands, the testes, located in the scrotum, in separate sacs below the penis. Male gametes, sperm, are constantly produced there, together with a substance that accompanies and nourishes them, semen, also produced thanks to the intervention of an internal organ known as the prostate. All this is ejaculated during intercourse inside the woman’s body, so that fertilization takes place there.
  • Female reproductive system. Like the male, it has sexual glands known as ovaries, where the female gametes are formed: the ovules. These descend to the uterus through a channel known as the fallopian tubes once a month, and if they are not fertilized, they are eliminated along with menstruation. There in the uterus is where the union of sperm and ovum occurs, to give rise to a zygote from which a fetus will be produced. During intercourse, the penis enters the female body through the vagina, a canal that connects the external genitalia (labia majora and minora and the clitoris) with the uterus.

Immune system

White blood cells
White blood cells do their best to isolate and expel the intruder.

The immune or immune system is the person in charge of the defense of the organism, identifying, chasing and eliminating foreign bodies and substances that can penetrate it. For this, it has a series of organs that produce white blood cells (lymph nodes, spleen, thymus and bone marrow) of different types: cells specialized in discovering, attenuating and expelling potentially harmful agents, such as bacteria, viruses, etc. .

These white blood cells or lymphocytes travel through the human body through the integument and the lymphatic system, as well as through blood and other fluids. When they find a sign of infection or intoxication, they trigger the body’s alerts and do their best to isolate and expel the intruder, either through the excretory or digestive system, or even through secretions such as pus or mucus, which sprout from mucous membranes or infected regions, as the case may be.

Locomotor system

Locomotor apparatus
The locomotor system allows the body to move or move its limbs at will.

The locomotor system is the union of the muscular apparatus and the skeletal apparatus, which are respectively composed of the almost 650 muscles of different sizes and shapes that allow the body to mobilize, and the 206 bones also of different shapes and sizes that support the body and serve as protection for the internal organs.

Thanks to these two systems the human body retains its shape and posture, and also can move or move its limbs at will, which is essential for life.