We explain everything about the human body, how it is composed and its characteristics. In addition, we explain the systems it presents and its vital stages.
What is the human body?
The human body is the physical, material presence of a human being. It is considered, from the traditional philosophical point of view, as one of the two aspects that constitute it in its entirety, together with the mind or the spirit.
From a biological point of view, the human body has the characteristics of a eukaryotic organismmulticellular, from the animal kingdom, belonging to the class of mammals and primates, the only member of the genus Homo (the others are extinct).
The constitution of the human body is the result of an evolutionary process almost 2 million years longfrom some common relative between the chimpanzee (Pan troglodytes) and man.
Numerous species of hominids emerged as the proto-human being configured his body to walk upright, oppose his thumbs and develop his brain, resulting in our species Homo sapiens with the body we already know, approximately 200,000 years ago.
Atomic composition of the human body
The human body It is composed mostly of water (H2O) which is found inside cells, in the blood and bathing all tissues. It is estimated that 65% of the adult human body is water.
Like that of every known living being, the human body is organic and is atomically composed of very complex molecular structures mainly from hydrogen atoms (60%), oxygen (25.5%), carbon (10.5%), nitrogen (2.4%), calcium (0.22%), phosphorus (0.13%), sulfur (0.13%), potassium (0.04%), chlorine (0.03%) among others.
Most of these elements make up our body Organic substances such as carbohydrates, lipids and proteins.
General characteristics of the human body
The human body It has an average height of 1.7 m (adult) and an average density of 933 kg/m3. Their weight ranges on average between 50 and 90 kg.
The surface of the body It is covered by about 2 m2 of skin with a variable thickness between 0.5 and 4mm.
Cellular composition of the human body
The human body It is made up of almost one hundred trillion eukaryotic cells. (with a defined nucleus), organized into tissues and these into organs. Human cells have a very high degree of specialization, and can be classified into:
- Nerve cells. Responsible for conducting electrical stimuli in the body.
- muscle cells. Which constitute the muscles that allow locomotion.
- Bone cells. In the bones that make up the skeleton and give structure and support to the body.
- Adipose cells. Which integrate the fatty tissues of energy storage and structure.
- Blood cells. Red blood cells to transport oxygen in the blood, white blood cells to defend the body, among other cell types.
- Reproductive cells. Eggs or sperm, called sex cells, for reproductive purposes.
- Parenchymal cells. They constitute the tissue without organs that provides density to the organism, called “parenchyma”.
Anatomy of the human body
At first glance, the human body is made up of three large segments:
- Head. Where are the sensing organs, the mouth and the nervous nucleus that controls the entire organism, the brain.
- Trunk. Where all the internal organs are located. Center of the body.
- Extremities. The various articulated members that allow locomotion (legs) and the handling of tools (arms), attached to the trunk.
The human body has bilateral symmetrythat is, it is organized in such a way that a vertical axis can be drawn that divides it in two and both halves will be similar.
Human body systems
The functioning of the various organs of the human body is classified into circuits called systems. The following are the main ones:
- Circulatory system. It is made up of the heart and the vast network of veins, arteries and capillaries, which allow blood to reach the different sectors of the body that need it.
- Cardiorespiratory system. System that includes the nose, trachea, bronchi, lungs and heart, and the tubes that connect them to the latter, allowing air to enter the body to extract the necessary oxygen and incorporate it into the blood.
- Nervous system. Composed of the brain, spinal cord and the network of nerve endings that allow control of the body and perception of sensations.
- Digestive system. It includes the mouth, esophagus, stomach and intestines, and fulfills the function of food: ingesting, dissolving and digesting the nutrients in food.
- Excretory system. It is responsible for eliminating residual liquid or solid substances from digestion and the body’s own functioning. It involves the kidneys, the bladder, the urinary tract.
Human skeleton
The human body It is supported and protected by more than 200 boneswhich are calcified and mineralized organic structures to gain resistance to impacts and the body’s own weight.
These bones make up the skeleton, a common and continuous structure that covers all areas of the body except the abdomenand that operates inside the body (endoskeleton) as opposed to the shell of other species (exoskeleton).
The skeleton also performs important functions in the segregation of blood cells or hematopoiesis.
Human microbiome
Inside the human body, and especially in the intestineinhabit numerous microbes (especially bacteria) that are harmless to the organism and often contribute to various functions of decomposition of organic matter.
It is estimated that There are about 10,000 bacteria on every square centimeter of human skin.and in total our body contains about 100 billion, which represents 1 to 3% of our body mass.
Sexual differentiation
The human body presents bodily sexual variation from the moment of birthsince individuals are born with defined sexual organs: penis and testicles in men and vulva and ovaries in women.
This differentiation It becomes more pronounced after adolescencewhen sexual awakening occurs due to hormones and the sexual maturation traits that distinguish the adult man from the adult woman take place, such as facial hair, erection and ejaculation, body hair and widening of the voice in men and emergence of the breasts, hip enlargement, menstruation in women.
It may be useful to you: Physical characteristics of men and women.
Getting energy from the body
Like all animals, the human body operates based on obtaining energy through the oxidation of glucosewhich requires both respiration to acquire oxygen and the consumption of organic matter to extract sugars.
This energy is what keeps the body running, and in the absence of food, the human body will proceed to extract organic matter from itself (from the fatty tissues first, then the muscle tissues). When it can no longer do so, it will stop working.
Life stages of the human body
The human body in its vital journey will normally go through the following stages from birth to death:
- Childhood. Helplessness stage that follows birth and during which breastfeeding is the only source of food. The bones of the head fuse and the body prepares to start growing.
- Childhood. Stage in which human beings learn to communicate, walk on their own and retain sphincters. The body begins its development and growth, accumulating the energy necessary for later stages.
- Adolescence. The stage of transition to adulthood, characterized by intense hormonal changes that entail physical, emotional and behavioral changes. Sexual differences develop.
- Adulthood. Full stage of development and sexual maturity.
- Old age. Stage of weakening of bodily functions due to fatigue and prolonged functioning. The body gradually abandons its reproductive needs and preserves its energy to maintain itself.