Depending on the affected organs or tissues and the reason for their appearance, we can classify any pathology or disease within one of these groups.
There are thousands of different diseases that can affect our body and it is totally normal, because the human body is extraordinary: it forms a perfect gear of many organs and tissues acting in synergy.
At this point in the sentence, maybe something sounds a little strange to you. If the human body is such a perfect machine, why are there so many diseases? Well, it is precisely in its richness of structures that this large number of pathologies can exist.
Although some people may think otherwise, our body is not made of stainless steel, quite the contrary. If our body were a material, it would be very plastic and malleable, precisely because adaptability is what makes the difference. But everything has a price, and the human being has paid for its structural complexity in this way.
In this article we will talk about the different types of diseases that can affect humans, all referring to their characteristics and causes. Do you dare to join us on this tour of the human body ?
The 15 types of diseases that affect humans
Faced with the multitude of different pathologies, the World Health Organization developed the International Classification of Diseases (ICD) , whose objective was to make a correct cataloging of all of them.
Currently, the ICD is one of the most widely used international standards for preparing morbidity and mortality statistics in the world, as well as being a very useful tool for understanding the classification of all diseases. Let’s see the different types of diseases that can affect the human being.
Oncological diseases
Known as cancer, it refers to a large number of diseases characterized by the development of tumors. Tumors are caused by an abnormal development of a group of cells that divide uncontrollably and have the ability to infiltrate and destroy body tissues. They can affect any part of the human body and have the ability to spread throughout the body through a process called metastasis.
Oncological diseases are the second cause of death in the world . However, survival rates are increasing for many types of cancer, thanks to advancing science driving improvements in detection and treatment.
Infectious and parasitic diseases
Infectious diseases are those that are caused by microorganisms such as bacteria, viruses, parasites or fungi considered. It is important to distinguish between pathogenic microorganisms and those that are not. During our day to day and since we are born we are in contact with thousands of microorganisms and not all of them have to cause us an infection or disease.
Due to the nature of their etiological agents, microorganisms, they are diseases that can sometimes be transmitted from one person to another . Sometimes, these microscopic agents need the participation of insects or other animals to be transmitted, they are called vector-borne infections, malaria being a clear example of these.
At other times, people can acquire infections when they consume water or food contaminated by pathogens. In the same way, there are also infectious agents that resist well in the environment, so there is also the possibility of acquiring infectious diseases by touching contaminated objects. If good hygiene habits are essential to prevent communicable diseases, in this last triad they acquire even more value.
Blood diseases
Blood is the tissue that circulates through the capillaries, veins and arteries of the human body. Its crimson color is due to the fact that red blood cells, the cells that are responsible for transporting oxygen throughout the body, have a pigment of this color. But the blood not only contains these but also contains white blood cells and platelets, all immersed in the plasma.
Blood diseases affect these aforementioned components, as well as the cells that are responsible for generating them (hematopoietic cells) and prevent them from fulfilling their functions.
Of the acute or chronic type, some can be hereditary such as hemophilia , while others can appear as a result of other diseases, side effects of some medication or due to the lack of certain nutrients in the diet, such as anemia.
Immune system diseases
The immune system performs “surveillance” tasks and is responsible for protecting the body against disease and infection. However, sometimes this can be weakened or altered and begin to perform its functions in an erroneous way and the person develops an immunodeficiency or an autoimmune disease.
When the immune system is unable to respond aggressively to an infection, it is called immunodeficiency. At the opposite pole, there is autoimmunity, where people also suffer the consequences of an overactive immune system that attacks their own cells as if they were foreign and dangerous agents.
Although a wide variety of diseases of the immune system are currently known (there are more than 300), their causes are not always well understood, although sometimes they tend to be hereditary. Many are similar in terms of symptoms, with the classic symptom of autoimmunity being inflammation. They are diseases that at a given moment can become more acute and worsen, but in the same way they can also remit and the symptoms can become lighter or even disappear for a long period of time.
Within this group of diseases there are also the so-called allergies , which occur when the immune system generates an exacerbated response to certain external agents such as pollen, food, substances and materials.
Endocrine diseases
The endocrine system, broadly speaking, is made up of eight glands distributed throughout the body and produces more than 20 hormones. Hormones act as clinical messengers and travel to tissues and organs via the bloodstream, serving roles in body processes that affect you from head to toe: assisting sexual function, modulating mood, metabolism, growth and development.
Endocrine diseases appear when the production of hormones is altered , either due to a decrease in secretion leading to a hormonal deficit or excessive production due to an increase in its secretion.
Hormone levels in the blood can become unbalanced for various reasons. It can be for genetic reasons, due to certain infections, stress or alterations in the composition of fluids and electrolytes in our body. Also, in some diseases, the problem can arise because the body does not properly recognize the hormones and they cannot carry out their functions.
Mental, behavioral and developmental disorders
There is a wide variety of mental disorders and each of them has different manifestations. They are syndromes that are characterized by causing an alteration in the cognition, emotional regulation or behavior of people. According to the WHO, its prevalence has been increasing over the years and causing considerable effects on the health of many people.
In general, these alterations are the result of a difference in mental functioning and can have repercussions on psychological processes or the development of people. An example of them are depression, anxiety, bipolar affective disorder or autism, a type of neurodevelopmental disorder.
The causes of this type of disease are very varied. It can be due to a genetic factor and, therefore, can be hereditary, as a result of stress or even food. In some, it may be due to perinatal infections or environmental hazards, such as Minamata disease, which is a serious syndrome caused by mercury poisoning.
There is a very interesting point that needs to be included. The determinants of mental health not only include individual characteristics such as the ability of people to manage their thoughts and behaviors, but also include social, cultural, economic and political factors . The standard of living and working conditions are two factors that can have a certain influence on its development, in addition to being able to hinder or benefit therapeutic strategies.
Diseases of the nervous system
Made up of the brain, spinal cord, and nerves, the nervous system acts as a communication center for our body . Divided into the central and peripheral nervous systems, it consists of neurons, cells specialized in transmitting signals between the different parts of our body.
We recommend you read: “The 4 parts of the nervous system (characteristics and functions)”
The nervous system is one of the most complex systems and receives the information from the sensory organs through the nerves, transmits it through the spinal cord and is finally processed by the brain. It coordinates the senses, movement and the ability to think and reason.
The symptoms of these neurological diseases will be conditioned by the area of the nervous system that is affected. In addition, they can be conditions of a degenerative nature , such as multiple sclerosis, which occur slowly and cause a gradual loss of neurological function.
Sometimes they can also appear suddenly or in response to an injury (accidental quadriplegia) and cause life-threatening problems. Causes include vascular disorders, head and spinal cord injuries, exposure to environmental toxins, brain infections, or excessive use of medications, drugs, and alcohol.
Ophthalmological and vision diseases
The eyes make up our organ of vision and without them our perception of the world would be, at least, a little different. They are a continuation of our nervous system and are responsible for capturing sensory stimuli. Many people suffer from eye defects. Myopia and astigmatism are a clear example of this, however, they are still refractive errors (non-sensitive) that can be corrected with the use of contact lenses or glasses.
Eye diseases vary depending on which part of the eye is affected (either the inner or outer part), so the causes can differ considerably. Sometimes, they can be caused by vascular problems. A clear example is a type of retinopathy that can occur in people with diabetes that damages the blood vessels of the eye. They can also be caused by trauma or degenerative processes.
With regard to diseases of the outer part of the eye, environmental agents play a favorable role. For example, blepharitis, a disorder that affects the eyelids, can be caused by dry eyes or mites (among others).
Hearing diseases
Auditory diseases follow the same trend as those of the vision group. Our ears house the auditory system, the set of organs that make the sense of hearing possible . These are diseases that can be caused by damage to the eardrum, a small membrane that acts like a drum, although they can also be the product of neurosensory conditions. The sign that defines them is hearing loss .
These hearing losses can originate from transitory causes. For example, in infancy, there are children who suffer from repeated otitis that compromises their hearing and can lead to adult deafness if not detected in time.
There are also a number of causes that cannot be reversed, such as genetic abnormalities, repeated exposure to noise (cumulative hearing loss), side effects of certain drugs, and more.
Cardiovascular diseases
Disorders that affect the heart and blood vessels are the leading cause of death worldwide . They are all those diseases that, after appearing for different reasons, affect the structure or physiology of the heart and the vessels that are responsible for supplying blood to the entire body.
The seriousness of these cardiovascular diseases lies in the fact that the circulatory system is jointly in charge of delivering oxygen and nutrients to all the other tissues of the body. Therefore, if this function fails, the body is seriously compromised. Among its causes is the consumption of tobacco and alcohol, diets high in sodium and fat, although they can also be due to congenital defects.
Respiratory diseases
The lungs are one of the most susceptible and sensitive organs in the body. They are constantly exposed to pathogens and contaminants from the external environment. Although they tend to affect the most disadvantaged countries more, they are diseases that do not understand economic income and affect all people equally.
Leaving behind those caused by bacteria and viruses (these are part of infectious diseases), respiratory diseases can include a variety of conditions including silicosis, asthma and chronic obstructive pulmonary diseases, among others. Among its causal agents are smoking, air pollution by dust and toxic gases, and occupational exposure to irritating agents.
Diseases of the digestive system
The digestive system is made up of many different organs, therefore, they are conditions that can occur in the stomach, intestines, esophagus, mouth… The symptoms depend a lot on the affected digestive organ , and the same happens with the level severity of each pathology.
Digestive disorders cause problems in the processing and elimination of food. But what are these digestive problems due to? Well, we are faced with a multifactorial problem. Some of these are the low production of certain digestive enzymes, lesions in the intestinal wall, deficiencies in the mucosa and the influence of certain cytokines of the digestive system…
Skin diseases
Being the skin the largest organ of the body, it is normal that there is a category for dermatological diseases that affect our main natural barrier . They are usually very visible disorders, but in the vast majority of cases they are not usually very serious.
Being a fabric that is in contact with the outside environment, the list of factors that can damage it is very long. Among them we highlight sunbathing without protection, tobacco, the use of non-respectful cosmetic formulas, environmental dryness and poor water quality. In addition, there are skin irritations that may be due to genetic conditions or autoimmune conditions.
Diseases of the genitourinary system
They are those that affect the urinary system and the reproductive system . Therefore, it groups diseases that affect the organs of the urinary system (kidney, ureter, bladder, urethra) and also those that perform reproductive functions. Among those that affect the urinary system that do not come from an infection, kidney stones, urinary incontinence and kidney failure stand out.
On the other hand, among those that affect the reproductive system, if sexually transmitted infections are not included, are those that can affect the uterus or womb, among other structures, an example being uterine polyps. In the case of penises, there is priapism: an affection that causes painful and permanent erections.
Congenital diseases and chromosomal abnormalities
It is a broad group of diseases caused by genomic alterations that may be heritable . In it, pathologies caused by chromosomal deformities and anomalies are part, which are generated by mutations in certain genes or abnormalities in the set of chromosomes that the individual presents. Therefore, people who suffer from these diseases usually present them from birth.
The vast majority express themselves at an early age, while others may take years to become noticeable. There are congenital diseases that only affect a particular organ, as is the case with congenital heart diseases, while others can affect more than one system.
In this cluster there are well-known chromosomal diseases, such as Down syndrome, which is caused by a trisomy on chromosome 21. As far as causes are concerned, sometimes the origin of these possible mutations is known, but in most cases sometimes not It is for this reason that within this group there are rare or minority diseases.