Roundworm Life Cycle - Development Cycle Of The Human Roundworm

Table of contents:

Roundworm Life Cycle - Development Cycle Of The Human Roundworm
Roundworm Life Cycle - Development Cycle Of The Human Roundworm

Video: Roundworm Life Cycle - Development Cycle Of The Human Roundworm

Отличия серверных жестких дисков от десктопных
Video: Ascaris Lumbricoides lecture 2023, February

Last updated 17 January 2018 at 15:26

Reading time: 4 minutes

Nematoda or ascaris is a multicellular organism, a parasitic roundworm.

Having the ability to survive at a certain temperature, mandatory humidity and oxygen access, they are perfectly preserved in the form of eggs and larvae. And the development cycle of human roundworm is directly related to the change of the next owner.

The life cycle of the roundworm is a parasitic way of existence and impact on other representatives of flora and fauna, as well as humans. Leads such an interaction to diseases such as Nematodes, Ascariasis. Striking plants, lead to their death, but roundworms peacefully coexist with animals.


  • 1 What is human roundworm
  • 2 Development of the human roundworm
  • 3 Human roundworm cycle
  • 4 Possible development of human roundworm

    4.1 Similar articles

What is human roundworm


It differs from other representatives of nematodes and helminths. Once in the body, the life cycle of the human roundworm takes place exclusively inside. She can change her habitat, but she does not change the carrier, the owner.

Consequently, a person is the first and last link that participates in the process of life, and the place where the helminth develops. Before the appearance in the human body, the embryos of future worms live in a favorable environment for 10-12 years.

Let's start with the simplest. Individuals are heterosexual: males and females. Their length is, respectively, from 20 to 40 cm in the female and from 15 to 25 cm in the male.

They got their name for the bent part at the end of their body. They mainly parasitize in the walls of the small intestine. But sometimes they move around the body. But we'll talk about this later. The movements of the human roundworm are chaotic. It has no attachment methods or characteristic suction cups. It mainly reacts to the intake of food debris and moves towards them.

Outside it has the so-called "hypoderm". It consists of 10 protective flexible layers. They protect it from the effects of digestive juice, mechanical action from cells and antibodies, as well as many poisonous toxins that, one way or another, enter the human body.

Inside the human roundworm there are longitudinal muscles. The underdeveloped sense organs are limited only to special small papillomas in the area of ​​a kind of mouth. The nerve endings are presented in the form of a ring near the pharynx, from which the stem nerves are visible along the body line.

Since the representatives of the human roundworm are heterosexual, we will consider separately their structure:

  • male. Has a testis and vas deferens. At the end of the body is the intestine, where the genitals exit. Another feature of the representative is that one end of it is twisted towards the abdominal cavity;
  • female. The structure of the reproductive system is quite unusual. 2 ovaries, multiple uterus that fall into unpaired vaginas. And all this variety of organs is found in the ventral side of the body.

The development of the human roundworm


Before moving on to the stages of life, let us consider in detail the main stages and the cycle of development of the human roundworm. Naturally, we start with the fact that the eggs fall into the soil. This happens by excreting feces from the human intestine.

A month later, future roundworms are already formed in the form of larvae. They get on plants, flowers and vegetables, into underground groundwater, and from there into water supply systems and household wells. This is why it is strictly forbidden to use unboiled raw water.

Having made their way through the stomach and into the intestines, the larvae do not stop there. With the help of their unusual oral cavity, they make a small microscopic hole in the wall and enter the circulatory system. Due to the movement through the blood vessels, future human roundworms penetrate the bronchi and throat.

And the previous stages of development of roundworms are repeated again towards the intestines. From the oral cavity, along with saliva, their path again follows into the stomach. After the final entry into the small intestine, the worms begin to grow and mature. This process does not take place until the onset of the stage of a sexually mature individual, a roundworm.

Human roundworm cycle


Until the larvae reach their host, man, they are absolutely harmless. As soon as they enter the small intestine for the first time, the first cycle begins, the stage of development in the human microflora of ascaris - the stage of gradual migration. It is here that, with its enzymes, the larva is released from the egg, dissolving it, and reaches a size of 0.2 mm.

Movement through the organs begins. The next stage is migration to the liver, biliary tract, and less often to the pancreas.

As a result, there is a disruption in the work of the organs of the gastrointestinal tract, followed by unpleasant painful symptoms:

  1. vomiting, bouts of nausea;
  2. lack of desire for food;
  3. diarrhea with bloody discharge characteristic of a violation of the integrity of the intestinal walls;
  4. sudden weight loss;
  5. allergies, redness, itching;
  6. lethargy, fatigue and weakness.

When it gets into the lungs, helminths cause coughing fits, shortness of breath, pneumonia and acute bronchitis, fever, bronchial asthma. Asphyxiation can be a serious consequence.

If they enter the heart through the blood, then the right ventricle of the organ is usually chosen. Naturally, the consequences of this combination are heart attacks, coronary artery disease and hemorrhages.

Possible development of the human roundworm

But in roundworms, the full life cycle and stages may change. As they move throughout the body, they can reach the brain.

And here the processes can be irreversible:

  • migraine. Begins from the moment when the larvae enter the outer layers of the brain;
  • seizures of epilepsy, convulsions. Parasites gradually invade the medulla;
  • dizziness, loss of consciousness;
  • causeless neuroses, depression.

Often confused with neoplasms of the brain. But this is not all that human roundworms are capable of.

With the same ease they reach the optic and auditory nerves, which leads to visual impairment, temporary deafness or partial hearing loss. And when they begin to parasitize through the opening of the skull into the brain, even death is possible.

Popular by topic