Organization of the nervous system in animals

Organization of the nervous system in animals

The animals have different types of nervous systems. Since the simpler the Cnidarios or as complex as vertebrates, the possibility is the presence of:

* A diffuse network
* A nervous system glanglionar ventral
* A radio system

The lifestyle of an animal is closely related to the type and complexity of their nervous system. The sponge sésil, with a very simple lifestyle, lacks specialized nerve cells and nervous system; their activities are limited to basic processes of life-sustaining as a trickle of food and reproduction. Whatever their response, depends on the actions of their individual cells.

1.-diffuse Network

The organization simplest Nervous System is the one that owns the sea anemone and others such as Medusa and the Hydra (Cnidarios) Cnidarios. This is a proper system for an animal that belongs in a fixed place, pending the food that captures with their tentacles. The anemone, reacts to predators and prey, downloading nematocistos (stinging structures) and coordinate movements of their tentacles to catch food.

Group Cnidaria: It is a nervous network where neurons (nerve cells) are scattered throughout the body. There is no central body to undertake the role inclusive or control. The Cnidarios possess nerve cells in the epidermis. The nerve impulse is spreading in all directions. This is because the neuron transmitting information in both directions.

Examples: jellyfish and hydras. thanks to this network nervosa the hydra moves its tentacles to catch food

The nervous system is a network simple and diffuse nervous throughout the body. There is no central body integrator.

In a nervous network, whose neurons are scattered throughout the body. There is an organ of central control or defined pathways.

The responses that produces a network involving simple nervous, simultaneously, much of the body. It is a diffuse pattern of transmission, which is adequate for an animal slowly and with radial symmetry. One advantage of the network is nervous that the Cnidaria can react to the food that was approaching from any direction.

2 .- Nervous system nodal ventral

This model of the nervous system is located in the ventral area of the body. It consists of nodes, which are clusters of neurons and nerve cords, which are formed by the extensions of neurons.

• Group platelminth.
• Shellfish Group.
  
• Group Anélidos.

Group platelminth: Worms flat as the whole region show a cephalic (head) which owns concentration of brain nerve cells called lymph. Lymph These are united and play a supervisory role and integration. Since the lymph two strips lengthwise extends to the rear end of the body. A cord nervous corresponds to a compact and elongated structure formed by neurons.

The worm known as the plenary level, the cephalic region (the head) contains concentrations of nerve cells called lymph brain that act as a "brain" primitive and exert some degree of control over the rest of the nervous system. Two cordons nervous longitudinal ventral solid stretch from the lymph to the rear end of the body. Nerves communicate cross the two cords connecting the brain and nervous with eye patches. This configuration is known as type ladder nervous system.

The nervous system are strings nerve longitudinal and transverse, connected with a rudimentary brain.

* Group molluscs: perisofágico appears a ring, around the digestive tract, with three lymph cerebroideos. In this area leaves a pair of cords inervan nervous that the foot and another pair visceral mass.

1.Bivalvos (clams, machas)
2.Gasterópodos (snails)
3.cefalópodos (octopus, squid)

The nervous system has some variations depending on the specific group they belong to. In general is composed of nodes connected by nerves formed by a ring nervous gastropods and cephalopods.

The cephalopods have a brain for further development compared to other vertebrates. The nervous system is more evolved and only has two cords that nervous start from a brain very advanced.

In the evolution of bilateral nervous systems can identify the following trends:

1 .- Increased number of nerve cells.

2 .- concentration of nerve cells to form masses of tissue that become nodes and brain, and thick cords of tissue that become nervous cords and nerves.

3 .- specialization of functions.

4 .- Increased number of neurons Association and complexity of synaptic contacts.

5 .- Cefalización or formation of a head. The answer can be faster if these sensory organs are linked by short routes with neighboring nerve cells responsible for making decisions.

Anel Group: earthworms and leeches.

Their nervous system is composed of nodes located in the anterior region, which form a "brain". Since they are prolonged into the region after two strips nervous longitudinal very close.

3.- Radio System

In animals from the group of echinoderms such as starfish and sea urchins, the nervous system, in general, presents a ring nervous (neural) Central connected with a main radial nerve in each arm. These animals have few specialized sense organs, including organs tactile, and quimiorreceptores photoreceptors.

In animals Cordes there is a nervous dorsal cord, whose edge widens and forms a gall brain in Cordes not vertebrates (such as Piura), but in all vertebrates (fish, amphibians, reptiles, birds and mammals) and engruesa how the brain consists of the brain, the cerebellum, brainstem and other organs nervous.