9.
Control & Coordination
, Introduction
Unicellular organisms have a simple organization of their life processes.
However a multicellular organization of the body organs and organ systems
required both, a control over their life processes as well as a coordination
between the various systems in order to maintain homeostasis of the
organism.
Plants Performs Coordination through chemical Signals :
(e.g. phototropic,
chemotactic,
thigmotactic, etc).
In this chapter, now you will study about development of nervous system in
different animal groups and details of the system in humans.
in higher and more complex animals, it is done by two coordinating systems - the
nervous (electrical) system and endocrine (chemical) control system.
These two systems will be studied separately though they work in coordination with
each other
,NERVOUS COORDINATION
, Nervous System in Hydra :
Hydra, a cnidarian shows the diffused nervous
system, which is the most primitive nervous
system. (Sensory Nerves)
The cnidarians are thus the first animal group
showing true simple nervous system.
It consists of the sensory cells and the nerve
cells or neurons along with their fibres.
The nerve cells are scattered or distributed
throughout the body and inter connected to
each other by synapses between their fibres to
form the nerve net.
There are two nerve nets both in the mesoglea,
one connected towards the epidermis and
second towards the gastrodermis.
Control & Coordination
, Introduction
Unicellular organisms have a simple organization of their life processes.
However a multicellular organization of the body organs and organ systems
required both, a control over their life processes as well as a coordination
between the various systems in order to maintain homeostasis of the
organism.
Plants Performs Coordination through chemical Signals :
(e.g. phototropic,
chemotactic,
thigmotactic, etc).
In this chapter, now you will study about development of nervous system in
different animal groups and details of the system in humans.
in higher and more complex animals, it is done by two coordinating systems - the
nervous (electrical) system and endocrine (chemical) control system.
These two systems will be studied separately though they work in coordination with
each other
,NERVOUS COORDINATION
, Nervous System in Hydra :
Hydra, a cnidarian shows the diffused nervous
system, which is the most primitive nervous
system. (Sensory Nerves)
The cnidarians are thus the first animal group
showing true simple nervous system.
It consists of the sensory cells and the nerve
cells or neurons along with their fibres.
The nerve cells are scattered or distributed
throughout the body and inter connected to
each other by synapses between their fibres to
form the nerve net.
There are two nerve nets both in the mesoglea,
one connected towards the epidermis and
second towards the gastrodermis.
