Coordination & Homeostasis

Today we are going to study about Coordination & Homeostasis. First, We will give our attention to Coordination. Coordination is a very important thing to living beings to continue their lives. Animals unlike plants, have two different but related systems for coordination.

1. 1      Nervous system
2. 2      Endocrine system

Types of nervous organization of animals

               •    All multicellular animals except sponges use a network of nerve cells to gather

                   information about the  external environment, process and integrate that information, and

                   to issue signals to the  muscles and glands.

               •    Unicellular

                     No nervous organization ,ability to respond to stimuli. Cell functions as the receptor and

                   effecter.

               •    Multicellular

               •      Cnidaria – Development of nerve cells. Presence of a nerve net composed of multipolar

                   neurons, synapses. Conduction tracts in sea anemones. Development of receptors.

               •    Platyhelminthes – longitudinal solid nerve cords, organized  from a nerve ring or pair of

                   cerebral ganglion in the anterior region of the body - cephalization. Development of

                   receptors. E.g., eyespots, sensory cells.

               •    Annelids  Cerebral ganglia, double ventral nerve cord, ventral ganglia, giant nerve fibers

                     in some. Receptors E.g.,  eyes and sensory cells.

               •    Athropoda – More developed nervous system than that of Annelids. Cerebral ganglion

                   present. Well developed receptor organs of various type. E.g.,  eyes, antenna, palps

               •    Mollusca – Well developed nervous system .Consists of ganglia and nerve fibers

                     Presence of Receptor organs. E.g., well developed eyes

               •    Echinodermata – Radial nerve cord & nerve net

               •    Chordates – Single, dorsal, hollow nerve cord. Anterior region enlarged to form the brain.

                   Complexity increased gradually. Highest complexity is in mammals.

               

                            

                

Human nervous system

•    Organization and main parts of the human nervous system.

       Central nervous system have to main parts.

1. .       Brain
2. 2      Spinal cord

•    The human brain has millions of neurons and is organized in to functional areas.

               •    The spinal cord is a cable of neurons extending from brain down through the backbone.

               •    Presence of three membranous coverings

               •    Presence of two zones in spinal cord should be explained.

               •    Messages from the body and the brain run up and down the spinal cord (the body’s

                   “information highway”)

               •    In addition to relaying messages, the spinal cord also functions in reflexes, the sudden,

                   involuntary movement of muscles.

                                    Peripheral nervous system divided to two parts

1. 1       Cranial Nerves
2. 2      Spinal Nerve

•    The peripheral nervous system consists of nerves and ganglia. Nerves are cable like

                   collections of axons, usually containing both sensory and motor neurons.

               •    Ganglia are aggregations of neuron cell bodies

               •    Briefly explain the cranial and spinal nerves

               •    Autonomic nervous system

               •    The autonomic nervous system should be explained as the part of the peripheral nervous

                   system that is concerned with the controlling of involuntary activities.

               •    General organization of the two main parts of the autonomic nervous system ie, the

                   sympathetic and parasympathetic systems should be explained using a diagram.

               •    The responses evoked by the parasympathetic and sympathetic systems should be listed.

               •    It should be pointed out that the effects produced by one system usually oppose those

                   produced by the other. It should also be pointed out that the sympathetic system have the

                   general result of preparing the body for an emergency.

               •    Overall function of autonomic nervous system. (Parasympathetic and sympathetic)

                   •    Nervous system is responsible for coordination and homeostasis.

Now we have good knowledge in Coordination. We will study about Homeostasis with future posts..