Page 220 - Biology_F5

Coordination and Irritability

Chapter
Four

Coordination and
FOR ONLINE READING ONLY
irritability

Introduction

In organisms, the body parts work together for various roles, resulting into a coordinated
body. Animals have two systems of coordination, namely nervous coordination and
endocrine coordination, while plants have hormonal coordination. In this chapter, you
will learn about physiology of coordination which includes mechanisms of transmission
of nerve impulse, seeing, hearing and body balance. You will also learn about the
application of synthetic phytohormones. The competences developed will enable you
to be aware of how the mammalian and plant bodies are coordinated as well as how the
human nervous and hormonal systems work to bring about proper body functioning.

of nerve cells. The nerves that transmit
Think signals from the body to the central
nervous system are called afferent nerves,
A human body without coordination and they include sensory neurones, while
system those nerves which transmit signals from
the brain are called motor or efferent
4.1 Nervous coordination in mammals nerves. Nervous coordination enables a
The nervous coordination in mammals mammal to respond rapidly to external
as in other animals is accomplished by and internal stimuli.
the nervous system. The mammalian
nervous system consists of a central 4.1.1 Nervous tissue
nervous system and peripheral nervous The nervous tissue is a specialised tissue
system. The central nervous system is made up of nerve cells (neurones). A
made up of the brain and spinal cord, neurone is the basic unit structure of the
whereas the peripheral nervous system nervous tissue which consists of the cell
is made up of the nerve fibres. The nerve body, dendrites and axon. Nervous tissues
fibres branch from the central nervous make up the Central Nervous System (CNS)
system and extend to all parts of the body. and Peripheral Nervous System (PNS).
Coordination is accomplished through The central nervous system consists of the
a set of signals channeled into a series brain and spinal cord, while the peripheral

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