Chapter 7

Control and Coordination

Introduction

Different organs work together in an organism to carry out different functions, this is known as coordination. Proper control and coordination is necessary to carry out essential functions of the life.

Animal Nervous Tissue

  • Animals’ nervous system consists of specialized nerve cells also known as neurons.
  •  A typical neuron consists of cell body, axon and dendrites.
  • Cell body contains nucleus.
  • Dendrites detects the information from the environment. This information is picked up by the dendritic tips and sets off the electrical impulse which travels from dendrite to cell body and then to axon.

Structure of Neuron

Reflex Action
A sudden response to some environment stimulus is known as reflex. For example, we sudden take off our hand from the flame without thinking.

Reflex Arch
Sensory neurons synapse in the spinal cord before it passes to the brain. This pathway is known as reflex arch.

Reflex Arch

Human Brain

Brain is divided into forebrain, midbrain and hindbrain.

  • Forebrain consists of cerebrum, hypothalamus and thalamus. Forebrain is specialized in hearing, sight, smell etc. It also controls voluntary movements in our body such as movement of leg muscles. Centre for hunger is also located in the separate part of forebrain. Cerebrum or the cerebral cortex consists of 4 lobes- parietal lobe, temporal lobe, occipital lobe and frontal lobes.

Different Lobes of the Brain 

  • Midbrain is located between the forebrain and hindbrain. It controls certain involuntary actions in the body.
  • Hindbrain consists of pons, medulla and cerebellum. It controls salivation, blood pressure and vomiting. Cerebellum also controls certain important functions such as riding a bicycle, picking up a pencil. It also maintains posture and balance of the body. 

Structure of Human Brain 

Brain is protected in a bony case known as cranium. Cranium also contains a fluid filled in it known as cerebrospinal fluid (CSF) that protects the brain from mechanical shock and injury. And spinal cord is protected by vertebral column.

How nervous tissue causes action?   

Information is received by nervous tissue, then it passes to brain muscles and then it causes the action. The junction between the two neurons is known as synapse. Information are passed from one neuron to another neuron via electrical or chemical transmission.