What are Control and Coordination?

  • Movements is one of the important characteristics of living beings.
  • Changes in the environment to which the organisms respond and react are called stimuli.
  • Various organs or parts of the body of an organism works in a coordinated and proper manner to produce a reaction to the given stimulus which is called coordination.
  • Nervous system and endocrine system are the two systems which play a major role in control and coordination.• Brain

Coordination in animals

Human Nervous SystemA

  • Nervous system coordinates and controls all the voluntary and involuntary actions by transmitting nerve impulses to and from different parts of the body.
  • Neuron is the structural and functional unit of nervous system.
  • Synapse is a point of contact between axon terminals of one neuron with dendrites of another neuron separated by a minute gap.
  • The terminals of axon have swollen ends which contain a chemical called acetylcholine – a kind of neurotransmitter.
  • Brain is protected inside cranium of skull.
  • Brain and spinal cord are protected by a three membranous layer called meninges.
  • The three layers of meninges are Dura mater, Arachnoid, Pia mater.
  • Space between covering membrane is filled with a fluid called cerebrospinal fluid which protects brain and spinal cord from shock or injury.
  • Cerebrum of brain is divided into four lobes – Frontal lobe, parietal lobe, temporal lobe and occipital lobe.
  • There are 31 pairs of spinal nerves – 8 pairs in neck region, 12 pairs in thorax, 5 pairs in lumbar, 5 pairs in sacral and 1 pair in coccygeal region.
  • Sympathetic and parasympathetic nervous system are antagonistic in functions.
  • Spinal cord is the extension of medulla oblongata which runs through our vertebral column along the whole length of backbone.
  • Reflex arc is the shortest route taken by an impulse from receptor to effector
  • Stimulus → Receptors → Sensory neuron → Brain or Spinal cord → Motor neuron →Effector organ →Response.
  • Cerebrum of brain is divided into four lobes – Frontal lobe, parietal lobe, temporal lobe and occipital lobe.
  • There are 31 pairs of spinal nerves – 8 pairs in neck region, 12 pairs in thorax, 5 pairs in lumbar, 5 pairs in sacral and 1 pair in coccygeal region.
  • Hypothalamus secretes neurohormones and it also controls secretions of pituitary gland.
  • The body has to maintain a normal state because too much or very less secretions of hormones is not good. If there is a rise in hormonal level the hormones secretion has to be reduced. Similarly if there is low hormonal level, its secretion has to be increased which is maintained by feedback mechanism.

Coordination in plants

  • There are two types of movements : (i) Growth dependent movement. (ii) Growth independent movement.
  • Curvature movements are changes in orientation of some plant parts in response to stimulus.
  • 1. Tropic movements: These are directional movements of plant parts which involve growth in response to stimuli.
  • 2. Movements of curvature: These are changes in orientation of some plant parts in relation to others caused by external or internal stimuli.
  • 3. Nastic movements: These are non-directional induced variation movements that do not involve growth which occurs due to change in turgour pressure in response to stimuli.
  • 4. Hormones: Hormones are chemical messengers secreted by endocrine glands which regulate various physiological processes in living organisms.
  • 5. Phytohormones: Phytohormones are naturally occurring organic chemical substances present in plants which control and coordinate various activities in them and are called as growth regulators.
  • 6. Coordination: The working together of various organs of the body of an organism in a proper manner to generate a proper reaction in response to a stimulus is called coordination.
  • 7. Stimuli: The changes in the environment to which the organisms respond and react are called stimuli.
  • 8. Sensory neurons: Sensory neurons receive stimuli through their dendrites and transmit impulses towards central nervous system from receptors.
  • 9. Motor neurons: Motor neurons transmit impulses from central nervous system to effectors.
  • 10. Receptors: Receptor is a sensory nerve cell or a group of sensory nerve cells which is sensitive to a specific stimulus or to a specific change in the environment.
  • 11. Reflex actions: It is a spontaneous, quick, automatic response to a stimulus acting on a specific receptor without the will of an animal.
  • 12. Reflex arc: It is the shortest route taken by a nerve impulse from receptor to effector during a reflex action.
  • 13. Cerebrospinal fluid: It is a clear, colourless, slightly alkaline fluid present in ventricles of brain, central canal of spinal cord and spaces between meninges which protects brain and spinal cord from injury and shocks.
  • 14. Endocrine glands: These are ductless glands which pour their secretion directly into blood stream and are carried by blood to the site of action or target organs.