12th Zoology

Nervous system

Nervous system

Co-ordination systems Nervous Co-ordination

All living animals maintain a constant inner state, irrespective of
changes happening in the environment. This phenomenon is named as
homoeostasis. It is achieved due to coordination of response. The
coordination is due to the animal body, acting as a self-regulating system
capable of making appropriate responses to stimuli.

The coordinating system of the body contains suitable structures for
detecting stimuli, transmitting information and responding to stimuli. There
are feedback mechanisms that ensure that degree of responses is
related to the intensity and direction of the stimuli.

Mammals have two main coordinating systems, namely the
nervous system and the endocrine system.

Nervous system

The neurons are the basic units of the nervous system. They help in
conducting the stimuli in between the receptor organs – spinal cord, brain
and effector organs.

The neurons conduct the stimulus as electrochemical events. These sequential events involve migration of ‘Na’ and ‘K’ ions outside and inside the neuronal cells. This phenomenon is known as Sodium- Potassium pump. This sequence of electro chemical events is known as the impulse.

The junctions of neurons in nerve pathway are called the synapses.
A synapse is formed between the bulb-like end structure of the axon called
boutons and the cyton or dendrite of the adjacent neuron. At the junction
there is a gap called the synaptic cleft, which is usually about 10 to 20 nm.
At this point, transmission of stimulus happens through transmitter
substances such as acetylcholine.

In the nervous system the bundles of parallel axons of the nervous
tissue having myelin sheath constitute the white matter. Collection of
neurons having unmyelinated axons form the grey matter.
The axons make up the white matter of the CNS for nerve tracts.

They propogate action potentials. The grey matter performs integrative
functions. The outer surface of the brain (cortex) and the central area of the
spinal cord consist of grey matter. Within the brain, collections of grey
matter form centers called nuclei.

Related Topics in Zoology:

Bio Zoology All Important Topics


  1. Human Physiology Introduction

  2. Nutrition

  3. Carbohydrates Poly hydroxyaldehydes (or) ketones

  4. Proteins (Polypeptides)

  5. Lipids

  6. Vitamins – Functions Of Vitamins

  7. Deficiency of Vitamin

  8. Minerals – Water – Role of water

  9. Balanced diet

  10. Obesity

  11. Digestive System

  12. Dental Caries (Tooth decay)

  13. Root Canal Treatment

  14. Peptic ulcer

  15. Hernia and Types

  16. Appendicitis (Appendix)

  17. Gall Stones

  18. Hepatitis

  19. Fractures – Types of fractures

  20. Mechanism of fracture

  21. Dislocation of joints

  22. Arthiritis

  23. Rickets and Osteomalacia – Orthopedics

  24. Muscles

  25. Mechanism of muscle contraction

  26. Types of muscle contraction

  27. Myasthenia Gravis

  28. Respiration – Process of pulmonary respiration

  29. Mechanism of Breathing

  30. Regulation of Respiration

  31. Pneumonia Tuberculosis Symptoms Treatment

  32. Bronchitis – Acute bronchitis, Chronic Bronchitis Causes

  33. Circulatory System – Functioning of Human heart

  34. Cardiac Cycle

  35. Coronary blood vessel and its significance

  36. Myocardial infarction

  37. Angina pectoris

  38. Angiogram – Angioplasty

  39. Atherosclerosis

  40. Heart block Echo cardiography Heart Valves

  41. Rheumatic Heart Disease (RHD), ICCU – (Intensive Coronary Care Unit)

  42. Blood Pressure

  43. Heart transplantation

  44. Pulse rate

  45. Cardio Pulmonary Resuscitation (CPR)

  46. Blood – Composition of plasma – Blood cells

  47. Clotting of Blood or Haemostasis

  48. Thrombosis

  49. Nervous system Co-ordination systems

  50. The Brain – Fore Brain, Midbrain, Hindbrain

  51. Memory

  52. Sleep – Types of sleep

  53. Stroke – Brain haemorrhage

  54. Alzheimer – Meningitis (Brain fever)

  55. Conditioned reflex

  56. Electroencephalography EEG

  57. Right and Left brain concept

  58. Spinal cord functioning

  59. Chemical co-ordination – Functions of Endocrine glands

  60. Hypothalamus

  61. Pituitary gland – hormone

  62. Hormones of Neurohypophysis – vasopressin

  63. Thyroid gland

  64. Parathyroid Gland

  65. Pancreas

  66. Adrenal gland

  67. Gonads

  68. Receptor Organs – Eye

  69. Photochemistry of Retinal visual Pigments

  70. Errors of refraction

  71. Optometry – Retinopathy

  72. Cataract – Lens Replacement – Glaucoma – Nyctalopia

  73. Eye Infections and Eye Care

  74. Ear

  75. Mechanism of hearing

  76. Defects of the ear

  77. Hearing Aid – Noise pollution

  78. Skin and functions of skin

  79. Melanin functions

  80. Effects of solar radiation / UV radiation – Skin grafting

  81. Dermatitis

  82. Tongue – Mechanism of Stimulation

  83. Excretion Ureotelism Nephron

  84. Mechanism of urine formation

  85. Renal Failure, Dialysis, Kidney Machines

  86. Kidney stone – Kidney transplantation

  87. Diabetes mellitus

  88. Functioning of male reproductive system

  89. Functioning of female reproductive system

  90. Ovulation and fate of the ovum – Menstrual cycle

  91. Fertilization

  92. Birth control

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