12th Zoology

Defects of the ear

Defects of the ear

Several defects of the ear lead to hearing loss or even deafness.
Hearing loss, or hearing impairment, happens when there is a problem with
one or more parts of the ear or ears.

Types of Hearing Loss

There are a few different types of hearing loss: conductive, sensory, mixed (conductive and sensory combined), and neural. Conductive hearing loss:- This happens when there is a problem with a part of the outer or middle ear. Most kids with conductive hearing loss have a mild hearing loss and it is usually temporary because in most cases medical treatment can help. (Defects of the ear)

Sensory hearing loss

This happens when the cochlea is not working correctly because the tiny hair cells are damaged or destroyed. Depending on the loss, a person may be able to hear most sounds (although they would be muffled); only some sounds; or no sounds at all. Sensory hearing impairment is almost always permanent and the ability to talk normally may be affected. (Defects of the ear)

Neural hearing loss

This happens when there is a problem with the connection from the cochlea to the brain. The hearing loss may be congenital or due to middle ear fluid, serious
infections, such as meningitis, head injury, listening to very loud music,
especially through headphones, repeated exposure to loud sounds, such as
machinery.

One of the common causes of conductive hearing loss is blockade of
the external auditory meatus with wax secreted from ceruminous glands in
the skin lining the meatus. In some people wax accumulates in the meatus
and hardens, sometimes pressing against the eardrum. Normal hearing is
usually restored after the hardened wax is removed with a special syringe.

Another cause of conductive hearing loss, is a perforated eardrum.
Perforation can be caused by infection in the middle ear or by
mechanical injury resulting from a nearby explosion or a sudden blow to the
head. Injury to the head can also cause the ossicles of the middle ear to
become disconnected from one another, thus breaking the
conductive path to the cochlea. (Defects of the ear)

Malfunction of the cochlea and acoustic nerve can be the cause of
hearing loss, even though vibrations are conducted perfectly into the inner
ear. Such hearing loss is called sensorineural (perceptive) hearing loss.
Acquired forms of this condition can result from infection, head injury, blast
from explosions or exposure to excessive noise. (Defects of the ear)

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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