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Function of Growth Hormone | Growth Hormone Deficiency |

 Function Of Growth Hormone

Growth hormone is a complex phenomenon which increase the size of different tissue and the organ of the body

Function of Growth Hormone | Growth Hormone Deficiency |
Image Credit : endocrineweb.com

General Growth

General growth is the growth of the whole body. this includes increase in weight, height and size of the organ system.
It is rapid in two phase
  1. Growth during infancy
  2. Growth during puberty

Growth During Infancy

  • After birth, the infant looses weight for few days and later start gaining weight 

  • He/She doubles its weight in next 6 months & triple in 1 year

  • Height gain at very faster rate in 1-2 year 25cm/yr and then decrease for next 8-10 years i.e 5-10cm/yr

Growth During Puberty

  • Puberty growth occurs at 12-18 years of age

  • There is a increase in weight and height

  • The gain in height 10cm/yr weight 2-3kg/yr
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Neural Growth

  • Neural growth includes growth of brain spinal chord and nerves.

  • The brain growth rapidly in the 1st year and reaches up to 70%.

  • Rest 30%grows up to next 5 years

Gonadal Growth

  • Gonads remain rudimentary during infancy.

  • It start growing at puberty and attain the maximum rate between 14 to 18 years of age

Lymphoid Growth

Lymphoid organs grow rapidly during childhood and start involution at puberty these region include lymph node, spleen, thymus, tonsils, adenoids 

Factor Affecting Growth Hormone

  • Genetic factor
  • Hormone (growth hormone, thyroid, insulin, gonadal hormone)
  • Environmental factor (sunlight , humidity, temperature )
  • Nutrition

Parathormone 

  • Parathormone is a polypeptide hormone
  • The normal plasma value is 10-55ng/ml
  • The plasma half life is 10min

Action Of Parathormone

Parathormone is mainly acts on the bone kidneys and intestine. its indirectly acts on the nervous system muscles and other endocrine gland.

Bones

Parathormone increases reabsorption of bone and mobilisation of calcium from the bone.

Kidney

  • Parathormone increase the reabsorption of calcium in the DCT
  • It increase the phosphate excretion in urine by decreasing phosphate reabsorption.
Read: Gross Anatomy of Uterus | External & Internal Feature |

Growth Hormone Deficiency 

Giantism

Gigantism occurs due to increased secretion of the growth hormone by the acidophilic tumor or excessive stimulation of the acidophilic cells before puberty.

There is excessive growth of long bones and the individual can grow to height of about 8ft. 
Overstimulation of B-cells of the islets of Langerhans by growth hormone results in its destruction. this leads to pituitary diabetes.

Acromegaly

Acromegaly is a condition in which the secretion of growth hormone is increased after puberty. acromegaly means enlargement of the peripheral parts of the body. after puberty, the person cannot grow taller but the bones become thick and soft tissues continues to grow.

Dwarfism

Dwarfism is due to reduced growth hormone production during childhood.

Lorain Dwarf

This condition is characterised by the deficiency of somatomedin C. However, growth hormone secretion is normal. Lorain dwarfs are not responsive to growth hormone secreted by the body.

Panhypopituitarism

Th condition is due to a decreased secretion of all anterior pituitary hormones.
Panhypopituitary dwarfs do not attain puberty and do not develop sexual functions.
In adults panhypopitutarism can occur due to destruction of the pituitary gland by tumors. the patient can develop thyroid, gonadal and adrenocortical insufficiency.

Sheehan's Syndrome

Sheehan's syndrome occurs in women during childbirth.
Excessive blood loss during delivery results in circulatory shock. Reduced blood flow causes infraction of adenohypophysis and hence pituitary insufficiency. 

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