INTRODUCTION
The hormone secretion plays a vital role in keeping our body healthy and fit. Hormones are essential for growth and development of the body.
The glands secrete the hormones in to the blood stream. The hormones have a message and it passed to the targeted organ via blood. There are two types of glands.
- Endocrine Gland
Here let us read about the Endocrine gland.
ENDOCRINE GLAND
The human body secretes many hormones (approximately 50 hormones) for the proper functioning of the body parts. Endocrine gland secretes most of the hormones. The endocrine system is a major communication system of the body since it linked with the nervous system so the nervous system controls the working of endocrine glands. The hormones secreted by this gland act as a bearer between the nervous system and organs of the body.
The word endocrine is a Greek word, in which ‘endo’, means ‘within’, and ‘krine’, means ‘to separate’ or ‘secrete’.
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| ENDOCRINE SYSTEM |
Image Source : Wikimedia Commons
Endocrine glands secretes the substances directly in to the blood stream and travels throughout the body and triggers the target parts or organs or tissues. This gland has no ducts as exocrine glands. The chemical substance secreted by this gland called as Hormones.
The endocrine system consists of many glands and each gland secretes certain hormones to regulate or control the functioning of the body parts. If there is any imbalance in the secretion of hormones by the glands, it leads to endocrine diseases. The endocrine system affects almost every organ and cells in the body. Endocrine gland helps and controls or regulates the body functions like metabolism, growth, homeostasis, sexual activities etc. Although each gland has its own unique function, hormonal secretions from one endocrine gland stimulate the other endocrine glands to secrete their hormones.
They have a built in mechanism i.e., the secretion of hormones are balanced by the glands thus preventing excess secretion. If there is lack of concentration of hormone, will stimulates the gland to secrete until the concentration raises in the blood then it stops the secretion until the concentration falls. This is a cycle process.
The hormones after completing their work will get destroy by the same target organ/tissues or by the liver. The kidneys excrete the destroyed wastes.
The major glands are
- Hypothalamus
- Pituitary gland
- Pineal gland
- Thymus gland
- Thyroid gland
- Parathyroid gland
- Adrenal gland
- Pancreas
- Testes
- Ovaries
These organs or glands secrete hormone in very small (microscopic) amounts. A very small amount of secretion can bring about major changes in the body. Even a very slight increase of hormone secretion can lead to disease and slight in decrease of hormone results in deficiency.
HYPOTHALAMUS
The hypothalamus is located at the lower middle part of the brain i.e., at the base of the optic chiasm and is attached to the pituitary via a stalk-like structure. Several nuclei present in the hypothalamus to control the autonomic nervous system. The nervous system and endocrine system connected via the pituitary gland by hypothalamus. The size of the hypothalamus in humans is as the size of ‘almond’.
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| HYPOTHALAMUS - LOCATION |
Image Source : Wikimedia Commons
Hypothalamus is in charge of regulating or controlling certain metabolic activities. The hormones secreted by hypothalamus called as neuro hormones, releasing hormones, or hypothalamic hormones.
The hypothalamus behaves as a collection centre. It gathers information like environment temperature, light, feelings etc that sensed by the brain and sent to the Pituitary gland. This stimulates or stops the pituitary gland to secrete the hormones and the secretions of hormones regulated by the hypothalamus.
The hypothalamus is responsible for maintaining body’s internal balance known as homeostasis. The hypothalamus helps in stimulating or inhibiting many processes like:
Heart rate and blood pressure, Fluid and electrolyte balance, body weight, body temperature, hunger, parenting aspects, thirst, fatigue, sleep cycles, Glandular secretions in the stomach and intestines, attachment behaviours, regulates emotions, moods and circadian rhythms.
HORMONES AND FUCTIONS OF THE HYPOTHALAMUS
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| GLANDS AND ITS HORMONES |
Image Source : Wikimedia Commons
Thyrotropin – releasing hormone (TRH) or Prolactin - releasing hormone (PRH) : Triggers Thyroid-stimulating hormone (TSH) and Prolactin from the anterior pituitary.
Corticotropin - releasing hormone (CRH) : Triggers adrenocorticotropic hormone (ACTH) from the anterior pituitary.
Dopamine (DA) or Prolactin - inhibiting hormone (PIH): it stops the prolactin release from the anterior pituitary.
Growth-hormone-releasing hormone (GHRH) : Triggers growth hormone release from the anterior pituitary.
Gonadotropin-releasing hormone (GnRH) : Triggers follicle stimulating hormone (FSH) and luteinizing hormone (LH) release from the anterior pituitary.
Somatostatin (SS) or Growth-hormone-inhibiting hormone (GHIH) : Inhibits/stops the Growth hormone (GH) and thyroid stimulating hormone (TSH) release from the anterior pituitary.
Oxytocin (OXY) : Responsible for the contraction of the Uterine and Lactation.
Vasopressin (antidiuretic hormone) ADH or AVP : Responsible for re absorption of water and excretion of concentrated urine.
DISORDERS
The disorder of the hypothalamus referred as hypothalamic disease. A physical injury to the head influences the hypothalamus and is one of the most common reasons of hypothalamic disease. The symptoms of hypothalamic diseases include appetite and sleep disorders. Since hypothalamus affects many parts of the endocrine system it is very hard to find whether the disorder related to other gland as well.
The hypothalamus and pituitary gland connected to each other so it is difficult for the Physicians to find in which gland it affected hence referred as hypothalamic-pituitary disorders. Hormone test can help to overcome this problem.
CONCLUSION
The endocrine system plays vital role in the human body and it connected to the nervous system. The hypothalamus though it is not a gland secretes many crucial hormones, and stimulates other glands to function. It is everyone’s responsibility to keep or maintain the body health fit and without any injuries.
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