CHEMICAL MESSAGES FOR HOMEOSTASIS IS ONE OF THE EASY CHAPTER ,WE AN STUDY IT BY COMPARING ONE TO OTHER TOPICS ESPECIALLY HORMONES AND FUNCTIONS
Endocrine glands ductless glands,that secrete hormones
Hormones are transported through blood.
each hormone act only in its target tissue, having specific receptors for accepting the same hormone. When hormone-receptor complex is formed in the plasma membrane,Following this, enzymes are activated within the cell and certain changes occur in cellular activities.
Pancreas is the gland produce two types of hormone,insulin and glucagon. The beta cells in the cell cluster of this gland called Islets of Langerhans, produce the hormone insulin and alpha cells produce the hormone glucagon.
functions of insulin
cellular uptake of glucose molecules converts glucose into glycogen in the liver and muscles
functions of glucagon
converts the glycogen stored in the liver to glucose. synthesizes glucose from amino acids.
The normal level of glucose in blood is 70-110mg/100ml. The level
of glucose in blood is maintained by the combined action of insulin
When glucose increases in blood, beta cells in the Islets of Langerhans secretes insulin. It accelerates the process of glucose intake by the cells and conversion of the excess glucose in to glycogen.When glucose decreases in blood, alpha cells in the Islets of Langerhans secretes glucagon, which converts glycogen and amino acids in to glucose.
Decreased production of insulin due to the destruction of beta cells or the inability of cells to utilize the insulin produced, raises the level
of glucose in blood. Excess glucose in the blood is expelled through urine. Normally, there is no
glucose in urine
Diabetes is clinically referred to as a condition when the level of glucose
before breakfast is above 126mg/100ml of blood
major symptoms;Increased appetite intense thirst frequent urination
World Diabetics Day ;November 14
The thyroid gland is the main endocrine gland that controls the
The thyroid gland secretes two hormones –
thyroxine and calcitonin
functions of thyroxine
- Increases energy production.
- Raises the rate of metabolism.
- Accelerates the growth and development
of the brain in the foetal stage and infancy
- Regulates growth in children
Funtions of Calcitonin –
Maintains the level of calcium in blood by depositing excess calcium in bones or by preventing the mixing of calcium with blood from the bones
This is a condition in which the production of thyroxine
decreases Low metabolic rate, Sluggishness,Sleeplessness, Increase in body weight,Hypertension, Oedema
Cretinism;The decrease in production of thyroxine during
the foetal stage or infancy, hinders proper physical and
Prolonged deficiency of thyroxine in adults leads to a
condition called Myxoedema
hyperthyroidism;High metabolic rate, Rise in body temperature,
Frequent sweating, Increased heartbeat, Sleeplessness,
Loss of weight, Emotional imbalance.It leads to the condition Grave’s disease.
Iodine is essential for the production of thyroxine. The production
of thyroxine is blocked in the absence of iodine. In an attempt to
produce more thyroxine, the thyroid gland enlarges. This
condition is called goitre.
normal level of calcium in blood;9-11 mg /100 ml blood
When the level of calcium in blood increases, thyroid gland secretes calcitonin, which lowers the level of calcium in blood, by depositing excess calcium in bones or by preventing the mixing of calcium with blood (from the bones).
When the level of calcium decreases in blood, parathyroid gland secretes parathormone, which increases the level of calcium by helping in its re-absorption from kidneys or by preventing the deposition of calcium in bones.
Thymus gland ;Secretes the hormone ‘thymosin’
Thymosin is also known as the ‘youth hormone’,because
during infancy, thymosin helps in the maturation and activities of lymphocytes and hence it is also known as the ‘youth hormone’.
It is gland situated above kidney;have 2 parts adrenal cortex and adrenal medulla
- Cortisol- Synthesis of glucose, Preventing inflammation and allergy (slows down the action of defense cells)
- Aldosterone – Maintains the salt-water balance.
- Sex hormones –
Epinephrine and Norepinephrine;Act along with the sympathetic nervous system in order to prepare the to overcome emergency situations like fear.
This gland secrete Melatonin, the hormone produced by this gland helps
to maintain the rhythm of our daily activities. The production of melatonin is high at night and low during the day.
The pituitary gland