Tag: biology

Aldosterone of the adrenal cortex is life-saving hormone because it serves to retain sodium and water to maintain a sufficient blood volume for circulation. So, it maintains the osmolarity and volume of ECF. The pituitary gland regulates secretion of other endocrine glands. Pineal gland secretes melatonin that regulates body’s daily rhythms. Thyroid hormones regulate the basic metabolic rate. Thus, the correct answer is C.

The adrenal medulla secretes 2 hormones - adrenalin and noradrenalin. 

Undersecretion of insulin causes diabetes mellitus type I while myxedema is caused by thyroxine deficiency in adults. Hyposecretion of parathyroid hormone causes increased excitability of muscles and their sustained contraction referred to as parathyroid tetany. Luteinizing hormone deficiency causes failure of ovulation as LH surge during midcycle stimulates rupture of Graffian follicle. 

Puberty begins with a surge in hormone production, which in turn causes a number of physical changes. It is the stage in life in which a child develops secondary sex characteristics as his or her hormonal balance shifts strongly towards an adult state. This is triggered by the pituitary gland which secretes a surge of hormonal agents into the blood stream, initiating a chain reaction. The male and female gonads are subsequently activated, which puts them into a state of rapid growth and development. The testes release testosterone and the ovaries release estrogen. The production of these hormones increases gradually until sexual maturation is met.

The synthesis and secretion of estrogen is stimulated by follicle-stimulating hormone (FSH), which is, in turn, controlled by the hypothalamic gonadotropin releasing hormone (GnRH).

FSH is primarily involved in stimulating the growth of ovarian follicles, while LH induces ovulation. At ovulation, the ovum or egg is released and the ruptured follicle is transformed into a corpus luteum, which secretes progesterone as its main product. 

Gonadotropin-releasing hormone (GnRH) is secreted by the hypothalamus and stimulates the release of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) from the anterior pituitary gland. 

When contraction of the uterus starts, oxytocin is released, which stimulates more contractions and more oxytocin is released. In this way, contractions increase in intensity and frequency. Oxytocin causes contractions during the second and third stages of labor.

Pheromones are chemicals released by an organism into its environment enabling it to communicate with other members of its own species. It changes the behaviour of another animal of the same species (animals include insects). 

Formic acid is the simplest carboxylic acid and occurs naturally, mostly in ant venom.