Tag: endocrine system and hormone

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 third ventricle (ventriculus tertius) is one of four connected fluid-filled cavities comprising the ventricular system within the rabbit's brain. The third ventricle is a narrow vertical cleft between the 2 lateral ventricles.

The main hormone secreted by the testes is testosterone, an androgenic hormone. The placenta is an endocrine gland, that is only present during pregnancy. It secretes human chorionic gonadotrophin hormone (hCG), which is present only during pregnancy.

The thymus gland is an integral part of immune system. It helps in the maturation of lymphocytes. The thymus serves a vital role in the training and development of T-lymphocytes or T-cells, an extremely important type of white blood cell. So, the correct answer is option B.

The adrenal medulla secretes 2 hormones - adrenalin and noradrenalin. 

The hypothalamus is a mass of grey matter present at the base of the cerebrum. The centre for thirst and drinking regulation is present in lateral hypothalamus while that for hunger and satiety is present in the arcuate nucleus, ventral nucleus and lateral hypothalamic area. The anterior hypothalamic region regulates body temperature.

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 hypothalamus is the control centre for many autonomic functions of the peripheral nervous system. Connections with structures of the endocrine and nervous systems enable the hypothalamus to play a vital role in maintaining homeostasis. The hormones produced by this area of the brain govern body temperature, thirst, hunger, sleep, circadian rhythm, moods, sex drive, and the release of other hormones in the body. Hence, if hypothalamus is damaged in an accident, control of water balance, hunger and body temperature will be lost. 

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).