Tag: control and coordination in living organisms

MSH is important in the regulation of melanin synthesis in cells called melanophores (a type of chromatophore) that are in the skin of amphibians, some fishes, and reptiles. Light reflected from water surface stimulates photoreceptors, which send information to the hypothalamus. Pituitary MSH then causes the pigment synthesis in the melanophores to disperse and the skin to darken.

The anterior pituitary is also known as the adenohypophysis, meaning glandular undergrowth. Gonadotropes (LH and FSH) are secreted from the anterior pituitary. Luteinizing hormone (LH) stimulates the ovulation cycle in female mammals, while in the males, LH stimulates the synthesis of androgen. FSH helps in the growth of the reproductive system.

Diabetes insipidus is a condition caused by hyposecretion of antidiuretic hormone (ADH). 

Excess amounts of androgens result in acne, hirsutism (excess hair growth on the chin or upper lip) and thinning hair. Many women with high levels of a form of testosterone have polycystic ovary syndrome (PCOS), infertility, blood sugar disorders. High levels of androgens are associated with insulin resistance and diabetes, high cholesterol, high blood pressure and heart disease.

Antidiuretic hormone, also known commonly as vasopressin, is a nine amino acid peptide secreted from the posterior pituitary. It has two principal sites of action: the kidney and blood vessels. Its two primary functions are to retain water in the body and to constrict blood vessels. 

Menstruation is the shedding of the lining of the uterus (endometrium) accompanied by bleeding. Bleeding occurs after oestrogen and progesterone levels decrease at the end of the previous cycle. This decrease causes the top layers of thickened lining of the uterus (endometrium) to break down and be shed. 

The adrenal cortex produces a hormone, called as aldosterone, that is involved in regulating the amount of salt and water in the body. Aldosterone is a mineralocorticoid, which acts on the principal cells of the collecting ducts, ducts of sweat and salivary glands.

In the male, luteinizing hormone promotes the development of the interstitial tissue (Leydig cells) of the testes and hence promotes the secretion of the male sex hormone, testosterone. 

Insulin helps control blood glucose levels by signaling the liver and muscle and fat cells to take in glucose from the blood. Insulin therefore helps cells to take in glucose to be used for energy.

Adrenaline is a natural stimulant hormone made in the adrenal gland of the kidney. Adrenaline is carried in the bloodstream and affects the autonomous nervous system, which controls functions such as the heart rate, dilation of the pupils, and secretion of sweat and saliva.