Tag: biology

Spermatogenesis depends on the action of the FSH and LH hormone of the hypophysis on the testicular cells. LH acts on the interstitial cells, stimulating the production of testosterone necessary for the normal development of spermatogenic cells. FSH acts on the sertoli cells, stimulating adenylate cyclase and consequently increasing the presence of cAMP; it also promotes the synthesis and secretion of androgen-binding protein. This protein combines with testosterone and transports it into the lumen of the seminiferous tubules. 

Adrenocorticotropic hormone (ACTH), also known as corticotropin, is a polypeptide tropic hormone produced and secreted by the anterior pituitary gland. It is an important component of the hypothalamic-pituitary-adrenal axis and is often produced in response to biological stress. Its principal effects are increased production and release of corticosteroids. 

Gonadotropins (or glycoprotein hormones) are protein hormones secreted by gonadotropes of the anterior pituitary of vertebrates. It includes the mammalian hormones follicle-stimulating hormone (FSH), luteinizing hormone (LH), placental chorionic gonadotropins hCG and chorionic gonadotropin.

The acidophils are the somatotropic cells and the lactotrophic cells. Thus, growth hormone and prolactin are secreted by acidophilic cells. In the anterior pituitary, the term acidophil is used to describe two different types of cells: somatotrophs, which generate somatotropin (also known as growth hormone) and mammotrophs, which generate prolactin.

The adrenal glands are endocrine glands that produce a variety of hormones including adrenaline and the steroids aldosterone and cortisol. Adrenal glands are concerned with salt equilibrium in the body. 

The growth process begins in the hypothalamus. When the hypothalamus releases growth hormone releasing hormone (GHRH), the anterior pituitary is stimulated to release growth hormone (GH). Growth hormone then acts on the liver and other tissues and stimulates them to secrete insulin like growth factor-1 (IGF-1). IGF-1 directly promotes the development of bone and muscle, causing bones to grow in length, and muscles to increase protein synthesis.

Prolactin is a peptide gonadotrophic hormone secreted by the pituitary gland; it stimulates growth of the mammary glands. Progesterone, secreted from the corpus luteum, prolongs the secretion of prolactin. Luteinizing hormone is a hormone produced by gonadotroph cells in the anterior pituitary gland. In females, an acute rise of LH triggers ovulation and development of the corpus luteum. 

If a person drinks enough water, this condition will not have significant effects on the fluid or electrolyte balance of the body. If the person does not drink enough fluids, high urine output may cause dehydration and high levels of sodium in the blood. The primary symptoms of diabetes insipidus are excessive thirst and urination. A person can produce large amounts of urine, usually more than 3 litres up to 15 litres per day.

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.