Chapter-14-Endocrine-System-complete-PDF-Notes-D

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Noteskarts Subscribe & Visit our Website For Notes For Notes Regular Visit our Website: www.noteskarts.com Chapter - 14 Endocrine system Endocrine system (Hormones and their functions) Pituitary gland Adrenal gland Thyroid and parathyroid gland Pancreas and gonads By Noteskarts.com
Noteskarts Subscribe & Visit our Website For Notes For Notes Regular Visit our Website: www.noteskarts.com Endocrine system Introduction Endocrine system is defined as the complex glandular structure (cell modification or aggregation) which secrete the hormones and neurotransmitter in the body and regulate the body physiology and major participate in the defensive mechanism of the body. Major endocrine gland
Noteskarts Subscribe & Visit our Website For Notes For Notes Regular Visit our Website: www.noteskarts.com Hormones are non-nutrient chemicals which act as intercellular messengers and are produced in trace amounts. Most hormones enter interstitial fluid and then the bloodstream. In endocrine system we have discussed about two types of glands. 1. Exocrine glands Exocrine glands secrete their products (enzymes) into ducts, that carry the secretions into body cavities, into the lumen of an organ, or to the outer surface of the body. Exocrine glands include sudoriferous (sweat), sebaceous (oil), mucous, and digestive glands 2. Endocrine gland Endocrine glands secrete their products (Hormone) into the interstitial fluid surrounding the secretory cells rather than into ducts, so it is also called as ductless glands. From the interstitial fluid, hormones diffuse into blood capillaries and blood carries them to target cells throughout the body. It is depending upon the heart for distribution of products. Functions and Importance of Hormones Pituitary gland. Introduction Pituitary gland or hypophysis is a small endocrine gland located in a depression called ‘sella turcica’ present in the sphenoid bone at the base of skull. It is connected with the hypothalamus by the pituitary stalk or hypophyseal stalk. Pituitary gland is divided into two divisions. 1. Anterior pituitary or adenohypophysis It secretes many hormones and regulates the other endocrine gland’s function, so it is also known as master gland. Adenohypophysis consists of two portions, pars distalis and pars intermedia. The pars distalis region of pituitary, commonly called anterior pituitary, produces. Growth/somatotropic hormone (GH/STH) GH is responsible for the general growth of the body. Over-secretion of GH stimulates abnormal growth of the body leading to gigantism and low secretion of GH results in stunted growth resulting in pituitary dwarfism. Thyroid stimulating hormone (TSH) TSH stimulates the synthesis and secretion of thyroid hormones from the thyroid gland.
Noteskarts Subscribe & Visit our Website For Notes For Notes Regular Visit our Website: www.noteskarts.com Adrenocorticotropic hormone (ACTH) ACTH stimulates the synthesis and secretion of steroid hormones called glucocorticoids from the adrenal cortex Prolactin (PRL) Prolactin regulates the growth of the mammary glands and formation of milk in them. Follicle stimulating hormone (FSH) and luteinizing hormone (LH) LH and FSH stimulate gonadal activity and hence are called gonadotrophins. In males, LH stimulates the synthesis and secretion of hormones called androgens from testis. In males, FSH and androgens regulate spermatogenesis. In females, LH induces ovulation of fully mature follicles (graafian follicles) and maintains the corpus luteum, formed from the remnants of the graafian follicles after ovulation. FSH stimulates growth and development of the ovarian follicles in females. NOTE Pars intermedia secretes the only one hormone melanocyte stimulating hormone (MSH). MSH acts on the melanocytes (melanin containing cells) and regulates pigmentation of the skin. 2 .Posterior pituitary or neurohypophysis Also known as pars nervosa and it release two hormone- Oxytocin Oxytocin acts on the smooth muscles of our body and stimulates their contraction. In females, it stimulates a vigorous contraction of uterus at the time of child birth, and milk ejection from the mammary gland. Vasopressin Vasopressin acts mainly at the kidney and resorption of water and electrolytes by the distal tubules and thereby reduces loss of water through urine (diuresis). Hence, it is also called as anti-diuretic hormone (ADH). NOTE Hypothalamus release the both type (stimulating as well as inhibitory) Hormone through the portal circulatory system and regulate the functions of Pituitary gland, so it called as master of master gland.
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