hormones are the chemicalessemgets that are followed.pptx

Hormones are chemical messengers that coordinate different functions in your body. Several glands, organs and tissues make and release hormones, many of which make up your endocrine system.

What are hormones?
Hormones are chemicals that coordinate different functions in your body by carrying messages through your blood to your organs, skin, muscles and other tissues. These signals tell your body what to do and when to do it. Hormones are essential for life and your health.

Scientists have identified over 50 hormones in the human body so far.

Hormones and most of the tissues (mainly glands) that create and release them make up your endocrine system. Hormones control many different bodily processes, including:

Metabolism.
Homeostasis (constant internal balance), such as blood pressure and blood sugar regulation, fluid (water) and electrolyte balance and body temperature.
Growth and development.
Sexual function.
Reproduction.
Sleep-wake cycle.
Mood.
With hormones, a little bit goes a long way. Because of this, minor changes in levels can cause significant changes to your body and lead to certain conditions that require medical treatment.

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What do hormones do?
Hormones are chemical messengers that affect and manage hundreds of bodily processes. Often, a bodily process involves a chain reaction of several different hormones.

A hormone will only act on a part of your body if it “fits” — if the cells in the target tissue have receptors that receive the message of the hormone. Think of a hormone as a key and the cells of its target tissue, such as an organ or fat tissue, as specially shaped locks. If the hormone fits the lock (receptor) on the cell wall, then it’ll work; the hormone will deliver a message that causes the target site to take a specific action.

Your body uses hormones for two types of communication. The first type is communication between two endocrine glands: One gland releases a hormone, which stimulates another gland to change the levels of hormones that it’s releasing. An example of this is the communication between your pituitary gland and thyroid. Your pituitary gland releases thyroid-stimulating hormone (TSH), which triggers your thyroid gland to release its hormones, which then affect various aspects of your body.

The second type of communication is between an endocrine gland and a target organ. An example of this is when your pancreas releases insulin, which then acts on your muscles and liver to help process glucose.

Which body tissues make hormones?
Specialized glands that make up your endocrine system make and release most of the hormones in your body. A gland is an organ that makes one or more substances, such as hormones, digestive juices, sweat or tears. Endocrine glands release hormones directly into your bloodstream.
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1. What are Hormones? “ A regulatory substance released by glands or specialized cells into the circulating blood to influence the function of target cells at another location in the body.”

2. Characteristics or properties of hormone Low molecular weight Small soluble organic molecules Rate of diffusion is very high It is effective in low concentration Travels in blood

3. Functions of hormones Regulatory and homeostasis functions Maintain consistency of interior of cell Permissive functions; movement of substance in and out of cell Integrative function; usually balance two system Developmental function; helps in development of foetus

4. Cell Signaling The effects of hormones depend on how they are released. Hence, signalling effects can be classified into the following: Autocrine : The hormone act on the cell that secreted it.e,g insulin Paracrine : The hormone act on a nearby cell without having to enter the blood circulation.e,g nitricoxide E xocrine system includes a series of glands all over your body. These glands secrete substances that help your organs function, including sweat, breast milk, mucus and oil. exocrine system is different from your endocrine system, in that it secretes these substances through ducts. Endocrine : The hormone act on the target cells once it is released from the respective glands into the bloodstream. E,g Pituatiry gland, ovaries

5. Endocrine glands release hormones into the bloodstream and include the pituitary and thyroid glands. Exocrine glands release substances, such as sebum, sweat, and digestive enzymes, through a duct to an organ or the surface of the body. Exocrine glands include salivary and sweat glands A hormone can be considered autocrine signaling when secreted by a cell and acts on that same cell. Several hormones fit this description, including  insulin Excellent examples of the paracrine actions of hormones are provided by the ovaries and testes. Estrogens produced in the ovaries are crucial for the maturation of ovarian follicles before ovulation

6. Classification of hormone Hormones are classified as. On the basis of chemical nature On the basis of mechanism of hormone action

7. A. On the basis of chemical nature Proteins & peptide Steroids Amines and amino acid derivatives

8. Peptide Hormones Peptide hormones are comprised of chains on amino acids. Peptide hormones do not readily pass through cell membranes (lipid bilayers) and they are referred to as water soluble. Receptors for peptide hormones are found on the cell surface of their target cells.

9. Steroid Hormones Steroid hormones are produced by the gonads and adrenal cortex. Steroid hormones are made from cholesterol in the smooth endoplasmic reticulum and mitochondria of endocrine cells. Steroid hormones cannot be stored in vesicles in the endocrine cells that produce them. As soon as steroid hormones are produced, they diffuse out of the endocrine cell and enter the bloodstream. Steroid hormones are lipid soluble and their receptors are located inside their target cell.

10. Difference

11. Amine Hormones Amine hormones are derived from the amino acid tyrosine and include adrenaline, thyroxin and triiodothyronine Amine hormones do not all share identical properties and have properties common to both peptide and steroid hormones

12. B. On the basis of mechanism of hormone action lipophilic hormone:These hormones are lipophilic in nature. They are mostly derivatives of cholesterol. These hormones binds to intracellular receptors Example: Steroid hormones, Estrogen, androgen, glucocorticoids, cholcalciferol , thyroxine etc water soluble hormone:These hormones binds to cell surface receptors and stimulates the release of certain molecules(secondary messengers) to perform biochemical functions

13. Mechanism of Hormone action Hormones are the chemical messenger secreted directly in the blood stream by endocrine gland. They are target specific and bind to the specific receptor. On the basis of binding of hormone on their specific receptor, the mechanism of hormonal action is categorized into two group. They are- 1. Fixed membrane receptor mechanism 2. Mobile receptor mechanism

14. Fixed membrane receptor mechanism The hormones that are protein or amines in compositions such as Growth hormone, ADH, oxytocin, Insulin, Adrenaline, FSH, TSH etc shows this mechanism of action. These hormones are water soluble and cannot passes through the lipid membrane and they have their target receptor on the cell membrane. The receptor are fixed on the cell membrane, so hormone can bind on the specific receptor. Binding of hormone on specific receptor on target cell activates the enzyme Adenylcyclase in the cell membrane and causes production of cyclic AMP (CAMP). CAMP act as secondary messenger. It diffuse through the cell membrane and activates (Protein Kinase) various enzymatic reaction to cause biochemical changes. After the target cell responded to the changes, cAMP is deactivated by a group of enzyme Phosphodiesterase

15. Mobile receptor mechanism The lipid soluble hormones such as steroid hormones and Fatty acids hormones can easily passes through the plasma membrane. They have their receptor inside the cell, freely floating in the cytoplasm. Binding of hormone to the specific receptor activates the enzymatic activity of the cell for biochemical changes. Some hormones (testosterone, progesterone, estrogen, cortisol, thyroxine) have their receptor localized inside the nucleus, the hormone-receptor complex are carried inside the nucleus. The hormone-receptor complex initiate transcription of the DNA to form specific mRNA. mRNA initiate protein synthesis in the cytoplasm. The protein (enzyme) causes biochemical changes in cell.

16. Glands secrete hormones and their funtion s

17. Hormones in Young Children

18. Gland: Hypothalamus Thyrotropin-releasing hormone (TRH): stimulates secretion of thyroid-stimulating hormone (TSH) and prolactin Corticotropin-releasing hormone (CRH): release of adrenocorticotropic hormone (ACTH) Growth hormone–releasing hormone (GHRH): causes release of growth hormone Growth hormone–inhibitory hormone (GHIH): inhibits release of growth hormone Gonadotropin-releasing hormone (GnRH): causes release of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) Dopamine or prolactin-inhibiting factor (PIF): inhibits release of prolactin

19. Gland: Anterior Pituitary Growth hormone : stimulates protein synthesis and overall growth of most cells and tissues TSH : synthesis and secretion of thyroid hormones (thyroxine and triiodothyronine) ACTH : synthesis and secretion of adrenocortical hormones (cortisol, androgens, and aldosterone) Prolactin : promotes development of the female breasts and secretion of milk FSH : growth of follicles in the ovaries and sperm maturation in Sertoli cells of testes LH : stimulates testosterone synthesis in Leydig cells of testes; stimulates ovulation, formation of corpus luteum, and estrogen and progesterone synthesis in ovaries

20. Gland: Posterior Pituitary Antidiuretic hormone (ADH/ vasopressin): increases water reabsorption by the kidneys and causes vasoconstriction and increased blood pressure Oxytocin : stimulates milk ejection from breasts and uterine contractions

21. Gland: Thyroid Thyroxine (T4 ) and triiodothyronine (T3 ): increases the rates of chemical reactions in most cells, thus increasing body metabolic rate Calcitonin : promotes deposition of calcium in the bones and decreases extracellular fluid calcium ion concentration

22. Gland: Adrenal Cortex Cortisol : multiple metabolic functions for controlling metabolism of proteins, carbohydrates, and fats; also has anti-inflammatory effects Aldosterone : increases renal sodium reabsorption, potassium secretion, and hydrogen ion secretion

23. Gland: Adrenal Medulla Norepinephrine & epinephrine : sympathetic stimulation

24. Gland: Pancreas Insulin (β cells): promotes glucose entry in many cells, and in this way controls carbohydrate metabolism Glucagon (α cells): increases synthesis and release of glucose from the liver into the body fluids

25. Gland: Parathyroid Parathyroid hormone (PTH): Increases serum calcium concentration by increasing calcium absorption from the stomach and kidneys, and releasing calcium from bones

26. Gland: Testes Testosterone: promotes development of male reproductive system and male secondary sexual characteristics

27. Gland: Ovaries Estrogen: promotes growth and development of female reproductive system, female breasts, and female secondary sexual characteristics Progesterone: stimulates secretion of “uterine milk” by the uterine endometrial glands and promotes development of secretory apparatus of breasts

28. Gland: Placenta Human chorionic gonadotropin (HCG): promotes growth of corpus luteum and secretion of estrogens and progesterone by corpus luteum Human somatomammotropin: helps promote development of some fetal tissues as well as the mother’s breasts

29. Gland: Kidney Renin: catalyzes conversion of angiotensinogen to angiotensin I (acts as an enzyme) 1,25-Dihydroxycholecalciferol: increases intestinal absorption of calcium and bone mineralization Erythropoietin: increases erythrocyte production for RBC synthesis