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ENDOCRINE SYSTEM BURÇİN
What does the endocrine system do? The endocrine system produces and regulates the body’s hormones, which are chemicals created by the body to control many of its functions.
Functions controlled by hormones controlled by the endocrine system include: activities of entire organs growth and development reproduction sexual characteristics usage and storage of energy levels of fluid, salt, and sugar in the blood
The endocrine system consists primarily of hormones and glands, and overlaps with the nervous system and the exocrine system.
Gland 1. 2. Gland , organ made of cells that secrete materials into other areas of the body Gland has two types: Exocrine glands Endocrine glands
Gland Exocrine glands secrete nonhormonal chemicals into ducts which transport chemicals to specific locations inside and outside the body Ex. Sweat, mucous, salivary glands Endocrine glands ductless glands located throughout body – secrete hormones into bloodstream
Hormones Chemical messengers Produced in endocrine glands Travel through blood Affect the target tissues
The hormones are released into the bloodstream and may affect one or several organs throughout the body.
Types of Hormones Amino acid-based hormones ( Peptide Hormones) Include proteins, peptides, amino acids, other forms derived from amino acids Not lipid soluble Ex. Epinephrine (adrenaline)
Types of Hormones Steroid hormones Lipids that made from cholesterol Lipid soluble Diffuse through cell membranes Ex. Estrogen, testosterone
Hormone Actions Steroid Hormones Pass straight through the plasma membrane. Combine with a receptor molecule in the cell cytoplasm
Hormone Actions Peptide Hormones Attachment to plasma membrane receptor (c) stimulates a secondary messenger Secondary messenger alter the action of the cell
Endocrine Glands Pituitary Gland Hypothalamus Pineal Gland Thyroid Gland Parathyroid Gland Adrenal Gland Pancreas Gonads : Ovaries & Testes
Hypothalamus Has many receptors for changes of internal conditions Serves as a link between the nervous system and the endocrine system (pituitary) Controls each lobe of the pituitary gland
Pituitary Gland Located at the base of the brain. Composed of two parts and called the “master gland” because it controls the activities of other glands.
Posterior Pituitary Posterior pituitary is part of the hypothalamus and does not secrete its own hormones Hormones released by the posterior lobe are synthesized by neurons in the hypothalamus Antidiuretic hormone (ADH)- Vasopressin regulates the kidneys to reduce water loss in the urine. Oxytocin stimulates uterine contraction during childbirth.
Anterior Pituitary Anterior pituitary releases 6 major hormones : Prolactin Growth Hormone ( GH) Luteinizing Hormone ( LH) Adrenocorticotropin hormone (ACTH) Thyroid Stimulating Hormone (TSH) Follicle Stimulating Hormone (FSH)
Anterior Pituitary 1. Prolactin Released after pregnancy, stimulates milk production in females 2. Growth Hormone (GH) This hormone controls the growth of the body by stimulating the elongation of bones.
Anterior Pituitary 3. Luteinizing Hormone (LH) Triggers ovulation and the development of the “ corpus luteum” in females. In males it stimulates the release of testosterone by the testes 4. Follicle Stimulating Hormone (FSH) Stimulates the activities of the ovaries and testes.
Anterior Pituitary 5. Adrenocorticotropin hormone (ACTH) Stimulates the adrenal cortex to release corticoid hormones. 6. Thyroid Stimulating Hormone (TSH) Stimulates the thyroid to release thyroxine
How to remember the 6 P GH LH FSH TSH ACTH Please Get Lunch For Their Aunt
Pineal Gland Located in the brain Secretes melatonin & serotonin Believed to be involved with daily biorhythms, such as sleep cycles Possibly responsible for mood disorders, such as “ winter depression ” or “ seasonal affective
Thyroid Gland � Located along the midline of the neck � Produces hormones that stimulate body heat production, bone growth, and the body's metabolism
Thyroid Gland This gland secretes thyroxin which contains iodine. Increases the rate at which you use energy = Metabolism Thyroxin secretion is regulated by TSH, which is secreted by the pituitary gland. Regulates the rate of metabolism in the body and is essential for normal physical and mental development
Thyroid Gland A person who suffers from hypothyroidism has a lower metabolic rate, which can cause obesity and sluggishness. The opposite condition, known as hyperthyroidism, occurs when the thyroid produces too much thyroxine. It can lead to excessive perspiration, high body temperature, loss of weight, and a faster heart rate
Thyroid Gland Lack of iodine in the diet will lead to lack of thyroxin secretion. This produces enlargement of the thyroid gland is called Goiter is the result of iodine deficiency in the diet.
Parathyroid Gland Releases parathyroid hormone ( PTH), which plays a role in regulating calcium levels in the blood and bone metabolism. Parathormone controls calcium metabolism. Calcium is necessary for proper growth of teeth and bones, blood clotting, and nerve function.
Thymus Gland Regulates the immune response, which helps your body fight disease
Adrenal Glands The adrenal glands are made up of two parts. The outer part is called the adrenal cortex The inner part is called the adrenal medulla.
Adrenal Glands Adrenal Cortex Aldosterone helps maintain salt-and-water balance in body by affecting kidneys Maintains electrolyte balance Stimulates the kidneys to reabsorb Na+ and secrete K+ into the urine
Adrenal Glands Adrenal Medulla Nervous system’s reaction to stress (“fight-orflight”) Epinephrine (Adrenaline) Increase respiration, metabolism Norepinephrine (Noradrenaline) House keeping system
Adrenalin Increases blood glucose level by speeding up the breakdown of glycogen to glucose Increases metabolic rate Constricts arterioles in skin Causes pupils to dilate to enhance vision Contracts hair muscles
Pancreas The pancreas has digestive and hormonal functions. One part of the pancreas, the exocrine pancreas, secretes digestive enzymes.
Pancreas The other part of the pancreas, the endocrine pancreas, secretes hormones called insulin and glucagon These hormones regulate the level of glucose (sugar) in the blood
Pancreas Islets of Langerhans Specialized tissues in which the endocrine functions of the pancreas occurs Secrete insulin and glucagon. � include 2 types of cells: alpha ( ) beta ( )
Pancreas Insulin ( Beta Cells ( ) ) Increases glucose uptake by the cells Convert glucose into glycogen Glucagon ( Alpha Cells ( ) ) Stimulates conversion of glycogen, fats, amino acids, and lactic acid into glucose
Insulin secretion Blood glucose level decreases Blood glucose level increases Glucagon secretion
Diabetes Insulin deficiency causes diabetes mellitus abnormally high blood glucose concentration Type 1 diabetes childhood disorder where insulin-producing islet cells die Usually treated with daily injections of insulin Sometimes islet cell transplant
Diabetes Type II diabetes usually happens over 40 years old More common, less severe than type I Caused by insufficient insulin or unresponsive target cell receptors Type II is hereditary Also related to obesity Can control through exercise and diet
Gonads : Ovaries & Testes Produce gametes and secrete hormones Ovaries produce estrogen and progesterone Testes produce testosterone Control sexual behavior and development
Ovaries Estrogen stimulates the growth of the uterine lining for pregnancy. Progesterone prepares the uterus for implantation.
Testes Testosterone necessary for sperm production responsible for secondary sex characteristics in males
Feedback Mechanisms is a mechanism that maintain homeostasis occurs when the level of one substance influences the level of another substance or activity of another organ There are two types… Negative Feedback Positive Feedback
Negative Feedback If hormone levels are found to be too high, the hypothalamus tells the pituitary to send out inhibitory factors which tell the gland that makes the hormone to stop producing so much So, inhibits the production of another hormone Final step of events inhibits initial signal in series
Positive Feedback If levels of a particular hormone are low in the blood, the hypothalamus senses this and tells the pituitary to send out releasing factors which turn on the gland that makes that particular hormone
ADH and Negative Feedback Control http: //www. abpischools. org. uk/res/co. Resource Import/modules/homeostasis_kidneys/fullscree nflash 6 -1. cfm http: //www. abpischools. org. uk/page/modules/h omeostasis_kidneys/kidneys 6. cfm? co. Site. Navi gation_all. Topic=1
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