Endocrine System Summary PDF

1 HAJI SALAAD PRIMARY AND SECONDARY SCHOOL ARMO SUB:BIO CHAPTER: ENDOCRINE SYSTEM PURPOSE: SUMMERY  Endocrine System: is the collection of glands that produce hormones which regulate growth, development and reproduction.  Endocrine contains two words "endo" means within or insi...

1 HAJI SALAAD PRIMARY AND SECONDARY SCHOOL ARMO SUB:BIO CHAPTER: ENDOCRINE SYSTEM PURPOSE: SUMMERY  Endocrine System: is the collection of glands that produce hormones which regulate growth, development and reproduction.  Endocrine contains two words "endo" means within or inside and "crinis"means to secrete  Comparison between endocrine and nervous system  Both involve transmission of messages  Both provide means of communication  Both bring about survival response  Both involve chemical transmission  Difference between endocrine and nervous system Endocrine System Nervous system Chemical transmitted through the blood Impulse is transmitted through the nerve fiber Chemical substance evokes a response Nerve impulse evokes a response Long term affect Short term affect Responses takes place involuntarily Responses takes place Both voluntary and involuntary  Glands: are organs that produce and release substances that perform certain functions  Types of glands  Exocrine gland: are glands that have ducts. These glands secrete enzymes.  Endocrine glands: are ductless glands. These glands produce hormones  Important exocrine glands include  Salivary gland , sweat gland, pancreas, liver.  Difference between 1. Hormone: are organic compounds which are either proteins or steroids in nature. 2. Enzyme: are proteins that help speed up metabolism  Difference between endocrine and exocrine glands Exocrine glands Endocrine glands Secrete enzymes Secrete hormones Have ducts Have no ducts Mostly controls short term activities of the body Mostly controls long term activities of the body Secrete their products through ducts Secrete their products directly into the blood  How hormones work  Hormone is released from gland it travels through blood stream and reaches its target cell.  Difference between  Up regulation: increase number of receptors for a particular Hormone  Down regulation: decrease number of receptors in a particular Hormone  Steroids: are biologically active organic compounds.  Steroid hormones:-  Are hormones made of lipids( cholesterol and phospholipids)  Are fat soluble  They can diffuse across the plasma membrane  bind with receptors in the cytoblasm of the cell  Eg( androgens , mineralocorticoids glucocorticoids, estrogen, progesterone)  Non-steroid hormones:- PREPARED BY:- ABDUHAKIM SAHAL MUSSE CONTACT: +252906402223 2  Are hormones made of amino acids  Are not fat soluble  They can not diffuse across the plasma membrane of target cells  Bind to a receptors on the cell membrane  Eg(insulin, thyroid hormones, glucagon, parathyroid hormone)  General features of endocrine glands  Ductless glands  Secrete hormones  Responsible for Chemical co-ordination of body  The hormones are highly specific  The main endocrine glands are  Pituitary gland(brain) - thyroid gland(neck) - adrenal gland(kidney) - pancrease(under stomach) - ovaries( sides of pelvic) - testes(scrotum)  The Pituitary gland  Is attached to the hypothalamus  It's known as master gland(because it Secretes number of hormones which control the activity of particular gland)  Is divided into two lobes 1. Anterior Pituitary lobe 2. Posterior Pituitary lobe  Hypothalamus  Located base of the brain above Pituitary gland  Links endocrine and nervous system  Produce Gonadotropin-releasing hormone(GnHR) that regulates the secretion of LH and FSH hormones from Anterior Pituitary and these two hormones are gonad-stimulating hormones. Endocrine gland Hormones Major Function target(organs) Pituitary gland Anterior lobe 1. Thyroid stimulating Thyroid gland Stimulates thyroid gland to hormone(TSH) produce thyroxine 2. Adrenocorticotropic Adrenal Stimulates the adrenal cortex to hormone(ACTH) gland(cortex) produce corticoid hormone 3. Follicle stimulating Ovary and testis Stimulates egg and sperm hormone (FSH) production 4. Luteinizing hormones Ovary and testis Cause ovulation in female and (LH) testosterone in male 5. Growth hormone(GH) Liver and adipose Control growth tissue 6. Prolactin (PRL) Mammary gland Stimulates milk production by the mammary gland Pituitary gland Posterior lobe 1. Oxytocin Ovary Stimulates uterine contractions in childbirth 2. Antidiuretic hormones Kidney Stimulates the kidney to reabsorb (ADH)or vasopressin water and produce less urine  Thyroid gland  Located in the neck  Produce hormone called thyroxine  Thyroxine contains 4 iodine PREPARED BY:- ABDUHAKIM SAHAL MUSSE CONTACT: +252906402223 3  Function of thyroxine  Increase metabolism  Stimulates normal physical growth and mental development.  Effects of thyroxine imbalance  Excessive o High metabolic rate o Increase rate of heart beat o Goilter( abnormally enlarged of thyroid gland)  Deficiency o Cretinism(defective development) in children o Myxedema( sluggishness of metabolism) in adult  Parathyroid gland  Located behind thyroid gland  Produce hormone called parathyroid hormone  Function of parathyroid hormone  Regulates calcium levels in the blood  Effects of parathyroid hormone imbalance  Excessive o Cause brittle of bones o Cause kidney stones  Deficiency o Blood calcium level falls  Adrenal glands  There are two adrenal glands Located above each kidney. 1. Adrenal medulla  Produce adrenaline(epinephrine) and noradrenaline(norepinephrine) hormones  Function of adrenaline hormone  Prepares the body for emergency situation of fight or flight by o Raising respiration and heart beat rate o Increasing blood flow to muscle and brain  Effects of excessive adrenaline hormone o Raise blood pressure o Raise blood glucose level o Cause glucose to be present in urine. 2. Adrenal cortex  Produce over 30 different steroid hormones collectively called corticosteroids or corticoid hormones include cortisol , aldosterone , and androgen.  Function of cortisol hormone o Raise blood glucose level o Are produced to response to stress  Effects of cortisol hormone imbalance  Excessive o Cause crushing's syndrome  Deficiency  Cause Addison's disease  Function of aldosterone hormone  Regulates blood osmotic pressure  Effects of aldosterone imbalance o Excessive  Body retains excess water  Blood pressure increases o Deficiency  Blood pressure drops  Water is excreted  Function of androgen hormone  Regulates maturity of sex organs PREPARED BY:- ABDUHAKIM SAHAL MUSSE CONTACT: +252906402223 4  Regulates development of secondary security characteristics  Effects of androgen imbalance  Excessive o Leads early physical maturity in children  Deficiency o Undeveloped sex organs in adult  The pancreas  Located behind the stomach  Made of small groups of cells called islets  Pancreatic islets contain two major types namely  Beta cells: produce insulin  Alpha cells: glucagon  Function of insulin hormone  Lowers blood glucose level  Convert glucose in the blood in to the glycogen  Effects of insulin imbalance  Deficiency  High blood glucose level  Excessive  Low blood glucose level  Function of glucagon hormone  Raise blood glucose level  Convert glycogen into glucose  Effects of glucagon imbalance  Deficiency o Weak o Lack of energy  Excessive  Over active  Gonads  Are gamete producing organs ovaries and testes  Ovaries Located in both sides of pelvic area  Testes Located in the scrotum  Ovaries produce estrogen and progesterone hormones  Testes produce testosterone hormone  Function of estrogen hormone  Regulates the development of secondary serial characteristics  Stimulates thickening of the uterus during ovulation  Effects of estrogen imbalance  Deficiency 1. Hinders normal development of secondary sexual characteristics  Excessive 1. Causes water retention 2. Causes difficult in memory 3. Causes headache  Function of progesterone hormone  Prepare the uterus for pregnancy  Effects of progesterone imbalance  Deficiency o Cause miscarriages  Excessive o Hinders Contraction of uterus during birth  Function of testosterone hormone  Regulates the development of secondary sexual characteristics  Effects of testosterone imbalance  Deficiency before puberty o Hinders secondary sexual characteristics  Deficiency after puberty o Cause impotence( erectile dysfunction): inability in a man to have an erection or orgasm. PREPARED BY:- ABDUHAKIM SAHAL MUSSE CONTACT: +252906402223 5  Regulation of hormonal secretion  Hormone may be regulated 1. Another hormone 2. Metabolites 3. The nervous system  Effects of GH hormone  Deficiency o In children can cause dwarfism o In adult can cause poor bone density  Excessive o In children can cause gigantic o In adults it can Causes acromegaly  3.2: Homeostasis  Homeostasis: is the maintenance of a constant internal environment. : is the state of balance  Feedback: is a process that allow the body to sense changing internal condition and respond to them.  Homeostasis is derived from two Latin words Homeo= same stasis=position  Factors or conditions which should be kept constant  Glucose concentration, Carbondioxide concentration, Temperature, pH.  Mechanism of Homeostasis  Homeostasis works on a feedback mechanism o There are two types of feedback mechanism 1. Negative 2. Positive  Body temperature - child birt  Regulation of blood sugar - blood clotting  Difference between a. Poikilotherms( ectoderms): animals whose body temperature varies. b. Homeotherms( endotherms): animals which maintain constant body temperature.  Factors affecting temperature Regulation  The surface area to volume ratio.  Whether or not the body has insulating material around it  The physical state of the surface of the body  Whether the body possess any mechanism for generating heat.  Four mechanisms for body temperature Regulation  Conduction , convection , radiation ,and evaporation.  Babies lose heat quickly why?  Because of their high surface area to volume ratio.  Heat control methods a. Physiological method ( evaporation by sweating) b. Behavioral methods ( clotting, moving to a shade)  Normal blood glucose  Before meal: 70-80mg per 100ml of blood  After meal : 110-120mg per 100ml of blood  Difference between  Glycogenolysis: creation of glucose from stored glycogen  Glycogenesis: the production of glucose from stored glycogen PREPARED BY:- ABDUHAKIM SAHAL MUSSE CONTACT: +252906402223 6 PREPARED BY:- ABDUHAKIM SAHAL MUSSE CONTACT: +252906402223