Presentation on theme: "Allied Health Sciences I Unit P"— Presentation transcript:
1 Allied Health Sciences I Unit P The Endocrine SystemAllied Health Sciences IUnit P
2 Functions of the Endocrine System Secrete hormonesHormones are chemical messengers that coordinate and direct target cells and organs.Hormone controlNegative feedback = drop in hormone level triggers a chain reactionBlood level of hormone fallsBrain gets message and sends out hormone to stimulate glandGland secretes more hormoneWhen blood level of hormone increases, brain hormones stop
3 Functions of Endocrine System Nervous controlIn some cases, sympathetic nervous system causes direct release of hormone from gland (for example, when stress causes the adrenal medulla to secrete adrenalin)
4 Two types of glands Endocrine Exocrine Secrete hormones directly into the bloodstreamductlessExocrineSecrete substance through a ductSweat, salivary, lacrimal and pancreas
5 Structures of the Endocrine System Anterior Pituitary GlandPosterior Pituitary GlandThyroid GlandParathyroid glandsThymus GlandAdrenal GlandsOvariesTestesPancreasPineal Gland
6 The Anterior Pituitary Gland The entire pituitary gland is the size of a grape.It is located on the underside of the brain in the sella turcica.The anterior lobe secretes 7 hormones:Growth hormone or GH or somatotrophin-responsible for growth and development.Prolactin hormone or PRL: responsible for stimulating milk production after childbirthThryroid-stimulating hormone or TSH: stimulates growth and secretion of the thyroid gland
7 The Anterior Pituitary Gland Hormones cont.:Adrenocorticotropic hormone or ACTH: stimulates growth and secretion of the adrenal cortexFollicle-stimulating hormone or FSH: stimulates the growth of the graafian follicle and production of estrogen in the female and production of sperm in the maleLuteinizing hormone or LH: stimulates ovulation and formation of the corpus luteum which produces progesterone in the femaleInterstitial-cell stimulating hormone or ICSH: needed for the production of testosterone in the male
8 The Posterior Pituitary Gland The posterior pituitary gland produces two hormones:Vasopressin: this converts to ADH in the bloodstream. ADH helps with water balance.Oxytocin: causes contractions of the uterus during childbirth and during breastfeeding
9 The Thyroid GlandIt is located behind the cricoid cartilage in the neck and is about 2 inches long.It produces three hormones:Thyroxine (T4) and triiodothyronine (T3): controls the rate of metabolism, protein synthesis and the breakdown of liver glycogen.Calcitonin: controls the calcium level in the bloodstream when it gets too high
10 The Parathyroid Glands There are four of these and are the size of a grain of rice. They are attached to the posterior side of the thyroid gland.It secretes one hormone:Parathormone: also controls the calcium level when it gets too low
11 The Thymus GlandThe thymus gland is located beneath the sternum and decreases in size after puberty.It secretes several hormones but the most important is:Thymosin: stimulates lymphoid cells to produce T cells which help with immunity
12 The Adrenal GlandsThere are two adrenal glands located on the top of each kidney.There are two parts: the cortex and the medulla.The cortex secretes three corticoids (which act as antiinflammatory agents):Mineralocorticoids: mainly aldosterone which speeds sodium and water reabsorption in the kidneysGlucocorticoids: mainly cortisone and cortisol, increases the amount of glucose in the bloodAndrogens: male sex hormones that produce male sexual characteristics
13 The Adrenal Glands (cont.) The medulla of the adrenal gland produces one hormone:Epinephrine: increases heart rate, blood pressure and flow of blood; decreases intestinal activities
14 The Ovaries They are located in the female pelvis. They produce two hormones:Estrogen: promotes growth of primary and secondary sexual characteristicsProgesterone- develops excretory portion of mammary glands, aids in maintaining pregnancy
15 The Testes They are located in the male scrotum. They produce one hormone:Testosterone: develops primary and secondary sexual characteristics; stimulates maturation of sperm
16 The Pancreas The pancreas is located behind the stomach. It produces two hormones:Insulin: essential to the metabolism of carbohydrates, reduces blood sugar levelGlucagon: stimulates the liver to release glycogen and converts it to glucose to increase blood sugar levels
17 The Pineal Gland The pineal gland is located at the base of the brain. It produces one hormone:Melatonin: relates to the sleep cycle
18 ProstaglandinsHormones called prostaglandins are secreted in various tissues. What the prostaglandins do depend on which tissue is secreting them. Some may cause constriction while others cause dilation. Prostaglandins can be used to induce labor and cause severe muscular contractions of the uterus.
19 AcromegalyThis occurs when hypersecretion of the growth hormone occurs.Overdevelopment of the bones of the face, hands and feet occur.Patients may have lethargy and headaches.Tx. is drug therapy and radiation therapy.
20 GigantismThis is an overgrowth of the long bones leading to excessive tallness.This is due to hyperfunctioning of the pituitary gland during preadolescence.Tx. is drug therapy and radiation therapy
21 DwarfismHypofunctioning of the pituitary gland during childhood leads to dwarfism.The body of a dwarf is normally proportioned and intelligence is normal.Tx. Is early diagnosis and injections of the human growth hormone.
22 HyperthyroidismHyperthroidism is an overactivity of the thyroid gland.The gland becomes enlarged.Patients may feel hot, have fast growing, rough fingernails, increased blood pressure and heart beat.Patients may exhibit goiter and exopthalmos.Tx. is partial or total removal of the thyroid, drugs to reduce thyroxine, radiation
23 Hypothyroidism The thyroid gland does not secrete enough thyroxine. Iodine deficiency may cause adult hypothyroidism.Myxedema causes the face to swell, weight gain and memory failure. Tx. is the thyroid hormone.Occuring in infancy and early childhood, cretinism causes mental retardation and lack of physical growth. Tx. Is the thyroid hormone; however complete recovery is not possible.
24 Cushing’s DiseaseThis results from hypersecretion of the glucocorticoid hormones from the adrenal cortex. It may be caused by a tumor or prolonged use of prednisone.The most common characteristics are a “moon” face and a “buffalo” hump.Tx. Is removal of the tumor or gradual decrease of use of the prednisone.
25 Addison’s DiseaseIt is caused by decreased functioning of the adrenal cortex.It is characterized by a “bronzing” of the skin.Tx. is replacement of the deficient hormones.
26 TetanyCaused by hypoparathyroidism, decreased calcium levels affect functions of nervesSymptoms = convulsive twitching develops, person dies of spasms in the respiratory musclesRx = vitamin D, calcium and parathormone
27 Diabetes MellitusThis is caused by decreased secretion of insulin in the islets of Langerhans.There are two types: Type I- children and young adults and Type II- adults.Type I requires insulin to control the glucose levels.Type II may be controlled through diet and oral meds or may require injections.Polyuria, polydypsia and polyphagia are typical symptoms.
28 Diabetes InsipidusThis is caused by a drop in the ADH (antidiuretic hormone) secondary to dysfunction of the posterior lobe of the pituitary gland. The person has excessive thirst.