Chapter 8 The Endocrine System Like the nervous system the endocrine system controls and monitors organs glands and processes in the body The endocrine system does this job by using hormones ID: 1036473
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2. Lesson 8.1Functions and Control of the Endocrine SystemChapter 8: The Endocrine System
3. Like the nervous system, the endocrine system controls and monitors organs, glands, and processes in the body.The endocrine system does this job by using hormones that first collect information and then stimulate organs, glands, and tissues.The nervous and endocrine systems work together to regulate bodily functionsFunctions and Control of the Endocrine System
4. The endocrine system is a collection of organs and small glands that directly or indirectly influence all the functions of the body such as:HypothalamusPituitary glandAdrenal glandPineal glandAnatomy of the Endocrine System
5. Endocrine GlandsThe endocrine system is made up of ductless glands called endocrine glandsThese glands secrete hormones directly into the bloodstreamThe endocrine glands include:Hypothalamus Pancreas Pituitary gland, Adrenal gland, Thyroid gland, Pineal gland, Testes (male), and Ovaries (female).Anatomy of the Endocrine System
6. Exocrine GlandsExocrine glands, which are glands of external secretionExocrine glands have a duct through which secretions are carried to the body’s surface or to other organs.The exocrine glands include:Sweat glands (sweat); Salivary glands (saliva); Mammary glands (breast milk); Lacrimal glands (tears); Pancreas glands (digestive enzymes).Functions as both endocrine and exocrine glandsAnatomy of the Endocrine System
7. Generally, hormones regulate carbohydrate, fat, and protein metabolism; water and electrolyte balance; reproductive activity; growth and development; and energy balance.Hormones also aid in the body’s response to infection and stress.Classified into two groups:Steroid hormones (fat / lipid based)Amino acid hormones (protein / protein related substances)Hormones
8. Hormones are transported throughout the body by the blood, which comes into contact with all the body’s tissues and organs.However, hormones affect only the tissues and organs that have receptors specific to those particular hormones.Hormone receptors
9. The activity of hormone receptors can be upregulated (increased) or downregulated (decreased), making them more or less sensitive to the hormone.Exercise upregulates insulin receptors, making them more sensitive to insulin (a hormone that promotes the uptake of glucose in body tissues).Less insulin is needed to promote glucose uptake in people who are physically active.Obesity downregulates insulin receptorsMore insulin must be present to promote glucose uptake by cells.Hormone receptors
10. Endocrine glands are regulated in three different ways: neural control, hormonal control, and humoral control.Neural controlNerve fibers stimulate the endocrine organs to release hormones. Ex.: During the fight-or-flight response, the CNS stimulates the release of epinephrine which:Increase heart rate, blood pressure, respiration, and blood flow to muscles; Decreased blood flow to organs; Dilation of the pupils.Hormone Secretion Control
11. Hormonal ControlDuring hormonal control, endocrine organs are stimulated by hormones from other endocrine organs, starting with the hypothalamus to achieve a particular goal.Hormonal control can be likened to the hierarchy of a business.Hypothalamus (President) directs the activity of the pituitary glandPituitary (vice president) releases many hormones to direct the managersOther endocrine glands managers: adrenal cortex, thyroid, reproductive organs, pancreas, adrenal medullaHormone Secretion Control
12. Hormone Secretion Control
13. After the goal has been achieved, the pituitary and hypothalamus can receive signals from the “manager” hormones that turn off the pituitary and hypothalamic hormones, thus ending the chain of hormonal control.This is an example of the negative feedback loopHumoral controlAchieved by monitoring the levels of various substances in body fluids, such as the blood.If a homeostatic imbalance is detected, corrective actions are undertaken to help the body regain homeostasis.Ex. when blood glucose levels rise, the pancreas secretes insulin, stimulating the absorption of glucose in body tissues.Hormone Secretion Control
14. Negative feedbackMechanism that reverses a condition that has exceeded the normal homeostatic range to restore homeostasisHormones and Homeostasis
15. Helps regulates (maintain) body temperature at 37oC (98.6oF)The Hypothalamus
16. True or False?Endocrine glands secrete hormones.2. Endocrine glands have ducts.3. Steroid hormones are proteins.4. Hormone receptors can only be upregulated.Review and Assessment TRUEFALSEFALSETRUE
17. Lesson 8.2Major Endocrine OrgansChapter 8: The Endocrine System
18. Major Endocrine Organs
19. The hypothalamus is a very small gland (about 4 grams) buried deep in the brain below the thalamus.Its job is to collect information from each body system and integrate the responses of the nervous and endocrine systems to maintain homeostatic balance.It helps regulatemetabolismheart rateenergy levelbody temperaturethirst The Hypothalamus
20. The pituitary gland is a pea-sized gland with two lobes—the anterior pituitary and the posterior pituitaryHormones secreted by the pituitary gland function in two ways. They can act directly on target tissue to cause a specific metabolic response, or They can stimulate other endocrine glands (tropic hormones) to release their own hormonesThe Pituitary Gland
21. Hormones of the Anterior PituitaryThe anterior pituitary gland secretes six different hormones:Prolactin (PRO)growth of mammary glands milk production in a nursing motherGrowth hormone (GH)Growth of bone and musclesHelps break down fats for use as a fuel during exerciseHormones of the Anterior Pituitary
22. Hormones of the Anterior Pituitary – Tropic HormonesAdrenocorticotropin hormone (ACTH)Release of steroid hormones from adrenal cortex.Thyroid-stimulating hormone (TSH)Release of T4 (Thyroxine) and T3 (Triiodothyronine) from thyroid gland.
23. Follicle-stimulating hormone (FSH)Stimulates the production of estrogen & eggs in females Stimulates the production of sperm in males luteinizing hormone (LH)Acts on ovaries to produce progesterone and estrogen in womenSignals the release of eggs (ovulation)Stimulates the testes to produce testosterone in malesHormones of the Anterior Pituitary – Tropic Hormones
24. The posterior pituitary gland is an extension of the hypothalamus, it does not produce hormones, but, stores two hormones:Antidiuretic hormone (ADH)Travels in the blood to reach the target organ Acts on kidney, decreases urine output (increase water reabsorption)Is secreted when plasma (liquid portion of blood) is lowHormones of the Posterior Pituitary
25. ADH can raise blood pressure because it causes the arteries to narrow, therefore increasing their resistance to blood flowAlcohol inhibits ADH, leading to increased urination, dehydration, and a dry mouth the morning after a person drinks alcoholic beverages. Caffeine and foods such as asparagus have a similar effect on ADH and act as diuretics.Hormones of the Posterior Pituitary
26. OxytocinFacilitates childbirth by stimulating the muscles of the uterus to contract. Oxytocin release is stimulated by the sucking mechanism of a nursing infant, causing the mammary glands to secrete breast milk from the mammary ducts.Pitocin is a synthetic form of oxytocin that is administered to induce, or speed up, delivery of a baby.Hormones of the Posterior Pituitary
27. Thyroid gland – Secrets two hormones:Thyroid hormone Thyroxine (T4) and triiodothyronine (T3)Controls rate of metabolism of all cells in the bodyCalcitoninCauses calcium in blood to be deposited and absorbed into boneOnce we reach adulthood and our bones are fully developed, very little (if any) calcitonin is released by the thyroid gland.Major Endocrine Glands
28. 8.2 notes cont..
29. Parathyroid glandParathyroid hormone is secreted in response to low blood calcium levels Blood calcium levels are increased in the following ways: Stimulating the breakdown of bone tissues by osteoclasts, thus moving calcium from the bone into the bloodIncreasing calcium absorption in the intestines with the aid of vitamin D during digestionStimulating kidney reabsorption of calcium from urine and excreting phosphorusMajor Endocrine Glands
30. Thyroid and Parathyroid Glands
31. Thymus glandIs both an endocrine gland and a lymphatic organSecretes thymosinA hormone essential for the development of white blood cells called T lymphocytes or T cells Pineal glandSecretes melatonin when the body is exposed to darkness causing the body to feel sleepyMelatonin levels are highest at nightMajor Endocrine Glands
32. Found on top of the kidneys, they are actually two organs:Adrenal medulla (part of nervous system) secretes two hormones:Epinephrine and norepinephrine released in blood during times of stress causing an adrenaline rush resulting in:Increased heart rate, blood pressure and breathing to name a few.Adrenal Glands
33. Adrenal cortex (gland) produces three groups of steroid hormones:Mineralocorticoids (aldosterone)Stimulates the kidneys to reabsorb sodium and water from urine thus regulating the concentration of blood electrolytes.Glucocorticoids (cortisone and cortisol)Maintain blood glucose levels ensuring that the brain an nervous system have a constant supply of glucoseSex hormones (female estrogen and male androgens)Maintains sexual characteristicsAdrenal Glands
34. Functions as an endocrine gland by secreting hormones that control blood glucose levels. Functions as an exocrine gland that excretes digestive enzymes.Islets of Langerhans are the hormone secreting cells of the pancreasAlpha cellsSecrete glucagon which increases blood glucose level Beta cellsSecrete insulin which decreases blood glucose level Normal range between 70 and 105 mg/dL Pancreas
35. Regulation of blood glucose levels by the pancreas
36. Are sex glandsTestes Produce testosterone responsible for sperm production, development of the male reproductive system, and the emergence of male secondary sex characteristics during puberty.Ovaries Produce eggs and the hormones: estrogen and progesterone Estrogen plays a key role in the development of the female reproductive glands and secondary sex characteristics.Along with progesterone, estrogen regulates the menstrual cycle and promotes breast development.Gonads
37. Fill in the blanks with: ADH, thyroxine, thymosin, cortisol or adrenal cortex.The thymus gland produces _______________.2. The posterior pituitary gland produces oxytocin and _______________. 3. Mineralocorticoids are produced by the _______________.4. T4 is also called _______________. Review and Assessment ThyroxineAdrenal cortexADHThymosin
38. Endocrine Disorders and DiseasesLesson 8.3Chapter 8: The Endocrine System
39. Endocrine Disorders and DiseasesBecause the endocrine system is hierarchical in nature, many of its glands depend upon one another yet also act independently. Therefore, when an endocrine gland is not functioning properly, the effects of its malfunction can be felt throughout the body or at a specific site.
40. Endocrine disease and disorders include:Pituitary disordersThyroid disordersDisorders of the parathyroid glandAdrenal medulla disordersDisorders of the adrenal cortexThe pancreas and diabetes mellitus Endocrine Disorders and Diseases
41. Hyperfunction – the excessive secretion of specific hormones. Hypersecretion of growth hormone, results in a rare condition called acromegaly, or gigantismUsually caused by a noncancerous tumor pressing on the pituitary gland.In children, acromegaly causes unusually tall height, large hands, and large feet.In adults, acromegaly causes thickened bones and enlarged facial features, hands, and feet.Treatment includes: Medications to shrink the tumor or surgery to remove the tumorPituitary Disorders
42. Hypofunction – the inadequate secretion of specific hormonesHyposecretion of GH by the pituitary gland can cause dwarfism, a condition in which adult height reaches less than four feet. When diagnosed at an early age, dwarfism is usually treated with supplemental growth hormones. Diabetes insipidus caused by hyposecretion of antidiuretic hormone (ADH) resulting in excessive loss of water and electrolytes.People with diabetes insipidus experience excessive thirst Pituitary Disorders
43. Hyperthyroidism or an overactive thyroid, is characterized by a visibly enlarged thyroid gland in the neck called a goiter.Goiter is caused by insufficient amounts of iodine, a chemical element necessary for the production of thyroid hormones. Graves disease is an autoimmune disorder that leads to an overactive thyroid gland causing eyes to bulge outward.Treatments for hyperthyroidism include: Surgery to remove part, or all, of the thyroid gland or tumor, Radioactive iodine to destroy thyroid cells, and Thyroid drugs to reduce thyroid hormones.Thyroid Disorders
44. Hypothyroidism or underactive thyroid, is usually caused by thyroiditis, the result of inflammation that damages thyroid cells.Myxedema – severe form of hypothyroidism seen in adults causingweight gain, dry skin, and decreased mental acuity. This condition can be treated with an oral form of thyroxine. Neonatal hypothyroidism – may develop congenitally (before birth) or soon after birth. Often causing a poorly developed thyroid gland or ineffective thyroid hormones leading to Dull, dry skin and dry and brittle hair.This condition can also be treated with an oral form of thyroxine. Thyroid Disorders
45. Disorders of the parathyroid glandHypercalcemia is the hypersecretion of (Parathyroid hormone) PTH causing too much calcium in the blood leading to:Brittle bonesKidney stones ( high calcium levels in kidney)Hypocalcemia or low blood calcium, leads to unstable nerve and muscle membranes that continuously fire electrical signals leading to:Tetany – sustained muscular contraction can affect the respiratory muscles, leading to asphyxiation and death.Parathyroid gland
46. Adrenal medulla disordersPheochromocytoma is a tumor on the adrenal medulla causing the adrenal medulla to hypersecrete the hormones epinephrine and norepinephrine leading to :High blood pressure, Rapid heart rate, Weight loss, NervousnessEndocrine Disorders and Diseases
47. Cushing syndrome caused by hypersecretion of cortisol or prolonged use of steroid drugs leading to:High blood glucose levelsHypertension Osteoporosis Addison’s disease caused by hyposecretion of adrenal corticoid hormones leading to:Muscle atrophyLow blood pressureKidney damageDisorders of the Adrenal Cortex
48. characterized by the body’s inability to produce sufficient amounts of insulin to regulate blood glucose levels.symptoms of diabetes mellitus include:Polyuria Excessive urination to eliminate glucosePolydipsia Excessive thirst to replace water loss due to polyuriaPolyphagia Increased hunger to replace fats and proteins used by the body as fuel sourcesThe Pancreas and Diabetes Mellitus
49. Type I diabetes mellitus or juvenile-onset diabetesAutoimmune disorder in which the immune system attacks and kills the insulin-secreting beta cells of the pancreas.Type II diabetes mellitus or adult-onset diabetesPancreas secretes insulin, but the body’s insulin receptors are downregulated (Insulin resistance)This causes elevated levels of glucose in the blood (Hyperglycemia)The Pancreas and Diabetes Mellitus
50. Match these words with 1–4 below: dwarfism, Cushing syndrome, goiter, polyuria, graves disease.A result of pituitary hypofunction 2. Excessive urination 3. Hypersecretion of cortisol 4. A result of hyperthyroidismReview and Assessment DwarfismPolyuriaCushing syndromeGoiter