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Home , Adrenal medulla, Endocrine system, Posterior pituitary

EndocrineEndocrine SystemSystem

Modified by M. Myers

1 TheThe EndocrineEndocrine SystemSystem

2 EndocrineEndocrine GlandsGlands z The is made of & tissues that secrete . z Hormones are chemicals messengers influencing a. of cells b. growth and development c. , d. .

3 HormonesHormones

Hormones (chemical messengers) secreted into the bloodstream and transported by blood to specific cells (target cells)

Hormones are classified as 1. ()

2.

4 HormoneHormone ClassificationClassification z Hormones: – Lipid soluble – Diffuse through cell membranes – Endocrine organs

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z Testes

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5 HormoneHormone ClassificationClassification z Nonsteroid Hormones: – Not lipid soluble – Received by receptors external to the – Endocrine organs

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z

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6 HormoneHormone ActionsActions z “Lock and Key” approach: describes the interaction between the and its specific . – Receptors for nonsteroid hormones are located on the cell membrane – Receptors for steroid hormones are found in the cell’s cytoplasm or in its nucleus

7 http://www.wisc- online.com/objects/index_tj.asp?objID=AP13704

8 EndocrineEndocrine SystemSystem

z There is a close assoc. b/w the endocrine & nervous systems. z Hormone secretion is usually controlled by either negative or antagonistic hormones that oppose each other’s actions

9 HypothalamusHypothalamus

1. regulates the internal environment through the autonomic system

2. controls the secretions of the pituitary gland.

10 HypothalamusHypothalamus && PituitaryPituitary GlandGland posteriorposterior pituitary/pituitary/ anterioranterior pituitarypituitary

11 PosteriorPosterior PituitaryPituitary The secretes zantidiuretic hormone (ADH) zoxytocin

12 13 14 AnteriorAnterior pituitarypituitary glandgland

1. (hGH) (Somatotropin) 2. Thyroid stimulating hormone (TSH) 3. Follicle-stimulating hormone (FSH) 4. (LH) 5. Interstisal cell stimulating hormone (ICSH) 6. (PRL): initiates milk production 7. Adrenocorticotrophic hormone (ACTH):

15 16 HypothalamusHypothalamus andand thethe pituitarypituitary

17 EffectsEffects ofof GrowthGrowth HormoneHormone

GH promotes and muscle growth.

Pituitary dwarfism results from too little GH during childhood. Giants result from too much GH during childhood.

If growth hormone is overproduced in an adult, it causes acromegaly.

18 EffectEffect ofof growthgrowth hormonehormone

19 AcromegalyAcromegaly

20 ThyroidThyroid andand ParathyroidParathyroid GlandsGlands

z The thyroid gland

z The four parathyroid glands are embedded in the posterior surface of the thyroid gland.

21 ThyroidThyroid GlandGland z The thyroid gland z requires iodine to increase produce thyroxine 1. Oxygen use z (T ) which contains 4 2. Cellular metabolism four iodine atoms 3. Growth & development z (T3) which contains three iodine atoms

22 z Effects of Thyroid Hormones z If iodine is lacking in the diet, a simple goiter develops. z Use of iodized salt helps prevent simple goiters. z in childhood produces cretinism; in adulthood it causes myxedema. z If the thyroid is overactive (Grave’s disease) an exophthalmic goiter develops.

23 SimpleSimple goitergoiter

24 CretinismCretinism

25 ThyroidThyroid GlandGland z which helps lower the blood level when it is too high. z deposits calcium in the z regulates calcium homeostasis

26 ParathyroidParathyroid glandsglands

z (PTH stimulates the activity of osteoclasts, thus releasing calcium from bone, & stimulates the of calcium by the kidneys and intestine

27 RegulationRegulation ofof bloodblood calciumcalcium levellevel

28 AdrenalAdrenal GlandsGlands z Cortex: corticosteroids- essential to . z Medulla: epinephrine and nor-epinephrine.

29 AdrenalAdrenal GlandsGlands

z Adrenal glands sit atop the kidneys and have an inner adrenal medulla and an outer adrenal cortex. z The uses ACTH-releasing hormone to control the ’s secretion of ACTH that stimulates the adrenal cortex. z The hypothalamus regulates the medulla by direct impulses.

30 z The adrenal medulla secretes epinephrine and , which bring about responses we associate with emergency situations. z On a long-term basis, the adrenal cortex produces similar to and to regulate salt and water balance. z The adrenal cortex also secretes both male and female sex hormones in both sexes.

31 AdrenalAdrenal glandsglands

32 GlucocorticoidsGlucocorticoids z promotes breakdown of muscle proteins to amino acids; the then breaks the amino acids into . z Cortisol also promotes metabolism of fatty acids rather than carbohydrates, which spares glucose. z Both actions raise the blood glucose level. z High levels of blood glucocorticoids can suppress function.

33 MineralocorticoidsMineralocorticoids z causes the kidneys to reabsorb sodium ions (Na+) and excrete potassium ions (K+). z When blood sodium levels and are low, the kidneys secrete ; the effect of the renin--aldosterone system is to raise blood pressure.

34 RegulationRegulation ofof BPBP andand FluidFluid volumevolume

35 MalfunctionMalfunction ofof thethe AdrenalAdrenal CortexCortex z Addison disease develops when the adrenal cortex hyposecetes hormones. z A bronzing of the skin follows low levels of cortisol, and mild infection can lead to death; aldosterone is also hyposecreted, and dehydration can result.

36 AddisonAddison diseasedisease

37 MalfunctionMalfunction ofof thethe AdrenalAdrenal CortexCortex z Cushing syndrome develops when the adrenal cortex hypersecretes cortisol.

z The trunk and face become round; too much aldosterone results in fluid retention

38 CushingCushing syndromesyndrome

39 PancreasPancreas z The pancreas is between the kidneys and the and provides digestive juices and endocrine functions. z secrete , which lowers the blood glucose level, and , which has the opposite effect, together regulating the glucose level in the blood.

40 RegulationRegulation ofof bloodblood glucoseglucose levellevel

41 DiabetesDiabetes MellitusMellitus z The most common illness due to hormonal imbalance is mellitus. z Diabetes is due to the failure of the pancreas to produce insulin or the inability of the body cells to take it up. z Causing

42 DiabetesDiabetes MellitusMellitus z Type I diabetes mellitus occurs when the pancreas does not produce insulin z Type II diabetes mellitus where the pancreas produces insulin but the body cells do not respond.

43 TestesTestes andand OvariesOvaries

Testes, hormone . Ovaries produce and . z Secretions from the are controlled by the anterior pituitary hormones. z These sex hormones maintain the sex organs and secondary sex characteristics.

44 TheThe effectseffects ofof anabolicanabolic steroidsteroid useuse

45 ThymusThymus GlandGland

z The under the produces that stimulate T production and maturation. z The thymus decreases in size with age and becomes fatty.

46 PinealPineal GlandGland

The in the brain produces which is involved in circadian rhythms and the timing of development of the reproductive organs.

47 TheThe EndocrineEndocrine GlandsGlands z Kidneys () – regulates red blood cell production

48 HormonesHormones fromfrom OtherOther TissuesTissues

Leptin z Adipose produces that acts on the hypothalamus where it signals satiety— that the individual feels “full” and has had enough to eat.

49 ProstaglandinsProstaglandins z a fatty acid.

z They cause uterine muscle contraction and are involved in the pain of menstrual cramps

50 ChemicalChemical SignalsSignals z A chemical signal is any substance that affects cell metabolism or behavior of the individual. z Chemical signals can be used between body parts, between cells, and between individual (). z Underarm secretions may be slightly attractive and may be involved in synchronizing the menstrual cycles of women who live together.

51 TheThe ActionAction ofof HormonesHormones z Steroid hormones enter the nucleus and combine with a receptor , and the hormone-receptor complex attaches to DNA and activates certain genes. z hormones are usually received by a hormone receptor protein located in the plasma membrane.

52 StudentStudent QuizQuiz z http://www.zerobio.com/drag_oa/endo.htm

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