The Endocrine & Reproductive Systems

The Endocrine & Reproductive Systems

1The Endocrine SystemThe endocrine system is made up of glands that release hormones into the blood.

2Hormones & GlandsHormones deliver messages throughout the body.Hormones - chemical messengers that are released in one part of the body and affect cells in other parts of the body.

Hormones act by binding to specific chemical receptors on cell membranes or within cells.Cells that have receptors for a particular hormone are called target cells.If a cell does not have receptors for a particular hormone, the hormone has no effect on it.

3Hormones & GlandsA gland is an organ that produces and releases a substance or secretion.Exocrine glands release secretions from ducts either out of the body or directly into the digestive system.sweat, tears, digestive enzymesEndocrine glands release their secretions (hormones) directly into the blood.4Hormones & GlandsProstaglandinsThe glands of the endocrine system were once thought to be the only organs that produced hormones.However, nearly all cells have been shown to produce small amounts of hormonelike substances called prostaglandins.

5Hormones & GlandsProstaglandinsSometimes called local hormones because they affect only nearby cells and tissues.Ex: some cause smooth muscles (uterus, bronchioles, and blood vessels) contract.One group causes the sensation of pain during most headaches.Aspirin inhibits the synthesis of these prostaglandins

6Hormone ActionSteroid HormonesSteroid hormones act by entering the nucleus of a cell and changing the pattern of gene expression.

7Hormone ActionProduced from a lipid called cholesterol.Steroid hormones help control metabolism, inflammation, immune functions, salt and water balance, development of sexual characteristics, and the ability to withstand illness and injury.

8Hormone ActionSome examples of synthetic steroid hormones:Glucocorticoids:prednisone,dexamethasone,triamcinoloneMineralocorticoid:fludrocortisoneVitamin D:dihydrotachysterolAndrogens:oxandrolone,testosterone,nandrolone(also known asanabolic steroids)Oestrogens:diethylstilbestrol(DES)Progestins:norethindrone,medroxyprogesterone acetate.

9Hormone ActionNonsteroid HormonesNonsteroid hormones bind to receptors on a target cell membrane and cause the release of secondary messengers that affect cell activities

10Hormone ActionNon-steroid hormones include: CholeckystokininEpinephrineDopamineInsulinNorepinephrineSerotoninVasopressin

11The Human Endocrine GlandsPituitary GlandBean shaped structure that dangles on a slender stalk of tissue at the base of the brain.It secretes hormones that directly regulate many body functions or control actions of other endocrine glands

Too much growth hormone during childhood results in gigantismToo little GH causes pituitary dwarfismCan be treated with GH produced by genetically engineered bacteria

12The Human Endocrine GlandsHypothalamusAttached to the posterior pituitary, it is the link between the CNS and the endocrine system.Controls the secretions of the pituitary glandThe hypothalamus contains the cell bodies of neurosecretory cells whose axons extend into the posterior pituitary.When cell bodies are stimulated, axons in the posterior pituitary release hormones into the blood.

13The Human Endocrine SystemHypothalamusIndirect control of the anterior pituitary.Produces releasing hormones, which is secreted into blood vessels leading to the anterior pituitary.Produces a specific releasing hormone that controls the secretion of each anterior pituitary hormone.Follicule-stimulating Hormone (FSH) Luteinizing hormone (LH) - Thyroid-stimulating Hormone (FSH)Adreno-corticotropic hormone (ACTH)Growth Hormone (GH)ProlactinMelanocyte-stimulating hormone (MSH)

The Human Endocrine GlandsAdrenal GlandsPyramid shaped structures that sit on top of the kidneys.Release hormones that help the body prepare for and deal with stress.Adrenal Cortex (outer part) produces more than two dozen steroid hormones ca called corticosteroids.Aldosterone regulates blood volume and pressureCortisol regulates helps control the rate of metabolism of carbohydrates, fats and proteins.Released during physical stress such as intense exercise.

15The Human Endocrine Glands

Adrenal Medulla (inner part) releases hormones that produce the heart pounding, anxious feeling you get when excited or frightened (fight or flight).Sympathetic nervous system stimulate cells to release large amounts of . . .Epinephrine (adrenaline) and norepinephrine.Increase heart rate and blood pressureCause air passageways to widen for increase O2 uptakeStimulate the release of extra glucose16The Human Endocrine GlandsPancreasBoth an endocrine AND exocrine gland.Exocrine: releases digestive enzymes to break down foodEndocrine: islets of LangerhansBlood Glucose Regulation:Insulin stimulates cells to take glucose out of the blood Glucagon stimulates the liver and skeletal muscle cells to break down glycogen and release glucose into the bloodDiabetes Mellitus

17The Human Endocrine Glands

Thyroid & Parathyroid GlandsThyroid wraps around trachea and has a major role in regulating metabolism.Produces thyroxine which increases the metabolic rate of cells throughout the body.Iodine needed to produce thyroxine.Calcitonin signals the kidneys to reabsorb less calcium and promotes absorption into bones.Parathyroid hormone increases calcium levels in the blood.Promotes proper nerve and muscle function and proper bone structure.Thyroid18The Human Endocrine GlandsReproductive GlandsGonads (ovaries and testes) are reproductive glands.Two important functions:Produce gamtesSecrete sex hormones

Ovaries produces eggs and secrete estrogens.Testes produce sperm and secrete testosterone.

19Control of the Endocrine SystemThe Endocrine System is regulated by feedback mechanisms that function to maintain homeostasis.Feedback inhibition occurs when an icrease in any substance feeds back to inhibit the process that produced the substance in the first place.

20Control of the Endocrine SystemMaintaining Water BalanceHypothalamus detects concentration of water in blood.As you lose water, concentration of dissolved materials in blood rises.Hypothalamus signals posterior pituitary to release antidiurect hormoneA water deficit stimulates the release of ADH, causing the kidneys to conserve water; Later you experience thirst a signal that you should drink to restore lost water.An oversupply of water causes the kidneys to eliminate the excess water in urine.

21Control of the Endocrine SystemControlling Metabolism

22The Reproductive System

23Sexual Development24The Male Reproductive SystemSperm DevelopmentSperm ReleaseSperm Structure25The Female Reproductive SystemFemale Reproductive StructuresThe menstrual cyclePregnancy

26Sexually Transmitted Diseases27Fertilization and DevelopmentFertilizationMultiple EmbryosImplantationGastrulationNeurulationThe Placenta28Later DevelopmentMonths 4-6Months 7-9ChildbirthInfant and Maternal Health29