Endocrine and reproduction


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Endocrine and reproduction

  1. 1. Endocrine• Produces chemical messages for the body• Controls body functions with chemicals• Chemical are called hormones• Location where chemicals are produced areglands, (group of cells that make specialchemicals for the body• Chemicals travel in the blood stream• Operates on feedback mechanisms• Ex: epinephrine – the fight or flight chemicalreleased in stressful situations
  2. 2. • Two types of hormones• Steroid – passes directly through cellmembrane• Binds to receptor proteins in specific cells toform hormone receptor complex• Enters nucleus and binds to a DNA controlsequence• Transcription of specific genes to mRNA• mRNA move into cytoplasm and directs proteinsynthesis
  3. 3. • Nonsteroid: cannot pass through cell membrane• Binds to receptors on the cell membrane• Activates enzyme on surface of cell membrane• Enzyme activates secondary messengers thatcarry hormone into cell• cAMP, nucleotides and fatty acids can act assecondary messengers• Messengers can activate or inhibit cell activities
  4. 4. Glands• Pituitary – secretes 9 hormones - (HGH)stimulates skeletal growth, controls water levelsin blood, keeps thyroid gland functioningproperly and stimulates the process ofpregnancy– Bean sized located in the base of the brain• Thyroid – controls the rate of metabolism– Located in the front of the neck• Parathyroid – controls calcium in the blood– Located in the neck behind the thyroid
  5. 5. • Thymus – regulates immune system tohelp fight disease• Located on top of the heart• Adrenal – releases epinephrine andnorepinephrine that deals with stress• Located on top of the kidneys• Pancreas – controls blood sugar (also partof the digestive tract
  6. 6. Reproductive glands• Gonads – production of gametes andsecretion of sex hormones• Ovaries – (female) hormones forreproduction• Testes – (male) hormones forreproduction
  7. 7. Endocrine disorders• Usually caused by an imbalance (to muchor to little of a chemical)• Insulin – controls the amount of bloodsugar in the body• Responds when food is eaten, cells aregiven instructions to take in glucose whenthe blood sugar increase
  8. 8. • diabetes mellitus – conditions where thepancreas doesn’t make enough insulin• May require a person to take insulin shotsto help balance glucose levels• Growth hormone – stunted growth due tothe pituitary glands failure to produceenough growth hormone (dwarfism)
  9. 9. • Some conditions can be treated withmedication to correct if found soonenough• Over active pituitary glands can result inover growth of the body (gigantism)
  10. 10. • Goiter – cause by a lack of iodine in thediet• Body lacks thyroxine• Thyroxine speeds up metabolism• Thyroxine deficient cells are less active,can cause a body to be fatigued, weightgain and additional problems• Used to be called “rich mans disease”
  11. 11. Reproduction• 1st6 weeks of development embryos areidentical in appearance• 7thweek – primary reproductive organsbegin to develop• Hormones released by testes(testosterone) and ovaries (estrogen)determine if embryo will be male or female
  12. 12. • After birth, gonads continue to producesmall amounts of sex hormones thatinfluence the development of reproductiveorgans• Neither the testes or ovaries can produceactive reproductive cells until puberty• Puberty – rapid growth and sexualmaturation during which the reproductivesystem becomes fully functional.
  13. 13. • Puberty varies among individuals butusually starts between ages 9 to 15 andstarts on average 1 year earlier in females• Hypothalamus increases production ofFSH and LH
  14. 14. Male Reproductive• Function – produce and deliver sperm• Primary organ is testes developed in theabdominal cavity and will descend justbefore or after birth into scrotum wheretemp is about 3° lower than body temp• Within each testis are hundreds of tubulescalled seminiferous tubules where spermis produced (millions)
  15. 15. • Sperm moves to the epididymis where fullymature are stored• Sperm moves to the vas deferens extending intothe abdominal cavity and eventually merges withthe urethra• Urethra is the tube that leads to the exterior ofthe body through the penis (urine and sperm exitbody in same structure)• Release of sperm through the penis is controlledby the autonomic nervous system
  16. 16. Female Reproductive• Function is to produce ova and preparefemale body for developing embryo• Primary organ ovaries located in the pelvicregion of the abdominal cavity• Produce one mature ovum (egg) a month• Each ovary contains about 400,000primary follicles, clusters of cellssurrounding a single egg
  17. 17. • Females are born with thousands ofimmature eggs but only about 400 willactually be released• Approx. every 28 days, FSH increasesand a follicle gets larger and completesthe 1stmeiotic cell division• When meiosis is complete, a single largehaploid egg and 3 polar bodies areproduced (where disintegrate)
  18. 18. • Egg is released in process called ovulation• Follicle breaks open and egg entersopening of Fallopian tube (two) and ispushed along fluid-filled tube by cilia (eggcan be fertilized here, not good)• After a few days, egg passes fromFallopian tube into the uterus• Uterus is ready to receive egg
  19. 19. • Outer part of uterus is cervix which leadsto a canal called the vagina that leads tothe outside of the body
  20. 20. • After puberty the interaction between thereproductive and endocrine system infemales forms a complex series of eventscalled the menstrual cycle (continues untilmid-40’s)• Uterus prepares for egg, if fertilized,embryo implants and development begins• If not, discharged with lining of uterus
  21. 21. 4 Phases• 1) Follicular: begins when estrogen islow, hypothalamus produces FSH and LHand cause the follicle to mature• Egg enlarges and surrounding cellsproduce more estrogen and levels inblood begin to rise causing lining of uterusto thicken (take about 10 days)
  22. 22. • 2) Ovulation: shortest phase, 4 days,hypothalamus sends releasing hormones to tellpituitary gland to make more FSH LH andcauses the follicle to rupture and release matureegg which is swept up into the Fallopian tube• 3) Luteal : as egg moves through Fallopiantube, ruptured follicle turns yellow changes tocorpus luteum and begins to releaseprogesterone which stimulates growth anddevelopment of blood supply and surroundingtissue
  23. 23. • During first 2 days of luteal phase, the chancesof fertilization are the greatest (10 to 14 daysfrom last menstrual cycle)• 4) Menstruation: if fertilization doesn’t takeplace, within 2 to 3 days the egg will passthrough the uterus, the corpus luteum willdisintegrate, the old follicle breaks downproducing less estrogen and progesterone andthe lining of uterus detaches from uterine walland all of this material is expelled out of the bodythrough the vagina lasting about 3 to 7 days.• Process repeats.
  24. 24. Fertilization and Development• Fertilization: process of joining egg (haploid) andsperm (haploid) form diploid(2N); contains a setof chromosomes from each parent• Fertilized egg is called zygote• While in the Fallopian tube, the zygoteundergoes mitosis, as each cell divides thenumber of cells doubles, 4 days afterfertilization, cell is a solid ball of approx. 64 cellscalled a morula
  25. 25. • 3 stages of early development• Implantation: morula forms cavity incenter, forming a hollow structure with aninner cavity called a blastocyst which in 6to 7 days attaches to uterus• Embryo secretes enzymes that digest apath into the soft tissue• Cell begins to differentiate due to geneactivation
  26. 26. • Gastrulation: formation of 3 cell layers,ectoderm, mesoderm, endoderm calledprimary germ layers: all organs andtissues will developed from them• Endoderm – digestive system• Ectoderm – skin and nervous system• Mesoderm – internal tissues and organs• Neurulation: development of the nervoussystem
  27. 27. • Extraembryonic membranes: amnion andchorion• Amniotic sac: fluid filled sac whichcushions and protects embryo• Chorion: 3rdweek of development –outermost membrane• chorionic villi form on outer surface andextend to uterine lining
  28. 28. • Resulting membrane is the placenta –connection between mother and embryo andperforms respiration, nourishment and excretion• At 8 weeks of development embryo is called afetus• At 3 months, most major organs and tissues arefully formed, umbilical cord connects fetus toplacenta and fetus is 8 cm long and a mass of28 grams
  29. 29. Development• Stem cells – unspecialized,undifferentiated cells found in fetal tissueand bone marrow and brains of adults• 4th5th6thmonths, tissues become morecomplex and specialized and more tissuesbegin to function; heart becomes audible,bones begin changing, hair grows on skin,movement
  30. 30. • Last 3 months, organ systems mature andfetus grows in size and mass• Lungs and other organs undergo series ofchanges to prepare of life outside theuterus• Babies born before 8 months arepremature and have breathing problemsand CNS problems
  31. 31. • At 9 months oxytocin is released frompituitary gland that will begin contractionsof large involuntary muscles in uterine wall• As contraction become more frequent andstronger, cervix expands, amniotic sacbreaks and is released• Born head first, baby will cough/cry toremove fluid from lungs, umbilical cord iscut (navel)
  32. 32. • Infancy – 1st 2 years of life, rapid growth,teeth appear, language is imitated andunderstood• Childhood: 2 years to 13, motorcoordination, permanent teeth, long bonesof skeletal system reach 80% of adultlength, personality, social skills, reasoning
  33. 33. • Adolescence: puberty to adulthood, sexhormones start puberty that producesgrowth spurt that will slow in mid-adolescences as long bones stop growingand ossification takes place, higherthinking skills develop and personalitychanges
  34. 34. Diseases• Bacterial infections: Chlamydia, syphilis(fatal), gonorrhea (treatment, antibiotics)• Viruses: hepatitis B, HIV, HPV, genitalherpes (no cure)
  35. 35. Multiple Births• Two eggs released and both are fertilizedby different sperm, fraternal twins are born• Single zygote splits apart producingidentical embryo’s, always the same sex