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Endocrine System Hormones. Reproduction. Hormones. Why are hormones needed? chemical messages from one body part to cells in other parts of body communication needed to coordinate whole body maintaining homeostasis energy production growth development maturation reproduction.
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Endocrine System Hormones Reproduction
Hormones • Why are hormones needed? • chemical messages from one body part to cells in other parts of body • communication needed to coordinate whole body • maintaining homeostasis • energy production • growth • development • maturation • reproduction growth hormones
Endocrine System • Endocrine system releases hormones • glands which secrete chemical signals into blood • chemicals cause changes in other parts of body • slow, long-lasting response • growth hormones • sex hormones • response hormones • metabolism hormones • and more….
Regulation by chemical messengers • Neurotransmitters released by neurons • Hormones release by endocrine glands endocrine gland neurotransmitter axon hormone carried by blood receptor proteins receptor proteins target cell
hormones hormones Body Regulation • Nervous system & Endocrine system work together • hypothalamus • “master nerve control center” • receives information from nerves around body about internal conditions • communicates with pituitary gland • “master gland” • releases many hormones • sexual development, growth, milk production, pain-relief
high Negative Feedback • Response to changed body condition • every time body is high or low from normal level a signal tells the body to make changes that will bring body back to normal level • once body is back to normal level, signal is turned off hormone 1 lowersbody condition gland specific body condition
high low Feedback Maintaining homeostasis hormone 1 lowersbody condition gland specific body condition raisesbody condition gland hormone 2
Dynamic Equilibrium and Feedback Loops Two Hormones Working in Opposite Ways to Regulate a “set point” Feed Back Loop One Hormone “feeds-back” to Regulate another Hormone or Product
high low Nervous System Control Feedback Controlling Body Temperature nerve signals brain sweat dilates surfaceblood vessels body temperature brain constricts surfaceblood vessels shiver nerve signals
pancreas high liver low pancreas liver Endocrine System Control Feedback Regulation of Blood Sugar insulin body cells takeup sugar from blood liver storessugar reducesappetite blood sugar level (90mg/100ml) liver releasessugar triggershunger glucagon
What do they do? Body Temperature • Maintain homeostasis • blood sugar level • temperature control • Start a new process • growth • fetal development • sexual development
Negative Feedback • Negative feedback • every time body is high or low from normal level a signal tells the body to make changes that will bring body back • body temperature • control of blood sugar
Sex & Growth Hormones • Large scale body changes • how do they work • turn genes on • start new processes in the body by turning genes on that were lying “dormant”
Responding to hormones • Lock and key system • hormone fits receptor on “target” cell targetcell secretingcell non-targetcells can’treadsignal can’treadsignal
Hormone Action at Target Cells Protein Hormone Two Messengers One Messenger Steroid Hormone Nonsteroid hormone (first messenger) Receptor Target cell membrane Target cell membrane Receptor cAMP (second messenger) Hormone-receptor complex Altered cellular function Nucleus Enzyme activities DNA Altered cellular function Protein synthesis Nucleus Cytoplasm Cytoplasm mRNA Steroid hormones Act Directly on DNA Protein Hormones affect Enzyme Activities and Cell Function
Glands • Pineal • melatonin • Pituitary • many hormones: master gland • Thyroid • thyroxine • Adrenal • adrenaline • Pancreas • insulin, glucagon • Ovary • estrogen • Testes • testosterone
Pituitary gland hormones • Sex & reproductive hormones • FSH • follicle stimulating hormone • stimulates egg & sperm production • LH • luteinizing hormone • stimulates ovaries & testes • prepares uterus for fertilized egg • oxytocin • stimulates childbirth contractions • releases milk in nursing mothers • prolactin • milk production in nursing mothers hormones hormones
Reproductive hormones • Testosterone • from testes • sperm production & secondary sexual characteristics • Estrogen • from ovaries • egg production, preparing uterus for fertilized egg & secondary sexual characteristics
Male reproductive system • Sperm production • over 100 million produced per day! • ~2.5 million released per drop!
seminiferoustubule sperm spermatocytes
Main Functions of Male Repro System • Sperm production in paired testes • Requires lower temperature • Scrotum adaptation for max. sperm production Flagellum Mitochondria 2. Delivery of Sperminto Female’s Reproductive Tract Head Nucleus
Male reproductive system • Testes & epididymis • sperm production & maturation • Glands • seminal vesicles, prostate, bulbourethal • produce seminal fluid • nutrient-rich
Male reproductive system • Testicles • produces sperm & hormones • Scrotum • sac that holds testicles outside of body • Epididymis • where sperm mature • Vas deferens • tubes for sperm to travel from testes to penis • Prostate, seminal vesicles, Cowper’s (bulbourethal) glands • nutrient rich fluid to feed & protect sperm
Female reproductive system • Ovaries • produces eggs & hormones • Uterus • nurtures fetus; lining builds up each month • Fallopian tubes • tubes for eggs to travel from ovaries to uterus • Cervix • opening to uterus, dilates 10 cm for birthing baby • Vagina • birth canal for birthing baby
Egg maturation in ovary releasesprogesterone maintainsuteruslining produces estrogen
LH Menstrual cycle • Controlled by interaction of 4 hormones • FSH & LH • estrogen • progesterone FSH ovulation = egg release egg development corpus luteum estrogen progesterone lining of uterus days 0 7 14 21 28
Menstrual Cycle Summary Chart • Follicle Stage • ↑FSH • Follicle develops • Follicle produces Estrogen • Egg Matures • Estrogen Thickens Uterus lining Lasts 10-14 days Low Estrogen + progesterone allows FSH to be released again from pituitary Day 14 4. Menstruation • Sudden decrease in estrogen and progesterone • Shedding of Uterine Lining 2. Ovulation • ↑ LH released • Mature egg released Ovulation Lasts 10-12 days 3. Corpus Luteum Stage • Ruptured follicle becomes the Corpus Luteum (yellow Body) • Corpus luteum produces Progesterone • Uterus lining becomes thicker, prepares For possible fertilization Corpus luteum Degenerates Causing Progesterone + estrogen to Drop
Female hormones • FSH & LH • released from pituitary • stimulates egg development & hormone release • peak release = release of egg (ovulation) • Estrogen • released from ovary cells around developing egg • stimulates growth of lining of uterus • decreasing levels causes menstruation • Progesterone • released from “corpus luteum” in ovaries • cells that used to take care of developing egg • stimulates blood supply to lining of uterus • decreasing levels causes menstruation
FertilizationOccurs In the Fallopian Tubes Fallopian tube Day 4 4 cells 2 cells Zygote Morula Day 7 Fertilization Blastocyst Day 0 Implantation of blastocyst Uterine wall Egg released “ovulation” ovary
Early Embryonic Development • All divisions of A zygote after Fertilization are Mitoticcell divisions Called Cleavage
The Three Germ LayersDifferentiation of Cells Mesoderm: Muscles and Skeleton, Circulatory and Reproductive systems Ectoderm: Nervous System Epidermis of skin Endoderm: Lining of Digestive And Respiratory tracts, Liver and Pancreas
Multiple Births • Fertilizationis the fusion of a sperm and an egg to form a zygote, the single cell from which all cells of the human body are derived. When an egg is fertilized, the remarkable process of human development begins. • 1.If two eggs are released during ovulation, each can be fertilized by a sperm. What do you think would be the result? Explain your answer. • 2.If one zygote splits into two, each can continue development on its own. What do you think would be the result? Explain your answer. • 3.Tripletsare three babies born at the same time. Describe three ways that triplets could develop.
Human Embryo: 3-8 weeks Gestation • Note, the period from week 12 to week 38 is considered Fetal Development
Fetus to Baby • In spite of the placental “barrier” Small molecules and Viruses can still cross And affect the baby Alcohol (FAS) Carbon Monoxide (Smoking) Narcotics (Heroine, Crack) HIV Measles Chicken Pox Antibodies Rh incompatibility
It’sAll About HORMONES Got Questions ?
Actions of Insulin and Glucagon Following a Meal Regulation of Blood Sugar Levels to Maintain Homeostasis Beta cells release insulin into the blood Body cells absorb glucose Blood glucose level increases Blood glucose level decreases Liver converts glucose in to glycogen Homeostasis: Normal blood glucose level Blood glucose level increases Blood glucose level decreases Missed a Meal Liver converts glycogen to glucose Alpha cells release glucagon into blood
corpusluteum ovary yes corpusluteum no Feedback Female reproductive cycle eggmatures & is released(ovulation) builds up uterus lining estrogen progesterone FSH & LH fertilized egg(zygote) maintainsuterus lining HCG pituitarygland pregnancy progesterone GnRH corpus luteum breaks down progesterone drops menstruation maintainsuterus lining hypothalamus
. Homeostasis biological processes which keep temperature & other body variables within a certain range • For example, temperature, weight, hydration (fluids; H2O) content of blood (acidity, oxygen, fat, glucose) Homeostasis is maintained by both (1) internal biological processes and (2) external behaviors. Set Point: homeostasis relies upon set points for each body variable, that is, a specific narrow range of acceptable values which the body must maintain. For example, the human body temperature generally stay between roughly 36.5 and 37.5 degrees Celsius (97.7 and 99.5 degrees Fahrenheit)
The Thyroid Gland • Location: found in the neck, just below the larynx and in front of the trachea
Thyroxine • Iodine-containing hormone secreted by the thyroid gland • Regulates rate of metabolism in body • Increases rate of protein, carbohydrate, and fat metabolism • Increases rate of cellular respiration • Necessary for normal mental and physical development
Thyroxine Factory hypothalamus TSH-releasing factor stimulates Low-level stimulates High-level inhibits FEED BACK LOOP anterior pituitary thyroxine TSH stimulates thyroid RELEASES