Presentation on theme: "Biology Main points/Questions"— Presentation transcript:
1Biology 103 - Main points/Questions Remember Plant Hormones?What are the major human endocrine glands?What hormones do you need to know?How are hormones controlled?
2In Summer plants need to balance root and shoot growth - too much of either is a waste of resources. Do you remember how they do this?
3shoot tipgradient ofauxinplants need to balance root and shoot growth – use AUXIN & CYTOKININ amounts(high)(low)Figure: 26-3Title:The role of auxin and cytokinin in lateral bud sproutingCaption:A simplified diagram of the interplay of auxin (blue dots) and cytokinin (red dots) in the control of sprouting of lateral buds. Auxin is produced by shoot tips and moves downward; cytokinin is produced by root tips and moves upward. Question What result would you expect if a plant's shoot tip were removed and auxin were applied to the cut surface?(high)gradient ofcytokinin
4positive phototropism – controlled by …? AUXIN!Light!
5In fall plants need to respond to changing environmental cues to trigger leaf senescence (death).
7Hormone Signals in Animals Used for longer term signals than neuronsDifferent cells respond to different hormonesHormones often key for homeostasis
833.02 The Timescale over Which Chemical Messengers Work CD33020.GIF
9There are three big advantages to using chemical hormones as messengers rather than speedy electrical signals (nervous)chemical molecules can spread to all tissues via the bloodchemical signals can persist much longer than electrical onesmany different kinds of chemicals can act as hormones
10Balancing water concentration The concentration of the urine is regulated to maintain homeostasisHormones are key signaling molecules in this process.
12Your body also releases a hormone ADH that signals to the kidneys. As you dehydrate you get thirsty (this is controlled by the nervous system)Your body also releases a hormone ADH that signals to the kidneys.Where does water get reabsorbed in the kidney?Page. 626
13The 5 steps of urine formation Pressure FiltrationReabsorption of waterSelective reabsorptionSecretionMore water reabsorption
14Further reabsorption of water Final step that balances water amountsWater can be variably reabsorbed into blood from collecting ductwaters ability to be reabsorbed is controlled by a hormone called ADH – how?
15Hormone signaling is a series of simple steps issuing the command – release of the hormone from a gland
21Hormone signaling is a series of simple steps issuing the command transporting the signalhitting the targethaving an effectAfter binding the receptor protein changes shape and triggers a change in cell activity
23Two basic categories of hormones ADH is a peptide hormone (remember a peptide bond?Built of amino acidsThe other class of hormones are steroid basedSteroids are lipids so can pass through membranes!
24Peptide based Steroid Bind to receptor on membrane Transported attached to a proteinBind to receptor inside the cellWater-solublehormoneFat-solublehormoneTransportproteinSignal receptorTARGETCELLSignalreceptorFigure 45.5 Receptor location varies with hormone type(a)NUCLEUS(b)
25Peptide basedSignals are often more transient (just in the cytoplasm)May alter gene expressionSteroidMostly alter gene expressionTend to be long lasting effectsWater-solublehormoneFat-solublehormoneTransportproteinSignal receptorTARGETCELLORSignalreceptorFigure 45.5 Receptor location varies with hormone typeCytoplasmicresponseGeneregulationCytoplasmicresponseGeneregulation(a)NUCLEUS(b)
26Hormones are produced in glands throughout your body
27Coordination of Endocrine and Nervous Systems in Vertebrates The hypothalamus receives information from the nervous system and initiates responses through the endocrine systemAttached to the hypothalamus is the pituitary gland composed of the posterior pituitary and anterior pituitary
28The posterior pituitary stores and secretes hormones that are made in the hypothalamus The anterior pituitary makes and releases hormones under regulation of the hypothalamus
29The posterior pituitary contains cells that originate in the hypothalamus
30The hypothalamus and the posterior pituitary are connected by a tract of neurons hormones are made by cell bodies in the hypothalamus & moved to posterior pituitaryantidiuretic hormone (ADH) regulates the kidney’s retention of wateroxytocin initiates uterine contractions during childbirth and milk release in mothers
31The anterior pituitary is a complete gland that produces the hormones that it secretes
32The Hypothalamus and the Pituitary The hypothalamus controls production and secretion of the anterior pituitary hormones by means of a family of special hormonesneurons in the hypothalamus secrete releasing hormonesthey travel to the anterior pituitary through a special capillary system,
33Portal system of the anterior pituitary gland and hypothalamus
34The Anterior Pituitary Secretes seven different hormones some you already know about…LH & FSHSome that are new to you…TSH & GH
36Follicle-stimulating hormone (FSH) in females, it triggers the maturation of egg cells and stimulates the release of estrogenin males, it regulates sperm developmentLuteinizing hormone (LH)in females, it triggers ovulation of a mature eggin males, it stimulates the gonads to produce testosterone
37Degenerating corpus luteum Control by hypothalamusInhibited by combination of estrogen and progesteroneHypothalamus–Stimulated by high levels of estrogenEstrogen production feeds back on the signal that drives estrogen releaseGnRH+Anterior pituitaryInhibited by low levels of estrogen–FSHLH(b)Pituitary hormones in bloodLHFSHFSH and LH stimulate follicle to growLH surge triggers ovulationFigure The reproductive cycle of the human female(c)Ovarian cycleGrowing follicleCorpus luteumDegenerating corpus luteumMaturing follicleFollicular phaseOvulationLuteal phaseDays||||||||5101415202528
38growth hormone (GH) Thyroid stimulating hormone (TSH) simulates the growth of muscle and bone throughout the bodyThyroid stimulating hormone (TSH)Stimulates thyroid to produce thyroxin – a key control of metabolism
39Negative feedback (feedback inhibition) controls how target gland hormones in the anterior pituitary are producedwhen enough of the target hormone has been produced, the hormone then feeds back to the hypothalamus and inhibits the release of stimulating hormones from the hypothalamus and the anterior pituitary
40What if you don’t have enough iodine? ThyroxineModifies metabolic rateRequires iodineWhat if you don’t have enough iodine?
42Hormones are key players in maintaining homeostasis Commonly used as signals in negative feedback loopsRemember Insulin & Glucagon?
43Insulin and Glucagon: Control of Blood Glucose Insulin and glucagon are antagonistic hormones that help maintain glucose homeostasisThe pancreas has clusters of cells that produce glucagon and insulin
44Body cellstake up moreglucose.InsulinBeta cells ofpancreasrelease insulininto the blood.Liver takesup glucoseand stores itas glycogen.STIMULUS:Blood glucose levelrises.Blood glucoselevel declines.Homeostasis:Blood glucose level(about 90 mg/100 mL)STIMULUS:Blood glucose levelfalls.Blood glucoselevel rises.Figure Maintenance of glucose homeostasis by insulin and glucagonAlpha cells of pancreasrelease glucagon.Liver breaksdown glycogenand releasesglucose.Glucagon
45Control of Blood Calcium Two antagonistic hormones regulate calcium (Ca2+) in the blood of mammalsParathyroid hormone (PTH) causes blood calcium levels to increaseCalcitonin causes blood calcium levels to decrease.
46PTH increases the level of blood Ca2+ It releases Ca2+ from bone and stimulates reabsorption of Ca2+ in the kidneysIt also has an indirect effect, stimulating the kidneys to activate vitamin D, which promotes intestinal uptake of Ca2+ from foodCalcitonin decreases level of blood Ca2+It stimulates Ca2+ deposition in bones and secretion by kidneys
47Draw the two negative feedback loops that involve these two hormones Increasing Blood Calcium levelBlood Calcium level (about 10mg/100ml)Decreasing Blood Calcium level
48Calcium Regulation What happens when calcium levels drop? Parathyroid hormone (PTH) is secreted & causes bone cells to release calcium from the bonesPTH also stimulates calcium reabsorption by the kidneys and absorption by the gutSo dropping Ca++ leads to raising Ca++
49Falling blood Ca2+ level Blood Ca2+ level (about 10 mg/100 mL) PTHParathyroid gland (behind thyroid)Figure The roles of parathyroid hormone (PTH) in regulating blood calcium levels in mammalsSTIMULUS:Falling blood Ca2+ levelHomeostasis:Blood Ca2+ level (about 10 mg/100 mL)
50Falling blood Ca2+ level Blood Ca2+ level (about 10 mg/100 mL) FigActive vitamin DStimulates Ca2+ uptake in kidneysIncreases Ca2+ uptake in intestinesPTHParathyroid gland (behind thyroid)Stimulates Ca2+ release from bonesFigure The roles of parathyroid hormone (PTH) in regulating blood calcium levels in mammalsSTIMULUS:Falling blood Ca2+ levelBlood Ca2+ level rises.Homeostasis:Blood Ca2+ level (about 10 mg/100 mL)
51Calcium Regulation What happens when calcium levels rise? Calcitonin is secreted & causes bone cells to sequester calcium in the bonesCalcitonin also slows calcium reabsorption by the kidneysSo raising Ca++ leads to falling Ca++
52Hormonal control of calcium homeostasis in mammals
53What do you need to know? Control Systems - Hormones: List major plant hormones and their roles.Explain how the two basic classes of animal hormones have their effects on a cell.Describe antagonistic hormones and explain how they work together to maintain homeostasis.List some major human hormones (certainly you should know ADH, insulin, glucagon, calcitonin & PTH and you should be familiar with FSH, LH, estrogen, and progesterone), where they are produced and their roles.
54For the Discovery Video Endocrine System, go to Animation and Video Files.
55Figure 45.1 What role do hormones play in transforming a caterpillar into a butterfly? For the Discovery Video Endocrine System, go to Animation and Video Files.
56Non-mammal HormonesIn insects, hormonal secretion influence both metamorphosis and moltingprior to molting, neurosecretory cells on the surface of the brain secrete brain hormonebrain hormone then stimulates a gland in the thorax to produce molting hormone (ecdysone)juvenile hormone is produced in the brain and determines the result of a particular moltwhen juvenile hormone levels are high, the molt produces another larva
57Juvenile hormone promotes retention of larval characteristics Ecdysone promotes molting (in the presence of juvenile hormone) and development (in the absence of juvenile hormone) of adult characteristics
58Brain Neurosecretory cells Corpus cardiacum PTTH Corpus allatum ProthoracicglandEcdysoneJuvenilehormone(JH)Figure Hormonal regulation of insect developmentEARLY LARVA
59Brain Neurosecretory cells Corpus cardiacum PTTH Corpus allatum ProthoracicglandEcdysoneJuvenilehormone(JH)Figure Hormonal regulation of insect developmentEARLY LARVALATERLARVA
60Brain Neurosecretory cells Corpus cardiacum PTTH Corpus allatum Low JH ProthoracicglandEcdysoneJuvenilehormone(JH)Figure Hormonal regulation of insect developmentEARLY LARVALATERLARVAPUPAADULT