ENDOCRINE SYSTEM. TWO GREAT CONTROLLING SYSTEMS Nervous System................ Endocrine System.
Endocrine System
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Transcript of Endocrine System
Regents Biology2009-2010
Endocrine System
Regulation - How we maintain homeostasis nervous system
nerve signals control body functions electrical (+/- charges) AND chemical
(neurotransmitters) endocrine system
hormones (proteins) chemical signals ONLY control body functions
Regents Biology
Homeostasis maintaining internal balance in the body-
organism must keep internal conditions stable even if environment changes
also called “dynamic equilibrium” use feedback mechanisms
example: body temperature – 37 C – monitored by nervous system
humans: too cold = shiver – (muscles contact – R – produce heat) too warm = sweat
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Hormones chemical messages from one body part to
cells in other parts of body travel through bloodstream hormones are proteins communication needed to coordinate
whole body maintaining homeostasis hormones work SLOWER than nerve
impulses
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Endocrine System Endocrine system releases hormones
glands which secrete (release) chemical signals into blood
chemicals cause changes in other parts of bodygrowth hormone (HGH)sex hormonesresponse hormonesmetabolism hormonesand more….
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Getting the correct signalhormone fits receptor on “target” cell
targettissue/cell
non-targetcells
secretingcell (gland)
can’tread
signal
can’tread
signal
hormone
receptor
Regents Biology
Review Protein Synthesis• Start with DNA (gene) in the nucleus• Transfer info to RNA – DNA can’t leave the
nucleus• RNA moves to ribosome – amino acid chain
is made• Moves to ER – packaged into a vessicle• Then to Golgi – repackaged in to another
vessicle• Vessicle moves to cell membrane• Secretion by exocytosis (active transport)
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Pituitary many hormones: master gland HGH – human growth hormone TSH – thyroid stimulating hormone FSH – follicle stimulating hormone; LH – leutinizing hormone
Thyroid thyroxine – regulates metabolism
Parathyroid Parathyroid hormone – regulates Calcium metabolism
Adrenal adrenaline – “fight or “flight”
Pancreas Insulin – lowers blood sugar Glucagon – raises blood sugar
Ovary - estrogen, progesterone Testes - testosterone
Glands
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Negative Feedback
Response to changed body condition if body is high or low from normal level
signal tells body to make changes that will bring body back to normal level
once body is back to normal level, signal is turned off
high
hormone 1
lowersbody condition
gland
specific body condition
Like the thermostat in your house
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Maintaining homeostasis
high
low
hormone 1
lowersbody condition
hormone 2
gland
specific body condition
raisesbody condition
gland
Feedback
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liver
pancreas
liver
Regulation of Blood Sugar
blood sugar level(90mg/100ml)
insulin
body cells take
up glucose from blood
liver storessugar as glycogen
reducesappetite
glucagon
pancreas
liver releasesglucose
triggershunger
high
low
After a meal
Between meals
Regents Biology
Feedback: Maintaining Homeostasis Balancing glucose levels in blood
pancreas
pancreas
insulin
liver takes upglucose
for storage
cellstake up
glucose from blood
liver releasesglucose to blood
depress appetite
stimulatehungerglucagon