Download Chapter 45 - Madeira City Schools

Chapter 45
Hormones and the Endocrine System
Receptor location varies
with hormone type.
Which one is fat soluble?
How do you know?
What is an example?
Which one is water
soluble?
How do you know?
What is an example?
Epinephrine
• Also known as Adrenaline
• Primarily secreted by Adrenal gland
• Also secreted by some neurons as a
neurotransmitter
• Mediates the “fight or flight” response
• Basically increases the amount of chemical
energy available for immediate use.
In addition, it increases heart rate, stroke volume (amount of blood
pumped from ventricles) and dilates the bronchioles in the lungs
Showing the signal
pathway for the
liver cells to know
to start breaking
down glycogen
How the Endocrine system works
• There are simple hormone pathways
– Negative feedback loops
– Positive feedback loops
• There are antagonistic hormones
– Insulin and glucagon
– Parathyroid hormone and calcitonin
Simple Hormone Pathway
Negative Feedback
• The response leads to
the reduction in the
stimulus and the
pathway shuts off.
• Here, release of
bicarbonate raises the
pH in the duodenum
• Negative feedback is
when the response
REDUCES the stimulus
Simple Hormone Pathway
Positive Feedback
• Oxytocin in mammals
regulates milk release
during nursing.
• Oxytocin also induces
target cells in the
uterine muscles
• Positive feedback is
when the response
REINFORCES the
stimulus
Antagonistic Hormones
• Two hormones that
operate in a simple
endocrine pathway
regulated by negative
feedback.
• Diabetes Type I
• Diabetes Type II
• Insulin and Glucagon
controlling blood
glucose levels
• Blood Glucose
– Insulin released which
triggers the uptake of
glucose from the blood
• Blood Glucose
– Glucagon promotes the
release of glucose into
the blood