Endocrine system: hormones that regulate the body

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Transcript Endocrine system: hormones that regulate the body

Endocrine system: hormones
that regulate the body
Hormones and glands
• Hormones are chemicals that
regulate: growth,
development, behavior, and
much more.
– Different hormones target
different cells
• Hormones are produced and
excreted from glands
common hormones
• Amino acid–based: usually
water soluble
– “first messenger” bind with
protein receptors on
outside of cell to trigger a
chain reaction of events
inside the cell
• Steroid: Usually fat soluble
– Crosses cell membrane and
binds with a protein
receptor inside the
cytoplasm then activates
DNA to produce new
proteins.
Other hormones
• Neuropeptides:
released by neurons
and impact emotions
• Prostagalandins:
released when
injured can change
blood pressure or
cause fever.
Hypothalamus and pituitary gland
• Many hormones are made
in the hypothalamus and
stored in the pituitary gland
• Coordination between the
endocrine and nervous
system occur here
• Produce a range of
hormones that control
kidney function, blood
sugar, growth, and
reproductive organs
Some major glands
• Thyroid: maintain heart rate, blood pressure,
temperature
• Adrenal glands: stress regulation hormones &
water and salt retention
• Thymus gland: part of immune system
Feedback Loops
• The body must self
moderate.
• Two types of
feedback loops:
– Negative
– Positive
• Negative feedback
counteracts condition
• Positive feedback
amplifies condition
• Negative more
common.
Negative Feedback
•
Prevents body
from moving away
from a set point
significantly.
• Allows body to
self-correct.
• Ex: controlling
tempurature
Negative Feedback Loop
Positive Feedback
• Accentuates
disturbance.
• Examples:
– Blood clotting
– Nursing a baby causes
production of milk
• Closely regulated by
negative feedback
loops.
Positive Feedback Loop