Chapter 9
The Endocrine
System
The Endocrine System
• Functions
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regulate growth
regulate reproduction
utilization of nutrients
salt and fluid balance
regulation of metabolic rate
adaptation to stress
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chemical messengers
responses may last
target tissues can be specific
entire body can be target
many have multiple effects
• Control w/ Hormone
Structure that Secrete
Hormones
• Endocrine Gland
– “ductless”
– hormones
– pituitary, thyroid, parathyroid, adrenals,
pineal, thymus
– organs
• pancreas & gonads
• Other Tissue & Organs
– wall of digestion organs
– placenta & kidneys
Chemistry of Hormones
• Steroid Hormone
– derived from cholesterol
– sex glands & adrenal cortex
• Amino Acid Base
– simplest hormones
– many types (I.e. epinephrine)
• Prostaglandins
– from fatty acids
How Hormones Work
• Receptors in the target cells
– hormones chemically bond w/ receptors
• Mechanisms
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alter activity of cells
change permeability
synthesize proteins
activate/deactivate enzymes
stimulate mitosis
• Onset & Duration
– <1 min ---> 30 minutes
Hormone Regulation of Secretion
• Hormonal
• Humoral
– blood levels
• Neural
Gigantism
Goiter
Graves Disease
Cushings Disease