Name: ____________________________
Chapter 45: Hormones and the Endocrine System
Nervous System
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The ______________________conveys high-speed electrical signals along specialized cells
called _____________.
These rapid messages control the movement of the body parts in response to sudden
environmental changes.
o Jerk your hand away from a hot pan
o Pupils dilate when you enter a dark room
Endocrine System
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Collectively, all of an animal’s hormone secreting cells constitute its _____________________.
Hormone-secreting organs, called _____________________, are referred to as ductless glands
because they secrete their chemical messengers directly into extracellular fluid.
Overlap Between Endocrine and Nervous Regulation
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Certain specialized nerve cells known as _______________________ cells release hormones into
the blood via the extracellular fluid.
These hormones are called _________________________ to avoid confusion with normal
hormones.
A few chemicals serve both as hormones in the endocrine system and as chemical signals in the
nervous system.
o Epinephrine, functions as the “fight or flight” hormone and as a neurotransmitter.
Overlap between Endocrine and Nervous Regulation cont…
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In addition, the nervous system plays a role in certain sustained responses— for example,
controlling _________/___________ and reproductive cycles in many animals— often by
increasing or decreasing ______________________ from endocrine glands.
Additions
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____________________— detects a stimulus
o a change in blood calcium level
… send information to the ______________________
… after, the control center sends out an ______________to respond
Local Regulators
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In contrast to long-distance endocrine signaling by hormones, local regulators convey messages
between neighboring cells— a process referred to as paracrine signaling.
Once secreted by the cells that make them, local regulators act on nearby target cells within
seconds or even milliseconds, eliciting cell responses more quickly than hormones can
Some local regulators have cell-surface receptors; others have intracellular receptors.
Types of Local Regulators
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Cytokines - play a role in immune responses
Growth factors – stimulate cell proliferation and differentiation
Nitric oxide (NO) – improves blood flow to tissues when blood oxygen level falls; nitric oxide also
plays a role in male sexual function
Prostaglandins (PGs) – modified fatty acids, often derived from lipids in the plasma membrane
Major Human
Endocrine Glands
Hypothalamus and Pituitary
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The hypothalamus and pituitary integrate many functions of the
______________________________________
The ________________________ plays an important role in integrating the vertebrate
endocrine and nervous systems
o Receives information from nerves throughout the body
o Initiates ____________________ signals appropriate to environmental conditions
 E.g.: Seasonal changes triggering release of reproductive hormones required for
breeding.
The hypothalamus contains two sets of neurosecretory cells whose hormonal secretions are
stored in or regulate the activity of the _________________________, a lima bean-sized organ
located at the base of the hypothalamus.
_________________ Pituitary (______________________): extension of the hypothalamus that
grows downward toward the mouth during embryonic development.
________________________ Pituitary (_________________________): develops from a fold of
tissue at the roof of the embryonic mouth; this tissue grows up toward the brain and eventually
loses its connection to the mouth.
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In humans and other mammals, the _______________ gland consists of two lobes
located on the ventral surface of the trachea.
o Produces
(T3 ) and
(T4)
o Secretion controlled by _________________and ____________________
o Plays a crucial role in vertebrate development and maturation
o E.g.: Metamorphosis of frog (tissue reorganization)
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When blood Ca2+ levels fall below a set point, __________________________ (PTH) is
released.
PTH is produced by the _______________ glands, embedded on the surface of the
________________.
The dual functioning ______________ functions in both the endocrine and digestive
systems.
Produces glucagon and insulin
o Produces bicarbonate and digestive enzymes
o Reactions to danger are part of the fight-or-flight response stimulated by
hormones of the __________________.
o The _____________________ of the adrenal glands releases these hormones
o ____________________ and ______________________
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Invertebrate Regulatory Systems
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Involve__________________ and _____________________ system reactions
o Function in ____________________ and ___________________________
In insect hormonal regulation, three hormones play major roles in molting and metamorphosis
into the adult form.
o
o
o
__________ hormone: produced by neurosecretory cells; stimulates release of
ecdysone
______________: Promotes molting and development of adult characteristics
______________ hormone: secreted by glands behind the brain; promotes retention of
larva characteristics