Download Hormones

Endocrine System Answers
8 organs/tissues that make up the
endocrine system:
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Hypothalamus
Pituitary gland
Thyroid gland
Parathyroid gland
Adrenal glands
Pancreas
Ovaries/Testes
Pineal gland
Difference between an endocrine
and exocrine gland
Endocrine glands are glands that
secrete their proteins into ducts
leading directly to the external
environment
Endocrine glands are ductless tissues
surrounded by vascular tissue that
produce and secrete chemical
messengers (hormones) directly into
the bloodstream, where they act upon
specific target tissues
What is a neurohormone?
How does the hypothalamus control
hormone release by the anterior
pituitary gland?
Neurosecretory (neuroendocrine)
cells = specialized neurons that
releasehormones (as opposed to
transmitting an electrical signal)
A neurohormone is secreted into
circulation BY neurosecretory cells
When stimulated, hypothalamic neurons secrete releasing /inhibiting hormones into
the hypophyseal portal system
A portal system is when one capillary bed pools into another through veins (without first
going through the heart)
So the blood it’s getting from the hypothalamus is deoxygenated, but it’s full of
hormones (so if it needs oxygenated blood it gets it from its own arteries)
Hypothalamic hormones travel through the portal veins to the ANTERIOR PITUITARY
where they stimulate or inhibit release of hormones from the anterior pituitary
Why is the pituitary gland the
master gland?
• Primary influencer of how other
glands operate
• Stores/secretes hormones to
stimulate other glands
What is the function of a hormone?
• Hormones are specialized substances that
coordinate the activities of specific target cells
in certain areas of the body
3 ways by which a gland can be stimulated
to release a particular hormone
• In response to another hormone (e.g. GHRH
from the hypothalamus will stimulate GH
release from the pituitary)
• By nerve impulses (e.g. nerve impulses can
stimulate ACh release into the synaptic cleft)
• Directly via internal changes (e.g. high blood
sugar will cause the pancreas to release
insulin)
Anterior pituitary hormones
• Adrenocorticotropic hormone
(ACTH)
• Thyroid stimulating hormone
(TSH)
• Follicle stimulating hormone
(FSH)
• Luteinizing hormones (LH)
• Prolactin (PRL)
• Growth hormone (GH)
• Endorphins (could anybody find
the short form??)
• Melanocyte-stimulating hormone
(MSH)
2 hormones stored/released from the
posterior pituitary. What stimulates
their release?
1) Oxytocin
2) Anti-diuretic hormone (ADH)
Stimulated by the hypothalamus (during such
times as increased plasma osmolality or
infant suckling)
How does a steroid hormone impact a
target cell versus a non-steroid hormone?