Anatomy and Physiology
Fisher
Chapter 11: Endocrine system questions
1. What are the components of the endocrine system?
Cells, tissues, and organs (glands) that secrete hormones into the internal environment
2. How do paracrine and autocrine secretions function differently than traditionally defined
hormones?
Local hormones—affect only neighboring cells (paracrine) or the secreting cell itself (autocrine)
3. What is the difference between endocrine and exocrine glands?
Endocrine secrete into internal environment; Exocrine secrete through tubes or ducts leading to
the surface of skin
4. Compare and contrast the nervous and endocrine systems.
Nervous: neurons as cells, neurotransmitters as chemical signals, specific to receptors on postsynaptic cell, speed is in seconds, duration of action is brief
Endocrine: glandular epithelium is cell, chemical signal is hormone, specific to receptors on
target cells, speed of onset is seconds to hours, duration may last for days
5. What determines whether a cell is a target cell for a particular hormone?
Whether the target cell has the particular receptor for that hormone or not
6. What is a target cell?
Cell with receptors (proteins or glycoproteins) with binding sites for the particular hormone that
gland produces
7. Describe 5 different functions of hormones.
Regulate metabolic processes by controlling the rates of reactions, aiding in the transport of
substances across cell membranes, help regulate water, regulate electrolyte balances, play roles
in reproduction, development, and growth
8. What are 9 major endocrine glands?
Pituitary, thyroid, parathyroid, adrenal, pancreas, pineal, testes, ovaries, kidneys, and thymus
9. How does a steroid hormone promote cellular changes?
Diffuse into cells, binds a specific protein which binds to a particular sequence of DNA and
activate transcription of a particular gene, mRNA leave the nucleus and direct the synthesis of
specific proteins that were coded for in the DNA
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10. How does a non-steroid hormone promote cellular changes?
Bind receptors in target cell membranes (not lipid soluble) at their binding sites, stimulating the
activity site to interact with other proteins triggering a cascade which in turn induces changes in
the cell (signal transduction). For example, cyclic AMP.
11. What is a second messenger?
Biochemical in the cell that induce changes in response to the hormone’s binding
12. What are prostaglandins?
Lipids synthesized from the fatty acid arachidonic acid—present in cell membranes Produced in
the liver, kidneys, heart, lungs, thymus, pancreas, brain and reproductive organs. Act more
locally than hormones and generally affect only the organ that produces them.
13. What are the effects of prostaglandins?
Relax smooth muscles in lungs and vessels or contract smooth muscles in walls of uterus and
intestines (opposite actions); stimulate hormone secretion from the adrenal cortex, and inhibit
secretion of HCl from stomach; influence the movements of sodium ions and water in kidneys,
regulate blood pressure, effect male and female reproduction.
14. What are three ways hormonal secretions are controlled?
Hypothalamus and anterior pituitary stimulate other endocrine glands; the nervous system
stimulates the gland directly; or changes in the internal environment stimulate the glands
directly
15. How are negative feedback systems involved in the control of hormone secretion?
All 3 control methods are negative feedback mechanisms. Once the gland detects the change
(concentration of hormone, or process, or the action) then this triggers the response and the
body goes back to the set point. Therefore as hormone levels rise in the blood and the hormone
exerts its effects, the system is inhibited and hormone secretion declines.
16. Where is the pituitary gland?
Base of the brain attached to the hypothalamus via a pituitary stalk.
17. How does the hypothalamus control secretions from the posterior and anterior lobes of the
pituitary?
Nerve impulses from the hypothalamus signal the axon terminals of neurosecretory cells in the
posterior pituitary. In the anterior pituitary, the hypothalamus controls secretion by releasing
“release-inhibiting hormones” which travel in capillary networks associated with the
hypothalamus traveling down the pituitary stalk into the anterior pituitary. These are very
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specific and can have various actions both inhibitory and stimulating. These are vital to negative
feedback mechanisms regulating hormones in the bloodstream.
18. How does growth hormone affect protein synthesis?
Triggers cell cycle to speed up, which means cells grow and divide more frequently. It also
increases the movement of amino acids (monomers of proteins) across cell membranes. Both of
these will increase protein synthesis.
19. What is the function of prolactin?
Stimulates and sustains milk production in females. Unclear if any function in males, but too
much will cause sexual dysfunction in both males and females.
20. How is secretion of thyroid-stimulating hormone regulated?
Hypothalamus partially regulates TSH by producing TRH (thyrotropin-releasing hormone).
Thyroid hormones inhibit TRH and TSH. As blood concentrations of these increases, TRH and
TSH secretion decreases—negative feedback mechanism.
21. What is the function of adrenocorticotropic hormone?
Controls the manufacture and secretion of hormones of the cortex of the adrenal gland.
22. What is a gonadotropin?
Hormones that exert their actions on the gonads (ovaries and testes)—examples include FSH &
LH.
23. What is the function of antidiuretic hormone?
Decreases urine formation by reducing the volume of water the kidneys excrete, this is how it
regulates the water concentration of body fluids.
24. How is ADH secretion controlled?
Hypothalamus regulates ADH secretion via osmoreceptors that sense changes in osmotic
pressure in body fluids. Dehydration increases blood solute concentration signaling
osmoreceptors because osmotic pressure increases. This signals the posterior pituitary to
release ADH which goes to the kidneys causing the kidneys to conserve water. Drinking too
much water inhibits ADH release, signaling the kidneys to excrete more urine.
25. What effects does oxytocin produce in females?
Stimulates uterine contractions in late stages of childbirth—OT release is triggered by stretching
of uterine and vaginal tissues in late pregnancy. In addition, OT contracts myoepithelial cells
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forcing milk from glands into ducts and ejecting from breast for breastfeeding. OT is also a mild
antidiuretic. Also a treatment to induce labor or post-delivery to minimize hemorrhage.
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