9 THE ENDOCRINE
SYSTEM
The endocrine system, vital to homeostasis, plays an important role in regulat-
ing the activity of body cells. By acting through bloodborne chemical messen-
gers, called hormones, the endocrine system organs orchestrate cellular
changes that lead to growth and development, reproductive capability, and the
physiological homeostasis of many body systems.
This chapter covers the location of the various endocrine organs in the body,
the general function of the various hormones, and the consequences of their
hypersecretion or hyposecretion.
THE ENDOCRINE SYSTEM
AND HORMONE FUNCTION—AN OVERVIEW
1. Complete the following statements by choosing answers from the key
choices. Record the answers in the answer blanks.
Key Choices
A. Cardiovascular system C. More rapid E. Nervous system
B. Hormones D. Nerve impulses F. Slower and more prolonged
_________________________ 1. The endocrine system is a major controlling system in the
body. Its means of control, however, is much (1) than that
_________________________ 2. of the (2) , the other major body system that acts to main-
tain homeostasis. Perhaps the reason for this is that the endo-
_________________________ 3. crine system uses chemical messengers, called (3) , instead
of (4) . These chemical messengers enter the blood and are
_________________________ 4. carried throughout the body by the activity of the (5) .
_________________________ 5.
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184 Anatomy & Physiology Coloring Workbook
2. Complete the following statements by choosing answers from the key
choices. Record the answers in the answer blanks.
Key Choices
A. Altering activity F. Negative feedback K. Steroid or amino acid–based
B. Anterior pituitary G. Neural L. Stimulating new or unusual activities
C. Hormonal H. Neuroendocrine M. Sugar or protein
D. Humoral I. Receptors N. Target cell(s)
E. Hypothalamus J. Releasing/inhibiting hormones
_________________________ 1. All cells do not respond to endocrine system stimulation. Only
those that have the proper (1) on their cell membranes are
_________________________ 2. activated by the chemical messengers. These responsive cells
are called the (2) of the various endocrine glands. Hormones
_________________________ 3. promote homeostasis by (3) of body cells rather than by
(4) . Most hormones are (5) molecules.
_________________________ 4.
The various endocrine glands are prodded to release their
_________________________ 5. hormones by nerve fibers (a (6) stimulus), by other hor-
mones (a (7) stimulus), or by the presence of increased or
_________________________ 6. decreased levels of various other substances in the blood (a
(8) stimulus). The secretion of most hormones is regulated
_________________________ 7. by a (9) system, in which increasing levels of that particu-
lar hormone “turn off” its stimulus. The (10) is called the
_________________________ 8. master endocrine gland because it regulates so many other
endocrine organs. However, it is in turn controlled by (11)
_________________________ 9. secreted by the (12) . The structure identified as #12 is also
part of the brain, so it is appropriately called a (13) organ.
_________________________ 10.
_________________________ 11. _________________________ 12. _________________________ 13.
3. For each key phrase, decide whether it better describes the mode of action
of a steroid or amino acid–based hormone, and insert its key letter in the
appropriate answer blank.
Key Choices
A. Binds to a plasma membrane receptor D. Activates a gene to transcribe messenger RNA
B. Binds to a receptor in the cell’s E. Acts through a second messenger such as
nucleus cyclic AMP (cyclic adenine monophosphate)
C. Is lipid soluble
Steroid hormones: ___________________ Amino acid–based hormones: ___________________
Chapter 9 The Endocrine System 185
THE MAJOR ENDOCRINE ORGANS
4. Figure 9–1 depicts the anatomical relationships between the hypothalamus
and the anterior and posterior lobes of the pituitary in a highly simplified
way.
(A) Identify each of the structures listed below by color coding and coloring
them on the diagram.
(B) On the appropriate lines, write in the names of the hormones that influ-
ence each of the target organs shown at the bottom of the diagram.
(C) Color the target organs that are affected by tropic hormones.
○ Hypothalamus ○ Anterior pituitary
○ Turk’s saddle of the sphenoid bone ○ Posterior pituitary
Releasing hormones
in portal circulation
Bones and muscles Adrenal cortex
Mammary glands Thyroid
and
Testes or ovaries
Figure 9–1
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5. Figure 9–2 is a diagram of the various endocrine organs of the body.
(A) Next to each letter on the diagram, write the name of the endocrine-
producing organ (or area).
(B) Select different colors for each and color the corresponding organs in the
illustration.
(C) To complete your identification of the hormone-producing organs, name the
organs (not illustrated) described in items K and L.
K. Small glands that ride
“horseback” on the thyroid
A
____________________________
L. Endocrine-producing
organ present only in B
pregnant women
____________________________
J
Figure 9–2
Chapter 9 The Endocrine System 187
6. For each of the following hormones, indicate the organ (or organ part)
producing or releasing the hormone by inserting the appropriate letters from
Figure 9–2 in the answer blanks. Items may have more than one answer.
______ 1. ACTH ______ 8. Glucagon ______ 15. PTH
______ 2. ADH ______ 9. Insulin ______ 16. Growth hormone
______ 3. Aldosterone ______ 10. LH ______ 17. Testosterone
______ 4. Cortisol ______ 11. Melatonin ______ 18. Thymosins
______ 5. Epinephrine ______ 12. Oxytocin ______ 19. Thyroxine
______ 6. Estrogen ______ 13. Progesterone ______ 20. TSH
______ 7. FSH ______ 14. Prolactin
7. Name the hormone that would be produced in inadequate amounts in the
following conditions. Place your responses in the answer blanks.
_________________________ 1. Sexual immaturity
_________________________ 2. Tetany
_________________________ 3. Excessive urination without high blood glucose levels; causes
dehydration and tremendous thirst
_________________________ 4. Goiter
_________________________ 5. Cretinism; a type of dwarfism in which the individual retains
childlike proportions and is mentally retarded
_________________________ 6. Excessive thirst, high blood glucose levels, acidosis
_________________________ 7. Abnormally small stature, normal proportions
_________________________ 8. Miscarriage
_________________________ 9. Lethargy, hair loss, low basal metabolic rate, obesity
(myxedema in the adult)
8. Name the hormone that would be produced in excessive amounts in the
following conditions. Place your responses in the answer blanks.
_________________________ 1. Lantern jaw; large hands and feet (acromegaly in the adult)
_________________________ 2. Bulging eyeballs, nervousness, increased pulse rate, weight loss
(Graves’ disease)
_________________________ 3. Demineralization of bones; spontaneous fractures
_________________________ 4. Cushing’s syndrome—moon face, depression of the immune system
_________________________ 5. Abnormally large stature, relatively normal body proportions
_________________________ 6. Abnormal hairiness; masculinization
188 Anatomy & Physiology Coloring Workbook
9. Using the key choices, complete the crossword puzzle by answering
each of the clues provided.
Key Choices
ACTH Estrogen LH PTH
ADH FSH Oxytocin TSH
Aldosterone Glucagon Progesterone Thymosin
Cortisol Insulin Prolactin Thyroxine
Epinephrine
Across
6. Estrogen and ______ directly regulate the menstrual uterine cycle.
7. ACTH, FSH, LH, and ________ are tropic hormones.
8. Hypothalamic hormone important in regulating water balance.
10. Adrenal cortex hormone involved in regulating salt levels of body fluids.
11. Basal metabolic hormone.
12. Acts antagonistically to insulin; produced by the same endocrine organ.
Down
1. Short-term stress hormone; aids in the fight-or-flight response; increases blood
pressure and heart rate.
2. _____ and oxytocin are hormones necessary for milk production and ejection.
3. Helps to protect the body during long-term stressful situations such as
extended illness and surgery.
4. Necessary if glucose is to be taken up by body cells.
5. Most important hormone regulating the amount of calcium circulating in the
blood; released when blood calcium levels drop.
9. Program T lymphocytes.
13. FSH and ______ are anterior pituitary hormones that regulate the ovarian
cycle.
2 3
5 6
8 9
10 11
12 13
Chapter 9 The Endocrine System 189
10. List the cardinal symptoms of diabetes mellitus and provide the rationale for
the occurrence of each symptom.
1. _________________________________________________________________________________________
_________________________________________________________________________________________
2. _________________________________________________________________________________________
_________________________________________________________________________________________
3. _________________________________________________________________________________________
_________________________________________________________________________________________
11. The activity of many end organs is regulated by negative feedback.
Figure 9 –3A shows the basic elements of a homeostatic control system.
Figure 9–3B shows a feedback loop with selected parts missing. Assume,
for this system, that the stimulus that initiates it is declining T3 and T4 levels
in the blood, which produce a drop in metabolic rate. Fill in the information
missing in the boxes to correctly complete this feedback loop. Also indicate
whether it is a negative or positive feedback loop.
Figure 9–3
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12. Circle the term that does not belong in each of the following groupings. Then,
fill in the answer blanks with the correct group name.
1. ADH Hormone storage Nervous tissue Anterior lobe Group: ____________
2. Steroid hormone Protein hormone Second messenger
Membrane receptors Group: ____________
3. Catecholamines Norepinephrine Epinephrine Cortisol Group: ____________
4. Decreases blood Ca2+ Increases blood Ca2+ Thyroid gland
Enhances Ca2+ deposit Group: ____________
5. Glucocorticoids Steroids Aldosterone Growth hormone Group: ____________
6. Thyroid follicles T3 and T4 Glucose metabolism
Parafollicular cells Group: ___________
OTHER HORMONE-PRODUCING TISSUES
AND ORGANS
13. Besides the major endocrine organs, isolated clusters of cells produce hor-
mones within body organs that are usually not associated with the endocrine
system. A number of these hormones are listed in the table below. Fill in the
missing information (blank spaces) on these hormones in the table.
Chemical
Hormone makeup Source Effects
Gastrin Peptide
Secretin Duodenum
Cholecystokinin Peptide
Erythropoietin Kidney in response
to hypoxia
Active vitamin D3 Skin; activated by
kidneys
Atrial natriuretic Peptide
peptide (ANP)
Human chorionic Protein
gonadotropin (hCG)
Leptin Adipose tissue
