Lab Exercise
Endocrine System
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Materials:
• Human torso model
• Compound light microscope
• Prepared slides of the pituitary gland, pineal gland, thyroid gland, parathyroid glands,
thymus gland, adrenal gland, pancreas, testes and ovaries.
• Anatomical chart of the endocrine system
1. Hypothalamus and Pituitary Gland
A. Using the microscope and histology slide of the pituitary gland as a guide, label the
parts of the pituitary gland including the anterior pituitary and posterior pituitary and
pituicytes in the picture below.
B. Match the hypothalamic hormone with the appropriate hormone of the anterior
pituitary.
____1. GnRH
a. TSH
____2. GHRH
b. ACTH
____3. TRH
c. GH
____4. CRH
d. FSH
C. Match the hormones below with their responses.
____1. GH
a. Production of gametes
____2. FSH
b. Production of sex hormones
____3. PRL
c. Secretion of hormones by the adrenal cortex
____4. LH
d. Milk production by the mammary glands
____5. ACTH
e. Secretion of thyroid hormones
____6. TSH
f. Growth of muscle and bone
2. Hormone Regulation
a. Explain how a negative feedback mechanism can help maintain homeostasis.
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b. Explain how a positive feedback mechanism might be harmful.
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3. Pineal Gland
a. Using the microscope and a histological slide of the pineal gland, draw and label the
tissue of the pineal gland in the space provided below.
b. Using a brain model, locate the pineal gland. Describe its location in the brain.
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c.
Describe the hormonal function of the pineal gland.
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4. Thyroid Gland
a. Using the microscope and a histological slide of the thyroid as a guide, label the
microscopic structures of the thyroid gland including the follicles, colloid, follicular
cells and parafollicular cells using the picture below.
b. Locate and identify the thyroid on anatomic models. Describe its location in the
body.
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c.
What are the functions of the thyroid hormones synthesized and secreted by the
follicular cells of the thyroid?
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d. What are the functions of the hormone synthesized by the C (parafollicular) cells of
the thyroid?
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e. What role does the thyroid play in maintaining the basal metabolic rate?
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f.
A patient presents with signs and symptoms of hyperthyroidism. Blood tests indicate
high T3, T4, and TSH levels; however, TRH levels are very low. What condition might
explain these findings?
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5. Parathyroid Gland
a. Using the microscope and a histological slide of the parathyroid as your guide, draw
and label the cells of the parathyroid gland in the picture below.
b. Identify the parathyroid glands on lab models. Describe their location.
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c.
A patient has had a thyroidectomy (surgical removal of the thyroid gland) during
which the parathyroid glands were also removed. What changes might be expected
in calcium levels found in the blood and urine? What changes would you expect to
see in the vitamin D levels of this patient?
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6. Thymus Gland
a. Using the microscope and a histological slide of the thymus as a guide, label the
structures of the thymus, lobules and Hassall’s bodies in the picture below.
b. Identify the thymus gland on the class models. Describe the physical changes that
occur in the gland as one goes from infancy into late adulthood and into old age.
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7. Adrenal Glands
a. Using the microscope and a histological slide of the adrenal glands, draw and label
the zones (glomerulosa, fasiculata and reticularis) and medulla of the gland in the
space provided below.
b. Describe the hormones that are secreted from each zone of the adrenal gland and
their functions.
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c.
During embryonic development, ectodermal tissues called the neural crests give rise
to the ganglia of the sympathetic chain and the adrenal medulla. Discuss the
functional relationship between the sympathetic nervous system and the adrenal
medulla.
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8. Pancreas
a. Using the microscope and a histological slide of the pancreas as a guide, label the
islets and the acini in the picture below.
b. Explain why the pancreas is considered to be both an endocrine organ and an
exocrine organ.
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c. List and describe the long term complications that arise with uncontrolled or poorly
controlled diabetes mellitus type I and II.
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9. Gonads
a. Using a microscope and a histological slide of the ovary as a guide, label a follicle
and ova in the picture below.
b. Using a microscope and histological slide of the testis as a guide, label the
seminiferous tubule, lobule and the interstitial cells in the picture below.
c.
During the reproductive life of woman, the estrogen produced during the reproductive
cycle inhibits activity of the osteoclasts. Explain why post-menopausal women are
more prone to osteoporosis than younger women.
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