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Human A&P Warm Up
When the carnival came to town, the local health
professionals and consumer groups joined forces
to enforce truth-in-advertising laws to protect
selected employees of the carnival. They
demanded that the fat man, the dwarf, the giant,
and the bearded lady be billed as “people with
endocrine system problems”. Identify the
endocrine disorder in each case and explain how
the disorder produced the characteristic features
of these four show people.
Warm Up continued
• Fat man
• Dwarf
• Giant
• Bearded lady
• T3 & T4 not being
produced efficiently
• GH deficiency
• Hypersecretion of GH
• Tumor on the adrenal
cortex
Objective
• We will…….discuss the
function of the thyroid
gland, parathyroid,
ovaries and testes.
Video
• Nova: Epigenetics
Thyroid Gland
 Found at the base of the throat
 Consists of two lobes and a connecting
isthmus
 Produces two hormones
 Thyroid hormone
 Calcitonin
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 9.23a
Thyroid Gland
Figure 9.6
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 9.23b
Thyroid Hormone
 Major metabolic hormone
 Composed of two active iodinecontaining hormones
 Thyroxine (T4) – secreted by thyroid
follicles
 Triiodothyronine (T3) – conversion of T4 at
target tissues
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 9.24
Calcitonin
 Decreases blood
calcium levels by
causing its
deposition on bone
 Antagonistic to
parathyroid
hormone
 Produced by C
(parafollicular)
cells
Figure 9.9
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 9.25
Conditions of Thyroid Gland
Goiter: enlargement of thyroid due to iodine
deficiency.
Cretinism: Dwarfism coupled with mental
retardation; caused by a hyposecretion of T4
Myxedema (hyposecretion in adults): mental and
physical sluggishness
Graves disease (hypersecretion in adults): high
metabolism, intolerance to heat, rapid heartbeat,
weight loss, nervous, & agitated
Parathyroid Glands
 Tiny masses on the posterior of the
thyroid
 Secrete parathyroid hormone
 Stimulate osterclasts to remove calcium
from bone
 Stimulate the kidneys and intestine to
absorb more calcium
 Raise calcium levels in the blood
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 9.26
Hormones of the Ovaries
 Estrogens
 Stimulates the development of secondary
female characteristics
 Matures female reproductive organs
 Helps prepare the uterus to receive a fertilized
egg
 Helps maintain pregnancy
 Prepares the breasts to produce milk
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 9.36
Hormones of the Ovaries
 Progesterone
 Acts with estrogen to bring about the
menstrual cycle
 Helps in the implantation of an embryo in
the uterus
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 9.37
Hormones of the Testes
 Produce several androgens
 Testosterone is the most important
androgen
 Responsible for adult male secondary sex
characteristics
 Promotes growth and maturation of male
reproductive system
 Required for sperm cell production
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 9.38
Conditions of the Reproductive/Endocrine
Organs
• Hyposecretion of testosterone can cause a male to
be sterile.
• Hyposecretion of ovarian hormones will reduce a
females chances to conceive and bear children.
Other Hormone-Producing Tissues
and Organs
 Parts of the small intestine
 Parts of the stomach
 Kidneys
 Heart
 Many other areas have scattered
endocrine cells
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 9.39
Endocrine Function of the Placenta
 Produces hormones that maintain the
pregnancy
 Some hormones play a part in the
delivery of the baby
 Produces HCG in addition to estrogen,
progesterone, and other hormones
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 9.40
hCG
• hCG is the hormone that is detected in pregnancy
test sold over the counter.
• hCG stimulates the continued production of
estrogen and progesterone so that the lining of the
uterus does not slough off
Developmental Aspects of the
Endocrine System
 Most endocrine organs operate smoothly
until old age
 Menopause is brought about by lack of
efficiency of the ovaries
 Problems associated with reduced estrogen
are common
 Growth hormone production declines with age
 Many endocrine glands decrease output with
age
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 9.41
Closure
• A young girl is brought to the clinic by her father.
The girl fatigues easily and seems mentally
sluggish. You notice a slight swelling in the
anterior neck. What condition do you suspect?
What are some possible causes and their
treatments?
• Hypothyroidism; iodine deficiency----treat with
iodine