Tanya Shepherd
Madison Reyna
P.2B
THYROID GLAND
Location
 Located in neck, superior to the
trachea
 Shaped like butterfly wings.
 Weighs less than an ounce
 During development, it starts in
the back of the tongue (lingual
thyroid) and then migrates to the
neck. Sometimes migrating too far
and ending up in the chest.
FUNCTION & HORMONES
 Produces T3 and T4 The thyroid gland needs assistance from the
pituitary gland in order to produce hormones.
 Thyroid cells are the only cells in the body that can absorb iodine.
 Combine iodine and tyrosine to make T3 and T4 which are then
released into the bloodstream to regulate the metabolism.
 If the body does not receive enough iodine, it cannot produce the
proper amount of hormones.
HORMONES CONT.
 Calcitonin-regulates calcium levels within the body
 Calcium is important for muscle contractions, nerve function, and blood
clotting.
 If we do not have enough calcium, the body will take it from the bones
which will result in bone fracture, twitching, convulsions, and even death.
 Too much calcium can result in weakening of muscle tone and kidney
stones.
NEGATIVE FEEDBACK
 Thyroid is part of the hypothalamic-pituitary-
thyroid axis
 When blood concentration of the thyroid
increases, they inhibit both TRH and TSH,
which shuts down the thyroid epithelial cells.
When the blood concentration has decayed,
the negative feedback signal fades and the
system wakes up again.
 Positive feedback occurs during childbirth
when oxytocin stimulates labor contractions.
HOMEOSTASIS
 Without the thyroid gland, the body
would not be able to break down
proteins or process carbohydrates.
 This can lead to uncontrollable
weight gain.
 A problem within the thyroid gland
can usally be fixed by prescribed
medications or surgery
 Hyperthyroidism – thyroid makes
too much of the thyroid hormone,
can cause rapid weight loss, fast
heart beat, and hair loss.
SOURCES
 http://umm.edu/programs/diabetes/health/endocrinology-health-
guide/thyroid-gland
 http://www.healthline.com/human-body-maps/thyroid-gland
 http://www.innerbody.com/image_dige01/endo04.html#full-description