Download Chapter 11: Parathyroid

Chapter 11:
Parathyroid
By: Nathan A., Ashley L., Max, and Dustin
Location and Basic Anatomy
Location
Posterior/Inferior Surface of the Thyroid Gland; Migration of the Thymus
Basic Anatomy
The parathyroid glands produce parathyroid hormones
There are 4 glands
Parathyroid glands have a distinct, encapsulated, and smooth surface
Parathyroid glands are typically light brown to a tan color
There is a thin capsule of connective tissue the covers each small, yellowish- brown parathyroid
gland
General Function
Main Function
Controls the Calcium (Ca+) Levels
Produces Parathyroid Hormone (PTH)
Secretions and Their Functions
Hormones
The parathyroid gland secretes a hormone called parathyroid hormone (PTH)
The PTH increases blood calcium concentration and decreases blood phosphate ion
concentration.
Negative Feedback
The secretion of the PTH hormone is controlled by negative feedback between
the gland and and blood calcium.
As blood calcium drops, more PTH is secreted. As blood calcium rises, less PTH is released.
Diseases Associated
A tumor within the parathyroid gland can cause hyperparathyroidism, this
increases PTH secretion.
The over-secretion of PTH stimulates osteoclast activity, the cells responsible for the breakdown
of bone cells. This softens the bone, making it more susceptible to fractures. The excess
calcium and phosphate may be deposited in random places, causing new problems such as
kidney stones.
Injury to or the surgical removal of the gland can cause hypothyroidism.
A decreases PTH secretion reduces osteoclast activity. The bones remain strong, but blood
calcium concentration decreases.
This causes the nervous system to trigger random impulses. Muscles undergo contractions or
spasms, this can lead to respiratory failure and death.
Work Cited
Shier, David, Jackie Butler, and Ricki Lewis. Hole's Essentials of Human
Anatomy & Physiology. 10th ed. N.p.: McGraw Hill, n.d. N. pag. Print