The parathyroid glands are small endocrine glands in the neck of humans and other tetrapods that produce parathyroid hormone.
positioned behind the left and right lobes of the thyroid.
The size of the gland ranges from 2-7 mm .
Two unique types of cells are present in the parathyroid gland:
Chief cells :which synthesise and release parathyroid hormone.
Oxyphil cells: which are lighter in appearance and increase in number with age,have an unknown function
2. Parathyroid gland
The parathyroid glands are
small endocrine glands in the neck
of humans and other tetrapods that
produce parathyroid hormone.
positioned behind the left and right
lobes of the thyroid.
The size of the gland ranges from 2-
7 mm .
3. Parathyroid cells
Two unique types of cells are
present in the parathyroid gland:
Chief cells :which synthesise and
release parathyroid hormone.
Oxyphil cells: which are lighter in
appearance and increase in number
with age,have an unknown function
4. Parathyroid hormone
Parathyroid hormone (PTH, also known
as parathormone) is a small protein that
takes part in the control of calcium and
phosphate homeostasis, as well as bone
physiology.
Parathyroid hormone has effects
antagonistic to those of calcitonin.
5. Calcium
PTH increases blood calcium levels
by stimulating osteoclasts to break
down bone and release calcium.
PTH also increases gastrointestinal
calcium absorption by the
activating vitamin D, and promotes
calcium conservation (reabsorption)
by the kidneys.
6.
7. Hyperparathyroidism
Hyperparathyroidism is the state in
which there is excess parathyroid
hormone circulating.
This may cause bone pain and
tenderness, due to increased bone
reabsorption.
Hypoparathyroidism
•The state of decreased parathyroid activity
is known as hypoparathyroidism.
• This is most commonly associated with
damage to the glands or their blood supply
during thyroid surgery.
8. Symptoms of hypoparathyroidism
Tingling in the lips, hands, fingers and toes
Dental malformations (eg, misshapen teeth,
loss of enamel)
Dry hair, dry skin, brittle nails, thinning hair
Cataracts
Headaches, memory loss, mental retardatio
Tetany (severe muscle spasm)
Impaired kidney function
Seizures caused by calcium deposits in the
brain.
Cardiac arrhythmias, fainting episodes
9. Parathyroid tumor
A parathyroid tumor develops as a result
of replication or growth of cells in the
parathyroid gland.
Parathyroid tumors tend to be benign
(non-cancerous). Benign tumors are called
adenomas.
A malignant form of tumor, called
parathyroid carcinoma, has been
described, but is rare.
Parathyroid tumors are common in cats
and dogs.
10. What are the signs of a parathyroid
tumor?
The signs of a parathyroid tumor are related
to a condition known as hypercalcemia.
Parathyroid tumors cause an
overproduction of parathyroid hormone
(PTH), a hormone that regulates the
circulating level of blood calcium, causing it
to rise. This condition is known as
hypercalcemia
11. What are the signs of a parathyroid
tumor?
With hypercalcemia, your pet may become
anorexic, start vomiting, drink and urinate
more, and show signs of weakness, muscle
trembling, and general lethargy.