Section 4 - Parathyroid Glands, Calcium & Vitamin D

Question 1

Describe the location of the parathyroid glands in the human body and identify key landmarks?

Answer 1

Typically four but range anywhere from 2 to 8. Adhere to the posterior surface of the thyroid gland. Vascularized and derive their blood supply from inferior thyroid arteries.

Question 2

Histological and micro-anatomical features of parathyroid gland

Answer 2

1) principal (chief cells)

2) oxyphil cells - degenerated principal cells. number INCREASES with age

Question 3

Summarize the distribution (throughout the body) and functions of both calcium and phosphorous (phosphate)

Answer 3

Calcium function - muscle contractions, exocytosis, blood clotting, formation of cardiac action potentials, enzyme activation, cell signaling, bone & teeth structure

Phosphate - essential for bone and teeth formation

Question 4

what is the chemistry of hormone for the parathyroid hormone (PTH)?

Answer 4

peptide hormone

Question 5

what stimulates PTH?

Answer 5

stimulation is hypocalcemia

Question 6

when, where and how is PTH synthesized?

Answer 6

synthesized and secreted by chief cells based. Chief cells sense minute fluctuations of ECF Ca2+

Question 7

what are the physiological effects of hormone?

Answer 7

stimulates osteoclast activity; reabsorption of Ca2+ in distal convoluted tubules; stimulates 1-hydroxylation of 25-hydroxycholecalciferol in kidneys, stimulates intestinal uptake of Ca2+ by “active” vitamin D; phosphaturia

Question 8

what is the chemistry of hormone of calcitonin?

Answer 8

peptide hormone

Question 9

what stimulates calcitonin?

Answer 9

hypercalcemia

Question 10

when, where and how is calcitonin synthesized?

Answer 10

synthesized and secreted by parafollicular cells of the thyroid gland

Question 11

what are the physiological effects of calcitonin?

Answer 11

it lowers the ECF Ca2+ by acting on bone.

Question 12

what is the chemistry of hormone of vitamin D?

Answer 12

steroid hormone

Question 13

what is the stimulation of vitamin D?

Answer 13

PTH stimulates secretion

Question 14

when, where and how is vitamin D synthesized?

Answer 14

made into active version in kidneys when PTH is released

Question 15

physiological effects of vitamin D

Answer 15

helps with calcium uptake in the intestines

Question 16

hyperparathyroidism (all forms)

Answer 16

primary hyperparathyroidism

Question 17

pathophysiology of primary hyperparathyroidism?

Answer 17

hypercalcemia

Question 18

etiology of hyperparathyroidism?

Answer 18

adenomas

Question 19

clinical manifestations of hyperparathyroidism?

Answer 19

stones (kidney, gallbladder)
thrones (frequent urination)
bones (pain in bone)
groans (constipation and muscle weakness)
psychiatric overtones (depressed mood, confusion)

Question 20

dental aspects of hyperparathyroidism?

Answer 20

gradual loosening
drifting and loss of teeth
spacing of teeth
"brown tumor" lesions raising the risk for fracture
malocclusion
dental pain
soft tissue calcification
sialothiasis (salivary duct stones)

Question 21

hypoparathyroidism (all forms)

Answer 21

primary hypoparathyroidism

Question 22

pathophysiology of primary hypoparathyroidism?

Answer 22

hypocalcemia and hyperphosphatemia

Question 23

what is the etiology of hypoparatyroidism?

Answer 23

adenoma

Question 24

what are some clinical manifestations of hypoparathyroidism?

Answer 24

cardiac arrhythmias, trousseau’s sign, chovestek’s sign, parathesia

Question 25

treatment of hypoparathyroidism includes

Answer 25

synthetic PTH, oral calcium carbonate tablets, and/or vitamin D

Question 26

dental aspects of hypoparathyroidism includes

Answer 26

- enamel hypoplasia - delayed eruption or multiple unerupted teeth - poorly calcified dentin - microdontia - malformed roots - dental caries - parathesia

Question 27

what is the pathophysiology of osteoporosis?

Answer 27

bone resorption is faster than bone formation

Question 28

what is the etiology of osteoporosis?

Answer 28

lifestyle - low calcium intake, vitamin D deficiency, excess vitamin A intake, inadequate physical activity, smoking and alcohol abuse genetic factors - parental history of hip fracture medical conditions - hyperparathyroidism, Cushing syndrome medication - corticosteroids

Question 29

Clinical manifestations of osteoporosis

Answer 29

fragility fracture, decreased bone mass

Question 30

Treatment of osteoporosis

Answer 30

include calcium and vitamin D supplements (insufficient alone), bisphosphonates, selective estrogen receptor modulators, and calcitonin.

Question 31

calcium supplements for osteoporosis

Answer 31

- calcium citrate: take with meals and can cause dyspepsia and constipation - calcium carbonate: best taken during fasting

Question 32

Bisphosphonates

Answer 32

Bisphosphonates inhibits osteoclasts by imbibing itself into the osteoclasts to fall off and apoptosis. Can cause transient hypocalcemia, musculoskeletal pain, acute flu-like reaction (IV), and osteonecrosis of the jaw. Should not give with patients who have esophageal disorders (achalasia, esophageal varices, Barrett's esophagus) and patients with severe renal impairment.

Question 33

What are the four types of bisphosphonates given?

Answer 33

alendronate risedronate ibandronate zoledronic acid

Question 34

alendronate

Answer 34

oral and liquid

Question 35

risedronate

Answer 35

oral

Question 36

ibandronate

Answer 36

oral and IV

Question 37

zoledronic acid

Answer 37

IV

Question 38

How does estradiol prevent osteoclast maturation?

Answer 38

Estradiol increases production of OPG to inhibit RANKL preventing RANKL/RANK (receptor) interaction -> prevents osteoclast maturation. That's why we have selective estrogen receptor modulators/SERMs.

Question 39

Type of estradiol that can cause increase risk of blood clots?

Answer 39

Raloxifine

Question 40

Calcitonin

Answer 40

increases in cAMP levels -> decrease in resorptive ability. Can cause nausea, flushing, and runny nose. Can cause increase in cancer rates

Question 41

Two types of calcitonin medications

Answer 41

miacalcin and fortical

Question 42

denosumab

Answer 42

antibody against RANKL. Administered as SC injection. Adverse effects include musculoskeletal pain, hypercholesterolemia, and cysititis. Can cause ONJ but not as frequent as BP.

Question 43

Dental aspects of osteoporosis

Answer 43

loss of bone mass in mandible | loosening of teeth or tooth loss and dentures to become ill-fitting; medication can cause osteonecrosis

Question 44

Rickets and osteomalacia pathology?

Answer 44

soft bones

Question 45

Etiology of rickets and osteomalacia?

Answer 45

calcium and vitamin D deficiency

Question 46

Clinical manifestations of rickets and osteomalacia

Answer 46

weight - bearing bones bend and deform in children. increased amount of fractures in adults