Thyroid gland (M1B1)

Question 1

how many parathyroid glands are there?

Answer 1

4

Question 2

thyroid gland consists of how many lobes?

Answer 2

2 lobes

Question 3

what connects both lobes of the thyroid?

Answer 3

isthmus

Question 4

the thyroid gland arises as median outgrowth from the floor of the……….. to near the base of………..

Answer 4

pharynx, tongue (foramen caecum)

Question 5

what marks the path of migration of the thyroid gland?

Answer 5

thyroglossal duct

Question 6

2 major arteries supply the thyroid gland which are?

Answer 6

1) superior thyroid artery

2) inferior thyroid artery

Question 7

the superior thyroid artery is the first branch of the?

Answer 7

external carotid artery

Question 8

superior thyroid artery branches out into 2 branches which are?

Answer 8

anterior and posterior glandular branches

Question 9

the inferior thyroid artery is a branch of the…………. which arises from the first part of the…………

Answer 9

thyrocervical trunk, subclavian artery

Question 10

inferior thyroid artery divided into?

Answer 10

inferior branch which supplies the lower part of the thyroid gland

Question 11

what supplies the parathyroid?

Answer 11

inferior thyroid arteries

Question 12

the thyroidima artery arises from the?

Answer 12

arch of the aorta or branchiocephalic trunk

Question 13

3 veins drain the thyroid gland which are?

Answer 13

• superior thyroid vein: drains area supplied by superior thyroid artery
• middle and inferior thyroid veins: drain the rest of the thyroid gland

Question 14

• superior and middle thyroid veins empty into?

- inferior thyroid vein empty into?

Answer 14

• jugular vein

- right and left branchiocephalic veins

Question 15

lymphatic drainage of the thyroid gland is to?

Answer 15

paratracheal nodes and deep cervical nodes

Question 16

recurrent laryngeal nerves?

Answer 16

…

Question 17

the final destination of the thyroid gland is in front of the?

Answer 17

trachea in the 7th week

Question 18

when does the thyroid gland begin to function?

Answer 18

end of the 3rd month

Question 19

follicular cells produce the colloid (a fluid) that serves as a source of?

Answer 19

thyroxine and triiodothyronine

Question 20

parafollicular or C cells derived from the ultimobranchial body serve as a source of?

Answer 20

calcitonin

Question 21

what’s the thyroglossal cyst?

Answer 21

it is a cystic remnant of the thyroglossal duct

Question 22

sometimes a thyroglossal cyst is connected to the outside by a?

Answer 22

thyroglossal fistula

Question 23

thyroglossal cysts are most frequently found near the?

Answer 23

hyoid region

Question 24

endocrine system consists of ductless glands such as?

Answer 24

pineal body, pituitary gland, thyroid gland, parathyroid gland, supra renal glands

Question 25

endocrine cells (APUD) are isolated in the epithelial lining of the?

Answer 25

digestive tract and respiratory system

Question 26

parenchyma of an organ consists of that tissue which conducts the specific function of the organ

Stroma is everything else connective tissue, blood vessels, nerves, ducts.

Answer 26

….

Question 27

parenchyma of the thyroid is formed of?

Answer 27

1) thyroid follicle (functional unit)

2) para follicular cells

Question 28

thyroid tissue is composed of how many thyroid follicules?

Answer 28

20-30 million

Question 29

the follicles are lined by………….. and their central cavity contains a gelatinous substance called…………..

Answer 29

simple epithelium, colloid

Question 30

thyroid colloid is composed of a glycoprotein called?

Answer 30

thyroglobulin

Question 31

• active follicular cells are what in shape?

- inactive cells are?

Answer 31

• columnar

- squamous

Question 32

follicular cells test on?

Answer 32

basal lamina

Question 33

endocrine cells of the parathyroid glands, called?

Answer 33

principal (chief) cells

(are small polygonal cells with round
nuclei and pale-staining, slightly acidophilic cytoplasm )

Question 34

Irregularly shaped cytoplasmic granules

contain the polypeptide parathyroid hormone (PTH), an important regulator of blood calcium levels

Answer 34

…

Question 35

PTH has three major target which are?

Answer 35

■ Osteoblasts respond to PTH by producing an osteoclast stimulating factor that increases the number and activity of osteoclasts. The resulting resorption of the calcified bone matrix and release of Ca2+ increase the concentration of circulating Ca2+, which suppresses PTH production. The effect of PTH on blood levels of Ca2+ is thus opposite
to that of calcitonin
■ In the distal convoluted tubules of the renal cortex, PTH stimulates Ca2+ reabsorption (and inhibits phosphate reabsorption in the proximal tubules).
■ PTH also indirectly increases the Ca2+ absorption
in the small intestine by stimulating vitamin D
activation.

Question 36

oxyphil cells, often clustered, are sometimes also present in parathyroid glands, more commonly in older individuals. These are much larger than
the principal cells and are characterized by very acidophilic cytoplasm filled with abnormally shaped mitochondria. Some oxyphil cells show low levels of PTH synthesis, suggesting that these cells are transitional derivatives of principal cells.

Answer 36

…

Question 37

• hypoparathyroidism, diminished secretion of PTH can cause bones to become more mineralized and denser and striated muscle to exhibit abnormal contractions due to inadequate calcium ion concentrations.
• Excessive PTH produced in hyperparathyroidism stimulates osteoclast number and activity, leading to increased levels of blood calcium that can be
  deposited pathologically in cartilage, arteries, or the kidneys.

Answer 37

…