Sfos - Lect. 73

Front 1

What is the embroyological remnant left by the thyroglossal duct during it's descent?

Back 1

pyramidal lobe

Front 2

What do the migrating ultimobranchial bodies, which arise from the 4th pharyngeal pouches, become to after they fuse with the thyroid?

Back 2

Parafollicular Cells

Front 3

What kind of epithelium line the thyroid follicles?

Back 3

simple cuboidal

Front 4

What is located within the follicle?

Back 4

Colloid

Front 5

Which surface of the follicular cells are in contact with the colloid (apical, basal)

Back 5

Apical

Front 6

What are the two types of cells found in the follicular epithelium of the thyroid?

Back 6

Follicular and Parafollicular

Front 7

This cell of the thyroid secretes calcitonin?

Back 7

Parafollicular Cells

Front 8

What kind of capillaries line the thyroid gland ?

Back 8

fenestrated

Front 9

A hormone secreted from this lobe of the pituitary Gland regulates thyroxine release?

Back 9

Anterior Lobe of the Pituitary (TSH)

Front 10

What is the principal component of colloid within the thyroid follicles?

Back 10

Thyroglobulin (inactive storage form)

Front 11

Which pharyngeal pouch is the inferior parathyroid gland derived from; which is the superior parathyroid gland derived from?

Back 11

Third; fourth

Front 12

What two cells constitute the epithelial cells of the parathyroid gland?

Back 12

Chief cells and Oxyphil cells

Front 13

This cell of the parathyroid gland secretes PTH?

Back 13

Principal/chief cells

Front 14

Osteoclast activity increases with the release of this hormone (calcitonin or PTH)?

Back 14

PTH

Front 15

These are multinuclear cells derived from the mononuclear phagocyte system and degrade bone matrix?

Back 15

Osteoclasts

Front 16

Hypothyroidism in juveniles will result in what general feature?

Back 16

Short Stature (thyroid is required for normal bone growth)

Front 17

Thyrotoxicosis (hyperthryoidism) will result in what in juveniles?

Back 17

Among other things…Accelerated bone growth and advanced skeletal development

Front 18

Where do parafollicular cells come from ebryologically?

Back 18

Neural crest cells (ultimobranchial bodies…***the histo book uses this term)

Front 19

The parenchyma of the thyroid comes from what embryological derivative (ectoderm, endoderm, mesoderm)?

Back 19

Oral endoderm (starts as an endodermal thickening at the floor of the primitive pharynx)

Front 20

What is the blood supply of the thyroid?

Back 20

superior and inferior thyroid arteries

Front 21

Where does the superior thyroid artery branch off of?

Back 21

External carotid

Front 22

Where does the inferior thyroid artery branch off of

Back 22

Thyrocervical trunk off of the subclavian artery

Front 23

True/False Height of the epithelial cells in the follicles reflects the level of activity of the thyroid follicle?

Back 23

TRUE; Columnar are more active than cuboidal

Front 24

Describe the general sequence of T3/T4 production?

Back 24

thyroglobulin is synthesized and stored in lumen; iodide is taken up from blood; iodide is oxidized by thyroid peroxidase to iodine; iodine is released into lumen; thyroid peroxidase at microvilli apical surface adds iodine to tyrosine residues of thyroglobulin; iodinated tyrosine residues are coupled to make either MIT, or DIT; thyroglobulin is taken up by endocytosis; broken doen by lysosomes; T3/T4 released; MIT/DIT recycled

Front 25

What two glands does thyroid hormone negatively inhibit?

Back 25

hypothalamus (TRH) and Anterior pituitary (TSH)

Front 26

Do the parafollicular cells come in contact with the colloid?

Back 26

NO

Front 27

TRUE/False Calcitonin increases the activity of osteoclasts?

Back 27

FALSE;

Front 28

Are parafollicular cells greater in number in adulthood or fetal life?

Back 28

Fetal Life (maternal calcitonin does not cross utero-placental barrier)

Front 29

What is myxedema?

Back 29

adult hypothyroidism

Front 30

TRUE/False PTH is essential for life?

Back 30

TRUE;

Front 31

TRUE/FALSE Parathyroid glands do not contain their own capsules?

Back 31

FALSE; They do and this makes them seperable from the thyroid during surgeries

Front 32

What is the blood supply of the parathyroid gland?

Back 32

Inferior thyroid artery

Front 33

Do elderly people have more or less adipose tissue in their parathyroid glands vs the young?

Back 33

More adipose tissue

Front 34

Hypocalcemia will result in the release of which hormone?

Back 34

PTH

Front 35

Are there any PTH receptors on osteoclasts?

Back 35

NO, the effect is mediated by osteoblasts

Front 36

What is expressed on osteoblasts after binding with PTH?

Back 36

RANK, which binds to RANKL on osteoclasts

Front 37

What is a decoy receptor for RANK and has been used to prevent bone resorption in post-menopausal women?

Back 37

Osteoprotgerin (OPG)

Front 38

Which enzyme is stimulated by PTH and affects intestinal absorption of calcium?

Back 38

1-hydroxylase (Vitamin D3 conversion)