Thyroid, Parathyroid and Adrenal

Question 1

Cell types of thyroid

Answer 1

1. Follicular

2. Parafollicular (aka clear cells)

Question 2

Follicular cell appearance

Answer 2

Cuboidal epithelium with microvilli on apical edge

Held together by tight junctions

Question 3

Parafollicular cell appearance

Answer 3

Isolated clusters beside follicle

Larger and paler

Produce calcitonin

Question 4

Phases of thyroid cels

Answer 4

Endocrine and storage phase

Question 5

Storage phase of follicular cells

Answer 5

Synthesize and secrete thyroglobulin which is stored in lumen of follicle

Question 6

Endocrine phase of follicular cells

Answer 6

1. Stored thyroglobulin is taken up by follicular cells
2. Broken down to active thyroid hormone
3. Released into blood

Question 7

Most abundant thyroid hormone

Answer 7

T4 (thyroxine) → prohormone

Question 8

Less abundant thyroid hormone

Answer 8

T3 (triiodothyronine) → active

Question 9

T4 is activated by what cells?

Answer 9

1. Liver
2. Kidney
3. Muscle

Question 10

Thyroid hormone function

Answer 10

Increase metabolic rate and mitochondrial respiration

Question 11

Colloid

Answer 11

Made up of thyroglobulin (glycoprotein) → storage phase

Question 12

Cell types of parathyroid

Answer 12

1. Chief cells (principle)

2. Oxyphil cells

Question 13

Oxyphil cells are found in?

Answer 13

Human, ox, horse

Question 14

Chief cells produce?

Answer 14

PTH to raise blood Ca

Question 15

Parenchyma of adrenal gland includes?

Answer 15

Fine reticular fibers and trabeculae from capsule

Question 16

3 regions of adrenal cortex

Answer 16

1. Zona glomerulosa
2. Zona fasciculata
3. Zona reticularis

Question 17

Zona glomerulosa is stimulated by?

Answer 17

Angiotensin

Not ACTH from the pituitary

Question 18

Zona glomerulosa produces?

Answer 18

Mineralcorticoids (esp. aldoserone) to increase blood Na

Question 19

Widest zone of adrenal cortex

Answer 19

Zona fasciculata

Question 20

Cells of zona fasciculata

Answer 20

Spongiocytes

Question 21

Spongiocyte appearance

Answer 21

Polyhedral with foamy cytoplasm (contains SER and lipid inclusions)

Question 22

Zona reticularis

Answer 22

Closely packed cells → produces some weak androgens and some glucocorticoids

Question 23

Zona fasciculata is stimulated by ___ to produce ____

Answer 23

ACTH to produce glucocorticoids

Question 24

Adrenal medulla are made up of?

Answer 24

Chromaffin cells