Wk1 Pineal, Thyroid, Parathyroid Histo

Question 1

95% of the cells making up pineal gland:

Answer 1

Pinealocytes

Question 2

What do pinealocytes do?

Answer 2

make melatonin at night

Question 3

What is “brain sand” and what is its significance?

Answer 3

Ca and P buildup in pineal gland

radiological marker for small pineal gland

Question 4

Nerve supply and NT released on pinealocytes:

Answer 4

superior cervical ganglion SNS fibers

epi

Question 5

Melatonin effects on hypothalamus:

Answer 5

suppress gonadotropins (FSH, LH)

**pineal tumors cause precocious puberty

**possibly contributes to seasonal affective disorder

Question 6

Two thyroid cell types:

Answer 6

follicular – surround colloid

parafollicular (C-cells)

Question 7

Thyroid hormone precursor found in colloid:

Answer 7

thyroglobulin

Question 8

Where are thyroid hormones synthesized?

Answer 8

follicular cells

Question 9

Slides 23-24

Answer 9

active vs resting follicular cells

Question 10

Role of parafollicular cells?

Answer 10

synthesize calcitonin

Question 11

3 roles of calcitonin:

Answer 11

1. lowers blood Ca by decreasing bone resorption
2. decreases osteoclast motility and number
3. promotes Ca and PO4 excretion by kidney

Question 12

Where does iodination of thyroglobulin occur?

Answer 12

colloid

Question 13

Nice summary on slide…

Answer 13

36-37

Question 14

Embryological origin of C-cells:

Answer 14

pharyngeal endoderm

Question 15

Embryological origin of parathyroid glands:

Answer 15

pharyngeal endoderm

Question 16

3 cell types in parathyroid gland:

Answer 16

1. Chief (principal) cells
2. Oxyphils
3. Fat cells

Question 17

Cells that produce parathyroid hormone (PTH):

Answer 17

Chief

Question 18

Role of PTH:

Answer 18

Ca regulation

1. stimulates osteoBlasts which in turn produce RANKL to stimulate osteoClasts (no PTH receptor)

–> bone resorption –> increased blood Ca

Question 19

Larger pink cells with small dark nuclei in parathyroid:

Answer 19

Oxyphhils