Pathology of the Endocrine System

Question 1

Describe the classic histology of endocrine glands

Answer 1

Packets of cells with secretory granules
Highly vascular
Ductless

Question 2

How is balance of hormones in the body maintained?

Answer 2

Feedback inhibition

Question 3

Define hyperplasia

Answer 3

increased number and secretory activity of cells

Question 4

Define atrophy

Answer 4

diminution of cells due to lack of stimulation

Question 5

Describe methods of tissue damage

Answer 5

Inflammation, autoimmune disease, compression, trauma, infarction

Question 6

What hormones does the thyroid gland synthesise, store and release that regulate basal metabolic rate?

Answer 6

Thyroxine (T4)

Triiodothyronine (T3)

Question 7

What hormone does the thyroid gland produce which regulates calcium homeostasis?

Answer 7

Calcitonin

Question 8

Describe 3 things found in the histology of the thyroid gland

Answer 8

• Follicles
• Colloid (contains thyroglobulin)
• Epithelial cells (TG synthesis, iodination, resorption + release of T4 and T3)

Question 9

What is one component of the thyroid gland which is not visible in a histology slide and requires special immunohistochemical stains?

Answer 9

C-cells - secrete calcitonin

Question 10

How does hyperthyroidism manifest?

Answer 10

Thyrotoxicosis

Question 11

How does hypothyroidism manifest?

Answer 11

Myxoedema
Cretinism
Subclinical

Question 12

How does thyroid enlargement manifest?

Answer 12

Goitre

Isolated nodule/mass

Question 13

Name the 3 main causes of hyperthroidism

Answer 13

Graves (70%)
Toxic multinodular goitre (20%)
Toxic adenoma

Question 14

Is Graves more common in men or women? What age group?

Answer 14

Women

20-40 yrs

Question 15

How does Graves happen?

Answer 15

Autoimmune condition; B-cells produce antibodies against thyroid proteins (commonly thyroid-stimulating immunoglobulin) which mimic TSH by binding to its receptors on thyroid cells and stimulate them to overproduce T3 + T4

Question 16

What happens to the thyroid in Graves?

Answer 16

Diffuse hyperplasia, hypertrophy and hyperfunction

Question 17

What are the ‘triad’ of Graves symptoms?

Answer 17

HYPERTHYROIDISM
OPTHALMOPATHY
DERMOPATHY

Question 18

Describe a Graves histology

Answer 18

Increased cell numbers due to increased activity; follicular cells elongated cos squished together

Question 19

What are the 4 causes of hypothyroidism?

Answer 19

Hashimoto’s thyroiditis (most common; auto-immune destruction)
Iatrogenic (surgery, drugs)
Iodine deficiency
Congenital hypothyroidism

Question 20

Is Hashimoto’s more common in women or men? What age group?

Answer 20

Women

45-65 yrs

Question 21

Describe the process in Hashimoto’s

Answer 21

Autoimmune; cytotoxic T cells, cytokine + antibody mediated destruction of thyroid epithelial cells; circulating antibodies to thyroglobulin + thyroid peroxidase

Question 22

What happens to the thyroid in Hashimoto’s?

Answer 22

Diffuse enlargement

Gradual failure

Question 23

Describe a Hashimoto’s histology

Answer 23

Hurthle cell change (large + pink)

Intense infiltrate of lymphocytes + plasma cells

Question 24

What is hashitoxicosis?

Answer 24

Period of transient hyperthyroidism due to T3 + T4 being spilled into blood from destruction of follicular cells; before thyroid fails

Question 25

What causes the thyroid to enlarge in Hashimoto’s?

Answer 25

Connective tissue buildup around follicles (from chronic inflammation) and extensive immune cell infiltration

Question 26

Describe the process of developing multinodular goitre

Answer 26

Iodine deficiency + goitrogens
=
impaired TH synthesis 
=
increased TSH
= 
hypertrophy and hyperplasia of epithelium

Question 27

Look over notes on these conditions

Answer 27

from osmosis vids