Pathology of the Endocrine System 1&2

Question 1

What are the seven components which make up the classic endocrine system?

Answer 1

Pineal Gland
Hypothalamus
Pituitary Gland
Thyroid Gland
Adrenal Glands
Parathyroid Glands
Pancreas

Question 2

What is hyperplasia of endocrine organs?

Answer 2

Increased number and change in activity of the secretory activity of cells

Question 3

What is atrophy in endocrine organs?

Answer 3

Diminution of cells due to a lack of stimulation

Question 4

What are the two types of tumour which may cause neoplasia in endocrine organs?

Answer 4

Adenoma

Carcinoma

Question 5

Which hormones is the thyroid gland responsible for?

Answer 5

Thyroxine T4
Triiodothyronine T3
- both responsible for regulating basal metabolic rate

Calcitonin - regulates calcium homeostasis

Question 6

Does T3 or T4 have a longer half life?

Answer 6

T4 by far and there is much more of it in the tissues

Question 7

Which of T3 and T4 is more potent?

Answer 7

T3 - but there is less of it

Question 8

What are found within thyroid follicular cells?

Answer 8

Colloid

Question 9

What is the function of thyroid C-cells?

Answer 9

Secrete calcitonin

Question 10

What two things are required to allow the epithelial cells of the thyroid to synthesise thyroglobulin?

Answer 10

Iodine and tyrosine

Question 11

What type of epithelial cells are found surrounding the follicular cells of the thyroid?

Answer 11

Cuboidal epithelial cells

Question 12

What external factors stimulate TRH release from the hypothalamus?

Answer 12

Cold and stress

Question 13

What may cause thyroid enlargement excluding hyper and hypothyroidism?

Answer 13

Goitre

Isolated nodule/mass

Question 14

Are the vast majority of thyroid diseases primary or secondary?

Answer 14

Primary

Question 15

What is the main cause of hyperthyroidism?

Answer 15

Grave’s disease

Question 16

Is TSH elevated in primary hyperthyroidism?

Answer 16

No

Question 17

Which gender is more susceptible to Grave’s disease?

Answer 17

Females

Question 18

What is the autoimmune pathology of Grave’s disease?

Answer 18

Production of anti-TSH receptor antibodies - they stimulate activity, growth and inhibit TSH from binding

Question 19

Is there a visible increase or decrease in cell number and activity on histological visualisation of thyroid tissue in hyperthyroidism?

Answer 19

A visible increase in both

Question 20

What is the main cause of hypothyroidism?

Answer 20

Hashimoto’s disease

Question 21

What are some other causes of hypothyroidism?

Answer 21

Iatrogenic - surgery/drugs
Iodine deficiency
Congenital hypothyroidism

Question 22

Which gender is more commonly affected by Hashimoto’s thyroiditis? Is this a hyper or hyposecreting condition?

Answer 22

Females -(genetic, predisposition) hyposecreting

Question 23

What is the autoimmmune pathology of Hashimoto’s thyroiditis?

Answer 23

Autoimmune destruction of thyroid epithelial cells - cytotoxic T cells, cytosine and antibody mediated

There is a loss of tolerance and and malfunction of regulatory T cells due t o exposure to hidden antigens - cytotoxic T cells, T cell mediated cytokines and antibodies

Question 24

What is the change that affects thyroid cells in hypothyroidism called?

Answer 24

Hurthle cell change

Question 25

What is the most common cause of multi nodular goitre?

Answer 25

Iodine deficiency - most commonly affects the elderly

Question 26

What is the physiological pathway of multi nodular goitre caused by iodine deficiency?

Answer 26

``` Iodine deficiency to Impaired synthesis of T3 and T4 to Increased TSH synthesis to Hypertrophy and hyperplasia of the epithelium ```

Question 27

What is the dominant nodule in a multinodular goitre known as?

Answer 27

The thyroid nodule

Question 28

What may be causing the thyroid nodule?

Answer 28

Multinodular goitre Cyst Follicular adenoma Carcinoma - most commonly differentiated thyroid carcinoma

Question 29

Are the majority of thyroid follicular adenomas functioning?

Answer 29

No, the majority are non-functioning

Question 30

What is relevant about the borders of a follicular adenoma in the thyroid?

Answer 30

It is encapsulated, often by a thick margin which can prevent the cells leaking out and causing local spread, however this may eventually happen and cause local invasion and possible metastasis, commonly to the blood and bone

Question 31

What are the two gene abnormalities linked with papillary carcinoma?

Answer 31

BRAF mutation RET/PTC rearrangement

Question 32

What is the general prognosis of papillary carcinoma?

Answer 32

Very good prognosis, 99% 1 yr survival

Question 33

What cells are affected in thyroid medullary carcinoma?

Answer 33

C-cells of the thyroid

Question 34

Are thyroid medullary carcinomas secretory? If so what do they secrete?

Answer 34

Yes, calcitonin

Question 35

What hormone is produced by parathyroid glands?

Answer 35

Parathyroid hormone (PTH)

Question 36

What is the action of PTH?

Answer 36

Regulating plasme Ca2+

Question 37

Which hormone opposes the action of PTH?

Answer 37

Calcitonin from the thyroid

Question 38

What is the main cause of hypoparathyroidism?

Answer 38

Secondary to thyroid surgery

Question 39

What is the most common cause for primary hyperthyroidism?

Answer 39

Adenoma (85-95%)

Question 40

What are some other causes of hyperparathyroidism?

Answer 40

Hyperplasia | Carcinoma

Question 41

An increase in what is commonly seen in patients with hyperparathyroidism?

Answer 41

Calcium - hypercalcaemia | And subsequent loss of phosphorus

Question 42

What is another name for the anterior pituitary?

Answer 42

Adenohypophysis

Question 43

What hormones are secreted by the anterior pituitary?

Answer 43

``` ACTH TSH GH Prolactin FSH/LH ```

Question 44

What is another name for th posterior pituitary?

Answer 44

Neurohypophysis

Question 45

What hormones are secreted by the posterior pituitary?

Answer 45

Vasopressin/ADH | Oxytocin

Question 46

What are the three main cell types of the posterior pituitary?

Answer 46

Adicophils Basophils Chromophobes

Question 47

Which hormones are secreted by the acidophils of the anterior pituitary?

Answer 47

GH | Prolactin

Question 48

Which hormones are secreted by the basophils of the anterior pituitary?

Answer 48

ACTH TSH FSH LH

Question 49

What is the most common cause of primary hyperfunciton of the pituitary? (hyperpituitarism)

Answer 49

Pituitary adenoma

Question 50

What is unusual about the histology of pituitary adenomas?

Answer 50

They have the same appearance as the normal gland

Question 51

What is a prolactinoma?

Answer 51

A prolactin secreting pituitary adenoma

Question 52

What hormones may a pituitary adenoma secrete?

Answer 52

Prolactin - prolactinoma GH ACTH = cushing's disease

Question 53

What is the mass pressure effect associate with some pituitary adenomas?

Answer 53

If the adenoma is large enough, regardless of whether it is secreting or not, may have mass effects on the surrounding structures, and may cause visual field defects - often bitermporal hemianopia and caused raised ICP and common cranial symptoms such as headaches, nausea, vomiting

Question 54

What effect may a large pituitary adenoma exerting mass effect have on the pituitary gland?

Answer 54

It may cause compression damage which results in hypopituitarism

Question 55

What percentage of the pituitary glands mass must be lost for there to be pituitary hypofunciton?

Answer 55

75%

Question 56

What are the most common causes of pituitary hypofunction?

Answer 56

Compression damage from tumours Trauma Infection (rare)

Question 57

Which hormones are produced by the adrenal cortex?

Answer 57

Mineralocorticoids Glucocorticoids Sex steroids

Question 58

What part of the adrenal gland secretes mineralocorticoids? Which is the most significant of these hormones?

Answer 58

The bona glomerulosa of the adrenal cortex Aldosterone

Question 59

What is the function of aldosterone?

Answer 59

To maintain plasma volume via secretion at the kidney tubules

Question 60

Which part of the adrenal gland produces glucocorticoids? Which of these hormones is the most significant?

Answer 60

The zona fasiculata of the adrenal cortex Cortisol

Question 61

What is the function of cortisol?

Answer 61

Increasing blood glucose levels by increasing gluconeogenesis, supressing the immune system, aiding in the metabolism of fat, protein and lipolysis, as well as decreasing bone formation

Question 62

What is produced by the zona reticularis?

Answer 62

Sex steroids - oestrogen, androgens

Question 63

What is produced by the adrenal medulla?

Answer 63

Adrenaline/noradrenaline in response to stress

Question 64

What is the main cause of adrenal cortical hyperfunction? What specifically does this cause in terms of hormones?

Answer 64

Cushing's syndrome Hypercortisolism

Question 65

What is the main cause of hyperaldosteronsim?

Answer 65

Conn's syndrome