3. (Histology) Endocrine System

Question 1

overall structure of endocrine glands

Answer 1

functional unit consists of cuboidal secretory cells with lumen at centre
secretory cells are supported by myoepithelial cells
(not all endocrine functional units have lumen, e.g. pituitary, parathyroid)

Question 2

clinical manifestations of endocrine disease

Answer 2

hormone overproduction
hormone underproduction
tumour/mass/lesion
non functional (pressure effect), associated with hormone overproduction

Question 3

cells in the anterior pituitary

Answer 3

somatotroph
lactotroph
corticotroph
gonadortoph
thydotroph

Question 4

what do somatotrophs produce?

Answer 4

growth hormone

Question 5

what do lactotrophs produce?

Answer 5

prolactin

Question 6

what do corticotrophs produce?

Answer 6

ACTH

Question 7

what do gonadotrophs produce?

Answer 7

FSH and LH

Question 8

what do thydrotrophs produce?

Answer 8

TSH

Question 9

pituitary adenomas

Answer 9

benign 
arise from anterior lobe 
can be functional or non-functional 
productive: cause hyperpituitarism 
pressure effect: causes hypopituitarism

Question 10

what effect can pituitary adenomas have?

Answer 10

headaches
vomiting 
nausea
diplopia 
impaired vision

Question 11

what causes goitre?

Answer 11

lack iodine

Question 12

normal thyroid tissue appearance

Answer 12

composed of follicles with variable sized lumina
follicles contain colloid with eosinophilic/pink appearance
follicles are lined by cuboidal cells

Question 13

features of thyroid gland

Answer 13

very vascular
endothelial cells lining capillaries = fenestrated
para-follicular cells / clear cells (c-cells) found between follicles
c-cells secrete calcitonin

Question 14

multi nodular goitre

Answer 14

lack of iodine leads to enlarged thyroid gland
hyperplasia and hypertrophy of cells
gland enlarges to maximise iodine absorbed
patients are euthyroid

Question 15

Grave’s disease

Answer 15

auto-antibodies stimulate TSH receptors
diffuse enlargement of thyroid gland
goitre due to cell hyperplasia
infiltrative opthalmopathy - accumulation of soft tissue and inflammatory cells

Question 16

Grave’s disease thyroid appearance

Answer 16

colloid has ‘soap bubble’ appearance, due to hyperactivity

Question 17

Hashimoto’s thyroiditis

Answer 17

most common cause of hypothyroidism in areas where iodine isn’t readily available
autoimmune: thyroid tissue destroyed
progressive depletion of cells by inflammation
replaced by fibrosis

Question 18

Hashimoto’s thyroid appearance

Answer 18

gland is irregular shaped

on histology, there is prominent lymphocytic infiltrate

Question 19

thyroid tumours

Answer 19

follicular adenoma

carcinoma (4 types)

Question 20

types of thyroid carcinoma

Answer 20

papillary
follicular
medullary
anaplastic

Question 21

papillary carcinoma

Answer 21

75-85%

increased risk of lymph node metastasis

Question 22

follicular carcinoma

Answer 22

10-20%

risk of metastasis to bone, lungs and liver

Question 23

medullary carcinoma

Answer 23

5%
arises from C cells
20% with MEN2 syndrome (multiple endocrine neoplasm)

Question 24

anapaestic carcinoma

Answer 24

<5%
presents in older patients
poor prognosis

Question 25

para-follicular cells

Answer 25

c-cells secrete calcitonin - promotes reduction of calcium concentration in blood found between follicles

Question 26

parathyroid glands

Answer 26

secrete PTH control calcium level in blood - PTH increases calcium conc chief cells with no lumen highly vascularised

Question 27

parathyroid glands pathology

Answer 27

adenoma - one gland hyperplasia - involves all 4 glands cause hypercalcaemia

Question 28

adrenal glands

Answer 28

``` paired glands upper poles of kidneys adrenal cortex from mesoderm adrenal medulla derived from neural crest cells are rich in lipids ```

Question 29

adrenal cortex zones

Answer 29

zona glomerulosa zona fasciculata zona reticularis

Question 30

what does the zona glomerulosa produce?

Answer 30

mineralocorticoid aldosterone absorption of sodium

Question 31

what does the zona fasciculata produce?

Answer 31

glucocorticoids cortisol & corticosterone sex hormones

Question 32

what does the zona reticularis produce?

Answer 32

17 ketosteroids | sex hormones

Question 33

pathology of adrenal glands

Answer 33

adrenocortical hyperactivity | adrenocortical insufficiency

Question 34

adrenocortical hyperactivity

Answer 34

hyperplasia, adenoma or cancer Cushing's syndrome Conn's syndrome androgenital syndrome

Question 35

adrenocortical insufficiency

Answer 35

Addison's disease

Question 36

adrenal cortex adenoma

Answer 36

non functional cortical adenoma incidental finding on abdominal imaging functional adenomas can cause Cushing's/Conn's

Question 37

adrenal medulla

Answer 37

compact cells which secrete adrenaline and noradrenaline | neuroendocrine cells - stain darker than cortex cells

Question 38

phaechromocytoma

Answer 38

tumour of adrenal medulla due to high levels of catecholamines 0.1-0.3 % cause of treatable hypertension