Nuts and Bolts of Endocrine system histology

Question 1

Endocrine

Answer 1

Hormone acts on target organ away from the secreting cell

Question 2

Autocrine

Answer 2

Hormone acts on secreting cells

Question 3

Paracrine

Answer 3

Hormone acts on adjacent cells

Question 4

Neuroendocrine

Answer 4

Neural stimulation of endocrine cells to secrete hormones e.g. adrenal medulla

Question 5

Typical structure of endocrine glands

Answer 5

Cuboidal secretory cells with a lumen

Secretory cells supported by myoepithelium

Question 6

Acidophilic cells of the anterior pituitary

Answer 6

Take up acidic dyes
Somatotrophes
Lactotrophes

Question 7

Basophilic cells of the anterior pituitary

Answer 7

Take up basic dyes
Thydrotrophes
Gonadotrophes
Corticotrophes

Question 8

Chromophobic cells of the anterior pituitary

Answer 8

No specific staining features

Corticotrophes

Question 9

Pituitary adenoma

Answer 9

Arises from anterior lobe
Functional - hyperpituitarism due to overproduction
Non-functional - hypopituitarism due to pressure effect

Question 10

Symptoms of pituitary adenoma

Answer 10

Headache
Vomiting
Nausea
Diplopia
Impaired vision e.g. bilateral hemianopsia

Question 11

Lack of iodine

Answer 11

Causes goitre

Thyroid enlarges to absorb the maximum concentration of iodine

Question 12

Thyroid gland structure

Answer 12

Composed of follicles with cuboidal cells containing colloid and with variable sized lumina
Fenestrations between endothelial cells allow hormone to enter bloodstream
Parafollicular/clear/C cells secrete calcitonin to decrease calcium concentration in blood

Question 13

Origin of medullary carcinoma of thyroid

Answer 13

Parafollicular/clear/C cells

Question 14

Euthyroid pathology

Answer 14

Goitre
Adenoma
Carcinoma

Question 15

Hyperthyroid pathology

Answer 15

Grave’s disease

Question 16

Hypothyroid pathology

Answer 16

Hashimoto’s disease

Question 17

Tracheomalacia

Answer 17

Softening and collapse of trachea to obstruct airways

Can occur following thyroidectomy if goitre was compressing trachea

Question 18

Grave’s disease

Answer 18

Auto-antibodies stimulate TSH receptors to cause diffuse goitre
Increased T3/T4 and decreased TSH (hyperthyroidism)
Infiltrative ophthalmopathy - accumulation of soft tissue and inflammatory cells behind eyes to cause proptosis
Infiltrative dermopathy - causes pre-tibial myxoedma (thickening and hardening of skin on anterior shin, may have oedema)

Question 19

Hashimoto’s thyroiditis

Answer 19

Autoimmune disease causing progressive destruction of the thyroid due to inflammation, tissue replaced by fibrosis
Low T3/T4, high TSH, prominent lymphatic infiltration/inflammation

Question 20

Thyroid tumours

Answer 20

Benign follicular adenoma

Papillary/follicular/medullary/anaplastic carcinomas

Question 21

Parathyroid pathology

Answer 21

Cause hypercalcaemia:
Adenoma affecting 1 gland
Hyperplasia affecting 4 glands

Question 22

Histological appearance of zona glomerulosa

Answer 22

closely packed round cells

Question 23

Histological appearance of zona reticularis

Answer 23

small dark staining cells

Question 24

Histological appearance of zona fasciculata

Answer 24

clear cells arranged in cords

Question 25

Causes of adrenocortical hyperactivity

Answer 25

``` Hyperplasia Adenoma (non-functioning may cause Cushing's syndrome or Conn's syndrome) Cancer (rare) Cushing's syndrome (excess cortisol) Conn's syndrome (excess aldosterone) Androgenital syndrome (excess androgens) ```

Question 26

Causes of adrenocortical insufficiency

Answer 26

Addison's disease

Question 27

Phaeochromocytoma

Answer 27

Tumour of adrenal medulla with increased catecholamine levels

Question 28

Causes of phaeochromocytoma

Answer 28

Treatable hypertension Tumour (MEN2, extra-adrenal, malignant, bilateral) Genetic causes: Von-Hippel Syndrome (retinal tumour), Multiple Endocrine Neoplasia type 2(MEN2 - thyroid medullary tumour), Neurofibromatosis type 1 (NF1)

Question 29

Treatment of phaeochromocytoma

Answer 29

Prescribed antihypertensive to block affects of high adrenaline and risk of dangerously high blood pressure during surgery (alpha or beta blockers given) Surgical excision of tumour

Question 30

Symptoms and signs of phaeochromocytoma

Answer 30

``` Hypertension Tachycardia Palpitations Headache Sweating Tremor Sense of apprehension ```

Question 31

Complications of high BP in phaeochromocytoma

Answer 31

Congestive cardiac failure Cerebrovascular accident Ischaemic heart disease Arrhythmia

Question 32

Cushing's syndrome vs Cushing's disease

Answer 32

Cushing's syndrome refers to the condition caused by excess cortisol in the body, regardless of the cause. When Cushing's syndrome is caused by a pituitary tumour, it is called Cushing's disease.