Pathology of the Endocrine System 1 Flashcards
what is the function of the endocrine system?
Integrated network of GLANDS - secrete chemical messengers – hormones - directly into bloodstream
HORMONES act on target cells distant from site of synthesis - bind to receptors – change cell activity
REGULATION of metabolism, growth and development, tissue function
maintain functional balance
what are the kind of hormones synthesised and stored in glands?
packets of cells with secretory granules
vascular
ductless
what are the contents of the classical endocrine system?
pineal gland hypothalamus pituitary gland thyroid gland parathyroid gland adrenal gland pancreas
what is hyperplasia?
increased number and secretory activity of cells
what is atrophy
diminution of cells due to lack of stimulation
what is tissue damage?
inflammation, autoimmune disease, compression, trauma, infarction
what are the two types of neoplasia?
adenoma
carcinoma
whats the difference between adenoma and carcinoma
adenoma- functioning or non functioning
carcinoma- 1ry or metastatoc
how would you determine the cause of congenital abnormality?
morphologic findings
biochemical measurements of hormone levels, regulators and metabolites.
what is the function of synthesis, storage, release of thyroxine T4 and triiodothyronine T3?
regulated basal metabolic rate
whats the function of calcitonin?
regulates calcium homeostasis
what is the histology of thyroid gland?
Follicles
Colloid-contains thyroglobulin
Epithelial cells – TG synthesis, iodination, resorption & release of T4 and T3
C-cells – secrete calcitonin (not visible)
what is the manifestation of thyroid diseases?
Hyperthyroidism
Thyrotoxicosis*
Hypothyroidism
Myxoedema, Cretinism
Subclinical
Thyroid enlargement
Goitre
Isolated nodule/mass
what are the causes of thyroid diseases?
Thyroiditis
Autoimmune
Others
Gland destruction
Multinodular goitre
Tumours
Benign
Malignant
what are the causes of hyperthyroidism?
Diffuse toxic hyperplasia (Graves disease) – 70%
Toxic multinodular goitre – 20%
Toxic adenoma
whos more likely to get graves disease?
females
peak- 20-40 years
genetic predisposition
what happens to the histology in graves disease?
cell activity increases and cell numbers increase
what are the causes of hypothyroidism?
Hashimoto’s thyroiditis
(auto-immune destruction)
Iatrogenic – surgery drugs
Iodine deficiency
Congenital hypothyroidism
whos more likely to get hashimotos thyroiditis?
females
45-65 yrs
what is graves disease?
Autoimmune production of anti- TSH receptor antibodies
stimulate activity, growth, inhibit TSH binding
ophthalmopathy immune mediated – ocular fibroblasts have TSH receptor
what is hashimotos thyroiditis?
Autoimune destruction of thyroid epithelial cells
Cytotoxic T cells, cytokine and antibody mediated destruction
Circulating autoantibodies to
thyroglobulin ,
thyroid peroxidase
what happens to the thyroid in hashimotos thyroiditis?
Diffuse enlargement gradual failure
what is the histology of hashimotos thyroiditis?
hurthle cell change
intense infiltrate of plasma cells
lymphocytes
crowded follicles
distended colloid filled follicles
haemorrhage, fibrosis, cycstic change
what is goitre?
enlarged thyroid
what is the pathway to multinodular goitre?
iodine deficiency, goitrogens –> impaired synthesis of T3 and T4 –> increase of TSH –> hypertrophy and hyperplasia of epithelium
goes from simple to multi nodular
what is a thyroid nodule?
dominant nodule in multinodular goitre
cysts
follicular adenoma
carcinoma
how would you investigate a thyroid nodule?
TFTs, ultrasound, FNA
name some thyroid tumours
Follicular adenoma
Carcinoma (5% of nodules) Differentiated thyroid carcinoma (DTC) Papillary carcinoma 75-85% Follicular carcinoma 10-20% Anaplastic carcinoma 5% Medullary carcinoma 5% (lymphoma)
what is the most non functioning thyroid neoplasm?
follicular adenoma
give some characteristics about follicular adenomas?
Most non-functioning
Circumscribed, encapsulated tumour
Histology often small microfollicles