T1 L3 p2 :The Nuts and Bolts of the Endocrine System: Anatomy and Histology Roadshow Flashcards
what is endocrine
Action of the hormone on a target organ away from the secreting cell
what is autocrine
- Action of the hormone on the secreting cell
what is paracrine
Action of the hormone on the adjacent cell
Neuroendocrine
Neural stimulation of endocrine cells to secrete hormones e.g. the medulla of adrenal gland
what are the clinical manifestations of endocrine diseases
Hormone overproduction
Hormone underproduction
Tumour/mass lesion which can be:
Non-functional → pressure effect
Associated over production of hormones
What is the pituitary gland divided into
Adenohypophysis/anterior lobe
Neurohypophysis/posterior lobe
what are the cells of the anterior pituitary gland
Acidophils – take up the acidic dyes
Basophils – take up the basic dyes
Chromophobe – no specific staining features
look at slide number 10
look at it
what hormones and targets are produced by these cells pituitary gland
1) Somatotroph
2) Lactotroph
3) Corticotroph
4) Gonadotroph
5) Thydrotroph
1) Growth Hormone - Bones
2) Prolactin - Breasts
3) Adrenocorticotrophic hormone (ACTH) -Adrenal glands
4)Follicle stimulating- Ovary & testis
hormone (FSH)
Luteinising hormone Ovary & testis
(LH)
5)Thyroid stimulating
(TSH)
Thyroid gland hormone
what hormones are secreted from the posterior pituitary and what are their functions (2m)
1) Antidiuretic hormone (ADH) facilitates the absorption of water in kidneys which concentrates the urine
2) Oxytocin promotes contractions of the smooth muscle in the uterus during childbirth and myoepithelial cells in the breast during breast feeding-milk let down-milk ejection
where does pituitary gland pathology occur
the adenohypophysis
what do productive adenomas cause
hyperpituitarism
what does excess pressure cause in the pituitary gland
hypopituitarism
adenomas can be functioning or non-functioning
creating headaches vomiting and nausea
when optic chiasma is compressed by the tumour what happens
Bitemporal hemianopsia
what is the thyroid gland responsible for the synthesis off
T3- triiodothyronine
T4- thyroxine
what causes an enlargened goitre
Lack of iodine as gland enlarges to absorb the max conc of iodine
what do the follicles of the thyroid contain
Colloid - has eosinophilic (pink ) appearance
where are Para-follicular cells-C cells found
they are found between follicles
what do C cells secrete
Calcitonin which promotes reduction of calcium concentration in the blood
what tests verify hyperthyroidism
elevated T4 and T3 level and a decreased TSH level
what tests verify a hypothyroidism
elevated TSH level and a decreased T3 and T4 level
What does Goitre have
euthyroid
Graves disease is
Hyperthyroid
Hashimoto’s disease is
Hypothyroid
Adenoma and cancer is
Euthyroid
describe the process of forming a multi-nodular goitre
Lack of iodine leads to an enlarged thyroid gland termed goitre due to hyperplasia and hypertrophy of the thyroid cells
The gland enlarges to maximise amount of iodine absorbed
The increase in size overcomes the hormone deficiency and the patients are euthyroid
what is a secondary effect of a successful thyroidectomy and why
Tracheomalacia - due to compression of the airways
Graves disease
(what causes it and what are the 2 effects in different organs)
(5m)
Auto-antibodies stimulate TSH receptors
Diffuse enlargement of the thyroid gland – goitre due to hyperplasia of thyroid cells
Infiltrative opthalmopathy – accumulation of soft tissue and inflammatory cells behind the eye leading to proptosis
Infiltrative dermopathy – thickening and induration of the skin on the anterior shin→ pre-tibial myxoedema
what is Hashimoto’s thyroiditis
It’s the most common cause of hyporthyroidism in an area where iodine is readily available
An autoimmune disease
characterised by high TSH and low T3/T4
what white cell infiltrates when hashimotos disease is prominent
Lymphocytes
what cells have tumurs in the thyroid gland
Follicular cells- creating follicular adenomas
what are the 4 main types of carcinomas
Papillary ( 75-85%); ↑ risk of lymph node metastasis
Follicular (10-20%); ↑ Mets to bone, lung and liver
Medullary (5%); arises from C cells ; 20% ass with MEN 2 syndrome (multiple endocrine neoplasm)
Anaplastic (<5%); older patients; poor prognosis
what is the function of para-follicular cells
C cells secrete calcitonin which promotes reduction of calcium concentration in the blood
Para-follicular cells or clear cells (C cells) are found between the follicles
C cells are the origin of medullary carcinoma of the thyroid
what are parathyroid glands
they secrete parathyroid hormones -PTH
they control the levels of calcium in the blood
low ca stims PTH secretion
Chief cells with no lumen
what pathology involves one parathyroid one gland
Adenoma
what pathology involves all 4 glands
Hyperplasia
which pathologies cause hypercalcaemia
Adenomas and hyperplasia
what are the 3 zones of the adrenal gland
Glomerulosa
fasciculata
reticularis
what does the glomerulosa produce
- Mineralocorticoid
- Aldosterone
- For absorption of sodium
what does the fasciculata
- Glucocorticoids
- Cortisol & corticosterone
- Sex hormones
Zona reticularis
- 17 Ketosteroids
- Sex hormones
What pathologies increase adrenocortical hyperactivity
Due to hyperplasia, adenoma or cancer (rare)
Cushing’s Syndrome ( excess cortisol)
Conn’s Syndrome ( excess aldosterone)
Adrenogenital syndrome ( excess androgens)
what pathologies increases adrenocortical insufficiency
Addison’s disease
What is adrenal cortex adenoma
Non-functional cortical adenoma
Incidental finding on abdominal imaging
Functional adenomas can cause Cushing’s Syndrome or Conn’s Syndrome
Adrenal Medulla
Compact cells which secrete adrenaline and noradrenaline in response to intense emotional reaction (such as exams!)
Flight or fight hormones
Secretion results in vasoconstriction,
↑heart rate, blood sugar levels
→ Part of the organism’s defence to stress
Phaechromocytoma
Tumour of the adrenal medulla 0.1-0.3% cause of treatable hypertension 10% Tumour 10% are familial as part of the MEN2 10% are extra-adrenal 10% bilateral 10% are malignant 10% arise in childhood
what are the signs for Phaecromocytoma
Due to high levels of catecholamines
Precipitous↑ BP + tachycardia, palpitations, headache, sweating, tremor & sense of apprehension
Complications of ↑ BP
CCF, IHD, cardiac arrhythmias, CVA
what are the features of multi-nodular goitre
- compression of the trachea
- softening of the trachea leading to collapse- tracheomalacia
