Endocrinology Flashcards
What will you cause if you prescribe your patient too much hydrocortisone?
Cushing’s syndrome
Which layer of the adrenal cortex synthesises aldosterone?
Glomerulosa
Which half of the pituitary has a vascular link to the hypothalamus?
Anterior
What class of drug is propylthiouracil?
Thioamine
Which hormone mediates the effects of growth hormone?
IGFs
What is another name for somatotropin?
Growth hormone
Which half of the pituitary is the neurohypophysis?
Posterior
Where is oxytocin synthesised?
Hypothalamus
Where is ADH synthesised?
Hypothalamus
Which hypothalamic nuclei send axons to the posterior pituitary?
Supraoptic and paraventricular nuclei
Which hormone inhibits prolactin release?
Dopamine
What causes acromegaly?
Overproduction of growth hormone during adulthood
What effect does T3 have on basal metabolic rate?
Increases
What do the results of a dexamethasone suppression test typically show in someone with Cushing syndrome?
Dexamethasone fails to suppress cortisol levels
Give a 4 word definition of Hashimoto’s thyroiditis
Autoimmune destruction of thyroid
What happens to TSH levels in Hashimoto’s thyroiditis?
Increased
What is the gross pathology of the thyroid gland in Grave’s disease
Diffuse symmetrical enlargement
What type of hypersensitivity is Grave’s disease?
Type 2 = antibody mediated
What effects does cortisol have on carbohydrate metabolism?
Increases gluconeogenesis and increases serum glucose levels
Which cells secrete testosterone?
Leydig cells of testis
What does leuprorelin inhibit?
FSH and LH release
Give a 1-word definition of Cushing’s syndrome
Hypercortisolism
What is pheochromocytoma?
Tumour of adrenal medulla causing hypersecretion of catecholamines
Which cells does cortisol act on?
Nearly every cell in the body
What causes cretinism?
Insufficient maternal iodine during pregnancy
What effect does long term treatment with cortisol have on ACTH?
Decreases it
What is another name for somatomedins?
IGFs
What is the autoimmune condition in which stimulatory autoantibodies cause increased secretion of thyroxine?
Grave’s disease
Which hormones are released from the posterior pituitary?
ADH and oxytocin
Which gland releases insulin like growth factor?
Liver
What effect does T3 have on the sympathetic nervous system?
Sympathomimetic
If someone is hot all the time, what is their likely thyroid state?
Hyperthyroid
Where is the only place in the body that adrenaline is synthesised?
Adrenal medulla
What happens to TRH levels in Grave’s disease?
Decreased
What happens to TSH levels in secondary hypothyroidism?
Decreases because of pituitary or hypothalamic damage
What happens to TSH levels in primary hyperthyroidism?
Decreased
How are thyroid hormones transported in the blood?
Bound to thyroid binding globulins (TBG)
Which organs primarily make oestrogen and progesterone?
Ovaries and placenta
What is the active ingredient in betadine?
Iodine
Which classes of hormones are lipophilic?
Steroids and thyroid hormones
Aldosterone increases excretion of which ion?
Potassium
Which amino acid are amine hormones derived from?
Tyrosine
Which inflammatory enzymes do glucocorticosteroids suppress the synthesis of?
PLA-2, iNOS and COX-2
What effect does cortisol have on the immune system?
Supresses it
Which hormone inhibits release of growth hormone?
Somatostatin
Name 3 visual signs on the body (not face) of someone with Cushing’s syndrome
Striae (stretch marks). Fat pads behind neck. Abdominal adiposity.
What are three complications of treatment with thioamines?
Goitre, hepatotoxicity and agranulocytosis
What is the RDI for iodine?
150 ug
When do cortisol levels peak?
Morning
Which hormones does the adrenal medulla release?
Adrenaline and noradrenaline
What causes gigantism?
Overproduction of growth hormone before puberty
Which class of drugs can be used to treat hyperthyroidism?
Thioamines
What are the 2 gonadotropins?
LH and FSH
Which foods are particularly naturally rich in iodine?
Sea fish, crustaceans and kelp
How is Hashimoto’s thyroiditis managed?
Thyroxine
Give a 4-word definition of Cushing’s disease
Pituitary adenoma causing hypercortisolism
Which thyroid hormone is released in greater amounts?
T4
What happens to TSH levels in primary hypothyroidism?
Increases
Which hormone stimulates release of ACTH?
Corticotropin releasing hormone
Which hormones are decreased in Addison’s disease?
Aldosterone and cortisol
Which hormone does growth hormone stimulate?
Insulin like growth factor 1 (IGF-1)
Which challenge test can be used for assessing adrenal gland function?
Dexamethasone suppression test
What effect does aldosterone have on sodium?
Increases sodium reabsorption
What effect will aldosterone deficiency have on potassium?
Increase in plasma [K+]
What will happen if you have too much iodine?
Goitre
List 4 main functions of glucocorticoids
Stimulate gluconeogenesis in liver. Mobilise amino acids from muscle. Stimulate lipolysis from adipose tissue. Immunosupression
Which organ does prolactin act on?
Breast
What is the pathway for thyroxine release?
TRH => TSH => T4
What may be the result of severe lack of maternal iodine during pregnancy?
Cretinism
What is cortisone?
A metabolite of cortisol that is almost biologically inactive
What is hydrocortisone?
Cortisol
Which hormones can increase the release of growth hormone?
Ghrelin and growth hormone release hormone
What happens to TSH levels in Grave’s disease?
Decreased
What connects the pituitary to the hypothalamus?
Infundibulum
Which layer of the adrenal cortex produces sex steroids?
Reticularis
What happens to T4 levels in Grave’s disease?
Elevated
Which hormone is used in the home pregnancy test?
human chorionic gonadotropin (hCG
Why don’t we often do thyroid biopsies?
It is very vascular => risk of bleed
Which hormone stimulates prolactin release?
PRF = prolactin releasing factor
What is suggested by the presence of anti-thyroid peroxidase antibodies?
Hashimoto’s thyroiditis
If someone is cold intolerant, what is their likely thyroid state?
Hypothyroid
Which antibodies are generated in Hashimoto’s thyroiditis?
Anti-thyroglobulin and anti-thyroid peroxidase
In which condition is there autoimmune destruction of the adrenal cortex?
Addison’s disease
Which cells of the adrenal medulla secrete catecholamines?
Chromaffin cells
What is the most common cause of hyperthyroidism?
Grave’s disease
Which enzyme iodinates thyroglobulin?
Thyroid peroxidase
Which half of the pituitary is the adenohypophysis?
Anterior
What is the autoimmune condition in which the thyroid gland is attacked?
Hashimoto’s thyroiditis
What is endogenous hydrocortisone called?
Cortisol
What do we call cortisol when it is given as a drug?
Hydrocortisone
Which hormone causes epiphyseal plates to close?
Oestrogen
Which layer of the adrenal cortex synthesises cortisol?
Fasciculata
What is the most active endogenous glucocorticoid?
Cortisol
Give a 3 word definition of goitre
Enlarged thyroid gland
Where in the body is hydrocortisone synthesised?
Nowhere - hydrocortisone is a drug so it’s probably made in Germany
What are the 6 hormones released from the anterior pituitary?
TSH, LH, FSH, prolactin, growth hormone, ACTH
How is iodine taken up into thyroid cells from the bloodstream?
Sodium iodine symport
What are the 3 layers of the adrenal cortex from superficial to deep?
GFR Glomerulosa Fasciculata. Reticularis
What is the pathway for cortisol release?
CRH => ACTH => cortisol
Where is thyroid stimulating hormone synthesised?
Anterior pituitary
Which protein is iodinated to synthesise T3 and T4?
Thyroglobulin
What’s the most common cause of goitre?
Iodine deficiency
Where is thyroid releasing hormone synthesised?
Hypothalamus
What is the half life of cortisol?
60-90 mins
Which reaction does HMG-coA reductase catalyse?
HMG-CoA => Melavonic acid + CoA
What effect does prolonged hypercortisolism have on blood pressure?
Raises it
Where are anterior pituitary hormones synthesised?
In the anterior pituitary
What does prolactin stimulate?
Milk production
Give a 4 word definition of Grave’s thyroiditis
Autoimmune stimulation of thyroid
What is the half life of thyroxine?
7 days
Which cells of which organ secrete calcitonin?
Parafollicular (or C cells) of thyroid gland
What type of cells are in the anterior pituitary?
Glandular epithelium
What are thioamines used to treat?
Hyperthyroidism
How many carbons are there in cholesterol?
27
Which half of the pituitary has a neural link to the hypothalamus?
Posterior
What is the most abundant steroid in the body?
Cholesterol
Which receptor is the target of the autoimmune antibodies in Grave’s disease?
Thyroid stimulating hormone receptor
Which hormone controls basal metabolic rate?
Thyroid hormones
Which hormones does gonadotropin releasing hormone stimulate?
LH and FSH
What are the two main functions of oxytocin?
Milk ejection from breast and uterine contractions during labour
In which bone does the pituitary sit?
Sphenoid bone
What type of cells are in the posterior pituitary?
Neural
What happens to follicular cells in Grave’s disease?
Hypertrophy and hyperplasia
Name 3 visual signs in the face of someone with Cushing’s syndrome
Red cheeks, acne and moon face
What are the 3 histological features of Hashimoto’s thyroiditis?
1 Mononuclear inflammatory infiltrate 2 Abundant eosinophilic, granular cytoplasm in follicular cells 3 Intersititial fibrosis
Define myxoedema
Hypothyroidism causes mucopolysaccharide depositions, resulting in puffiness around eyes, chin, pretibial and exophthalmos
POMC is cleaved to yield what?
ACTH and beta endorphin
What does thyroid stimulating immunoglobulin target?
TSH receptor
What happens to TSH levels in iodine insufficiency?
Increases
What effect does aldosterone have on potassium?
Increases potassium excretion
What is the most potent synthetic glucocorticoid?
Dexamethasone
What do we call it when someone has too much cortisol?
Cushing’s syndrome
What happens to plasma [glucose] in Cushing’s syndrome?
Elevated
Which hormones does the adrenal cortex release?
Aldosterone, cortisol and androgens
What is the gold standard for diagnosing diabetes?
Glucose tolerance test
Which organ makes testosterone?
Testes
Aldosterone increases reabsorption of which ion?
Sodium
Which drug is used to treat hypothyroidism?
Thyroxine
Which half of the pituitary is linked to the hypothalamus via a capillary bed?
Anterior
Which thyroid hormone is more active?
T3
Give a 2-word definition of Conn’s syndrome
Primary hyperaldosteronism
Where is prolactin released from?
Anterior pituitary
What class of drug is carbimazole?
Thioamine
Where is cortisol converted into cortisone?
kidney
Where is cortisone converted into cortisol?
Liver
Which drug would be used to replace missing aldosterone?
Fludrocortisone
Where would you find a phaeochromocytoma?
Adrenal medulla
What type of epithelium normally lines the thyroid follicles?
simple cuboidal
What is the colour of the cut surface of the normal thyroid gland?
Pale brownish red due to its iodine content and high vascularity
Follicles or Hürthle are typically seen in which condition?
Hashimoto’s thyroiditis
