Endocrinology Flashcards
Where are ADH and oxytocin synthesised?
Hypothalamus
Where are ADH and oxytocin stored?
Posterior Pituitary
What stimulates glucagon?
Hypoglycemia
Epinephrine
Arginine
Alanine
Acetylcholine
Cholecystokinin
What inhibits glucagon?
Somatostatin
Insulin
Uraemia
Increased free fatty acids and keto acids into the blood
What do islet cells produce?
Alpha cells secrete glucagon
Beta cells secrete insulin
Delta cells secrete somatostatin
Gamma cells secrete pancreatic polypeptide
What inhibits TSH?
Somatostatin
(T3 is predominant inhibitor of TSH)
What hormones are produced by the medulla of the adrenals?
Epinephrine
Dopamine
Norepinephrine
What is produced by the zona glomerulosa?
Aldosterone
What is produced by the zona fasciculata?
Cortisol
What is produced by the zona reticularis?
Androgens
What is a typical FBC finding in Addison’s disease?
Eosinophillia and lymphocytosis
What hormones does somatostatin inhibit?
Insulin
Gastrin
Cholecystokinin (CCK)
Secretin
Motilin
Vasoactive intestinal peptide (VIP)
Gastric inhibitory polypeptide (GIP)
Enteroglucagon
Which dopamine agonists may be used to inhibit milk production, and which receptors do they act on?
Cabergoline + bromocriptine
Both act on D2 receptors
In what proportion of children does delayed puberty occur?
3%
What are 2 recognised galactagogues (stimulators of milk production)?
Dopamine Antagonist
1. Domperidone
2. Metoclopramide
Amount of maternal flow through the uterine artery at term?
750ml/min
Amount of flow through the uterine artery when not pregnant?
45ml/min
What are the 3 types of oestrogen?
Estrone (E1)
Estradiol (E2)
Estriol (E3)
What is the predominant oestrogen during female reproductive years?
Estradiol E2 (except in the early follicular phase when estrone predominantes)
What is the predominant oestrogen during pregnancy?
Estriol E3
Which drugs can cause an increased prolactin?
Opiates
H2 antagonists e.g. Ranitidine
SSRI’s e.g. Fluoxetine
Verapamil
Atenolol
Some antipsychotics e.g risperidone and haloperidol
Amitriptyline
Methyldopa
What are the ratios of testosterone free:albumin-bound:SHBG-bound
1% free: 19% albumin-bound: 80% SHBG-bound
Which cells are responsible for androgen production in the ovary?
Theca cells
Which cell are responsible for aromatisation of androgens into oestrogen?
Granulosa cells
Where are the juxtaglomerular cells located?
Afferent arteriole in the kidney
What is the most common cause of delayed puberty?
Constitutional delay
What is the definition of puberty in women?
Physical maturation whereby the women becomes capable of sexual reproduction
What is the lifespan of the corpus luteum?
14 days
How many hours after the LH surge does ovulation occur?
24-36 hours
Where is calcidiol produced?
Liver
During pregnancy, from where is bHG produced?
Syncytiotrophoblast
What tumour marker is used for granulosa cell tumours?
Inhibin
What are the features of hyperaldosteronism?
Hypertension
Hypokalaemia
Alkalosis
What are the causes of primary hyperaldosteronism?
- Unilateral adrenocortical adenoma - Conn’s syndrome (most commonly)
- Bilateral adrenal hyperplasia
What is the cause of secondary hyperaldosteronism?
Renal artery stenosis
What are the laboratory findings in Addison’s disease?
Hyperkalaemia
Hyponatraemia
How is Addison’s disease diagnosed?
Short ACTH stimulation test (i.e. the synacthen test)
What is the first catecholamine to be produced in the synthesis of catecholamines?
Dopamine
From what are catecholamines derived?
Tyrosine (the amino acid)
What blood finding is found in phaeochromocytoma?
Hyperglycaemia
Diagnosis of phaeochromocytoma is with 24-hour collection of urinary catecholamine - but which one?
Vanillylmandelic acid
What is an insulin antagonist?
Somatostatin
What are the physiological effects of progesterone?
- Increased respiratory drive
- Reduced bowel motility
- Increased basal body temperature
What endocrinological manifestation gives rise to the clinical manifestation of PCOS?
Elevated insulin - it is thought to be the insulin that stimulates androgen secretion
At what age is menarche considered precocious puberty?
If occurs prior to age 10
How frequently does GnRH pulse?
Every 90 minutes
What is the overall function of insulin?
Decreased gluconeogenesis
What is the function of GH?
Stimulate lipolysis
What hormones is GH structurally similar to?
Prolactin
hPL