Lecture 15 Endocrine system Flashcards
What links the CNS to the endocrine system?
hypothalamus
What does the posterior pituitary gland release?
Oxytocin and ADH
What does the anterior pituitary release?
Growth hormone, TSH, ACTH, FSH, LH, Prolactin
What does ACTH do?
Adreno-corticotrophic hormone (stimulates production & release of cortisol)
What causes hyperpituitarism?
Adenoma (most common an anterior lobe) (prolactinoma)
Types of pituitary adenoma?
Macrodenomas (>1cm), Microadenomas (
What syndrome can ACTH cause?
Cushing’s disease
What syndrome can growth hormone cause?
Gigantism (children) and acromegaly (adults)
What syndrome can prolactin cause?
Galactorrhea, amenorrhea, sexual gysfunction and infertility
What syndrome can TSH cause?
Hyperthyroidism
What syndrome can FSH and LH cause?
Hypogonadism, mass effects/hypopituitarism
What is hypopituitarism?
When 75% or more of the anterior pituitary parenchyma is lost
What causes hypopituitarism?
Sheehan’s syndrome (ischemic necrosis). Non-functioning adenomas, surgery/irradiation, inflam lesions.
What is the optic chasm?
Part of the brain where optic nerves (CNII) partially cross
In regards to thyroid, what does the hypothalamus release?
Thyrotropin releasing hormone (TRH) -> anterior pituitary -> TSH
What are the thyroid hormones?
T3 and T4
What do thyroid hormones do?
^metabolism, growth, development and ^ catecholamine effect (dopamine)
What causes hyperthyroidism?
Too much thyroxine (T4), De Quervain’s thyroiditis, toxic multimode goiter, graves disease.
Define goiter
enlarged thyroid gland (swollen neck)
What is Grave’s disease?
Autoimmune disease, same effect as TSH -> unregulated overproduction of thyroid hormones. (no TSH = no neg feedback)
What are the main symptoms of graves disease?
Heat intolerance, blushing, tachy, ^SBP, tremors, local oedema, diarrhea, finger clubbing, weight loss, muscle wasting.
Hyperthyroid treatment?
Carbimazole or thyroidectomy
What causes hypothyroidism?
Iodine deficiency, hashimoto’s thyroiditis
What is hashimoto’s thyroiditis?
Chronic inflam -> thyroid failure. Autoimmune.
Who is hashimoto’s thyroiditis most common to?
Women. 45-60.
Hypothyroidism treatment?
Thyroxine
What is a papillary thyroid carcinoma?
a non-functional tumour
What do the parathyroid glands do?
regulate blood calcium levels.
What are the causes of hypoparathryroidism?
Thyroidectomy, congenital, hereditary (autoimmune)
What are the symptoms of hypoparathyroidism?
Low calcium so irritability, seizures, tetany.
What causes primary hyperparathyroidism?
Adenoma
What causes secondary hyperthyroidism?
Chronic renal failure
What causes tertiary hyperthyroidism?
Post renal transplant
How do parathyroid glands increase blood Ca2+?
Ca2+ reabsorption from bones, intestines and kidneys. Vit D hydroxylation in kidneys
What are the symptoms of hypercalcemia?
Seizures, constipation, depression, polyuria, muscle wasting, bone # and kidney stones
Process of adrenal cortex being stimulated?
Hypothalamus -> CRH -> Pituitary -> ACTH -> Adrenal cortex
What are the three layers of the adrenal cortex called and function?
Zona Reticularis (sex hormones) Zona Fasciculata (Cortisol - glucocorticoids) and Zona Glomerulosa (Aldosterone - mineralocort)
What does the middle of the adrenal cortex release?
Catecholamines
adrenaline/noradrenaline
What is the middle of the adrenal cortex called?
Adrenal medulla
What causes hyperaldosteronism?
Primary - Conn’s disease in >50%
Secondary - ^renin
Symptoms of Conn’s disease
Oedema, low K+, ^ Na+ and hypertension
What does renin do?
promotes protein angiotensin production
What does angiotensin do?
^ aldosterone secretion and ^BP
When/why is cortisol release?
When stressed, ^ glucose in blood.
Why would someone get Cushing’s syndrome?
Excess release of cortisol
What causes Cushing’s syndrome?
ACTH releasing tumour and steroids.
What are the common symptoms of Cushing’s syndrome?
Moon face, baffalo hump, osteoporosis, obesity, abdominal striae, weak muscles, thin skin and skin ulcers (poor healing)
What is addison’s disease?
Adrenal insufficiency
What causes addison’s disease?
Autoimmune, infection, neoplasms.
What are the symptoms of addison’s disease?
Diarrhoea, N/V, anorexia, weight loss, low Na+ (all due to low aldosterone). Hyperpigmentation&K+
What are gonadocorticoids?
Sex hormones (testosterone, oestrogens) secreted from gonads
What does adrenaline and noradrenaline control?
HR, BP & metabolism
What is phaeochromocytoma?
tumour of adrenal gland -> ^ adrenaline and noradrenaline
Symptoms of phaeochromocytoma?
Hypertension, sweating, palpitations, nervousness, ^metabolic rate, rapid HR
What is multipleendocrine neoplasia (MEN)
Group of inherited diseases resulting in proliferative of lesions of multiple multiple endocrine organs)
