endocrine disorders Flashcards
endocrine action
the hormone is distributed in blood and binds to distant target cells
paracrine action
the hormone acts locally by diffusing from its source to target cells in the neighbourhood
autocrine actions
the hormone acts on the same cell that produced it
types of endocrine hormones
fat soluble - slow acting and long half life
water soluble - fast acting and short half life
pineal gland
synthesises and secretes melatonin from serotonin, that communicates info about environmental lighting to various parts of the body
posterior pituitary gland
stores and releases oxytocin and antidiuretic hormone
they are produced in the hypothalamus, transported down to posterior lobe
anterior pituitary gland
stores and releases growth hormone, thyroid stimulating hormone, adrenocorticotropic hormone, prolactin, luteinizing hormone, follicle-stimulating hormone
thymus
located in mediastinum, superior to the heart
secretes hormones that regulate development and later activation of T lymphocytes
thyroid gland
converts iodine into thyroid hormones
C cells in the thyroid produce calcitonin that reduces Ca2+, promotes Ca2+ deposition and bone formation
parathyroid glands
function is to maintain calcium and phosphate levels parathyroid hormone (PTH): increases Ca2+ calcitonin: promotes synthesis of calcitriol - increased absorption of Ca2+, reduced urinary excretion, increased bone reabsorption
adrenal medulla
makes catecholamines: adrenaline and noradrenaline
adrenal cortex
mineralcorticoids - control electrolyetes
glucocorticoids - stimulates fat and protein catabolism
sex steroids - androgens and estrogens convert testosterone and estrogen
pancreatic hormones
insulin - secreted after a meal with carbs raises glucose blood levels
functions of estadiol and progesterone
development of female reproductive system and psychique including bone growth
function of testes
development of male reproductive system and pshysique, sustains sperm production and sex drive
endocrine functions of the heart
atrial natriuretic peptide released with an increase in BP
endocrine function of skin
keratinocytes have entire vitamin D metabolic pathway
endocrine function of the liver
convert vitamin D3 to calcidiol
source of IGF
secretes erythropietin
secretes angiotensinogen
endocrine function of kidneys
converts calcidiol to calcitriol
produces EPO
convert angiotensinogen to angiotensin I
endocrine function of stomach and small intestines
coordinate digestive motility and secretion
endocrine function of placenta
secretes estrogen, progesterone and others
SIADH
syndrome of innappropriate anti-diuretic hormone
due to production of ADH like substances from tumours, lung, lymphoid and others
symptoms of SIADH
water retention relative hyponatraemia thirst dyspnoea anorexia fatigue vomiting abdo cramps
diabetes insipidus
neurogenic DI
- deficiency in secretion of ADH from posterior pituitary
nephrogenic DI
- kidney is unable to respond to ADH
hypopituitarism
lack of hormones?
symptoms of hypopituitarism
ACTH - lack of cortisol
TSH - hypothyroidism
ADH - diabetes insipidus
FSH and LH - gonadal failure, loss of secondary sex characteristics, menstrual irregularity
GH - dwarfism, normal proportions and intelligence
hyperpituitarism
primary adenomas are usually benign, slow growing tumours
hypersecretion of hormones secreted by adenoma
acreomegaly
an uncommon condition where abnormally large levels of growth hormone are secreted during adulthood
leads to increase in appositional growth but no increase in length of bones
giantism
will occur if growth adenoma presents in childhood
as the epiphyseal plates have no closed, there will be increase in length of bones as well as symptoms of acreomegaly
prolactinomas
primary tumours that secrete PL and lead to hyperprolactinaemia
symptoms include amenorrhea, galarorrhea, hirsuism, osteopenia and infertility
thyroid disorders
hyperthyroidism - graves, nodular thryoid
hypothyroidism - acute, subacute, autoimmune, congenita, thryoid carcinoma
thyrotoxicosis
greater than normal concentration of TH in blood
primary hyperthyroidism
excess sythesis of TH such as graves or multinodular goitre
secondary hyperthyroidism
tends to be from a pituitary adenoma releasing excess TSH
graves disease
autoimmune disease - lymphocytes stimulate B lymphocyte production of IgG antibodies
Ab stimualte TSH receptors to synthesise and secrete T3 and t4 and also stimulate drug therapy, radioactive iodine and surgery
nodular goitre
enlargement of gland due to increase demand of TH
increase in follicle due to increased TSH
thyrotoxic crisis
person with underlying hyperthyroidism is triggered by stress such as: infection, cardio or pulmonary disorder, obstetric complications, emotional distress
symptoms and signs of hyperthyroidism
hypermetabolism enhanced epinephrine effecy lid lag atrial fibrillation milky diarrheoa osteoporosis
hashimoto thyroiditis
autoimmune reaction to thyroid tissue, destruction of follicles, impaired TH production
symptoms of hypothyroidism
overall decrease in rate of body metabolism
myxedema coma
loss of consciousnes, hypotermia without shivering, hypotension, hypoglycaemia, hypoventilation, lactic acidosis
cretinism
TH deficiency during embryonic/neonatal life
due to adenesis or severe iodine deficiency
goitre
endemic goitre - dietary iodine deficiency, no TH, no feedback, increased TSH
diffuse toxic goitre - antibodies mimic TSH, increased TH, exophtalmos
euthyroid goitre - TH is normal
hyperparathyroidism
primary - hypercalcaemia results frm failure of normal feedback mechanism that decreases PT secretion
seconary - high PTH levels initiated by renal disease, low calcium diet, pregnancy, rickets
