hormones Flashcards
functions of cortisol
Cortisol has numerous actions and is essential for life
Increases blood pressure: permits normal response to angiotensin II and catecholamines byup-regulating alpha-1 receptors on arterioles
Inhibits bone formation: decreases osteoblasts, decreases type 1 collagen, decreases absorption of calcium from the gut, increases osteoclastic activity
Increases insulin resistance
Metabolism: increases gluconeogenesis, lipolysis and proteolysis
Inhibits inflammatory and immune responses
Maintains function of skeletal and cardiac muscle
The water deprivation test is designed to help evaluate patients who have
polydipsia - given to excessive thirst
method of a water deprivation test
prevent patient drinking water
ask the patient to empty their bladder
hourly urine and plasma osmolalities
A 3-month-old boy is suspected of having hypospadias. At which of the following locations is the urethral opening most frequently located in boys suffering from the condition?
The defect is located ventrally and most often distally. Proximally located urethral openings are well recognised. Circumcision may compromise reconstruction.
prolactin function
simulates breast development
stimulates milk production
blocks action of LH on testes or ovaries
secretion is under constant inhibition by dopamine
too much aldosterone effect
Usually, aldosterone balances sodium and potassium in your blood. But too much of this hormone can cause you to lose potassium and retain sodium.
Primary hyperaldosteronism was previously thought to be most commonly caused by an adrenal adenoma, termed Conn’s syndrome. However, recent studies have shown that bilateral idiopathic adrenal hyperplasia is the cause in up to 70% of cases. Differentiating between the two is important as this determines treatment. Adrenal carcinoma is an extremely rare cause of primary hyperaldosteronism.
features
hypertension
hypokalaemia
hypernataumia
muscle weakness in exam questions due to potassium
alkalosis
managament
drenal adenoma: surgery
bilateral adrenocortical hyperplasia: aldosterone antagonist e.g. spironolactone
in stress or surgery what hormones are reduced
insulin , testosterone and oestrogen and thyroxine sometimes
what hormone plays a key role in the regulation of body weight and is produced by adipose tissue acting on the satiety centres.
Leptin is thought to play a key role in the regulation of body weight. It is produced by adipose tissue and acts on satiety centres in the hypothalamus and decreases appetite. More adipose tissue (e.g. in obesity) results in high leptin levels.
leptin stimulates the release of what other hormones
and low levels of leptin stimulate the release of what
Leptin stimulates the release of melanocyte-stimulating hormone (MSH) and corticotrophin-releasing hormone (CRH). Low levels of leptin stimulates the release of neuropeptide Y (NPY)
as we know leptin induces satiety but what hormone stimulated hunger
ghrelin
ghrelin is produced by which cells
It is produced mainly by the P/D1 cells lining the fundus of the stomach and epsilon cells of the pancreas
when do gherlin levels decrease and increase
Ghrelin levels increase before meals and decrease after meals
GH released by what and released in what kind of manner
Growth hormone (GH) is an anabolic hormone secreted by the somatotroph cells of the anterior lobe of the pituitary gland. It has actions on multiple organ systems and is important in postnatal growth and development. Growth hormone is also responsible for changes in protein, lipid, and carbohydrate metabolism
what enzyme does PTH act on
PTH increases the activity of 1-α-hydroxylase enzyme, which converts 25-hydroxycholecalciferol to 1,25-dihydroxycholecalciferol, the active form of vitamin D.
Osteoclasts do not have a PTH receptor and effects are mediated via osteoblasts.
PTH secreted by what cells
chief cells
3 effects of pth on bone , kidneys and intestine
Effects of PTH
Bone
Binds to osteoblasts which signal to osteoclasts to cause resorption of bone and release calcium.
Kidney
Active reabsorption of calcium and magnesium from the distal convoluted tubule. Decreases reabsorption of phosphate.
Intestine via kidney
Increases intestinal calcium absorption by increasing activated vitamin D. Activated vitamin D increases calcium absorption.
A 50-year-old man comes into your clinic with numbness and paraesthesia felt in his right thumb and index finger. His hands appear to be quite large and you notice wide spaces in between his teeth. Which hormone is most likely to be raised?
GH
Jaw prominence (prognathism), spade like hands and tall stature are all signs that would be seen in growth hormone excess. Patients may complain that their hats or shoes no longer fit, as well as joint pain, headaches and visual problems. Note that excess growth hormone secretion before growth plate fusion results in gigantism, whilst excess secretion after growth plate fusion results in acromegaly.
Antidiuretic hormone (ADH) is secreted from the posterior pituitary gland. It promotes water reabsorption in the collecting ducts of the kidneys by the insertion of
aquaporin-2 channels
dibetes insidious characterised by defiecney of ADH or insensitivity to it
Diabetes insipidus (DI) is a condition characterised by either a deficiency of antidiuretic hormone, ADH, (cranial DI) or an insensitivity to antidiuretic hormone (nephrogenic DI) Cranial DI can be treated by desmopressin, an analog of ADH
what hormones decrease and increase appetite respectively
gherlin increases and leptin decreases
thyroxin also increases
what hormone known as the growth inhabiting hormone is produced in the pancreas by delta cells ( pylorus and duodenum ) and inhibits the secretion of insulin and glucagon
somatostatin
Glucagon increases the secretion of somatostatin via the feedback mechanism, while insulin decreases its secretion. Somatostatin also controls the emptying of the stomach and bowel.
Decreases acid and pepsin secretion, decreases gastrin secretion, decreases pancreatic enzyme secretion
Inhibits trophic effects of gastrin
Stimulates gastric mucous production
what does somatostatin regulate
Increases secretion
fat, bile salts and glucose in the intestinal lumen
glucagon
Decreases secretion
insulin
what can use to manage acromegaly and why
Somatostatin analogs are used in the management of acromegaly, as they inhibit growth hormone secretion
GH is somatotropin which make up 50% of the anterior pituitary what are some example of gonadotrophs
FSH and LH
Prolactin release is persistently inhibited by
dopamine and dopaminergic agonists
Prolactin release is upregulated by what two hormones
what drug increases its secretion
thyrotropin-releasing hormone and oestrogen
pregnancy
breastfeeding
sleep
stress
drugs e.g. metoclopramide, antipsychotics
Prolactin has an inhibitory effect on
gonadotropin-releasing hormone and luteinising hormone.
what is the function of prolactin
Stimulates breast development (both initially and further hyperplasia during pregnancy)
Stimulates milk production
It decreases GnRH pulsatility at the hypothalamic level and to a lesser extent, blocks the action of LH on the ovary or testis.
what do antipsychotics block
Risperidone is an atypical antipsychotic. Antipsychotics all block dopamine activity to various degrees.
what condition is indicative of a lack of ADH
Diabetes insipidus (DI) is a condition characterised by either a deficiency of antidiuretic hormone, ADH, (cranial DI) or an insensitivity to antidiuretic hormone (nephrogenic DI) Cranial DI can be treated by desmopressin, an analog of ADH
Where does parathyroid hormone act in the kidney to increase calcium reabsorption?
DCT
functions of glucagon
Glycogenolysis
Gluconeogenesis
Lipolysis
what does insulin do to potassium
Insulin decreases serum potassium through stimulation of the Na+/K+ ATPase pump
Important for meLess important
when is growth hormone stopped in the body
it isn’t In fully grown adults, adequate growth hormone levels are still required for maintenance of tissues
what hormone increases the volume of pancreatic secretions
Cholecystokinin will often increase the volume of pancreatic secretions.
A 38-year old male presents to the GP with nipple discharge. On investigation his serum prolactin is markedly elevated. Apart from prolactin releasing hormone which other hypothalamic hormone can increase the secretion of prolactin?
TRH
