S3 Endocrine Tissue Flashcards
What does the anterior pituitary gland secrete?
TSH, ACTH (adrenocorticotropic hormone), FSH, LH, GH (growth hormone), prolactin, MSH (melanocyte-stimulating hormone)
What does the posterior pituitary gland secrete?
ADH, vasopressin, oxytocin
Where is the pituitary gland located?
Base of the brain
Where is the thyroid gland located?
Anterior to the trachea
What does the thyroid gland secrete?
T4 (thyroxine) and T3 (triodothyroinine)
Where is the parathyroid gland located?
Lies on the dorsal surface of the thyroid gland (4 glands, 2 pairs)
What does the parathyroid hormone secrete?
Parathormone/parathyroid hormone (PTH)
Where are adrenal glands located?
Top of each kidney (made up of 2 sections - medulla and cortex)
What do adrenal glands secrete?
Cortex - corticosteroids (glucosteroids and mineralcorticoids), androgen, oestrogen and progestin
Medulla - adrenaline and noradrenaline
Where is the pancreas located?
Left of and behind the stomach
What does the pancreas secrete?
It has exocrine and endocrine glands
Exocrine - digestive enzymes into duodenum
Endocrine - insulin secreted by beta cells, glucagon secreted by alpha cells (of islets of Langerhans - cell clusters)
What hormone does the heart secrete?
ANP (atrial natriuretic factors)
What does the stomach secrete?
Gastrin, ghrelin, lepton, somatostatin and secretin
What does the liver secrete?
Insulin-like growth factor, angiotensinogen, angiotensin, THROMBOPOIETIN
What does the duodenum secrete?
Secretin and cholecystokinin
What does the kidney secrete?
Renin, ERYTHROPOIETIN, calcitriol and THROMBOPOIETIN
What are the two types if amino-acid derived hormones?
- Catecholamines
2. Thyroid hormones
What are the four types of hormones?
- Peptide hormones (glycoproteins)
- Steroid hormones
- Catecholamines
- Thyroid hormones
What does the hypothalamus produce?
- vasopressin (ADH) and oxytocin - travel to posterior pituitary through nerves (neurocrine)
- produces 6 hormones that travel via the hypothalamo- hypophyseal portal system (blood) to the anterior pituitary
What does the hypothalamus control (6 items)?
- Thermoregulation
- Heart rate and blood pressure
- Feeding
- Circadian rhythms
- Emotion
- Lactation
What is another name for the pituitary gland?
Hypophysis
What is a portal system?
Blood from first set of capillaries collects in a portal vessel (portal vein) which branches again to supply a capillary network in a second location, before entering a series of beings which will lead to the heart
What are the locations of the two portal systems in humans?
- Hypothalamo-hypophyseal (hypothalamus to anterior pituitary)
- Small intestine to liver
What are all pituitary hormones subject to?
Constitutive and regulated merocrine secretion - so always a small concentration of these hormones in the blood
What are the TSH, T3 and T4 levels in hyperthyroidism (Grave’s disease)?
TSH - low
T3 - high
T4 - normal to high
What are the TSH, T3 and T4 levels in hypothyroidism (Hashimoto’s disease)?
TSH - high
T3 - low
T4 - normal to low
What are parafollicular cells? What do they produce? What is their role?
Neuroendocrine cells found in the thyroid
Produce calcitonin (peptide hormone)
Monitor plasma Ca2+ concentrations and decrease levels of Ca2+ (opposite of PTH) - inhibit osteoclast activity and inhibit renal Ca2+ and (PO4)3- reabsorption in tubular cells (more calcium and phosphate secreted)
What are the roles of the parathyroid gland?
Monitor plasma calcium concentrations - if low Ca2+, make PTH
Negative feedback loop, when Ca2+ concentration reaches a set point, parathyroid glands stop making PTH
What does PTH do?
It causes bones to release calcium into the blood and absorb more from the GI tract
What is parathyroid disease?
Over-production of PTH from a parathyroid tumour which leads to high plasma calcium concentrations.
Causes symptoms of the brain, muscles and bones.
Which adrenal gland is bigger, the left or right?
Right
What makes up the medulla?
Chromaffin cells (modified neurons)
And myelinated presynaptic sympathetic nerve fibres
What happens when a nerve impulse reaches the chromaffin cells?
Release adrenaline and noradrenaline
What are two examples of catecholamines?
Adrenaline and noradrenaline
What are the 3 layers of the adrenal cortex?
- Zona glomerulosa
- Zona fasciciulata
- Zona reticularis
What hormone does the zona glomerulosa secrete?
Aldosterone - regulates BP
What hormones does the zona fasciculata secrete?
Glucocorticoids (cortisone/cortisol) - mobilise fats, proteins and carbs
What hormones does the zona reticularis secrete?
Androgen precursors (androstenedione, DHEA, etc)
What is stress defined as?
A state of real or perceived threat to homeostasis
What is a stress response?
Maintenance of homeostasis through the activation of the endocrine, nervous and immune systems by stimuli
What are chromaffin cells considered the equivalent of?
Postsynaptic neurones
What do mineralcorticoids do?
- Involved in the retention of sodium and water by the kidneys
- Increase the blood volume and blood pressure
What type of granules are found in the pancreas?
Zymogen granules
How is the pancreas connected?
Through intercalated ducts to the pancreatic duct which joins with the bile duct to make the common bile duct
What cells line the intercalated ducts of the pancreas?
Cuboidal epithelial cells
What hormone is secreted from delta cells in the islets of Langerhans?
Somatostatin
What do the exocrine glands of the pancreas secrete?
- trypsinogen (—> trypsin)
- chymotrypsinogen (—> chymotrypsin)
- lipase
- amylase
- ribonuclease and deoxyribonuclease
- gelatinase
- elastase
What do the endocrine glands of the pancreas secrete?
- glucagon (alpha cells)
- insulin (beta cells)
- somatostatin (delta cells)
- pancreatic polypeptide (PP cells)
- secretin (EC cells)
- ghrelin (E cells)
- gastrin (G cells)
What structure are the exocrine glands in the pancreas?
Acinar
