Day 7 - Endocrine, Bone, Tumors Flashcards
Define endocrine vs exocrine
Endocrine - secrete hormones directly into bloodstream
Exocrine - secrete digestive enzymes outside body
-pancreas can do both
Hormones affect specific cells called… These cells are able to respond to hormones because they have ___ for the hormones
Target cells
Receptors
Define hormone
Organic compounds produced in one tissue, released into bloodstream to affect another tissue, binding to receptor and producing a specific response
4 main chemical classes of hormones
Amino acid derivatives
Peptides, proteins
Steroids (derived from cholesterol, lipids)
Eicosanoids (derived from fatty acids)
-focus on first 3
TRH (thyroid releasing hormone) is made by the ___. Its action is to…
Hypothalamus
Stimulate pituitary to release TSH
TSH (thyroid stimulating hormone) is made by the ___. Its action is to… Its chemical class…
Pituitary (anterior)
Stimulate thyroid to secrete thyroxine (T4)
Peptide/proteins
T4 (thyroxine) and T3 (triiodothyronine) made by the ___. Their action is to… Their chemical class…
Thyroid
Increase metabolism in most tissues
Amino acid derivatives
- tyrosine derivatives
- hydrophobic, requires transporter
PTH is made by the ___. Its action is to… Its chemical class…
Parathyroids
Stimulate calcium resorption from bone (calcium release from bones)
Peptide/proteins
Catecholamines are made by the ___. Name two catecholamines made there…. Their action is to (2)… Their chemical class…
Adrenal medulla
Adrenaline
Epinephrine
-fight or flight
Increase blood pressure
Glycogenolysis in liver
Amino acid derivatives
Insulin is made by the ___, specifically, in the region called… Its action is to… Its chemical class…
Pancreas
Islets of Langerhans (beta cells)
Stimulate cells to uptake glucose
Peptide/protein
Glucagon is made by the ___, specifically, in the region called… Its action is to… Its chemical class…
Pancreas
Islets of Langerhans (alpha cells)
Stimulate liver to release glucose
Peptide/protein
ACTH (adrenocorticotropic hormone) is made by the ___. It is stimulated by… Its action is to… Its chemical class…
Pituitary (anterior)
CRH (corticotropin releasing factor)
-secreted by hypothalamus
Stimulate adrenal cortex to secrete cortisol
Peptide/protein
ADH (anti-diuretic hormone) is also called… It is made by the ___. Its action is to… Its chemical class…
Vasopressin
Hypothalamus
-stored in posterior pituitary gland
Stimulate kidneys to reabsorb/retain water, vasoconstriction
-opposite of diuretic peptides (excrete water)
Peptide/protein
Calcitonin (thyrocalcitonin) is made by the ___. Its action is to… Its chemical class…
Thyroid parafollicular cells (C cells)
Deposit calcium into bones
-opposite of PTH
Peptide/protein
Aldosterone is made by the ___. Its actions are to (3)… Its chemical class…
Adrenal cortex
Stimulate kidneys: Reabsorb sodium Reabsorb water Excrete potassium -opposite of natriuretic peptides (excrete sodium and water)
Steroid
Cortisol is made by the ___. Its action is to… Its chemical class…
Adrenal cortex
Gluconeogenesis in muscle, liver
Steroid
Name two steroids made by the adrenal cortex… Name two catecholamines made by the adrenal medulla…
Cortisol
Aldosterone
Adrenaline
Epinephrine
-neurotransmitters
-fight or flight
Peptide/protein hormones - hydrophobic or hydrophilic? Do they require a transporter molecule?
Hydrophilic
No
-water soluble
Steroid hormones - hydrophobic or hydrophilic? Do they require a transporter molecule?
Hydrophobic
Yes
- require transport proteins
- albumin, prealbumin (TBPA), TBG
Which classes of hormones require receptor binding to target cells and which classes of hormones can diffuse through the cell membrane?
Peptides/proteins
Steroids
- hydrophobic, easy to diffuse through cell membrane
- bind to cytoplasmic receptor within cell instead
-AA derivatives can be hydrophilic or hydrophobic
Do protein based hormones or steroids affect more types of cells? Why?
Steroids affect more cells
Steroids do not require receptor to bind and enter cell
-can diffuse straight through
What is ADH stimulated by?
Hyperosmolality, hypernatremia
-causes kidneys to retain water to decrease osmolality
Does aldosterone increase or decrease blood pressure? Does AHD/vasopressin increase or decrease blood pressure? Does a natriuretic peptide increase or decrease blood?
Increase
- aldosterone cause kidneys to retain sodium and water
- angiotensin II precursor cause vasoconstriction
- renin-angio system
Increase
-vasoconstriction
Decrease
- opposite of aldosterone
- vasodilation
What are tropic hormones? What are direct effector hormones?
Hormones that affect another endocrine gland
-TSH stimulates thyroid
Hormones that act directly on peripheral tissues
-T4 stimulates peripheral tissues’ metabolism
Treatment for endocrine disorders are usually (2)
Surgery
-more common
Irradiation
Growth hormone (GH or HGH) is also called… Release of growth hormone is controlled by ___, which is made in the ___
Somatotrophin
Growth hormone-releasing hormone (GHRH)
Hypothalamus
GH is stored and released from the ___. Excessive growth hormone release is called…
Pituitary (anterior)
Acromegaly
GH is usually inhibited by…
Glucose
-after eating a meal, GH levels drop
The glucose suppression test indicates whether a person has…
Tumor causing acromegaly
- glucose infusion does not inhibit GH release
- stimulation test is the opposite of this test
Some hormones are made by dimerization of subunits. When testing for hormones, why should we be careful when measuring a particular subunit?
Subunit could be nonspecific to hormone and shared across different hormones
AHD deficiency can cause these 3 conditions…
Hypothalamic diabetes insipidus - failure to produce ADH
Nephrogenic diabetes insipidus - failure of ADH to act on kidneys or failure to respond to ADH
-kidney disease, drugs, metabolic disorders
Psychogenic polydipsia - excessive water intake without thirst
What is the ADH stimulation test?
Lab test done by overnight water deprivation to induce dehydration and stimulate ADH release
-measure plasma and urine osmolality at start and end of 24 hr fast
The condition associated with primary adrenal insufficiency is… Secondary adrenal insufficiency is due to…
Addison’s disease
Low cortisol due to decreased ACTH
Addison’s disease vs Cushing’s syndrome - which hormones are elevated and decreased in each? Which electrolytes are elevated and decreased in each?
Addison’s - low cortisol, low aldosterone, low sodium, high potassium
-sodium lost in urine and potassium retained due to low aldosterone
Cushing’s - high cortisol, high sodium
Cushing’s syndrome can be ACTH dependent or independent. Explain each
ACTH dependent - pituitary tumors produce excess ACTH
ACTH independent - tumors in other locations that produce pseudo-ACTH
What is a pheochromocytoma? What test can we use to screen for it?
Benign or malignant tumor of cells in the adrenal medulla
- excess catecholamines
- hypertension, weight loss, sweating, headache, palpitations, anxiety
Urinary metanephrine test
- metanephrine = main metabolite of catecholamines produced by adrenal medulla
- false positives if patient is stressed or taking drugs
Besides the urinary metanephrine test for pheochromocytomas, this urinary excretion product can be used as an indicator of epinephrine production…
Vanillylmandelic Acid (VMA) -less sensitive, more specific
What does the clonidine suppression test for? How does clonidine affect a normal vs ill patient?
Pheochromocytoma
Clonidine (adrenergic blocker drug) given to patient:
Normal = inhibits release of catecholamines
Patient = catecholamines released due to adrenal tumor (pheochromocytoma)
3 major classes of steroid hormones made by the adrenal cortex… Which class do cortisol and aldosterone fall under?
Glucocorticoids (includes synthetics)
-type of corticosteroid
Mineralocorticoids (cortisol/aldosterone)
-type of corticosteroid
Androgens
-sex hormones, anabolic steroids