phgy 216 mod. 1
what are the 6 major functions of the endocrine system?
1. growth 2. reproduction 3. RBC production 4. adaptive stress response 5. maintain internal environment 6. regulate circulation and digestive systems
what are the 2 types of hormones?
hydrophilic & lipophilic
between hydrophilic and lipophilic hormones, which requires a carrier hormone to transport it?
lipophilic
are peptide hormones hyrophilic or lipophilic?
hyrophilic
the two major types of hydrophilic hormones are peptide hormones and amines. what are the two types of amine hormones?
catecholamines (norepinephrine & epinephrine) & thyroid hormones (not hydrophilic)
name 2 types of lipophilic hormones
amine thyroid hormones and steroid hormones
what are the steps of synthesis of peptide hormones? (4 steps)
in doc
what is the molecule that synthesizes all steroid hormones?
cholesterol
what is the name of the organ that creates cortisol? (it is the only organ that can do this)
adrenal cortex
sort: thyroid hormones, steroid hormones, peptide hormones, & catecholamines - which are dissolved in plasma, bound to carrier molecules or proteins, or both.
dissolved in plasma: peptide hormones.
bound to carrier molecules or proteins: thyroid hormones, steroid hormones.
both: catecholamines.
true or false: lipohilic hormones must be unbound fromm their carrier protein to act on a target cel.
true
where on the cell are the receptors for peptide hormones and catecholamines located? why?
on the outer surface of the plasma membrane bc they can't cross the lipid bilayer
true or false: steroid and thyroid hormones can pass through the plasma membrane on cells and bind to receptors on the inside.
true
what happens after a hormone binds to its receptor?
in doc
what are the 6 steps involved in lipophilic hormones regulating protein synthesis?
in doc
what are the 2 lobes of pituitary gland? what type of tissues are in each?
posterior pituitary gland (neurohypophysis tissues) & anterior pituitary gland (adenohypophysis tissues -->epithelial)
name the area of the brain that controls the release of hormones from pituitary gland
hypothalamus
name the 2 nuclei in the hypothalamus from which axons travel and terminate on the blood vessels of the posterior pituitary gland?
supraoptic nucleus & paraventricular nucleus
name the vascular link that connects the hypothalamus to the anterior pituitary gland
hypothalamic-hypophyseal portal system (HHPS)
name two hormones released from the posterior pituitary gland
vasopressin (ADH) & oxytocin
name the 2 major functions of vasopressin
1) enhancing the retention of water by the kidneys. 2)contracts arteriolar smooth muscle.
name the 2 major functions of oxytocin
1)stimulates contraction of uterine smooth muscle cells during childbirth. 2) promotes milk ejection during breastfeeding.
name the 6 hormones synthesized by the anterior pituitary gland (hint: they're all peptide hormones)
1. GH (growth hormone) 2. ACTH (adrenocorticotropin hormone) 3. LH (luteinizing hormone) 4. TSH (thyroid-stimulating hormone) 5. FSH (follicle-stimulating hormone) 6.PRL (prolactin)
what are tropic hormones?
hormones that stimulate other glands to release their hormones
which hormone (of the 6) of the anterior pituitary gland is responsible for ovulation and formation of the corpus luteum, as well as stimulates the secretion of estrogen and progesterone from the ovaries in females?
LH (luteinizing hormone)
which hormone (of the 6) of the anterior pituitary gland stimulates the release of testosterone from the interstitial cells of Leydig in males?
LH (luteinizing hormone)
which hormone (of the 6) of the anterior pituitary gland stimulates growth and development of ovarian follicles and promotes secretion of estrogen in females?
FSH (follicle-stimulating hormone)
which hormone (of the 6) of the anterior pituitary gland is required for sperm production in males?
FSH (follicle-stimulating hormone)
name the only anterior pituitary gland hormone that is not tropic (hint: it enhances breast development & milk production in females)
prolactin
describe the process of the hypothalamic-hypophyseal portal system
in doc
name the 7 hypothalamic hormones
1. TRH (Thyrotropin-Releasing Hormone) 2. GnRH (Gonadotropin-Releasing Hormone) 3. GHIH (Growth Hormone Inhibiting Hormone) 4. CRH (Corticotropin-Releasing Hormone) 5. GHRH (Growth Hormone Releasing Hormone) 6. PRH (Prolactin-Releasing Hormone) 7. PIH (Prolactin-Inhibiting Hormone)
TRH (thyrotropin-releasing hormone) stimulates the release of?
TSH (thyroid-stimulating hormone) and prolactin
GnRH (gonadotropin-releasing hormone) stimulates the relase of?
FSH (follicle-stimulating hormone) and LH (luteinizing hormone)
GHIH (growth-hormone inhibiting hormone) inhibits the release of?
growth hormone and TSH (thyroid-stimulating hormone)
CRH (corticotropin-releasing hormone) stimulates the release of?
ACTH (adrenocorticotropic hormone)
GHRH (growth-hormone releasing) stimulates the release of?
growth hormone
PRH (prolactin-releasing hormone) stimulates the release of?
prolactin
PIH (prolocatin inhibiting hormone) inhibits the release of?
prolactin
fmk: hypothalamic neurons receive inputs that are both...
neuronal and hormonal
sections of the hypothalamus can access samples of blood due to lack of a?
blood-brain barrier
fmk: general chain of command - from hypothalamic hormone to endocrine gland
hypothalamic hormone is released to the portal system --> it travels to the pituiatry gland to regulate the output of a tropic hormone --> tropic hormone is transported to target endocrine gland thru circulation --> tropic hormmone regulates secretion of the third hormone producing a physiological effect
what is the name of the section that separates the 2 lobes of the thyroid gland?
isthmus
what is the name of the cells arranged into hollow spheres in the thyroid gland?
follicular cells
where are C cells found and what do they secrete?
thyroid gland. secretes calcitonin
the spaces within the follicular cells of the thyroid gland are filled with colloid. what protein is colloid made of? what is the function of the colloid?
thyroglobulin. the colloid makes and stores thyroid hormones.
name the 2 thyroid hormones and the unique substance they contain
T3 and T4 - both contain iodine.
how many iodine molecules are in T3 and T4 respectively? and which respresents 90% of thyroid hormones secreted and which represents 10%?
T3 - 3 iodine molecules, 10%. T4 - 4 iodine molecules, 90%.
how much iodine a week is needed for the body to ensure a sufficient levels of thyroid hormone?
1 mg per week
although most lipophilic hormones are released upon secretion which type is not but instead stored bound to thyroglobulin in colloid?
thyroid hormones (colloid in thyroid gland)
what are the 5 step of thyroid hormone synthesis?
in doc
what are the 3 steps for the release of thyroid hormones?
in doc
describe a few of the actions/functions of thyroid hormones
in doc
complete: the hypothalamus secretes thyrotropin-releasing hormone (TRH) which acts on the anterior pituitary to secrete _____?
thyroid-stimulating hormone (TSH)
what is the hormone that causes a shrinking of the thyroid gland in its absence and enlarging in its excess?
TSH (thyroid stimulating hormone)
is the release of TSH and TRH under negative or positive feedback control?
negative feedback control
give a simple explanation of what hypothyroidism is?
when the thyroid gland does not secrete enough thyroid hormone into the blood (low thyroid).
what are the 3 main causes of hypothyroidism?
1. primary failure of the thyroid gland 2. secondary failure of the thyroid gland 3. inadequate dietary supply of iodine
provide an example of primary failure of the thyroid gland (hypothyroidism)
Hashimoto's thyroiditis - autoimmune disorder, antibodies target thyroid gland stopping it from prducing thyroid hormones. low levels of T3 and T4, elevated levels of TSH bc no T3 and T4 is being produced to provide negative feedback and decrease TRH and TSH.
what is secondary failure hypothyroidism?
when the hypothalamus and/or pituitary gland fail to secrete enough TRH and/or TSH. low levels of T3 and/or T4 & TSH and/or TRH.
describe the characteristics of hypothyroidism caused by inadequate dietary supply of iodine?
low T3 and T4, elevated TSH.
what is congenital hypothyroidism also called? and what are its symptoms?
cretinism. dwarfism and intellectual disability.
name some symptoms of hypothyroidism?
cold intolerance, slower reflexes, reduced mental alertness, weight gain (bc of decreased metabolism)
what is hyperthyroidism (in simple terms)?
increased levels of thyroid hormone
what are the 3 primary causes of hyperthyroidism?
1. secondary to excesss hypothalamic or anterior pituitary secretions 2. thyroid tumour 3. Graves' disease
what is secondary to excesss hypothalamic or anterior pituitary secretions? (one cause of hyperthyroidism)
when there is a tumour in the hypothalamus (secretes excess TRH) or the anterior pituitary (secretes excess TSH). tumours ignore negative feedback = elevated T3 & T4 and TRH/TSH.
what is thyroid tumour? (cause of hyperthyroidism)
a tumour in thyroid gland causing increased secretion of thyroid hormones. elevated T3 & T4, decreased TSH.
what is Graves' disease? (cause of hyperthyroidism)
most common cause of hyperthyroidism. (autoimmune) body produces long-acting thyroid stimulator (LATS) - antibody that activates TSH receptors on follicular cells. causes follicles to grow and increase. LATS ignores negative feedback so T3 & T4 are elevated and TSH levels are low.
name some symptoms of hyperthyroidism
increased heart rate, heat production, increased metabolism, muscle weakness, mood swings
what is a goiter and what causes it?
an enlarged thyroid gland. symptoms of hypo- and hyper- thyroidism. caused by increased TSH which increases number and size of follicles.
under which condition(s) would a goiter be present (hypothyroidism): primary failure of thyroid, secondary failure of thyroid gland, lack of dietary iodine.
primary failure of thyroid, lack of dietary iodine.
under which condition(s) would a goiter be present (hyperthyroidism): secondary to hypothalamus or anterior pituitary tumour, thyroid tumour, Graves' disease
secondary to hypothalamus or anterior pituitary tumour, Graves' disease (LATS acts as TSH in Graves' disease).
where are the adrenal glands located?
above the kidneys
name of the outer layer of the adrenal glands that secretes steroid hormones
cortex
name of the inner layer of the adrenal glands that secretes catecholamines
medulla
name the 3 zones of the adrenal cortex
zona glomerulosa, zona fasciculata, zona reticularis
finish: the hormones produced in the adrenal cortex are all steroid hormones based on ______ as the precursor molecule.
cholesterol
name the 3 categories of adrenal cortex hormones
1. mineralocorticoids 2. glucocorticoids 3. sex hormones
adrenal cortex hormone that influences mineral (electrolyte) balance and which zone of the adrenal cortex is it produced by?
mineralocorticoids - produced by zona glomerulosa
name the adrenal cortex hormone that influences glucose, lipid, and protein metabolism. also name which zone(s) it is produced in?
glucocorticoids - produced in zona fasciculata and zona reticularis
where are the sex hormones of the adrenal cortex produced?
in the zona fasciculata and zona reticularis
name the major mineralocorticoid produced in the adrenal cortex
aldosterone
what are the 2 primary stimuli for the secretion of aldosterone?
1. activation of the renin-angiotensin aldosterone system in response to reduced Na+ and blood pressure.
2. direct stimulation of adrenal cortex by increased K+ concentration.
name the primary glucocorticoid (plays a major role in metabolism)
cortisol
explain the 2 major roles of cortisol (adaptation to stress and metabolic effects)
in doc
what are two alternative influences that can adjust cortisol secretion?
stress and diurnal rhythms
what does it mean when it says "cortisol follows a diurnal rhythm"?
means cortisol follows sleep-wake cycle to be highly secreted whenever person is most active
explain the negative feedback system of cortisol secretion that keeps cortisol concentrations around its set point
hypothalamus releases corticotropin-releasing hormone (CRH), then anterior pituitary releases adrenocorticotropic hormone (ACTH). ACTH stimulates adrenal galnds to release cortisol. plasma cortisol feeds back into hypothalamus and anterior pituitary to reduce CRH & ACTH release
name the most important adrenal cortex sex hormone and the physiological effects it plays in females
dehydroepiandrosterone (DHEA) - growth of pubic and armpit hair, growth spurt at puberty, and maintenance of female sex drive.
where are the catcholamines epinephrine and norepinephrine stored once synthesized in the adrenal medulla?
chromaffin granules
which beta-adrenergic receptor is exclusively activated by epinephrine?
B2
does a sympathetic response constrict or dilate vasculature?
constrict
*review effects of epinephrine*
in slides (section 04: 11)
name the morphine-like substance produced during the formation of ACTH that can act as an analgesia in case of physical injury
β-endorphin
name the 3 main patterns of symptoms of hyperadrenalism
cortisol hypersecretion, adrenal androgen hypersecretion, hyperaldosteronism
what is Cushing's syndrome?
an increase in cortisol and plasma glucose. caused by overstimulation of adrenal cortex, adrenal tumours hypersecreting cortisol, and ACTH-secreting tumours located outside the pituitary.
- physical features: buffalo hump and moon face
what is buffalo hump and moon face (features of Cushing's syndrome)?
buffalo hump: redistribution of fat causing increased depositions on the back.
moon face: cortisol causes excessive oedema in the cheeks.
excessive mineralocorticoid secretion can be caused by either an aldosterone-secreting tumour or abnormally high activity of the renin-angiotensin-aldosterone system. Which of these scenarios is primary and secondary hyperaldosteronism?
aldosterone-secreting tumour = primary hyperaldosteronism
abnormally high activity of the renin-angiotensin-aldosterone system = secondary hyperaldosteronism
what would happen if you were to lose only one adrenal gland?
the remaining gland would fulfill task of secreting hormones - you must lose both for problems to occur
explain the two types of adrenocorticol insufficiency
in slides (section 04:15)
the two metabolic states are absorptive and postabsorptive. which of these includes anabolism and whoch catabolism?
absorptive = anabolism (build up)
postabsorptive = catabolism (break down)
name 3 energy sources the body utilizes for metabolism, and which is specifically used during times of starvation?
glycerol, lactic acid, ketone bodies - ketone bodies used in starvation (produced from acetyl coA)
where are the endocrine functions of the pancreas focused?
the Langerhans
name the 4 cells of the pancreas' langerhans and what each of them secrete
alpha cell = glucagon. beta cell = insulin.
delta cell = somatostatin. PP cell = pancreatic polypeptide.
what is the effect of somatostatin (released by delta cells) on the digestive system?
slow down digestion to prvent too many nutrients from being absorbed.
explain the regulation of insulin secretion
in doc
explain the effects of glucagon on carbs, fats, and proteins
in slides (section 05:11)
name the cell that deposits new bone and the cell that dissolves bone
deposits = osteblasts. dissolves = osteoclasts
explain bone growth by length
in doc
between IGF-1 and IGF-2, which of these growth hormones is important in fetal growth?
IGF-2
not a question: flip
"Laron dwarfism" responds to IGF-1 treatment
what is acromegaly?
excess growth hormone. includes jaw and cheekbones becoming large, along with hands and feet.
name the 3 hormones that regulate plasma concentrations of calcium
parathyroid hormone (PTH), calcitonin, vitamin D
what is vitamin D (cholecalciferol) called in its active form?
calcitriol