Term
| How is the endocrine system connected? |
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Definition
Via hormones traveling through blood
(In contrast to the nervous system, which is physically connected by nerves) |
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Term
| How concentrated are hormones, generally, in the blood? |
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Definition
| Very low – 10^-9 M to 10^-12 M |
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Term
| What hormones are associated with the autonomic nervous system? |
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Definition
| epinephrine, norepinephrine |
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Term
| What hormones are associated with the cardiovascular system? |
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Definition
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Term
| What hormones are associated with the gastrointestinal system? |
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Definition
| gastrin, secretin, cholecystokinin, motilin |
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Term
| What hormones are associated with the renal system? |
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Definition
| renin-angiotensin, aldosterone, parathyroid hormone, vitamin D, ADH |
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Term
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Definition
| An organ that secretes particular chemical substances for use in the body or for discharge into the surroundings |
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Term
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Definition
| Pituitary gland, thyroid gland, parathyroid gland, testes, ovaries, adrenal gland, pancreas |
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Term
| What are some non-gland tissues that secrete hormones? |
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Definition
| Central nervous system – especially the hypothalamus, GI tract, liver, heart, kidneys, placenta, adipose tissue |
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Term
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Definition
A tumor
Can secrete hormones; lung cancers commonly secrete hormones including parathyroid hormone, antidiuretic hormone and ACTH |
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Term
| Do glands secrete multiple hormones? Do single cells in the same gland secrete multiple hormones? |
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Definition
1. Glands may secrete multiple hormones
2. Single cells usually secrete a single hormone (one exception are the gonadotrophs with LH and FSH) |
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Term
| What are the three chemical classifications of hormones? |
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Definition
1. Amines
2. Steroids
3. Peptides |
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Term
| What are the amine hormones derived from? |
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Definition
Tyrosine
(Tyrosine -> L-dopa -> dopamine -> norepinephrine -> epinephrine) |
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Term
| What is the precursor to steroid hormones? |
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Definition
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Term
| Where does the cholesterol for hormone synthesis come from? |
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Definition
| 20% of cholesterol for hormone synthesis comes from denovo synthesis, 80% of cholesterol comes cholesterol in blood bound to low density lipoproteins (LDL). |
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Term
| List some steroid hormones |
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Definition
a. aldosterone (mineralocorticoid)
b. cortisol (glucocorticoid)
c. androgens - testosterone
d. estradiol
e. progesterone
f. Vitamin D |
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Term
| What are the three zones in the adrenal cortex, in order from outside to inside? |
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Definition
| Zona glomerulosa, zona fasiculata, zona reticularis |
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Term
| What does the zona glomerulosa secrete? |
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Definition
| mineralocorticoids (aldosterone) |
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Term
| What are the steroid secreting glands? |
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Definition
| Adrenal cortex, gonads, and placenta |
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Term
| What does the zona fasciculata secrete? |
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Definition
| glucocorticoids (cortisol) and androgens |
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Term
| What does the zona reticularis secrete? |
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Definition
| glucocorticoids (cortisol) and androgens |
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Term
| What does the adrenal medulla secrete? |
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Definition
| Epinephrine and norepinephrine |
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Term
| Describe peptide hormone synthesis |
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Definition
| Preprohormone -> prohormone -> hormone |
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Term
| List examples of peptide hormones that start from preprohormones |
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Definition
| Proopiomelanocortin (POMC), insulin |
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Term
| What hormones can transport freely in the blood? |
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Definition
| Catecholamines and peptides (except growth hormone and IGF-1) |
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Term
| What hormones travel through blood bound to protein? |
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Definition
| All steroid hormones, thyroid hormone, growth hormone & insulin-like growth factor-1 (IGF-1) |
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Term
| What are functions of bound hormone? |
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Definition
1. Reservoir of hormone
2. Extends half-life
3. Minimizes fluctuations |
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Term
| What are three functions of metabolism of hormones? |
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Definition
1. Inactivation
2. Activation
3. Elimination |
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Term
| What two hormones function with intracellular receptors? |
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Definition
| Steroid hormones, thyroid hormone |
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Term
| Describe complementary actions of hormones and give an example |
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Definition
Two hormones have similar effects.
e.g. epinephrine and cortisol increase lipid and carbohydrate metabolism during stress |
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Term
| Describe antagonistic actions of hormones and give an example |
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Definition
Two hormones having opposite effects
e.g. insulin and glucagon |
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Term
| Describe permissive actions of hormones and give an example |
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Definition
Effect of one hormone requires the presence of a second hormone
Thus, the effect of the second hormone permits the actions of the first hormone.
e,g, thyroid hormone has permissive effects in that it is needed for epinephrine to have its effects |
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Term
| Give an example of a hormone that releases in pulses |
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Definition
| LH (spikes prevent down-regulation) |
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Term
| Give an example of a hormone that releases cyclically |
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Definition
| GH and cortisol operate with the circadian rhythm (both increase at night) |
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Term
| Give an example of a hormone that releases in monthly cycles |
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Definition
| LH, FSH, estrogen, progesterone in the menstrual cycle |
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Term
| What are four control inputs that regulate hormone release? |
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Definition
1. Plasma concentration of mineral ions/nutrients
2. Neuronal control
3. Physical stimuli (mechanoreceptors, light)
4. Trophic hormones |
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Term
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Definition
| A hormone that stimulates the release of another hormone |
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Term
| What hormone is activated by light? |
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Definition
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