Recap of normal endocrine function Flashcards
(20 cards)
Characteristics of Amino-based Hormones?
- Water soluble
- Travel in blood freely
- Bind to cell surface receptor
Ex. of PROTEIN & PEPTIDE HORMONES?
Insulin, glucagon, GLP-1
Ex. of AMINES & AMINO ACIDS hormones?
Adrenaline (and thyroxine*) … derived from tyrosine
Characteristics of Steriod Hormones & ex?
- Lipid soluble
- Travel in blood bound to carrier
- Bind to intracellular receptor
- *Thyroid hormones (but derived from amines)
- e.g. cortisol, oestrogen, testosterone, aldosterone
Endocrine glands are stimulated to synthesize and release hormones in response to one of three stimuli.
- Hormonal stimuli
- Neural stimuli
- Humoral stimuli
The production of many hormones is regulated by negative feedback
What is humoral stimuli?
Hormones stimulate other endocrine organs to release their hormones:
Hypothalamic hormones stimulate the release of most_____hormones?
Anterior Pituitary
Anterior pituitary hormones stimulate targets to release?
more hormones
Hormones from the final target organs inhibit the release?
of AP and Hypothalamic hormones
Hypothalamic is what type of hormone?
Releasing hormone
AP releases what types of hormones?
Tropic hormone
What is neural stimuli?
Nerve fibers stimulate hormone release from glands such as the medulla
What is humoral stimuli?
Changing blood levels of ions and nutrients directly stimulate secretion of hormones
Ex. of humoral stimuli?
- Declining blood Ca2+ concentration stimulates parathyroid glands to secrete PTH (parathyroid hormone)
- PTH causes Ca2+ concentrations to rise, and stimulus is removed
Target gland hormone from target gland inhibit the release of?
Releasing & tropic hormones
Adrenal cortex hormones?
- Mineralocorticoids (Aldosterone) – stimulated by high K+ in blood and angiotensin II to increase Na+ and water in blood
- Glucocorticoids (Cortisol) – stimulated by ACTH during stress for protein, lipid and glucose metabolism, and supress immune system for resistance against stress
- Androgens –
Adrenal medulla hormones?
Epinephrine & norepinephrine stimulated by sympathetic nerves for sympathetic functions during stress
Low levels of T3 & T4 hormones, metabolic rate or puberty, or pregnancy stimulate the secretion of?
Thyrotropin-releasing-hormone TRH in the hypothalamus
How is short-term stress regulated?
- APs triggered by the hypothalamus travel to the adrenal medulla
- Medulla secretes 80% epinephrine and 20% norepinephrine
- epinephrine & norepinephrine reinforce other sympathetic responses to make ready for “fight or flight”
- High BP, increased HR, and respiration, metabolic rate
How is long-term stress regulated?
- Stressor cause hypothalamic neurons to release CRH
- CRH travel to AP
- AP release ACTH
- ACTH travels to adrenal cortex
- Adrenal cortex releases glucocorticoids (cortisol) and some mineralocorticoids
- Glucocortocoids have metabolic effects and increase breakdown of fat, protein and glycogen for energy and suppress immune system
- Mineralocorticoids work on renals and retain salt and water = high BP