Endocrine Flashcards
illness thats caused by secretion of too much of a hormone
hypersecretion, usually occurs bc tumor in gland
loss of responsiveness of the cells that detect the hormone
down regulation of receptors. ex: adult onset diabetes mellitus
endocrines systems are systems of:`
glandular cells that produce a chemical signal thats released into the blood (hormones)
chemical signals that are released into the blood:
hormones
endocrinology is:
the study of the endocrine system. endocrine referes the glands that produce these hormones, and the hormones themselves.
paracrine signals:
similar to hormone but effects are limited to vicinity o cells secreting it.
neuroendocrine:
basically hormone and the hormone producing cells are neural. Neurons produce these into the blood as signaling molecules. Targets can be organ or cells within the organ.
receptors:
are proteins on the cell surface or inside the cell that detect hormones
Chemical signals are produced by cells. specific cells that produce specific hormones. Cells are often given a specific name. ex:
pancreous has alpha and beta cells
some of the organs that produce hormones as their main job:
ohers are just desperced in some organ:
- endocrine glands.
- non endocrine glands but still produce hormones. ie: skin heart kidnes stomach intestines and adipose tissue
Difference btw endocrine and exocrine glands:
exocrine has a duct that leads from the gland to some open space. Endocrine releases into the blood
One major gland is the hypothalamus and pituitary gland, which are closely related. how?
pituitary gland produces a number of hormones, but the release of those hormones is controlled by the hypothalamus
Thyroid gland:
endocrine gland
thymus gland:
above the heart. endocrine gland
adrenal gland:
on top of the kidneys
pancreas
both an endocrine and exocrine gland
hormones do what:
regulate development, physiology.
example of nonhormonal stimulation:
- non hormonal stimulation: Direct stimulation by regulated factor. ex. insulin
- Nervous system stimulation of secretion. ex: adrenal medulla
- hormonal stimulation of secretion
example of nonhormonal stimulation:
insulin. its a direct stimulation by regulated factor.
example of nervous stimulation of secretion:
adrenal medulla
hormonal stimulation of secretion:
cascade of release of hormones.
Thyroid releases ___, which goes to the ____ which causes a release of ____.??????????
thyrotropin releasing hormone goes to ant. pituitary, causes release of the ????????
Negative feedback.
target organ hormone levels inhibit release of tropic hormones.
define tropic. give examples
tropic is a hormone that releases hormones. gonadotropin, thyrotropin
Name the 3 classes of hormones:
- steroids
- monoamines
- peptides, polypeptides, and glycoproteins
Steroids:
- lipids
- derived from cholesterol
- Choloesterol > progesterone > (testosterone>estradiol), cortisol, aldosterone
Monoamines:
- derived amino acids
- hormones: dopamine, epi&norepinephrine, theyroid hormones T3&T4, melatonin.
- Serotonin does not act as hormone
Examples of peptide hormones:
OT, ADH, all releasing & inhibiting hormones of hypothalamus; most of anterior pituitary hormones, insulin, glucagon etc.
7 mechanisms of hormone action:
- hydrophobic vs hydrophilic hormones
- receptors
- ligand gated channels
- second messenger systems (hydrophilic only)
- phosphorylation of proteins and protein kinases
- activation of metabolic pathways
- changes in gene expression (many of the hydrophobic ones)
what is protein kinases:
an enzyme that phosphoralates other enzymes. it adds a phosphate group to them and that changes their activity
What do hydrophobic hormones do?
- may enter the cell
- may change gene expression
- make new proteins or enzymes
- tend to have a long term effect
What do hydrophilic hormones do?
- have cell surface receptor
- many act through a 2nd messenger system
- rapid effects (you can tell the difference in seconds)
- dont act very long
- act on existing proteins (basically turning on enzymes that are already there inside the cell)
a hydrophilic does not require:
a carrier in the plasma. it diffuses out of capillaries to the cell
hydrophilic hormones usually act though:
second messenger systems
Net result of the adenylate cyclase system:
to respond to the hormone with the production of a chemical enzyme cell known as cAMP.
Walk through the adenylate cyclase system:
(hydrophilic pathway)
receptor binds to hormone, G protein leaves receptor and goes to adenylate cyclase enzymes and turns it on. adenylate cyclase cranks out cAMP, cAMP levels change inside the cell acting on protein kinases activating them, protein kinases start phosphoralating enzymes that are already there turning them on. Depending on what enzyme they are, they carry out a diff metabolic pathway.
Walk through discylglycerol pathway:
(hydrophilic pathway)
G protein acts on phospholipase ennzyme that acts one of the lipids of the cell membrane, which becomes diacylglycerol(DAG). DAG activates protein kinases, which phosphoralate diff enzymes.
Other phospholipiase is producing IP3 (inositol triphosphate). in general it increases calcium levels inside the cell.
guanylate cyclase produces signaling molecule called cGMP
Basically the lipid produces diacyclglycerol & inositol triphosphate.
Insulin pathway:
hormone receptors phosphorylate intracelluar proteins itself. bypasses the second messenger system.
hydrophobic hormones:
steroid hormones
hydrophilic hormones:
peptides, polypeptides, monoamines, except for thyroid hormones
Hormones from the hypothalamus are examples of tropins or tropic hormones. they’re called:
hypophysiotropic hormones.
hypothalamus releases ______, which goes to the ____, which causes release of ____(two types: ___&___), these go to the gonads which control another release of another hormone
gonadotropin releasing hormone (GnRH), goes to ant. pituitary, which causes release of gonadotropins: FSH & LH.
ACTH:
adrenocorticotropic hormone, acts on the adrenal cortex
TSH:
thyroid stimulating hormone, acts on the thyroid and causes release of thyroid hormone. its controlled by hormones from the hypothalamus as well
What are tropins/trophic hormones?
hormones released from one gland that control the release of hormones from another gland.
Names that contain tropin:
are going to go to a third gland and control the release of another hormone.
what are hypophysiotropic hormones?
hypothalamic hormones that control release of hormones from the anterior pituitary
Name the 5 sets of hypophysiotrpic hormones:
TRH: thyrotropin releasing hormone
CRH: corticotropin-releasing hormone
GnRH: gonadotropin-releasing hormone
PRH&PIH: prolactin releasing and inhibiting hormones.
GHRH&GHIH (somatostatin): Growth hormone releasing and inhibiting PRH & PIH
Stimulating or inhibiting hormones are generally from the ____.
ant. pituitary
Stimulating or inhibiting hormones are what?
hormones released from one gland that stimulate or inhibit release of a hormone from another gland.
- hypothalamus and anterior pituitary
- anterior pituitary and other glands
if its got “stimulating” in its name, its most likely from the
ant. pituitary
Anterior pituitary is also known as the
adenohypophysis
Ant pituitary has what hormones?
- FSH: gonadotropins
- LH: gonadotropins
- GH: growth hormone
- PRL: prolactin
- ACTH: adrenocorticotropic hormone
- TSH: thyroid stimulating hormone
posterior pituitary is also called:
neurohypophysis
posterior pituitary produces two hormones:
ADH: antidiuretic hormone
OT: oxytocin
