Endocrine System Flashcards
What can hormones control
Rate of enzymatic reactions, transport of ions/molecules across membranes, and gene expression/synthesis of proteins
What types of ligands have cytoplasmic/nuclear receptors
Small, non polar, lipophilic, steroid-like ligands
What are the features of the endocrine system and hormones
One gland/tissue may secrete multiple hormones, but one cell usually only makes one kind of hormone
What is typically the largest endocrine gland in the body
Adipose tissue
What are endocrine disruptors
Exogenous mimics (antagonists)
What is the half-life of a hormone
How long it takes for the concentration to decrease by 1/2
What 2 organs are mainly responsible for inactivating or removing hormones
The kidneys and the liver
What is a chaperone protein
A protein that binds to hormones in the blood (that hormone can’t leave) to prevent it from degradingW
What are the 3 kinds of hormones
Peptide, steroid, amine (act peptide or steroid-like)
How are peptide hormones made
Synthesis similar to other proteins (mRNA, RER, Golgi)
mRNA translates into preprohormone, modified into prohormone, signal peptide sequence removed, folded into hormone
What is a preprohormone
A string of amino acids translated by the ribosome
Where are peptide hormones kept before release
Secretory vesicles
What are the characteristics of peptide hormones
Most common, water soluble (lipophobic/hydrophilic), bind to surface membrane receptors, short 1/2 life (seconds to minutes), rapid effects (must be secreted continually for long-lasting effects), released on demand
What are the characteristics of steroid hormones
Cholesterol-derived (lipophilic/hydrophobic), have protein carriers/chaperones, can’t be stored, made on demand (RER and mitochondria) based on rate of release because released immediately, only made in a few organs, longer 1/2 life, cytoplasmic or nuclear receptors (mostly)
What determines whether a cell can make a particular hormone
What enzymes it has
What type of effects do steroid hormones have
Slower acting, longer lasting, usually genomic/altering gene expression and protein synthesis
What are the two amino acids amine hormones come from
Tryptophan (makes melatonin in pineal gland), and tyrosine (makes catecholamines and thyroid hormones)
What amine hormone is peptide-like
Catecholamines (epinephrine, norepinephrine, and dopamine)
Which amine hormones are steroid-like
Melatonin and thyroid hormones
What is 1 difference between steroid hormones and thyroid hormones
Thyroid hormones are made in advance and kept in secretory vesicles
What is characteristic of a simple endocrine pathway
Endocrine cell directly senses stimulus, integrates, and responds by secreting its hormones (no neurons)
What are 2 examples of a simple endocrine pathway
Parathyroid glands and pancreas (insulin and glucagon)
What are the characteristics of a complex endocrine pathway
Hypothalamic-pituitary (HP) axes have 3 integrating centers
What are the 3 integrating centers in an HP axis
Hypothalamus (neural), pituitary (master controller of ES), and endocrine gland/target of pituitary hormone)
What does the hypothalamus do
Links NS to ES, receives and integrates info about body’s homeostasis, and uses that info to control the secretion of pituitary hormones
What are the 2 parts of the pituitary gland
Posterior is extension of hypothalamus (neural tissue), and anterior is endocrine gland made of epithelial tissue
What does the posterior pituitary gland secrete
Vasopressin and oxytocin (neurohormones)
What is a tropic hormone
A hormone that controls the secretion of another hormone
What are the 6 tropic hormones secreted by the anterior pituitary
Prolactin, growth hormone, thyroid stimulating hormone (thyrotropin), adrenocorticotropic hormone (corticotropin), and gonadotropins (luteinizing hormone and follicle-stimulating hormone)
What are the releasing hormones
Short peptides stores in hypothalamic cells, released into median eminence, TRH, RH (GHRH), Gonadotropin RH (GRH/GnRH), PRF, and CRH
What connects the hypothalamus to the anterior pituitary and why
A portal system (2 capillary beds) to avoid dilution
How is hormone release regulated
Long-loop feedback (hormone goes to pituitary and hypothalamus), and short-loop feedback (pituitary hormone goes to hypothalamus)
Which feedback loop holds more weight in terms of controlling hormone release
Long-loop feedback
What are the 2 regions of the adrenal gland
Cortex (true endocrine gland that secretes 3 kinds of hormones), and the medulla (modified sympathetic ganglion/nervous tissue) that secretes catecholamines (mostly epinephrine) due to sympathetic nervous system
What 3 major kinds of steroid hormones does the adrenal cortex secrete
Mineralocorticoids, glucocorticoids (slower, longer lasting, e.g cortisol), and sex hormones (a little)
What is synergism
When the sum of 2 hormones efforts is more than the simple sum of each hormone on its own
What is permissiveness
When 1 hormone (which doesn’t have an effect) is necessary to allow the other to have a full affect
What is antagonism in hormone interactions
When 2 hormones have opposite effects
What is hypersecretion and how is it usually caused
Hormone excess caused by tumors/cancer and autoimmune diseases where antibodies bind and activate receptors in the body
What is hypo secretion and how is it caused (endocrine system)
Hormone deficiency caused by decreased synthesis or damage of a gland
What are the 3 endocrine pathologies
Hypersecretion, hypo secretion, or abnormal responsiveness of target tissue to hormones (caused by changes in receptors by phosphorylation, etc. or 2nd messenger)
What are the classifications of endocrine pathologies
Primary (endocrine gland dysfunction), secondary (pituitary dysfunction), or tertiary (hypothalamus dysfunction)
