Intro to Endocrine System Flashcards
What is autocrine signaling?
The hormone secreted from one cell type effects the same cell or the same type of cell.
What is paracrine signaling?
The hormone secreted from one cell type effects a different type of cell.
What is endocrine signaling?
The hormone secreted from one cell type travels through the bloodstream before effecting a cell of a different type.
What is neuroendocrine signaling?
The hormone secreted from a neuron travels through the bloodstream to affect a cell of a different type.
What hormones does the hypothalamus secrete? (6)
TRH, CRH, GnRH, GHRH, Somatostatin, and Dopamine
What hormones does the anterior pituitary secrete? (7)
TSH, FSH, LH, ACTH, MSH, Growth Hormone, and Prolactin
What hormones does the posterior pituitary secrete? (2)
Oxytocin and ADH
What hormones does the thyroid release? (3)
T3, T4, and Calcitonin
What hormone does the parathyroid release? (1)
PTH
What hormones does the pancreas release? (2)
Insulin and Glucagon
What hormones does the adrenal medulla release? (2)
Norepinephrine and Epinephrine
What hormones does the kidney release? (2)
Renin and 1,25-Dihydroxycholecalciferol
What hormones does the adrenal cortex release? (3)
Cortisol, Aldosterone, and Adrenal androgens
What hormone does the testes release? (1)
Testosterone
What hormones do the ovaries release? (2)
Estradiol and Progesterone
What hormones does the corpus luteum release? (2)
Estradiol and Progesterone
What hormones does the placenta release? (4)
HCG, Estriol, Progesterone, and hPL
What is the sequence of peptide hormone synthesis?
DNA>mRNA>preprohormone (in ER)>prohormone (golgi apparatus)>hormone (secretory vesicles)
Proteolytic enzymes cleave to form a ______ ______.
Functional hormone
An endocrine cell stimulus such as increased intracellular _____ or increased _____ and ____ activation, cause release of peptide hormone.
calcium; cAMP; PKA
______ hormones are synthesized and secreted by the adrenal cortex, gonads, corpus luteum, and placenta.
Steroid
____ hormones are derived from tyrosine.
Amine
______ are synthesized in the cytosol and secretory granules and act through cell-membrane associated receptors.
Catecholamines
Thyroid hormones are synthesized by thyroid gland and stored as ______ in follicles within the gland.
thyroglobulin
Thyroid hormones cross the cell membrane and act through _____ _____.
nuclear receptors
The more protein binding, the _____ the plasma half life and the _____ the metabolic clearance (for the most part).
longer; slower
The ______ mechanism of hormone secretion is where neuronal input increases or decreases hormonal stimulation.
neural
The feedback mechanisms of hormone secretion is when some element of the pathway feeds back, directly or indirectly, on the endocrine gland to change _____ ____.
secretion rate
_____ endocrine feedback is when some feature of hormone action causes additional secretion of the hormone.
Positive
Examples of positive endocrine feedback include _____ and ____ _____.
ovulation; labor contractions
______ endocrine feedback is when some feature of hormone action inhibits further secretion of the hormone.
Negative
______ endocrine feedback confers stability by keeping a physiological parameter within a normal range.
Negative
____-loop feedback is when a hormone released from a peripheral endocrine gland feeds back all the way to the hypothalamus and pituitary.
Long
____-loop feedback is when a hormone secreted from the pituitary feeds back to the hypothalamus.
Short
____ ____-loop feedback is when a gland inhibits its own secretion.
Ultra short
Descending and ascending neuronal inputs modulate hormonal secretion from the ______.
hypothalamus
The _______ ______ imposes a circadian rhythm on the secretion of hypothalamic releasing hormones and endocrine axes.
suprachiasmatic nucleus (SCN)
The _____ _____ releases melatonin which feedbacks to the SCN information about day-night.
pineal gland
______ _____ influences the release of hormone from the hypothalamus.
Physiological stress
Regulation of hormone receptors is influenced by the _____-_____ complex and by responsiveness of target tissue which is expressed in a ____-____ relationship.
hormone-receptor; dose-response
Sensitivity of a hormone receptor is defined as hormone concentration that produces __% of maximal response.
50
Responsiveness can be changed by changing the _____ of receptors or changing the _____ of the receptors for the hormone.
number; affinity
__-_____ is the increase in the number of receptors or sensitivity of target tissue when hormone levels are low.
Up-regulation
__-_____ is the reduction in the number of receptors or the sensitivity of target tissue when hormone levels are chronically high.
Down-regulation
What are the first messengers in the adenylyl cyclase mechanism? (5)
ACTH, LH, FSH, TSH, and glucagon
What is the primary effector in the adenylyl cyclase mechanism?
adenylyl cyclase
What is the second messenger in the adenylyl cyclase mechanism?
cAMP which cleaves to 5’AMP (inactive)
What is the secondary effector in the adenylyl cyclase mechanism?
PKA
What are the first messengers in the phospholipase C mechanism? (3)
GnRH, TRH, and oxytocin
What is the primary effector in the phospholipase C mechanism?
phospholipase C
What are the second messengers in the phospholipase C mechanism? (3)
IP3, DAG, and Ca2+
What is the secondary effector in the phospholipase C mechanism? (2)
PKC or calmodulin
Only ____ steroid hormones can diffuse into the target cells.
unbound
Steroid hormone receptors are located in the _____ or _____.
cytoplasm; nucleus
The steroid receptor-hormone complex binds to DNA and activates or represses on or more genes. The activated genes create new ____ and that moves back to the _____.
mRNA; cytoplasm
Some steroid hormones also bind to membrane receptors that use second messenger systems to create ____ ____ _____.
rapid cellular responses
Guanylyl cyclase activation converts ___ to ___.
GTP; cGMP
cGMP activates ___ _____ which results in relaxation of vascular smooth muscle by ____ ____.
cGMP kinases; nitric oxide
Tyrosine kinases phosphorylates downstream proteins. What are the two types of tyrosine kinases?
Receptor tyrosine kinases (RTKs) and tyrosine kinase-associated receptors
RTKs are the intrinsic tyrosine kinase activity and include ____ ____ ____ receptor and _____ receptor.
nerve growth factor; insulin
Tyrosine kinase-associated receptors associate non-covalently to proteins that have kinase activity and include ____ ____ receptors.
growth hormone
