Hormones Flashcards
how many glands in the endocrine system
eight
liquid chemical messengers
hormones
produced and secreted in the blood when levels of glucose in blood becomes too high
insulin
is any member of a class of signaling molecules in multicellular organisms, that are transported to distant organs to regulate physiology and behavior.
hormone
hormone means
setting in motion
are required for the correct development of animals, plants, and fungi.
hormones
Among the substances that can be considered hormones are
eicosanoids
amino acid derivatives
protein/peptides
steroids
example of hormones
prostaglandins
thromboxanes
amino acid example
epinephrine
auxin
protein/peptides example
insulin
In ___, hormones are responsible for the regulation of many physiological processes and behavioral activities such as digestion, metabolism, respiration, sensory perception, sleep, excretion, lactation, stress induction, growth and development, movement, reproduction, and mood manipulation.
vertebrates
In ___, hormones modulate almost all aspects of development, from germination to senescence
plants
When a hormone binds to the receptor, it results in the activation of a _____ _____pathway that typically activates gene transcription, resulting in increased expression of target proteins.
signal transduction
generally act on the surface of target cells via second messengers.
water soluble hormones
water soluble hormones examples
peptides
amines
generally pass through the plasma membranes of target cells (both cytoplasmic and nuclear) to act within their nuclei.
lipid-soluble hormones
example of lipid soluble hormones
steroids and eicosanoids
can also act in rapid, non-genomic pathways that can be synergistic with genomic effects
hormones
are cellular processes that can lead to rapid cellular responses within seconds.
non genomic pathways
are mediated by nuclear receptors that regulate genes
genomic pathways
are specialized organs that secrete hormones into the endocrine signaling system.
endocrine glands
occurs in response to specific biochemical signals and is often subject to negative feedback regulation.
hormone secretion
For instance, high blood sugar (serum glucose concentration) promotes ____ ___
insulin snythesis
acts to reduce glucose levels and maintain homeostasis, leading to reduced glucose levels.
insulin
Upon secretion, ___-soluble hormones are readily transported through the circulatory system.
water
must bond to carrier plasma glycoproteins (e.g., thyroxine-binding globulin (TBG)) to form ligand-protein complexes
lipid-soluble hormones
what carrier does lipid-soluble hormones must bond to
carrier plasma glycoproteins
example of carrier plasma glycoproteins
thyroxine-binding globulin
Lipid-soluble hormones must bond to carrier plasma glycoproteins (e.g., thyroxine-binding globulin (TBG)) to form
ligand-protein complexes
Some hormones are completely active when released into the bloodstream
what example
insulin
growth hormones
that must be activated in specific cells through a series of activation steps that are commonly highly regulated
prohormones
secretes hormones directly into the bloodstream, typically via fenestrated capillaries
endocrine system
endocrine system secretes hormones directly into the bloodstream, typically via
fenestrated capillaries
are a type of blood vessel. They have tiny pores that allow nutrients, waste and oxygen to flow from the blood to the organs.
fenestrated capillaries
secretes its hormones indirectly using ducts
exocrine system
Hormones with ___ function diffuse through the interstitial spaces to a nearby target tissue.
paracrine
a term used in cellular biology to describe a type of cell signaling where a cell secretes a signal to change the behavior of nearby cells
paracrine
lack specialized organs for the secretion of hormones, although there is a spatial distribution of hormone production
plants
is produced mainly at the tips of young leaves and in the shoot apical meristem
auxin
The lack of specialized glands means that the main site of hormone production cannot/can change throughout the life of a plant
can
and the site of production is dependent on the plant’s
what two factors
age
environment
chemical messengers synthesized at one location that deliver messages to a different location
hormones
5 main types of hormones that influence plant growth
auxin
gibberellin
cytokinin
ethylene
abscisic acid
hormones that allows plants to bend towards the light
auxin
is the way plants and other organisms grow in response to light.
phototropism
the directional growth or turning of an organism in response to an external stimulus
tropism
where is auxin synthesized
stem tips
required for a plant to germinate
gibberellins
promote elongation of internodes
gibberellins
stem between notes
internodes
counters senescence in plants
cytokinin
produced in the root apical meristem
cytokinin
tips of the roots where cytokinin is produced
root apical meristem
uses this ratio to determine if the plant develops roots or shoots
cytokinin:auxin
more auxin promotes the formation of
roots
more cytokinin promotes the formation of
shoots
works with ethylene to cause the abscission of leaves, flowers, and fruits
cytokinin
ripens fruits
ethylene
gaseous, with low solubility in water
ethylene
more produced by rapidly growing and dividing cells
ethylene
important in germinating plants, preventing leaf expansion
ethylene
allows shoots to dig upward through the tsoil until it reaches llight
ethylene
hormone that signals dehydration
abscisic acid
synthesized in the chloroplast to makes leaves close their stomata to prevent water loss through phototranspiration
abscisic acid
a substance which produced in any one part of an organism, is transferred to another part and there influences a specific physiological prcoess
hormone
term hormone is derived from the greek word “___”
hormao
hormao means
to excite
the tissues where hormones are produced are called as
effectors
tissue or organs which hormoens exert their influence are called as
targets
hormones are produced in
duct-less glands/endocrine glands
hormone is a ___-cellular messenger
intra
what medium are hormones transported in from endocrine cell
blood
target cell has specific ___ to recognize homrone
receptor
have low molecular weight and diffuse readily
hormones
readily oxidized and their effects do not remain permanent unless supplied continuously
hormones
hormones are classified based on (2)
chemical nature
mechanism of action on target cell
chemically, hormones are group as (3)
protein or peptide hormones
steroid hormones
amino acid derivatives
example of protein or peptide hormones
insulin
glucagon
antidiuretic hormone
oxytocin
example of steroid hormones
glucocorticoids
mineralocorticoid
sex hormones
example of amino acid derivatives
epinephrine
norepinephrine
thyroxine
triiodothyronine
hormones based on mechanism of action on target cell (2)
group 1 hormones
group 2 hormones
bind to intracellular complexes, which then binds to the DNA and activates transcription of certain genes
group I hormones
bind to cell surface receptors and stimulate release of second messengers
group II hormones
group II hormones are further divided based on the type of group II messenger released on target cells (3)
cAMP
phosphatidylinositol/calcium
uncharacterized
all steroid hormones and amino acid derivatives fall in the category of
lipophilic
protein or peptide hormones are __
hydrophilic
steroid hormones and amino acid derivatives fall in what group of hormones
group I hormones
group I hormones are lipophilic/hydrophilic
lipophilic
group II hormones are lipophilic/hydrophilic
hydrophilic
protein or peptide hormones are what type of homrones
group II hormones
lipophilic hormone action
endocrine gland releases lipophilic hormone
hormones travels in the blood and reaches target cell (receptor is present in the cell nucleus)
cell is lipophilic so it can easily enter the cell through the cell membrane and through the nuclear pore
binds to the receptor and forms hormone receptor complex
complex binds to DNA and activates transcription to induce desired effect
hormones that act in the mechanisms of lipophilic hormone action
estrogens
progestins
androgens
glucocorticoids
mineralocorticoids
calcitriol
thyroid hormones
hydrophilic hormone action
endocrine gland releases hydrophilic hormone
hormone travels in the blood and reaches target cell
receptor of hydrophilic hormone is present in the cell membrane
hormone cannot enter the cell since it is hydrophilic
receptor induces the release of 2nd messengers (cAMP/phosphatidylinositol/calcium)
2nd messengers activates or deactives cellular enzymes to induce desired effect
hormones that undergo hydrophilic hormone action
Adenocotricotropic homrone (ACTH)
follicle stimulating hormone (FSH)
luteinizing hormone (LH)
chorionic gonadotropin (hCG)
thyroid stimulating hormone (TSH)
antidiuretic hormone (ADH)
glucagon
parathyroid hormone (PTH)
calcitonin
epinephrine
norepinephrine
insulin
gastrin
major endocrine glands found in the body
pineal gland
pituitary gland
thyroid gland
pancreas
adrenal glands
testis (male)
ovary (female)
endocrine gland found in the head
pineal
pituitary gland
endocrine gland located in the neck
thyroid gland
gland located in the abdomen
pancreas
adrenal gland
steps in hormone signaling
Biosynthesis of a particular hormone in a particular tissue
Storage and secretion of the hormone
Transport of the hormone to the target cell(s)
Recognition of the hormone by an associated cell membrane or intracellular receptor protein
Relay and amplification of the received hormonal signal via a signal transduction process: This then leads to a cellular response. The reaction of the target cells may then be recognized by the original hormone-producing cells, leading to a down-regulation in hormone production. This is an example of a homeostatic negative feedback loop.
Breakdown of the hormone.
are typical of a specialized cell type, residing within a particular endocrine gland, such as the thyroid gland, ovaries, and testes.
hormone producing cells
Hormones exit their cell of origin via ___ or another means of membrane transport.
exocytosis
refers to the fusion of secretory vesicles with the plasma membrane and results in the discharge of the vesicle content into the extracellular space and the incorporation of new proteins and lipids into the plasma membrane.
exocytosis
communication of ten invloves a signal sent from one location to another that instructs the second organ about the status of some cellular feature
insulin signalling
is a process that involves the use of signaling proteins and molecules to relay information within a cell and to the mitochondria
cytoplasmic signalling
process that occur when phosphate binds itself on the receptors during insulin signalling
autophosphorylation
are made of a chain of amino acids that can range from just 3 to hundreds of amino acids.
peptide hormones
Examples of peptide hormones
oxytocin and insulin.
Their sequences are encoded in DNA and can be modified by alternative splicing and/or post-translational modification.
peptide hormones
They are packed in vesicles and are hydrophilic, meaning that they are soluble in water.
peptides
they can only bind to receptors on the membrane, as traveling through the membrane is unlikely.
peptide hormones
some of them can bind into intracellular receptors through an intracine mechanism
peptide hormones
refer to hormones that are produced and act inside the same cell.
intracine
are derived from an amino acid, most commonly tyrosine.
amino acid hormones
stored in vesicles
amino acid hormones
example of amino acid hormones
melatonin
thyroxine
are derived from cholestero
steroid hormones
example of steroid hormones
estradiol
tesosterone
cortisol
how many fused rings does steroid have
four fused rings
are lipophilic and hence can cross membranes to bind to intracellular nuclear receptors.
steroid hormones
are derived from lipids such as arachidonic acid, lipoxins, and prostaglandins.
eicosanoid hormones
example of eicosanoids
prostaglandins
thromboxane
hormones that are produced by cyclooxygenases and lipoxygenases
eicosanoid
are hydrophobic and act on membrane receptors.
eicosanoid
form most of body’s hormones
proteins/polypeptides
Receptors for most peptides as well as many eicosanoid hormones are embedded in the plasma membrane at the surface of the cell and the majority of these receptors belong to the
G protein-coupled recptor class
The interaction of hormone and receptor typically triggers a cascade of secondary effects within the cytoplasm of the cell, described as
signal transduction
often involving phosphorylation or dephosphorylation of various other cytoplasmic proteins, changes in ion channel permeability, or increased concentrations of intracellular molecules that may act as secondary messengers (e.g., cyclic AMP).
signal transduction
For steroid or thyroid hormones, their receptors are located inside the cell within the ___of the target cell.
cytoplasm
first step of protein synthesis.
mRNA synthesis
EFFECTS OF HORMONES ON THE BODY
stimulation or inhibition of growth
wake-sleep cycle and other circadian rhythms
mood swings
induction or suppression of apoptosis (programmed cell death)
activation or inhibition of the immune system
regulation of metabolism
preparation of the body for mating, fighting, fleeing, and other activity
preparation of the body for a new phase of life, such as puberty, parenting, and menopause
control of the reproductive cycle
hunger cravings
may also regulate the production and release of other hormones.
hormone
Hormone signals control the internal environment of the body through
homeostasis
The rate of hormone biosynthesis and secretion is often regulated by a
homeostatic negative feedback control mechanism
Thus, higher hormone concentration alone cannot trigger the negative feedback mechanism. Negative feedback must be triggered by the overproduction of an “___” of the hormone.
effect
Blood glucose levels are maintained at a constant level in the body by a ___feedback mechanism.
negative
When the blood glucose level is too high, the pancreas secretes ____and when the level is too low, the pancreas then secretes ___.
insulin
glucagon
Hormone secretion can be stimulated and inhibited by:
other hormones
plasma concentration of ions or nutrients
neurons and mental activity
environmental changes, e.g. of light or temperature
One special group of hormones is the ___ hormones that stimulate the hormone production of other endocrine glands.
tropic
are hormones that have other endocrine glands as their target
tropic hormones
Most tropic hormones are produced and secreted by the
anterior pituitary gland
causes growth and increased activity of another endocrine gland, the thyroid
thyroid stimulating hormone
To release active hormones quickly into the circulation, hormone biosynthetic cells may produce and store biologically inactive hormones in the form of
pre or prohormones
which cells produce and store prehormones
hormone biosynthethic cells
are considered to act as local hormones.
eicosanoids
considered to be “local” because they possess specific effects on target cells close to their site of formation
eicosanoids
have a rapid degradation cycle, making sure they do not reach distant sites within the body.
eicosanoids
Hormones are also regulated by receptor
agonists
are ligands, which are any kind of molecules that produce a signal by binding to a receptor site on a protein.
hormones
any kind of molecules that produce a signal by binding to a receptor site on a protein
ligans
Hormone effects can be inhibited, thus regulated, by ___ ____s that bind to the same target receptor as the hormone in question.
competing lignds
These competing ligands are called ___of the hormone.
antagonist
what hormone is produced by the pineal gland
melatonin
function of melatonin
biological clock
FSH/LH
ADH
Growth hormone
Oxytocin
Prolactin
are produced where?
Thyroid gland
target organ of FSH/LH
ovaries
function of FSH and LH
menstrual cycle
target organ and function of ADH
kidneys
osmoregulation
target organ and function of growth hormone
uterus
growth and division
target organ and function of oxytocin
breast tissue
birth contractions
target organ and function of prolactin
many others
milk production
target organ and function of thyroxin
liver
metabolic rate
thyroxin is produced where
thyroid gland
adrenal glands produce which hormones (2)
adrenaline
cortisol
target organ and function of adrenaline
many
fight or flight
target organ and function of cortisol
many
anti-stress
pancreas produces which hormone
insulin
glucagon
target organ and function of insulin and glucagon
liver
blood sugar levels
ovaries produce which hormone
estrogen
progesterone
target organ and function of estrogen and progesterone
uterus
menstrual cycle
testes produce which hormone
testosterone
target organ and function of testes
many
male characteristics
consume a very small fraction of the total steroids available in the organism,
steroid hormones
five principles classes of steroids
progestins
glucocorticoids
mineralocorticoids
estrogens
androgens
all steroids are derived from
cholesterol
steroid hormones that are active during pregnancy
progestins
steroid hormones that promotes the synthess of glucose and suppressing inflammatory reactions
glucocorticoids
steroid hormones that regulates ion balances
mineralocorticoids
steroid hormones that promotes female sex characteristics
estrogens
steroid hormones that male sex charactersitics
androgens
With the exception of progesterone, all of these closely related biologically active molecules have in common a shortened side chain in ring D and, in some cases, an oxidized OH group on ring A.
steroids
Except ___, steroids have closely related biologically active molecules that have in common a shortened side chain in ring D and, in some cases, an oxidized OH group on ring A.
progesterone
invoke changes in gene expression; that is, their action is to turn on or off the instructions issued by deoxyribonucleic acid (DNA) to produce proteins that regulate the biosynthesis of other important proteins.
lipid hormones
are carried in the circulation bound singly to specific carrier proteins that target them to the cells in particular organs.
steroids
first step in protein biosynthesis.
DNA transcription
For steroids, the structural backbone is called the
steroidal nucleus
The chemical name of the steroidal nucleus is
peryhydrocyclopentanopheanthrene
Any compound that contains the steroidal nucleus is considered a
steroid
example of steroids
cholesterol
cortisone
estrogen
testosterone
important biological regulators that nearly always show dramatic physiological effects when they are administered to living organisms
steroids
are major components of biological membranes in eukaryotes
steroids
is the principal steroid of animals
cholesterol
the major steroid in fungi is
ergosterol
major steroid in plants
sitosterol
The characteristic feature of each of these three important molecules is ___ rigidly fused carbon rings forming the steroid nucleus and a hydroxyl (OH) group attached to the ___ring
four
first
This is a group of steroids that regulate events during pregnancy and are the precursors of the other steroid hormones
progestins
is secreted by the adrenal cortex as well as the gonads. It is secreted by the ovarian corpus luteum during the first ten weeks of pregnancy, followed by the placenta in the later phase of pregnancy.
progesterone
are synthetic forms of the body’s naturally occurring hormone progesterone
progestins
Progestins are synthetic forms of the body’s naturally occurring hormone
progesterone
were designed to interact with progesterone receptors in the body in order to produce progesterone-like effects.
progestins
Examples of progestins include natural or bioidentical progesterone such as
medroxyprogesterone acetate
norethisterone
is used for any natural or man-made substance that has properties similar to natural progesterone
progestin
There are ___ different types of progestins that may be found in combination birth control pills along with estrogen.
eight
are cholesterol-derived steroid hormones synthesized and secreted by the adrenal gland.
glucocorticoids
anti-inflammatory in all tissues
glucocorticoids
control the metabolism in muscles, fat, liver, and bone
glucocorticoids
also affect vascular tone
vascular tone
the contractile activity of vascular smooth muscle cells in the walls of small arteries and arterioles,
vascular tone
influences mood, behavior, and sleep-wakefulness cycle in the brain
clucocorticoids
are powerful medicines that fight inflammation and work with your immune system to treat a wide range of health problems. They control how your cells use sugar and fats. They also control inflammation.
glucocorticoids
example of glucocorticoids
cortisol
cortisone
prednisone
dexamethasone hydrocortisone
are a class of steroid hormones that regulate salt and water balances.
mineralocorticoids
promote sodium and potassium transport usually followed by changes in water balance.
mineralocorticoids
group of steroids that regulates ion balances between the interior and the exterior of the cell.
mineralocorticoids
is the primary example of a mineralocorticoid
aldosterone
where is aldosterone produced
zona glomerulosa of the adrenal cortex
It also acts on the kidneys particularly involved in the reabsorption of sodium ions as well as the passive reabsorption of water.
aldosterone
is a group of any natural or synthetic hormone that regulates the development and maintenance of male characteristics in vertebrates by binding to androgen receptors
androgen
esponsible for the development of secondary sexual characteristics in men, including facial and body hair growth, and voice change
androgens
affect bone and muscle development
androgens
The principal examples of androgens are (2)
testosterone
androstenedione
is produced mainly by the testes
testosterone
are produced primarily from the adrenal glands
androgens
this can also play roles in converting weak adrogens to more potent ones
peripheral tissues (fat and skin)
is a class of sex hormones that is responsible for the development and regulation of the female reproductive system and secondary sex characteristics such as the development of breasts and pubic hair
estrogen
also contributes to cognitive health, bone health, the function of the cardiovascular system, and other essential bodily processes.
estrogen
There are three major endogenous estrogens that have estrogenic hormonal activity namely
estrone
estradiol
estriol
is the main sex hormone responsible for sexual and reproductive development.
estrogen
estrogen is produced in (3)
ovaries
adrenal glands
fat tissues
target organs of glucocorticoids
liver
retina
kidney
oviduct
pituitary
target organs of estrogen
oviduct
liver
target organs of progesterone
oviduct
uterus
target organs of androgens
prostate
kidney
oviduct
there are two types of hormones that are hydrophobic in nature
steroids
eicosanoids
consist of three types of locally acting signaling molecules derived biosynthetically from C20 polyunsaturated fatty acids, principally called arachidonic acid.
eicosnaoids
eicosanoids consist of three types of locally acting signaling molecules derived biosynthetically from C20 polyunsaturated fatty acids, principally called
arachidonic acids
Twenty-carbon fatty acids are all known collectively as
eicosanoid acids
three types of eicosanoids
prostaglandins
thromboxanes
leukotrienes
are synthesized from different cell types such as blood cells, endothelial cells, and connective tissue cells.
eicosanoids
Eicosanoids are synthesized from different cell types such as
blood cells
endothelial cells
connective tissue cells
They are typically not stored within cells but rather synthesized as required.
eicosanoids
eicosanoids are derived from
fatty acids that make the cell membrane and nuclear membrane
The eicosanoids interact with specific cell surface receptors to produce a variety of different effects on different tissues, but generally, they cause (3)
inflammatory response
change in blood pressure
affect the clotting of blood
For prostaglandins, the basic chemical structure common to these compounds is a 20-carbon carboxylic acid called
prostanoic acid
represent a family of fatty acid derivatives which have a variety of potent biological actions of a hormonal or regulatory nature
prostaglandin
who coined the term prostaglandins
Ulf von Euler
was coined by Ulf von Euler for this lipid-soluble acidic substance because they are found in the seminal plasma, prostate gland, and seminal vesicles.
prostaglandins
In very small amounts, ___lower blood pressure and stimulate some smooth muscles to contract.
prostaglandins
There are at least __ different prostaglandins in human seminal plasma.
14
are named according to their ring substituents, and the number of additional side chain double bonds which have cis-configuration.
prostaglandins
Prostaglandins are named according to their ring substituents, and the number of additional side chain double bonds which have ___-configuration.
cis
In multicellular organisms (eukaryotes), the internal mechanisms that control and coordinate basic biochemical reactions are connected to other cells by means of
nerves and chemical messengers
The overall process of receiving these messages and converting the information they contain into metabolic and physiological effects is known as
signal transduction
Many of the chemical messengers are ___and are thus of special interest here
lipids
With the exception of the ____ hormones, most hormones such as insulin and glucagon interact with a receptor on the cell surface.
steroid
The activated receptor then generates so-called ___ messengers within the cell that transmit the information to the biochemical systems whose activities must be altered to produce a particular physiological effect.
second messengers
The magnitude of the end effect is generally proportional to the ___ of the second messengers.
concentration
Activation of ___C by one of the agents listed in the table causes the hydrolysis of a minor membrane phospholipid, phosphatidylinositol bisphosphate.
phosphalipase
What does diacylglycerol activate without leaving the membrane bilayer
Diacylglycerol activates the membrane-bound enzyme, protein kinase C.
What is the role of protein kinase C in cellular signaling?
Protein kinase C catalyzes the addition of phosphate groups to a soluble protein.
: What is the significance of the soluble protein phosphorylated by protein kinase C?
The soluble protein is the first member of a reaction sequence leading to an appropriate physiological response in the cell.
What other product is generated from the hydrolysis of phospholipase C besides diacylglycerol?
The other product is triphosphoinositol
What effect does triphosphoinositol have in the cell?
Triphosphoinositol causes the release of calcium from intracellular stores
Why is calcium important for protein kinase C activation?
Calcium, along with triacylglycerol, is required for the activation of protein kinase C.
