Chapter 17 Endocrine Part 2 Flashcards
prevents hormones from being broken down by hydrolytic enzymes after entering the blood stream
binding proteins
act as chaperones=
protect hormone and remain intact and functional when arrive at target
when hormones attach to binding proteins=
bound hormones
hormones bind to specific what
binding proteins
testosterone binds to
testosterone-binding globulin
progesterone bind to
progesterone-binding globulin
binding proteins reversible action is
detaching at target tissues
when binding proteins are detachs it means
free hormones
some binding proteins are always free which means
not having specific binding proteins
only free hormones can diffuse through what and bind what
capillary walls and bind target tissue
if binding proteins are bound it means it is
too bid to diffuse through
bound hormones=
reservoir for hormones and if hormone levels decrease, bound hormone releases from binding protein
what are water-soluble hormones
LH
TSH
ADH
PTH
insulin
EPI
can water-soluble hormones pass through cell membrane
no
what can water-soluble hormones travel easily in
the blood
what are lipid-soluble hormones
steroids- testosterone, estrogen
thyroid hormones
can lipid-soluble. hormones pass through cell membrane
yes
what are two classes of receptors
nuclear and membrane-bound
what receptor is bound by lipid-soluble hormones=
nuclear receptors
what receptor is bound by water-soluble hormones
membrane-bound receptors
lipid soluble hormones are small and nonpolar or large and polar
small and nonpolar
where are nucleus receptors usually found
in the nucleus
sometimes in cytoplasm
what do nuclear receptors modify
gene transcription
what do nuclear receptors stimulate
synthesis of new proteins
do nuclear receptors have a rapid effect on target cells
yes
what binds to DNA to stimulate protein synthesis
hormone-receptor complex
testosterone stimulates protein synthesis->
secondary sexual characteristics
are membrane bound receptors small or large
large
are membrane bound receptors able to pass through the plasma membrane
no
hormone- receptor complex initiates cell response bound by
proteins, amino acid derivatives
3 types of membrane-bound receptors
- ligand-gated ion channels
- g protein-couple receptors
- enzymatic receptors
what membrane bound receptor is bound by neurotransmitter and open gates to allow Na+, K+, Cl-, Ca2 ions through
ligand gated ion channels
what is the most common membrane bound receptor
g protein- coupled receptors
what membrane bound receptor does extracellular signal to intracellular signal
g protein coupled receptors
what activated protein kinase in g protein couple receptors
cAMP
what membrane bound receptor is linked to enzymes in target cell
enzymatic receptors
examples of enzymatic receptors
Guanylate Cyclase Receptors, Receptor Tyrosine Kinases
are hormone concentrations stable in the blood stream
yes
what kind of hormones are more stable
large/ more complex
what varies according to chemical composition
lifespan
the amount of time it takes for 50% of circulating hormone to be removed from circulation and excreted, which is again variable timefrime
half life
what is a 3 AA hormone that is simple with short half life and degrades quickly in circulation
TRH
steroid hormone with longer half life= lipid soluble and takes longer to degrade
cortisol
all hormones are destroyed in
circulation or by enzymes at target cell
destruction limits the
time of activity
what type of hormones have shorter half lives
water soluble
water soluble hormones are quickly broken down by
hydrolytic enzymes in the blood
once water soluble hormones are broken down what removes the hormone products from the blood
kidneys
when else can target cells be destroyed
when they are internalized via endocytosis
are parts of the hormones reused to make new proteins
yes
so short half life has concentrations that change rapidly in the blood and tend to regulate what
activities with rapid onset and short duration
what are three ways to prevent destruction or hormones
- have carb attached to them
- modified terminal end
- binding proteins
when you have a carb attached to the hormone what is it now
glycoprotein
when a hormone has a modified terminal end this does what
provided protection from protease activity which makes it last longer
when a hormone has a binding protein this causes
circulation to last longer than free water-soluble hormones
hormones specifically bind to receptor where
at binding site
is there specificity in hormones
yes, each are designed to have a specific receptor
example of lock and key
thyroid hormone binds to throid receptor not other hormone receptors due to specificity
some hormones have what ability in regards to binding
they can bind to a family of receptors similar in structure with different effects
do hormones have the same effect on different target areas
no different effects
how many targets to epinephrine have
1
what does epinephrine stimulate
smooth muscle contraction and smooth muscle relaxation in another
receptors have a high what
binding affinity
receptors have high binding affinity for what
hormones that bind to them
when is small concentration affective
in activation of higher number of receptors
does target tissue sensitivity of hormone levels vary
yes
how do we optimize target tissue response
increase the number of receptors
if there is down regulation of receptors what does this result in
target tissue will be desensitized
is nutrients and energy level decreases cell is
unable to respond to hormone
what is densensitization
it is where the number or receptors quickly drops after hormonal exposure
target cells internalize receptors and
destroys them
up-regulation of receptors does what
increase sensitivity
increase sensitivity cause increase rate of
receptor synthesis in target cells
the increase rate of receptor synthesis in target cells causes
increase in total number of receptor molecules in the cell
what are three types of hormonal interactions
- permissive
- synergistic
- antagonistic
Hormones help one another, otherwise weaker response by target tissue. Example: TH promotes synthesis of Epinephrine Receptors in the Heart. Need to monitor a Hyperthyroid individual.
permissive
2+ synergistic hormones exert effects on target tissue. Increased response compared to 1 hormone only. Example: Reproductive Steroid hormones work with Hypothalamic hormones to lead to Synthesis of Gonad regulating Tropic Hormones (FSH, LH)
synergistic
Hormones oppose one another TIGHT regulation of a specific parameter. Example: PTH & Calcitonin regulating Blood Calcium levels. Also Insulin & Glucagon to control Blood Glucose levels.
antagonistic
drugs similar in design to certain hormones compete for
the same receptor
if drug binds to receptor and leads to activation it is
agonist
the medication in asthma inhalers MIMIC epi which result in
smooth muscle in lung bronchioles to relax
medication to prevent stroke are epi antagonist which do what
prevent epinephrine-stimulated platelet aggregation and prevent blood vessel bloackage
