Endocrine System Intro to Hormones Flashcards
- Classically endocrine glands were thought to secrete chemicals called hormones (in Greek, to excite or set into motion) that regulate or coordinate a wide variety of physiological processes.
- Survival of multicellular organisms depends on their ability to adapt to a constantly changing environment and modify their homeostasis in response to these changes.
- Classically endocrine glands were thought to secrete chemicals called hormones (in Greek, to excite or set into motion) that regulate or coordinate a wide variety of physiological processes.
- Survival of multicellular organisms depends on their ability to adapt to a constantly changing environment and modify their homeostasis in response to these changes.
•Functions to integrate and coordinate the actions of various organs and tissues.
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•Acts in concert with nervous system -neuroendocrine system - but has a longer latent period and a sustained effect.
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•Endocrine cells arranged individually, in cords, clumps or follicles.
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•Functions to integrate and coordinate the actions of various organs and tissues.
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•Acts in concert with nervous system -neuroendocrine system - but has a longer latent period and a sustained effect.
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•Endocrine cells arranged individually, in cords, clumps or follicles.
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- Removing the gland causes a ___
- Giving back an___ from the gland corrects the deficit.
- Effective in ___ amounts
___ regulators
____ Balance
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It wouldn’t be good to remove an endocrine gland.
You affect bodies ability to control whatever they control
You don’t secrete large amts of hormone
Thyroid can store hormone in large amts but most don’t do that.
They make it and secrete it.
- Removing the gland causes a deficit
- Giving back an extract from the gland corrects the deficit.
- Effective in minute amounts
- Physiogical regulators
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•Homeostatic Balance
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It wouldn’t be good to remove an endocrine gland.
You affect bodies ability to control whatever they control
You don’t secrete large amts of hormone
Thyroid can store hormone in large amts but most don’t do that.
They make it and secrete it.
–Amines
- Example-___
- Mostly water soluble
–Small peptides (___ amino acids)
- Example-_____
- Mostly water-soluble.
–Polypeptides (___ amino acids)
- Example-___
- Mostly water-soluble.
–Proteins (___+ amino acids
- Example-__ __
- Mostly water soluble
–Amines
- Example-epinephrine
- Mostly water soluble
–Small peptides (3-9 amino acids)
- Example-Antidiuretic Hormone (ADH)
- Mostly water-soluble.
–Polypeptides (10-100 amino acids)
- Example-Insulin
- Mostly water-soluble.
–Proteins (100+ amino acids
- Example-Growth Hormone
- Mostly water soluble
–Glycoproteins (protein + carbohydrate)
- Example-__ __ ___
- Mostly water soluble
–Iodinated thyroid proteins (protein + iodine)
- Example-___
- Mostly water soluble.
–Steroid Hormones
- Example-___ and ___
- Lipid soluble!
–Prostaglandins and Cytokines
–Glycoproteins (protein + carbohydrate)
- Example-Thyroid Stimulating Hormone (TSH)
- Mostly water soluble
–Iodinated thyroid proteins (protein + iodine)
- Example-Thyroxine
- Mostly water soluble.
–Steroid Hormones
- Example-Estrogen and Testosterone
- Lipid soluble!
–Prostaglandins and Cytokines
Two hormone categories based on solubility:
HYDROPHYLIC versus LIPOPHYLIC HORMONES
HYDROPHYLIC HORMONES:
- Circulate in the blood largely dissolved in blood plasma.
- Since they cannot cross the plasma membrane of the cell, they bind to specific receptors present on the surface of the cell.
- Primarily act through the second-messenger system to alter the specific activity of preexisting proteins, such as certain enzymes, within the target cell to produce their desired physiological response.
- Famous Examples: Peptide hormones, Catecholamines
LIPOPHYLIC HORMONES:
- Since they cannot dissolve in blood plasma, they circulate in the blood by specific binding to plasma proteins.
- They readily cross the cell plasma membrane and bind to intracellular receptors which leads to the expression of specific genes, resulting ultimately in the synthesis of new proteins inside the target cell that carry out the desired physiological response.
- Famous Examples: Steroid hormones, Thyroid hormones
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Two hormone categories based on solubility:
HYDROPHYLIC versus LIPOPHYLIC HORMONES
HYDROPHYLIC HORMONES:
- Circulate in the blood largely dissolved in blood plasma.
- Since they cannot cross the plasma membrane of the cell, they bind to specific receptors present on the surface of the cell.
- Primarily act through the second-messenger system to alter the specific activity of preexisting proteins, such as certain enzymes, within the target cell to produce their desired physiological response.
- Famous Examples: Peptide hormones, Catecholamines
LIPOPHYLIC HORMONES:
- Since they cannot dissolve in blood plasma, they circulate in the blood by specific binding to plasma proteins.
- They readily cross the cell plasma membrane and bind to intracellular receptors which leads to the expression of specific genes, resulting ultimately in the synthesis of new proteins inside the target cell that carry out the desired physiological response.
- Famous Examples: Steroid hormones, Thyroid hormones
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•A single endocrine gland may produce multiple hormones. Example: the __ ___ gland secrets six different hormones, each having a distinct function.
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- A single hormone may be secreted by more than one endocrine gland. Example: ___n is secreted by both the ___ and ___•
- A single hormone may have multiple target-cell types which allows coordination of the activities of various tissues toward a common end. Example: the effects of the hormone insulin on muscle, liver, and fat all act in concert to store nutrients after the absorption of a meal.
- A single target cell may be influenced by more than one hormone and sometimes these hormones can have the opposite effect on the same target cell. Example: Insulin promotes the conversion of glucose into glycogen within liver cells by stimulating one particular hepatic enzyme; whereas another hormone, glucagon, by activating yet another hepatic enzyme in the same target cell, enhances the degradation of glycogen into glucose within liver cells.
•A single endocrine gland may produce multiple hormones. Example: the anterior pituitary gland secrets six different hormones, each having a distinct function.
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•A single hormone may be secreted by more than one endocrine gland. Example: Somatostatin is secreted by both the hypothalamus and the pancreas.
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•A single hormone may have multiple target-cell types which allows coordination of the activities of various tissues toward a common end. Example: the effects of the hormone insulin on muscle, liver, and fat all act in concert to store nutrients after the absorption of a meal.
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•A single target cell may be influenced by more than one hormone and sometimes these hormones can have the opposite effect on the same target cell. Example: Insulin promotes the conversion of glucose into glycogen within liver cells by stimulating one particular hepatic enzyme; whereas another hormone, glucagon, by activating yet another hepatic enzyme in the same target cell, enhances the degradation of glycogen into glucose within liver cells.
Development, Growth and Stress
1___-___ through ___
- ___
- ___
4____y production, storage, and use
Diff hormones can act at diff times.
Some will act thruout our life
Development, Growth and Stress
- Differentiation-conception through puberty
- Reproduction
- Growth
- Energy production, storage, and use
Diff hormones can act at diff times.
Some will act thruout our life
- Adaptation to stress
a. ____-shift in blood flow
b. ___metabolism, ANS
c____s-pain balance
d.___ ___ ____ e-water balance
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5.Adap
- Adaptation to stress
a. Epinephrine-shift in blood flow
b. Cortisol-metabolism, ANS
c. Endorphins-pain balance
d. Antidiuretic Hormone (vasopressin), Aldosterone, Atria Natriuretic Hormone-water balance
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Determinants of the Concentration of a Hormone at a Target Cell
1___ of Synthesis
- ___ of the hormone concentration. Typically acts in high concentration near the site of release (insulin/glucagon-liver) or lower concentration farther from release (pituitary- target organs)
- Disassociation constant from ___ proteins, if any
- Conversion of___ or less active form to a more active form- T4 T3
- Rate of ___ of the hormone-minutes versus hours
How much of a hormone is enough at a cell
Rate of syn Determines how much will be in the bloodstream
As it goes to the blood stream it is diluted out. Lower levels further away from the release
Autocrine vs Endocrine
Autocrine: High conc present. Maybe Not as many receptors present. You trying to get as much hormone to target what few receptors are present.
Endocrine: Maybe the cells express lots of receptors so it doesn’t take much hormone to activate the cell at a distant site
Paracrine: Often express receptors close to where the receptor is coming from
T3 is the more active form.
Most of what you release is T4.
T3 has higher affinity.
Can also internalize receptors so that it can’t be stimulated again.
Determinants of the Concentration of a Hormone at a Target Cell
- Rate of Synthesis
- Dilution of the hormone concentration. Typically acts in high concentration near the site of release (insulin/glucagon-liver) or lower concentration farther from release (pituitary- target organs)
- Disassociation constant from carrier proteins, if any
- Conversion of inactive or less active form to a more active form- T4 T3
- Rate of clearance of the hormone-minutes versus hours
How much of a hormone is enough at a cell
Rate of syn Determines how much will be in the bloodstream
As it goes to the blood stream it is diluted out. Lower levels further away from the release
Autocrine vs Endocrine
Autocrine: High conc present. Maybe Not as many receptors present. You trying to get as much hormone to target what few receptors are present.
Endocrine: Maybe the cells express lots of receptors so it doesn’t take much hormone to activate the cell at a distant site
Paracrine: Often express receptors close to where the receptor is coming from
T3 is the more active form.
Most of what you release is T4.
T3 has higher affinity.
Can also internalize receptors so that it can’t be stimulated again.
Hormonal Adjustment
- In general, hormones either work together or have opposing effects.
Hormonal Adjustment
- In general, hormones either work together or have opposing effects.
2.Hormones do not ___ reactions, but instead they just ___ or ___ the ___of the reaction.
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Many times they do this by having___ effects on a pathway.
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2.Hormones do not initiate reactions, but instead they just INCREASE or DECREASE the speed of the reaction.
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Many times they do this by having opposing effects on a pathway.
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3.Must distinguish between physiological and pharmacological effects.
Gastric Inhibitory Peptide’s (GIP) effects on gastric motility are pharmacological, but its effect on insulin secretion is physiological and it is now called Glucose-dependent Insulinotrophic Polypeptide (GIP). GIP is one of the few feed-forward hormones.
If you give a drug at a certain [] you may get an effect. Often called a pharm effect.
Pharm: Given at such a high dose you got a response; maybe not the same response of low dose
Physi: Dose of body
High enough dose it will act on GI but that’s not its true fcn
At its true physiological conc, it will have certain effect.
If you increase that dose high enough you can get pharm effect that is diff from physio effect
3.Must distinguish between physiological and pharmacological effects.
Gastric Inhibitory Peptide’s (GIP) effects on gastric motility are pharmacological, but its effect on insulin secretion is physiological and it is now called Glucose-dependent Insulinotrophic Polypeptide (GIP). GIP is one of the few feed-forward hormones.
If you give a drug at a certain [] you may get an effect. Often called a pharm effect.
Pharm: Given at such a high dose you got a response; maybe not the same response of low dose
Physi: Dose of body
High enough dose it will act on GI but that’s not its true fcn
At its true physiological conc, it will have certain effect.
If you increase that dose high enough you can get pharm effect that is diff from physio effect
Types of Chemical Messengers
- Hormones
- Neurohormones or Neurohumors
- Autocrine
- paracrine
- __
- ___
Types of Chemical Messengers
- Hormones
- Neurohormones or Neurohumors
- Autocrine
- Paracrine
- Juxtacrine
- Parahormone
Endocrine and Related Secretions Either:
- Reach__ ___
- __ __
- Reach General Circulation
- Act locally
Comparison of the Endocrine and Nervous System
- ___of Action
- ___
- ____of Action
- ____-how they work together
NS quick on quick off
ES: turns on slower, prolonged effect
Both are distributed all around the body but endocrine seems to be conc in specific place and NS is distributed everywhere
Both are very selective
If neuron synapses with something, nt released and act on that something. If neuron synapses on something, it will act on it.
ES: They are selective. Need receptor for it to act on it. Something could be right next to a hormone but if it doesn’t have a receptor, there will be no effect
•Speed of Action
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•Distribution
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•Selectivity of Action
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•Interrelationships-how they work together
NS quick on quick off
ES: turns on slower, prolonged effect
Both are distributed all around the body but endocrine seems to be conc in specific place and NS is distributed everywhere
Both are very selective
If neuron synapses with something, nt released and act on that something. If neuron synapses on something, it will act on it.
ES: They are selective. Need receptor for it to act on it. Something could be right next to a hormone but if it doesn’t have a receptor, there will be no effect
If you have a cell and it has an insulin receptor to it, it may not have a glucagon receptor on it but inside the cell it is genetically capable of making one, but those genes are repressed
If you have a cell and it has an insulin receptor to it, it may not have a glucagon receptor on it but inside the cell it is genetically capable of making one, but those genes are repressed
- The hormone-receptor interaction causes a conformational change to the receptor, which leads to a physiological signal being generated.
- For this to occur, the cell must be genetically programmed to:
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- The hormone-receptor interaction causes a conformational change to the receptor, which leads to a physiological signal being generated.
- For this to occur, the cell must be genetically programmed to:
–Form the receptor
–Respond to binding of the receptor
- Hormone = Ligand
- Agonist: More than one hormone may bind to the ___ receptor and ____ it. They are “agonists” for that receptor.
–Example-adrenal epinephrine and norepinephrine both bind to the __ receptors of the heart.
•Antagonist: a substance that binds to a receptor bu___ activate it. Thus, the antagonist prevents normal receptor activation via ligand binding.
–Example- ___ inhibiting the action of ___n by binding to the stomach gastrin receptors
- Hormone = Ligand
- Agonist: More than one hormone may bind to the same receptor and activate it. They are “agonists” for that receptor.
–Example-adrenal epinephrine and norepinephrine both bind to the b1 receptors of the heart.
•Antagonist: a substance that binds to a receptor but doesn’t activate it. Thus, the antagonist prevents normal receptor activation via ligand binding.
–Example- CCK inhibiting the action of gastrin by binding to the stomach gastrin receptors
Regulation of Physiological Responses at
1.
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2
Regulation of Physiological Responses at
1.Membrane Receptors
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2.Regulatory “G” Proteins
____hormones may have the same receptors and the same Gstimulatory Protein (GS) and cause the same physiological effect.
__- and ____ (___) causing___
HARBGS2 IP3
HBRBGS2 IP3
Different hormones may have the same receptors and the same Gstimulatory Protein (GS) and cause the same physiological effect.
Epinephrine and Norepinephrine α1 ( IP3) causing vasoconstriction
HARBGS2 IP3
HBRBGS2 IP3
Different hormones may use ____ receptors, but use the same GS Protein to cause the same physiological effect.
__- nd ___ to ____
HARAGS1 c-AMP
HBRBGS1 c-AMP
Different hormones may use different receptors, but use the same GS Protein to cause the same physiological effect.
Epinephrine and glucagon to glycogenolysis
HARAGS1 c-AMP
HBRBGS1 c-AMP
The same hormone may have different receptors, different GS Proteins, and different second messengers resulting in different physiological effects.
Example: ___e affects different receptors (___ and ___) on vascular smooth muscle cells, which activate different G-proteins. This leads to the release of different second messengers causing different physiological effects, vasoconstriction or vasodilation, respectively.
HARAGS1 c-AMP ___
HARBGS2 IP3 ___
The same hormone may have different receptors, different GS Proteins, and different second messengers resulting in different physiological effects.
Example: epinephrine affects different receptors (α1 and b2) on vascular smooth muscle cells, which activate different G-proteins. This leads to the release of different second messengers causing different physiological effects, vasoconstriction or vasodilation, respectively.
HARAGS1 c-AMP vasoconstriction
HARBGS2 IP3 vasodilation
Some hormones influence another type of G-Protein, a GInhibitory Protein (Gi-Protein). Activation of Gi-Proteins causes a ____ in second messenger.
HARAGi c-AMP
Some hormones influence another type of G-Protein, a GInhibitory Protein (Gi-Protein). Activation of Gi-Proteins causes a decrease in second messenger.
HARAGi c-AMP
Some hormones have very similar s____, but different___.
Because of the structural similarity between the hormones they show a ___ degree of binding to the other hormone’s receptors.
If one hormone’s concentration is pathologically ___ it may have an effect on the other hormone’s receptors.
___ and ___activity when they are in pathological levels, as seen in ____disease.
___ and ___
Made in two different nuclei
Because of where they are made they have similar structure.
Some hormones have very similar structures, but different receptors. Because of the structural similarity between the hormones they show a small degree of binding to the other hormone’s receptors.
If one hormone’s concentration is pathologically high it may have an effect on the other hormone’s receptors.
Glucocorticoids have mineralcorticoid activity when they are in pathological levels, as seen in Cushing’s disease.
ADH and oxytocin
Made in two different nuclei
Because of where they are made they have similar structure.
Normal concentration of HA HARATF mRNA
Normal concentration of HB HBRATF slight mRNA
Pathogical concentration of HB HBRATF mRNA
With a higher than normal concentration of HB it has a greater probability of interacting with RA receptors
TF = Transcription Factors/DNA
Normal concentration of HA HARATF mRNA
Normal concentration of HB HBRATF slight mRNA
Pathogical concentration of HB HBRATF mRNA
With a higher than normal concentration of HB it has a greater probability of interacting with RA receptors
TF = Transcription Factors/DNA
Negative Feedback Control
of Hormones
1.Ultra short loop
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2.Short loop
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3.Long loop
1.Ultra short loop
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2.Short loop
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3.Long loop
Negative feedback provides for a__ ___ of secretion. It dampens rapid____ fluctuations in the secretion of the hormone.
However, this method does not provide for adjustments in hormone secretion during changing ___, such as ___ ___ ____s demands.
For the ___/ __ these changes are directed by the __ __ __, which overrides the ___ feedback
Negative feedback provides for a steady state of secretion. It dampens rapid large fluctuations in the secretion of the hormone.
However, this method does not provide for adjustments in hormone secretion during changing needs, such as metabolic, reproductive, and stress demands.
For the hypothalamus/anterior pituitary these changes are directed by the central nervous system, which overrides the negative feedback
Feedback may be:
___e on hormone:
___ on hormone:
___l on hormone:
While not as prominent, Positive Feedback also is present. Example - Oxytocin release during childbirth
Feedback may be:
Hormone on hormone: Cortisol on ACTH
Substrate on hormone: glucose on glucagon
Mineral on hormone: Calcium inhibition of PTH
While not as prominent, Positive Feedback also is present. Example - Oxytocin release during childbirth
- Excessive, deficient, or inappropriate production or release of hormones and their subsequent intracellular regulatory molecules are a major cause of disease.
- Many pharmacotherapeutic agents are aimed at correcting or otherwise influencing deficient or aberrant actions of hormones.
- Often some form of Hormone Replacement Therapy (HRT) is used.
- Excessive, deficient, or inappropriate production or release of hormones and their subsequent intracellular regulatory molecules are a major cause of disease.
- Many pharmacotherapeutic agents are aimed at correcting or otherwise influencing deficient or aberrant actions of hormones.
- Often some form of Hormone Replacement Therapy (HRT) is used.
