ENDOCRINOLOGY Flashcards
2 PHYSIOLOGIC REGULATORY SYSTEMS
Significant in order to maintain stable internal
environment; to ensure homeostasis which
describes a continuously ongoing process allowing the body to function at an optimal level
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ENDOCRINOLOGY
Endocrine system
Nervous system
-Neuroendocrine system
Release of chemical (Neurotransmitter) across synapse
Effect will be restricted to those target cells actually innervated
Effect will be generated within milliseconds
Nervous System
Release of chemical (hormone) into bloodstream
Effect can be on many target cells spread
throughout the body
Effect will take place over a relatively long
time span ranging from seconds to days
Endocrine System
TYPES OF GLANDS
Endocrine
Exocrine
Ductless glands; the hormones will be
directed towards the circulatory system
reaching its target tissue/organ
Products/chemicals: ___
Endocrine
- hormones
Contains ducts; are
attached to specific ducts and the
secretion are released directly towards the
outer body surface or in the internal organs
Products: ___,__,__
Exocrine
- enzyme, mucus, sweat
A network of ductless glands that secret hormones directly into the blood.
considered to be the regulatory system of the body.
It is regulated by means of control of hormone
synthesis rather than by degradation
ENDOCRINE SYSTEM
TYPES OF ENDOCRINE CONTROL
POSITIVE FEEDBACK
NEGATIVE FEEDBACK
An increased in the product also increases the
activity of the system and production rate
Increased need for a particular compound
= increased hormone to be released
Ex: __ and __
POSITIVE FEEDBACK
- gonadal hormone & adrenocortical
hormone
An increased in the product decreases the activity of the system and the production rate
Once the hormone was released and has
caused a significant effect/ increase in a
particular product, automatically the body
signals the particular gland to stop
releasing hormones.
Ex._____
NEGATIVE FEEDBACK
- Luteinizing hormone
MAJOR GLANDS OF ENDOCRINE SYSTEM
Pituitary Gland
Thyroid Gland
Parathyroid Gland
Adrenal Gland
Pancreas
Reproductive Glands
(ovaries & testes)
Thymus Gland
Pineal Gland
Are chemical compounds secreted into the blood that affect target tissues generally at a site distant from original production (can also be at immediate site)
- Play an important role in the equilibrium,
homeo stasis, growth, and development of an
organism
- Regulated by the metabolic activity depending on the characteristic of the hormone:
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HORMONE
- Positive Feedback
- Negative Feedback
secreted in one location and release
into blood circulation; binds to specific receptor to elicit physiological response.
Endocrine
secreted in endocrine cells and
released into interstitial space; binds to specific
receptor in adjacent cell and affects its function.
Paracrine
secreted in endocrine cells and
sometimes released into interstitial space; binds to specific receptor on cell of origin resulting selfregulation of its function
Autocrine
secreted in endocrine cells and
remains in relation to plasma membrane; acts on immediately adjacent cell by direct cell- to –cell contact.
Juxtacrine
secreted in endocrine cells and
released into lumen of gut; it affects their function
Exocrine
secreted in neurons and released
into extracellular space; binds to receptor nearby cell and affects its function.
Neurocrine
secreted in neurons and
released from nerve endings; interacts with
receptors of cells at distant site.
Neuroendocrine
secreted in the endocrine cells and
remained as well as function inside the synthesis of origin.
Intracrine
HORMONAL INTERACTION
Pertains to activity/actions of hormones that are not stand alone. Some hormones need other organs to make its activity more potent and effective.
When two or more hormones work
together to produce a particular result.
May be complimentary or additive
Synergistic
When the action of a second hormone enhances the responsiveness of a target organ to the
second hormone, or when it increases
the activity of the second hormone
Permissive
The actions of on hormone antagonize
the effects of another
Antagonistic
from hypothalamus; promote
secretion of Ant. Pituitary hormones
Ex: __ and __
Releasing hormones
-Thyrotropin-releasing
hormone, Somato
from hypothalamus & GIT; suppress the secretion of a particular hormone
Ex: ____
Inhibitory hormones
- Somatostatin/ growth
inhibitory hormone
stimulate growth & activity of
other endocrine glands
Tropic hormones
secreted by all endocrine glands & w/ non endocrine cells as targets
Effector hormones
Synthesized and stored within the cell in the form of secretory granules and are cleaved as needed.
Cannot cross the cell membrane due to their large molecular size
Water soluble and not bound to carrier protein
PEPTIDES & PROTEINS
Glycoprotein
TSH, LH, FSH, HcG, EPO
Polypeptides
GHRH, CRH, TRH, GnRH,
Somatostatin, PRF, ADH, Oxytocin,
GH, ACTH, PRL, Calcitonin, PTH,
Insulin, Glucagon
Lipid molecules that have cholesterol as a common precursor.
Produced by: ___, ____, ___ and ____
Water insoluble (hydrophobic) and circulate bound to a carrier protein
Example: __,_____,___,___,___
STEROIDS
- Adrenal glands, ovaries, testes &
placenta
- Cortisol, Aldosterone, Estrogen,
Progesterone, Testosterone
( those having cholesterol as precursor ends with “ol” or “one)
Derived from an amino acid and they are
intermediary between steroid and protein
hormones.
Not considered as polypeptides/proteins
Example: ___,____,____,___,____
AMINES
- Melatonin, Serotonin, Thyroid
hormones (T3 & T4), Epinephrine,
Norepinephrine
Derived from fatty acids
with 20 carbon atom fatty acid (arachidonic fatty acid), involved in cellular activity
Example: ___,___,___
EICOSANOIDS
- Prostaglandin, Thromboxane,
Leukotrienes
Portion of the brain located in the walls and third floor of the third ventricle.
Lies around the 3RD VENTRICLE in the brain
Above the pituitary gland and is connected to the ____
Serve as the link between the nervous system and endocrine system.
HYPOTHALAMUS
-Infundibulum
Regulates endocrine system
- is responsible for releasing compounds that are significant in
the regulation of the pituitary gland
HYPOTHALAMUS
lies at the front of the hypothalamus, and has
an important role in sight
Anterior: OPTIC CHIASMA
at the back of the hypothalamus is important in the development of the nervous system
Posterior: MAMMILLARY BODY
secretes compounds toward the
pituitary gland in order for the hypothalamus to regulate compounds which will be released by the pituitary gland.
Neurons
There is release of triiodothyronine so the thyroid
hormones which are already present in the blood
circulation will stop the Ant. Pituitary and Hypothalamus from further inducing the release of
hormones which will stimulate the release of thyroid gland. The negative feedback mechanism tells the Ant. Pituitary to stop/decrease the release of TSH. Also, in order to decrease TSH release, the
hypothalamus must also decrease the TRH release.
Open-loop negative feedback mechanism
in circulation means if the thyroid
hormone already decreases, the hypothalamus and
ant. Pituitary can go back again to promote the release of hormones in order to induce again the release of thyroid hormone.
Open-loop negative feedback mechanism
All anterior pituitary hormones are secreted in pulsatile fashion. This dictates how frequent the endocrine glands release a particular hormone. The release of compounds is by intervals.
Pulsatility (pulse frequency of secretion)
In variables during blood extraction, we consider diurnal/circadian rhythm of a
compound. These are applicable in
hormones. This means that the level of hormones vary depending on the time of the day that the sample is obtained. Majority of ant. Pituitary hormones have diurnal/circadian variation.
Cyclicity
HORMONES OF THE HYPOTHALAMUS categories
Target: Activity of Pituitary gland
RELEASING HORMONES
INHIBITING HORMONES
- Activity of Pituitary gland
stimulates the production of
TSH (Thyroid Stimulating
Hormone
TRH (Thyrotrophin
Releasing Hormone)
stimulates the production of
ACTH (Adrenocorticotrophic
Hormone)
CRH (Corticotrophin
Releasing Hormone)
stimulates production of GH
(Growth Hormone)
GHRH ( Growth
Hormone Releasing
Hormone)
stimulates production of FSH
(Follicle Stimulating Hormone),
LH (Luteinizing Hormone)
GnRH (Gonadal
Releasing Hormone)
stimulates production
prolactin
PRF (Prolactin
Releasing Factor)
Inhibit Release-Inhibiting
Hormone)
GHIH (Growth Hormone
Inhibitory Hormone)
aka Somatostatin
aka SRIH (Somatotropin
Inhibits release of
Prolactin
PIF (Prolactin Inhibiting
Factor)
secretion is stimulated by systemic physiologic stress via:
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Corticotropin Releasing Hormone (CRH)
Neurons of subfornical origin
Neurons of nucleus tractus solitarius
Hypothalamic glutamatergic neurons
Hydroxytryptamine-secreting neurons
Corticotropin Releasing Hormone (CRH)
Physiologic stimulus – ___,___,___
____– inhibitory neurotransmitter
CRH specifically affects ACTH release which is affected by the level of___,___,___
- stress, inflammation,
hypoglycemia
-GABA (gamma-aminobutyric acid) - serotonin, endorphins,
acetylcholine
Tripeptide hormone; the release is regulated by this secreting neurons in the paraventricular nucleus. This are innervated by the
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- secretion is dependent on energy state and temperature of the organism.
- directs its effect on the release of
TSH which in turn affects the release of hormones from thyroid gland.
Thyrotropin Releasing Hormone (TRH)
- Leptin
- Neuropeptide Y & AgRP (Agouti
related protein)
produced by adipose tissue →
acts to reduce appetite and raise
energy expenditure as body fat
stores rise
Leptin
promote food intake
Neuropeptide Y & AgRP (Agouti
related protein)
Produced by neurons in the arcuate nucleus of the medial basal hypothalamus
Simulators: ___,__,___
___ is a neuropeptide expressed in endocrine, CNS, and PNS
___ - suppresses both GHRH and GH
__ and ____ - increasing GHRH and GH secretion
____ is from stomach which promotes food intake
Growth Hormone Releasing Hormone (GHRH)
-dopamine and galanin-secreting
neurons, brainstem neurons w/ catecholaminergic
inputs
- Galanin
- SRIH (Somatostatin release-inhibiting hormone)
- Leptin and Ghrelin
- Ghrelin
Regulates the release of FSH & LH; the regulatory mechanism varies on the patient’s status specifically its menstrual cycle
- secretion is stimulated by neurons that secrete:
Galanin-like peptide (GALP)
Kisspeptin – regulates puberty and reproduction
Glutamate
Neuropeptide Y
Norepinephrine
GABA
Acetylcholine
Stimulates gonadotropin release
Suppressed by: __,__,___
Gonadotropin-releasing Hormone (GnRH)
- endorphins, dopamine, serotonin
Found in 3rd cerebral ventricle of brain and midline
Attached to midbrain
Termed, bc it looks like a pine cone with latin term of “pinea”
Produces melatonin (regulates circadian rhythm)
-Tryptophan based hormone; decreases the pigmentation of the skin
- Secretion are controlled by nerve stimuli
PINEAL GLAND| CONARIUM| EPIPHYSIS CEREBRI
