Vol.3-Ch.4 "Endocrinology" Flashcards
How do endocrine glands differ from other glands? (2)
- they do NOT secrete through ducts like Exocrine glands, they secrete DIRECTLY into the blood supply
- They affect DISTANT tissues with a specific effect on their target tissue or organ but can can cause widespread effects on the body as a whole
What are the 8 major endocrine glands?
- Hypothalamus
- Pituitary Gland
- Thyroid Gland
- Parathyroid Gland
- Thymus
- Pancreas
- Adrenal Gland
- Gonads
Which endocrine gland shrinks as you age and why?
The Thymus is primarily used in the early development of the immune system, and as you grow older it is not needed as much so it shrinks
What are the 7 Hormones secreted by the Hypothalamus?
all target the anterior pituitary = AP which is to say it causes the AP to release other hormones
- Growth Hormone Releasing Hormone (GHRH)
(Stimulates release of Growth Hormone) - Growth Hormone Inhibiting Hormone (GHIH)
(Somatostatin)
(Suppresses release of Growth Hormone) - Corticotropin Releasing Hormone (CRH)
(Stimulates the release of adrenocorticotropic (ACTH)) - Thyrotropin Releasing Hormone (TRH)
(Stimulates release of Thyroid Stimulating Hor. (TSH)) - Gonadotropin Releasing Hormone (GnRH)
(Stimulates release of Luteinizing and Follicle Stim.Hor.) - Prolactin Releasing Hormone (PRH)
(Stimulates the release of Prolactin (PRL)) - Prolactin Inhibiting Hormone (PIH)
(Suppresses release of Prolactin (PRL))
What are the 2 Hormones secreted by the Posterior Pituitary?
- Antidiuretic Hormone (ADH) (Vassopressin)
(Stimulates increased reabsorption of water into blood ; targets kidneys) - Oxytocin
(Stimulates uterine contractions and milk release ; targets uterus and breasts in females , kidneys)
What are the 6 Hormones secreted by the Anterior Pituitary?
- Growth Hormone (GH)
(stimulates growth in childhood; causes switch to fats
as energy source ; targets all cells) - Adrenocorticotropic Hormone (ACTH)
(stimulates release of corticosteroid hormones cortical
and aldosterone ; targets Adrenal Cortexes) - Thyroid Stimulating Hormone (TSH)
(Stimulates release of thyroid hormones thyroxine and
triiodothyronine ; targets the Thyroid) - Follicle Stimulating Hormone (FSH)
(Stimulates development of sex cells (Ovum or Sperm)
; targets ovaries or testes) - Luteinizing Hormone (LH)
(Stimulates release of hormones: estrogen,
progesterone, or testosterone ; targets ovaries or
testes) - Prolactin (PRL)
(Stimulates production and release of milk ; targets
Mammary glands)
What are the 3 Hormones secreted by the Thyroid Gland?
- Thyroxine (T4)
(Stimulates cell metabolism ; targets all cells) - Triiodothyronine (T3)
(Stimulates cell metabolism ; targets all cells) - Calcitonin
(Stimulates calcium uptake by bones, decreasing
blood calcium level ; targets bone)
What is the 1 Hormone Secreted by the Thymus?
- Thymosin
(Stimulates reproduction and functional development
of T lymphocytes ; targets white blood cells especially
T lymphocytes)
What are the 3 Hormones secreted by the Pancreas?
- Glucagon
(Stimulates hepatic gluconeogenesis, increasing
blood glucose levels ; targets All cells but particularly
in the liver, muscle, and fat) - Insulin
(Stimulates cellular upatke of glucose; increases rate
of synthesis of glycogen, proteins, and fats;
decreases blood glucose level ; targets All cells but
particularly in the liver, muscle, and fat) - Somatostatin
(Suppresses secretion of glucagon and insulin within
islets of Langerhans ; targets Alpha and Beta cells in
the pancreas)
What are the 2 hormones secreted by the Adrenal Medulla?
- Epinephrine (adrenaline)
(Stimulates the fight or flight response to stress ;
targets muscle, liver, cardiovascular system) - Norepinephrine
(Stimulates vasoconstriction ; targets muscle, liver,
cardiovascular system)
What are the 3 classes of Steroidal Hormones and the individual Hormones in those classes, secreted by the Adrenal Cortex?
Class of Glucocorticoids:
- Cortisol
(Stimulates glucagon-like effects; acts as anti-
inflammatory and immunosuppressive agents ; targets
most cells particularly white blood cells)
Class of Mineralocorticoids:
- Aldosterone
(Contributes to salt and fluid balance by stimulating
kidneys to increase potassium excretion and decrease
sodium excretion, increasing blood volume)
Class of Androgenic Hormones
- Estrogen
(targets most cells) - Progesterone
(targets uterus) - Testosterone
(targets most cells)
What are the 2 Hormones secreted by the Ovaries?
- Estrogen
(Stimulates development of secondary female sexual
characteristics ; plays role in maturation of egg prior
to ovulation ; targets most cells particularly those of
female reproductive system) - Progesterone (“hormone of pregnancy”)
(Stimulates uterine changes necessary for successful
pregnancy ; targets Uterus)
What is the Hormone secreted by the Testes?
- Testosterone
(Stimulates development of secondary male sexual
characteristics ; plays role in development of sperm
cells ; targets most cells particularly those of the male
reproductive system)
What is the Hormone produced by the Pineal Gland?
- Melatonin
(Released in the response to light ; may help
determine daily, lunar, and reproductive cycle; may
affect mood ; target is unknown)
What makes the hypothalamus special from other glands?
- It is the link between the CNS and the endocrine system
- It receives impulses from the Autonomic system
- It has cells that act as nerve cells and gland cells
What is the difference between the Anterior Pituitary and the Posterior Pituitary relationship with the Hypothalamus?
Which one was previously known as the “Master Gland?
The Anterior Pituitary responds to hormones given off by the Hypothalamus where as the Posterior Pituitary responds to nerve impulses.
The Anterior Pituitary was once known as the “Master Gland” b/c of it’s ability to affect almost all other glands. This was dismissed however when it reliance on the Hypothalamus was discovered which commands the AP and tells it what to release
What is diabetes Insipidus and what is its relationship to Antidiuretics Hormone (ADH)?
It is a disorder marked by large outputs of urine which is caused by a inadequate amounts of ADH compared to blood volume.
Oxytocin (stimulates uterine contractions and lactation) has a relationship with ADH. How is this relationship useful when trying to keep a pregnant woman from delivering pre-term without the use of drugs?
Since Oxytocin and ADH have a similar chemical makeup, oxytocin actually has minor ADH properties.
So a woman can be given an IV bolus to increase the circulating blood volume which is detected by the autonomic nerves in the kidneys. An impulse is then sent to the Hypothalamus to tell the Posterior Pituitary to stop producing so much ADH. This reduction of ADH in turn triggers a decrease in Oxytocin. Hopefully this will cause increased urine output which means its working.
What two hormones have antagonistic effects on Calcium levels that keep it in balance? What gland produces which?
The THYROID Gland produces CALCITONIN that DECREASES calcium levels in the blood by increasing uptake of it into the bones and inhibiting the breakdown of bone tissue
The PARATHYROID produces PARATHYROID HORMONE which INCREASES blood calcium levels via 3 different ways:
- in BONE it (primary target) it causes the release of calcium
- in the INTESTINES it converts vitamin D into it’s active form which causes an increase in calcium absorption
- in the KIDNEYS it causes the reabsorption of calcium
What makes the Pancreas different from the other glands?
It has both exocrine and endocrine tissues
Exocrine to secrete digestive enzymes
What are the names of the endocrine and exocrine tissues in the pancreas?
Exocrine tissue = Acini
Endocrine tissue = Islet of Langerhans
What important 3 cells are created in the Islet of Langerhans in the Pancreas?
What does each cell do?
- Alpha Cells:
Produce Glucagon which breaks down Glycogen into
Glucose. This process of breakdown is called
Glycogenolysis (breakdown or lysing of Glycogen). - Beta Cells:
Produce Insulin which lowers blood sugar by
increasing the uptake of glucose by body cells. It also
promotes energy storage by increasing the synthesis
of glycogen, protein, and fat. It is removed by the liver
within 10-15 minutes after secretion so it must be
secreted constantly. - Delta Cells:
Produce Somatostatin which acts within the Islet of
Langerhans to inhibit the secretion of Glucagon and
Insulin. Note that Somatostatin is the same substance
as Growth Hormone Inhibiting Hormone (GHIH).
Glucagon (secreted by the Pancreas and created by Alpha cells), breaks down _____ into _____ in a process called _____.
Where does this process primarily take place
What is a secondary or backup process caused by glucagon if the first process fails?
Glucagon (secreted by the Pancreas and created by Alpha cells), breaks down Glycogen into Glucose in a process called GLYCOGENOLYSIS (breakdown or lysing of Glycogen).
This primarily takes place in the liver b/c liver cells can store up to 5-8% of their weight as glycogen, as opposed to 1-3% in skeletal muscle.
If the first process fails, Glucagon can also stimulate the liver breakdown of body proteins and fats with chemical conversion to glucose. This process is called GLUCONEOGENESIS (the creation of new glucose), this is not preferred though as it leads to ketone release.
What other gland besides the Hypothalamus has nerve and gland cells?
The Adrenal Medulla
Which is the outer or inner layer of the adrenal gland?
The outer layer is the Adrenal Cortex
The inner layer is the Adrenal Medulla
secretes catecholamine hormones epi and norepi
What are the 3 different steroidal hormones secreted by the Adrenal Cortex (outer layer) and what do they do?
(These are not all that are secreted, just the ones that are steroidal)
- Glucocorticoids
Cortisol is the most important and it increases the
blood glucose levels by promoting Gluconeogenesis
and decreasing glucose utilization as an energy
source. - Mineralocorticoids
Aldosterone is the most important, it contributes to
salt and fluid balance in the body by regulating Na & K
excretion through the kidneys - Androgenic Hormones (Estrogen, Progesterone,
Testosterone)
Have the same effect as those secreted by the
Gonads
The Ovaries and Testes are under the direction of what 2 hormones secreted by what glands?
Follicle Stimulating Hormone (FSH) and Luteinizing Hormone (LH) ; both secreted by the Anterior Pituitary
What other organs can be considered to have endocrine properties but not be considered one of the great endocrine glands?
- Placenta
Produces Human Gonadotropin (hCG) throughout
gestation and is actually what is tested for in at home
pregnancy tests - Walls of the heart
- Kidneys
Release Renin which acts on Angiotensin turning it
into Angiotensin I. Angiotensin I is then turned into
Angiotensin II in the lungs by Angiotensin Converting
Enzyme (ACE). Angiotensin II stimulates the adrenal
gland to produce Aldosterone which stimulates water
retention in the kidneys causing increase blood
volume and blood pressure
Kidneys = Makes renin converts Angiotensin into Ang. I Lungs = Make Angiotensin I into II with ACE Adrenal = Makes Aldosterone b/c of Angiotensin II stim Kidneys = Retains water b/c of aldosterone
Diabetes Insipidus VS Diabetes Mellitus
Diabetes = "To Siphon" Insipidus = "neutral" Mellitus = "sweet"
Insipidus is caused by a lack or inhibition of ADH which causes large amounts of urine output but the urine is neutral in smell and taste
Mellitus is caused by a lack of insulin and the excretion of excess glucose causing sweet smelling and tasting urine
(enough so that it got its name because the pee attracted bees and ants)
Glucose is the only substance that the ____ can readily and efficiently use as an energy source.
Glucose is the only substance that the BRAIN can readily and efficiently use as an energy source.
What is the definition of metabolism?
The sum of the process that produce the energy and molecules needed for cell growth and repair
Anabolism VS Catabolism
The two types of change that can occur in metabolism
- Anabolism
“Ana” = “up” ; which is to say that Anabolism is the building up of molecules into more complex molecules. This takes energy to do and therefore requires energy to drive it. - Catabolism
“Cata” = “down” ; which is to say that catabolism is the break down of molecules into simpler molecules which gives off or produces energy
Is Insulin anabolic or catabolic?
Is Glucagon anabolic or catabolic?
Insulin stimulates anabolic pathways, or to say it stimulates the use of energy to build or repair cells
Glucagon stimulates catabolic pathways, which is to say it gives off or produces energy from the bodies storage
How does insulin allow for the easier (like 10x more easily) uptake of glucose by cells?
It attaches to a cells receptors made of a specific protein that reacts specifically with insulin, and it makes that receptor more permeable so that the glucose go enter quickly and easily
What 2 requirements are there for insulin effectiveness?
- There must be sufficient insulin circulating in the blood to satisfy cellular needs
- Insulin must be able to bind to body cells in such a way that adequate levels of stimulation occur (stimulation of the receptor it binds to)
What conditions may cause fats to be used as energy instead of carbohydrates (glycogen and glucose)?
- low or no insulin
- high fat and low carb diets
- starvation
(all either mess with the ability for carbs to be used or the amount of carbs stored in the body)
What is the process of ketones developing in the blood at high levels?
Adipose cells break down fats into their component free fatty acids, which causes the level of fatty acids in the blood to rise considerably. The fatty acids not used by the body for energy go into the liver where they produce (catabolize into) Acetoacetic acid. When more Acetoacetic acid is released from the liver than can be used by the body it accumulates in the blood along with Acetone and Hydroxybutyric acid (all three together = ketones). As the over all level of these rises it turns into what is called Ketosis.
(not exactly diabetic ketoacidosis but this is a major process of it)
What three substances together are deemed Ketones?
- Acetoacetic Acid
- Hydroxybutyric Acid
- Acetone
What is the normal blood glucose (in mg/dL) of pts before and after a meal if healthy?
Before a meal it should be around 80-90mg/gL
After a meal it should be around 120-140mg/dL
What mg/dL is considered to be Hypoglycemic?
Hyperglycemic?
Hypoglycemic = lower than 80 mg/dL
Hyperglycemic = higher than 140 mg/dL
may be ok if a little higher right after a meal
Briefly describe the filter process of the kidneys in respect to glucose and water?
At what mg/dL does glucose stop being reabsorbed back in and begins to be excreted out with urine?
Blood is filtered into the glomeruli of the kidneys; blood, glucose, and other substances pass from the blood into the proximal tubule. Water and glucose and other useful things are then reabsorbed (the waste is not and becomes part of the urine)
At about 180mg/dL, glucose will no longer fully be absorbed and it will start to be filtered out with the urine.
What is Osmosis?
How does Osmotic Diuresis play a factor when glucose is being excreted out with urine in times of hyperglycemia and how can it lead to dehydration?
Osmosis is the tendency of water to migrate across a semipermeable membrane so that the concentration of particles approach equivalence on each side.
Osmotic Diuresis can be seen in action when there is more glucose being excreted in urine than there is in the blood, such as with hyperglycemia. When the glucose is going through kidney filtration, it eventually goes into the Proximal tubule and what is necessary can come back but any extra (when its above 180mg/dL in the blood) gets excreted with the urine. The problem arises when water begins to follow the higher concentration of glucose in the urine (apply osmosis here) to be excreted. This leads to excessive water loss with high glucose levels which is characteristics of Glycosuria (presence of glucose in urine)
What is Type One Diabetes Mellitus and what is the root cause?
Type 1 Diabetes Mellitus (Juvenile Onset Diabetes ; Insulin-Dependent Diabetes Mellitus (IDDM))
Is the destruction of Beta cells causing very little or usually no insulin to be secreted by the pancreas.
It is less common that type 2 but is more serious and accounts for more deaths.
Often hereditary
Treatment requires regular daily (multiple times a day) injections of insulin
What is Polydipsia?
Polyuria?
Polyphagia?
Polydipsia = Extreme thirst Polyuria = Excessive urination Polyphagia = Extreme appetite
What is Type Two Diabetes Mellitus and what is the root cause?
It is a combo of a moderate decline in insulin production with a decline in response to insulin by the cell receptors (Insulin resistance)
Initial therapy often starts with a change in diet and exercise plan. If that does not help often an oral hypoglycemic agent will be prescribed which will stimulate insulin production by beta cells to increase the amount of insulin in the blood. In extreme cases, insulin injections will be prescribed
Does NOT cause diabetic ketoacidosis nearly as much as type 1
What is the root cause of diabetic ketoacidosis and what can cause the problem?
Profound insulin deficiency coupled with increased glucagon activity.
Can be seen in pts who have skipped their insulin injection, high physiological stress, or infections
Explain how diabetic ketoacidosis arises and how it is sort of caused by a double edged sword.
It is a double edged sword because on one hand you have the excess glucose being secreted out of the urine taking an excessive amount of water with it b/c of osmotic diuresis causing dehydration. While at the same time you have a switch from carb based metabolism to fat based metabolism which will lead to Ketosis. It is the joining of these two processes that causes Diabetic Ketoacidosis
Why is gluconeogenesis not always good or how can it be bad?
It is a reflex of having low amounts of glucose in cells, even though it is actually low amounts of insulin that is causing it. So it creates more glucose anyway b/c the body thinks that is what is wrong, but really it is just causing the blood sugar levels to rise further
What are early vs late signs of ketoacidosis?
How long does the entire process normally take?
Early signs will include diuresis, and resulting warm/dry skin, elevated heart rate and general feelings of weakness. Also polydipsia, polyuria, and polyphagia.
As it progresses you will see Kussmaul’s Respirations (rapid, deep breathing) in an effort to reduce CO2 levels, that may have a fruity smell from the acetones being released by the lungs. Additionally the dehydration that has set in by now may cause electrolyte imbalances and specifically a low potassium level may cause heart arrhythmias
The entire process can take 12-24 hours
What is Hyperosmolar Hyperglycemic State (HHS)?
AKA Hyperglycemic Hyperosmolar Non-ketonic Coma (HHNK)
HHS develops when two things happen:
- sustained hyperglycemia causes osmotic diuresis sufficient to produce marked dehydration
- the water intake is inadequate to replace lost fluids
(essentially it is a coma caused from hyperglycemia, possible to see up to 1000 mg/dL, and dehydration. This occurs with normal levels of insulin, just way too much glucose and urinated water + glucose)
What is Hypoglycemia (Insulin Shock)
Occurs when a pt has taken too much insulin or overexerts themselves and uses almost all available blood glucose. This is obviously bad as glucose is the brains food source so prologues hypoglycemia will cause brain death
May start out with restlessness, then move to anger or erratic behavior, and ending in possible seizure or coma
How can you correct hypoglycemia pharmacologically?
With 50-100mL of Dextrose 50 (D50W)
or
0.5-1.0mg of Glucagon (if IV cannot be started)
(if there is adequate stored glycogen)
if pt awakens and can swallow you can continue therapy orally
If you suspect alcoholism remember to also give 100mg of Thiamine
What are 4 common Thyroid problems that we may see?
- Hyperthyroidism
the presence of excess thyroid hormones in the blood - Thyrotoxicosis
a condition that reflects prolonged exposure of body
organs to excess thyroid hormones, with resultant
changes in structure and function (usually causes
Grave’s Disease - Hypothyroidism
the presence of inadequate thyroid hormones in the
blood - Myxedema
a condition that reflects long-term exposure to
inadequate levels of thyroid hormones, with resultant
changes in structure and function
GO OVER THYROID AND ADRENAL GLAND DISORDERS
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GO OVER THYROID AND ADRENAL GLAND DISORDERS
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