Intro Flashcards
Hormones released by the hypothalamus include:
Hormones released by the hypothalamus include:
* CRH- corticotropin-releasing hormone
* TRH- thyrotropin-releasing hormone
* Somatostatin
* Dopamine
* GHRH- growth hormone-releasing hormone
* GnRH- gonadotropin-releasing hormone
CRH stimulates the release of _ from the anterior pituitary
CRH stimulates the release of ACTH from the anterior pituitary
* ACTH acts on the adrenal glands to release cortisol
TRH stimulates the release of _ from the anterior pituitary
TRH stimulates the release of TSH from the anterior pituitary
* Note that TRH can also nonspecifically stimulate prolactin release
Somatostatin, released from the hypothalamus, functions to inhibit _
Somatostatin, released from the hypothalamus, functions to inhibit TSH, Prolactin, GH
Dopamine, released from the hypothalamus inhibits the secretion of _ from the anterior pituitary
Dopamine, released from the hypothalamus inhibits the secretion of prolactin from the anterior pituitary
GHRH stimulates the anterior pituitary to secrete _
GHRH stimulates the anterior pituitary to secrete GH
GnRH stimulates the anterior pituitary to secrete _
GnRH stimulates the anterior pituitary to secrete LH/FSH
ACTH acts on its target organ _ to secrete _
ACTH acts on its target organ adrenal gland to secrete cortisol and aldosterone
TSH acts on its target organ _ to secrete _
TSH acts on its target organ thyroid glands to secrete T4,T3
Prolactin acts on its target organ _ to stimulate _
Prolactin acts on its target organ, the breast to stimulate lactation
GH stimulates its target organ _ to secrete _
GH stimulates its target organ the liver to secrete IGF-1 (insulin-like growth factor)
* IGF-1 then acts on the bones to stimulate growth
IGF-1 is secreted from the _ and acts on the _
IGF-1 is secreted from the liver and acts on the bones to stimulate growth
LH/FSH act on the target organs the _ to secrete _
LH/FSH act on the target organs testes, ovaries to secrete testosterone/ estradiol, progesterone
Prolactin release can be stimulated directly via _ or indirectly via _
Prolactin release can be stimulated directly by nipple stimulation or indirectly via TRH
Somatostatin released from the hypothalamus inhibits _ , somatostatin released by delta cells in the stomach inhibits _
Somatostatin released from the hypothalamus inhibits GH, TSH, prolactin , somatostatin released by delta cells in the stomach inhibits gastric acidity
Cortisol, T3, T4, estradiol, progesterone, testosterone, inhibin feed back and suppress the secretion of hormones from the _ in a negative feedback mechanism
Cortisol, T3, T4, estradiol, progesterone, testosterone, inhibin feed back and suppress the secretion of hormones from the hypothalamus in a negative feedback mechanism
The posterior pituitary receives _ stimulation from the _
The posterior pituitary receives direct neural stimulation from the hypothalamus
The neurons in the posterior pituitary are an extension of the _ in the hypothalamus where the hormones are produced
The neurons in the posterior pituitary are an extension of the neuroendocrine cell nuclei in the hypothalamus where the hormones are produced
(True/False) the posterior pituitary produces hormones
False; the posterior pituitary does not make hormones but just stores and releases hormones
The two hormones stored and released from the posterior pituitary are _ and _
The two hormones stored and released from the posterior pituitary are oxytocin and ADH
Role of oxytocin
Oxytocin is released during labor to increase contractions in the uterus
* It also causes the milk ejection reflex that contracts the breast during lactation
Which hormones are released from the anterior pituitary?
FLAT PiG
* FSH
* LH
* ACTH
* TSH
* Prolactin
* GH
Explain why primary adrenal insufficiency and Addison’s disease can lead to hyperpigmentation
Adrenal insufficiency –>
Low cortisol levels –>
High ACTH and CRH –>
ACTH derives the POMC protein that gets cleaved into ACTH and MSH –>
Melanocyte-stimulating hormone increases melanin
Ultimately the adrenal insufficiency impairs negative feedback and results in high ACTH
In addition to stimulating the anterior pituitary to secrete ACTH, CRH also stimulates _ and _
In addition to stimulating the anterior pituitary to secrete ACTH, CRH also stimulates beta-endorphins and melanocyte-stimulating hormone
The POMC gene produces the POMC protein which gets cleaved into _ and _
The POMC gene produces the POMC protein which gets cleaved into MSH and ACTH
The negative regulator of the female HPG axis is _ ; the positive regulator is _
The negative regulator of the female HPG axis is progesterone ; the positive regulator is estrogen
Primary hypercortisolism is a problem with the _
Primary hypercortisolism is a problem with the adrenal cortex
Secondary hypercortisolism is a problem with the _
Secondary hypercortisolism is a problem with the anterior pituitary
Tertiary hypercortisolism is a problem with the _
Tertiary hypercortisolism is a problem with the hypothalamus
GH has _ effect on adipose cells
GH stimulates adipose cells to break down stored fat
* We call this the glucose sparing effect
GH stimulates growth by increasing the uptake of _ from the blood and enhancing cellular proliferation while reducing _
GH stimulates growth by increasing the uptake of amino acids from the blood and enhancing cellular proliferation while reducing apoptosis
GH has four target cell types:
GH has four target cell types:
1. Bone cells
2. Muscle cells
3. Nervous system cells
4. Immune system cells
Explain the diabetogenic effect of GH
Diabetogenic effect: GH stimulates the liver to break down glycogen into glucose
GH stimulates two things in the liver _ and _
GH stimulates two things in the liver glycogen breakdown and release of IGF-1
T3 and T4 control metabolism and heart rate through stimulating _ throughout the body
T3 and T4 control metabolism and heart rate through stimulating gene expression throughout the body
Growth hormone has _ effect on insulin
GH antagonizes insulin
Prolactin has _ effect on LH and FSH
Prolactin decreases LH and FSH
FSH stimulates _ synthesis and the development of _
FSH stimulates estrogen synthesis and development of germ cells
LH stimulates _ and _ synthesis
LH stimulates progesterone and testosterone synthesis; also stimulates egg development in females
Three actions of ADH
- Renal water retention
- Vasoconstriction
- Increases release of ACTH
(LH/FSH) is involved in egg development
LH is involved in egg development
(LH/FSH) is involved in the development of germ cells
FSH is involved in the development of germ cells
Central or secondary adrenal insufficiency is a deficiency of _
Central or secondary adrenal insufficiency is a deficiency of ACTH
Central/Secondary adrenal insufficiency leads to a deficiency in _
Central/Secondary adrenal insufficiency leads to a deficiency in cortisol but not aldosterone or androgens
Signs of adrenal insufficiency include:
Signs of AI:
* Weight loss
* Fatigue
* Hypotension
* Hypoglycemia
* Vascular collapse and death
Vasopressin deficiency results in _
Vasopressin deficiency results in central diabetes insipidus
* Excessive urination with dilute urine
* Dehydration can be life threatening
* Causes hypernatremia
The most common cause of hypopituitarism is _
The most common cause of hypopituitarism is sellar mass effect resulting from a tumor
* The second most common cause is surgery
Causes of hypopituitarism
Causes of hypopituitarism:
* Sellar mass causing mass effect
* Resection of sellar mass
* Head trauma
* Stroke
* Granulomatous disease
* Radiation
* Pituitary infarction (Sheehan or pituitary apoplexy)
* Empty sella
Macroadenoma
Empty sella
_ is a term used when there is any number of pituitary hormone deficiencies;
_ is the term used when there is more than 1 pituitary deficiency
_ is the term used when all hormones are deficient
Hypopituitarism is a term used when there is any number of pituitary hormone deficiencies;
Multiple pituitary hormone deficiency is the term used when there is more than 1 pituitary deficiency
Panhypopituitarism is the term used when all hormones are deficient
We diagnose a prolactin deficiency via _ lab finding
We diagnose a prolactin deficiency via low prolactin
We diagnose a GH deficiency via _ lab finding
We diagnose a GH deficiency via low IGF-1 and lack of stimulation by provocative testing with glucagon, arginine, insulin
What testing should be done if an FSH, LH deficiency is suspected
Check FSH, LH, estradiol, testosterone
What testing should be done if TSH deficiency is suspected?
TSH, T3, T4
How do we diagnose ADH deficiency?
- Patient has polyuria and decreased urine osmolality
- Water deprivation test does not improve it
- Improvement when ADH is given (if central DI)
The treatment for TSH deficiency is _
The treatment for TSH deficiency is levothyroxine (T4 supplementation)
Panhypopituitarism results in _ deficiencies first
Panhypopituitarism results in ACTH and coritsol deficiencies first
* These develop quickly
(TSH/T4) has a short half life
TSH has a short half life; T4 has a long half life
* Deficiencies will develop over a long period of time
When do we use dynamic testing for hypopituitarism?
- Adrenal insufficiency
- GH deficiency
Growth hormone is a _ type hormone and it binds to receptors _
Growth hormone is a hydrophilic peptide hormone that binds to receptors on the cell surface
Glucose (increases/decreases) release of GH
Glucose decreases release of GH
Ghrelin (increases/decreases) release of GH
Ghrelin increases release of GH
Somatostatin (increases/decreases) the release of GH
Somatostatin decreases the release of GH
Somatostatin comes from the _
Somatostatin comes from the hypothalamus
IGF-1 comes from the _
IGF-1 comes from the liver (hepatocytes)
Ghrelin comes from the _
Ghrelin comes from the stomach
GHrH comes from the _
GH comes from the _
GHrH comes from the hypothalamus
GH comes from the anterior pituitary
(GH/IGF-1) increases glucose and increases growth
Both GH and IGF-1 increase glucose and growth
The single best lab for diagnosing GH abnormalities is _
The single best lab for diagnosing GH abnormalities is IGF-1
* Longer half life than GH
(True/False) Isolated GH deficiency in newborn population does not cause any specific sx
True; Isolated GH deficiency in newborn population does not cause any specific sx
GH deficiency in children may present as _
GH deficiency in children may present as “falling off the growth curve”
* Bone and muscle growth is inhibited
* Bone age is lower than expected
Adults with GH deficiency have vague sx such as _
Adults with GH deficiency have vague sx such as decreased bone mineral density, decreased muscle mass, increased fat mass
_ is an autosomal recessive mutation in the GH receptors that leads to GH insensitivity in newborns/children
Laron syndrome is an autosomal recessive mutation in the GH receptors that leads to GH insensitivity in newborns/children
_ is a chromosome 15 deletion that leads to GH deficiency and therefore short stature, increased body weight, and increased ghrelin levels
Prader-Willi syndrome is a chromosome 15 deletion that leads to GH deficiency and therefore short stature, increased body weight, and increased ghrelin levels
Prader willi syndrome is a deletion of chromosome _
Prader willi syndrome is a deletion of chromosome 15
GH deficiency in children and adults are often either from _ or they are idiopathic
GH deficiency in children and adults are often either from sellar tumors causing mass effect or they are idiopathic
Treatment for GH deficiency is _
Treatment for GH deficiency is recombinant GH replacement (for all ages)
Another lab value that can be evaluated besides IGF-1 for GH deficiency is _
Another lab value that can be evaluated besides IGF-1 for GH deficiency is IGFBP-3
If a patient has normal GH levels then the administration of insulin will cause (hyperglycemia/hypoglycemia) which will induce GH to (increase/decrease)
If a patient has normal GH levels then the administration of insulin will cause hypoglycemia which will induce GH to increase to restore glucose levels
* A patient with GH deficiency will not have a rise in GH
The most common cause of a GH excess is _
The most common cause of a GH excess is pituitary adenoma
Children with an excess of GH have _ ; adults have _
Children with an excess of GH have gigantism ; adults have acromegaly
Clinical features of acromegaly include:
Clinical features of acromegaly include:
* Enlarged hands/feet
* Hoarse voice
* Snoring
* Arthralgias
* Coarse facial features, enlarged jaw
Complications associated with agromegaly in adults include:
Complications associated with agromegaly in adults include:
* Diabetes
* Hypertension
* Obstructive sleep apnea
* Carpal tunnel
* Colon cancer
Macroadenoma
Insulin tolerance test is used to diagnose (GH excess/ GH deficiency)
Insulin tolerance test is used to diagnose GH deficiency
Oral glucose tolerance test is used to diagnose (GH excess/ GH deficiency)
Oral glucose tolerance test is used to diagnose GH excess
In a normal individual, a large glucose load will _ GH levels
In a normal individual, a large glucose load will suppress GH levels
* If GH does not suppress after the intake of oral glucose, GH excess is confirmed
List the three most important tests to diagnose GH excess:
List the three most important tests to diagnose GH excess:
1. IGF-1 or IGF1BP3
2. Oral glucose tolerance test
3. MRI for pituitary adenoma
Most pituitary adenomas will cause increased secretion of only one pituitary hormone; the exception is that some adenomas can secrete both _ and _
Most pituitary adenomas will cause increased secretion of only one pituitary hormone; the exception is that some adenomas can secrete both GH and prolactin
What is the preferred therapy for GH pitiutiary adenoma?
- Transsphenoidal resection
- Radiation
- Medication (octreotide, cabergoline, pegvisomant)
Steps for GH excess diagnosis:
1. IGF-1 & IGFBP3 levels checked
2. _ test
3. MRI of pituitary
Steps for GH excess diagnosis:
1. IGF-1 & IGFBP3 levels checked
2. Oral glucose tolerance test
3. MRI of pituitary
Steps for GH deficiency diagnosis:
1. IGF-1 & IGFBP3 levels checked
2. _ test
3. MRI of pituitary
Steps for GH deficiency diagnosis:
1. IGF-1 & IGFBP3 levels checked
2. Insulin tolerance test
3. MRI of pituitary
Hyperpituitarism is almost exclusively caused by _
Hyperpituitarism is almost exclusively caused by pituitary adenomas
* Prolactinemia can also be caused by stalk compression or trauma of the head
A pituitary adenoma < 1 cm is a _
A pituitary adenoma < 1 cm is a microadenoma
A pituitary adenoma > 1 cm is a _
A pituitary adenoma > 1 cm is a macroadenoma
Microadenoma
Macroadenoma
The most important mass effect caused by macroadenomas is _
The most important mass effect caused by macroadenomas is bitemporal hemianopia
The direct effect of hyperprolactinemia is _
The direct effect of hyperprolactinemia is galactorrhea
Indirect effects of hyperprolactinemia result from prolactin’s (stimulation/suppression) of GnRH
Indirect effects of hyperprolactinemia result from prolactin’s supression of GnRH –> hypogonadotropic hypogonadism
* Low libido
* Infertility
* Amenorrhea
A pituitary adenoma that secretes excess ACTH will present as _
A pituitary adenoma that secretes excess ACTH will present as cushing’s disease
* Hyperglycemia
* HTN
* Weight gain
* Abdominal striae
* Moon face
* Truncal obesity
* Easy bruising
Signs of excessive TSH from an adenoma include:
Signs of excessive TSH from an adenoma (very rare) include:
* Weight loss
* Tremor
* Palpitations
* Anxiety
* Diarrhea
* Heat intolerance
Large pituitary adenomas can encroach on the optic nerve and result in _
Large pituitary adenomas can encroach on the optic nerve and result in bitemporal hemainopia
5 types of cells that are overactive in adenomas:
5 types of cells that are overactive in adenomas:
1. Lactotrophs
2. Somatotrophs
3. Corticotrophs
4. Gonadotrophs
5. Thyrothrophs
What is the workup for a patient with suspected pituitary adenoma?
Labs:
* Prolactin
* LH/FSH with estrogen/testosterone
* ACTH with cortisol
* TSH with T3/T4
* GH with IGF-1
Imaging: MRI with contrast
The expected labs in a prolactinoma would be high _ and low _
The expected labs in a prolactinoma would be high prolactin and low LH/FSH, estrogen/testosterone
For most adenomas, the first line treatment is _ , followed by _ and _
For most adenomas, the first line treatment is surgery , followed by medication and radiation
For prolactinoma the first line treatment is always _
For prolactinoma the first line treatment is always medical
Endocrine hormones enter the _
Endocrine hormones enter the bloodstream to travel to distant organs
Glands are just _
Glands are just envaginations of epithelial cells
Exocrine glands are glands that _
Exocrine glands are glands that produce substances for secretion outside the body
Steroid hormones are derived from _ ; they easily cross the cell membrane and therefore bind to (extracellular/intracellular) receptors
Steroid hormones are derived from cholesterol ; they easily cross the cell membrane and therefore bind to intracellular receptors (nuclear receptors)
Peptide hormones are hydrophilic, meaning they cannot easily cross the cell membrane and will bind _ receptors
Peptide hormones are hydrophilic, meaning they cannot easily cross the cell membrane and will bind membrane bound receptors
The pineal gland is located behind the _ and secretes _
The pineal gland is located behind the third ventricle and secretes melatonin
The pituitary gland is a pea sized gland that rests on the _ within the _ bone
The pituitary gland is a pea sized gland that rests on the sella turcica within the sphenoid bone
Adrenal glands are located _ and secrete _
Adrenal glands are located above the kidneys and secrete steroid hormones (cortisol, aldosterone, androgens)
Adipose cells contain an enzyme called _ that converts androgens to estrogen
Adipose cells contain an enzyme called aromatase that converts androgens to estrogen
The anterior pituitary is also called the _ ; the posterior pituitary is also called the _
The anterior pituitary is also called the adenohypophysis ; the posterior pituitary is also called the neurohypophysis
D- the anterior pituitary is an upward growth of the oral ectoderm
Where is the posterior pituitary?
C: The posterior pituitary is the downward extension of the neuroectoderm- extension of the hypothalamus
These are acidophils
* The anterior pituitary contains both acidophils and basophils
Which anterior pituitary cells are acidophils?
Somatotrophs (making GH) and Mammotrophs (making prolactin)
Which anterior pituitary cells are basophils?
B-FLAT:
* Gonadotrophs (FSH, LH)
* Corticotrophs (ACTH)
* Thyrotrophs (TSH)
Storage structures in the posterior pituitary are called _
Herring bodies store ADH and oxytocin
* They are really just dilated terminal portions of the axons
What kind of capillaries are found in the anterior pituitary?
Fenestrated capillaries
* Can see the somatotrophs, gonadotrophs, thyrotrophs and their many secretory vesicles
What is contained in the X?
Colloid
Thyroxine (T4) is a _ type of hormone
Thyroxine (T4) is a hydrophobic amine
These cells are _ and they function to _
These cells are parafollicular cells and they function to secrete calcitonin, which decreases calcium levels
These are _ cells in the parathyroid
These are chief cells in the parathyroid –> make PTH
What does the yellow cell represent?
Osteoblasts –> when stimulated by PTH it reduces bone deposition and releases osteoclast stimulating factor
Which region secretes aldosterone?
The zona glomerulosa (A) secretes aldosterone
What stimulates these cells?
ACTH stimulates these cells in the zona fasciculata to make cortisol
What hormone is produced here?
Zona reticularis produces sex hormones
What do these cells secrete?
Chromaffin cells secrete epinephrine and norepinephrine
Epinephrine is derived from _
Epinephrine is derived from tyrosine
Tyrosine is the precursor for many important amine hormones including _
Tyrosine is the precursor for many important amine hormones including thyroxine and dopamine –> NE –> E
Where do these cells secrete their products?
These are acinar glands of the exocrine pancreas and they secrete their products (digestive enzymes) into ducts
What do these cells most likely secrete?
These are most likely beta cells which secrete insulin; these cells are the most numerous and centrally located in the islet of langerhan
In MEN1 syndrome patients have an insulinoma and high C-peptide; C-peptide is made in the _
In MEN1 syndrome patients have an insulinoma and high C-peptide; C-peptide is made in the rough ER
Alpha cells make _
Alpha cells make glucagon
Which is the mechanism by which insulin signals?
Insulin is a polypeptide, hydrophilic hormone that binds receptors on the outside of the cell
Beta cells make _
Beta cells make insulin and amylin
Delta cells make _
Delta cells make somatostatin
Epsilon cells make _
Epsilon cells make ghrelin
PP cells (gamma or F cells) make _
PP cells (gamma or F cells) make pancreatic polypeptides
Steroid secreting cells have extensive _ ER and lots of _
Steroid secreting cells have extensive smooth ER and lots of fat droplets
Identify the categories of hormones
Which hormones might be enhancing transcription here?
Cortisol or thyroxine
Which hormone might be binding to the receptor here?
Catecholamines
The endocrine organ that secretes melanin is _
The endocrine organ that secretes melanin is pineal gland
