Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
127 Cards in this Set
- Front
- Back
Which type of secretion (autocrine, paracrine or endocrine) are the following examples of? Inhibition of glucagon from pancreatic alpha cells by insulin from beta cells, and inhibition of insulin an dglucagon secretion by somatostatin secrtion from pancreatic delta cells?
|
Paracrine
|
|
a. What type of secretion causes the release of neuronal product directly into the blood stream? b. where does this type of secretion occur
|
a) Neuroendocrine secretion b) adrenal medulla, hypothalamus and posterior pituitary
|
|
What type of cellular communication occurs with thyroid hormones?
|
these hormones, like steroid hormones, enter cells directly and interact with receptors at the nuclear level
|
|
Which part of the pituitary arises from Rathke's pouch?
|
Anterior pituitary
|
|
What is Rathke's pouch?
|
an evatination from the foregut of the region of the 3rd ventricle within the diencephalon
|
|
Where are Adenohyophysis cells located and what do they do?
|
these cells are in the anterior pituitary and produce hormones.
|
|
What does the term neurohypophysis refer to?
|
the posterior pituitary
|
|
I which bony structure does the pituitary rest in ?
|
sella turcica
|
|
what is the sella turcica formed from?
|
the spenoid wings at the base of the skull
|
|
What is the median eminence?
|
protruding base of the brain before entering the pituitary stock leading to the pituitary
|
|
What is the function of the intermediate lobe (pars intermedia) in the pituitary?
|
none
|
|
Which 6 hormones does the anterior pituitary secrete?
|
FSH, LH, TSH, ACTH, GH and PRL
|
|
which two hormones does the posterior pituitary secrete? What type of secretion is this?
|
Oxytocin and ADH… neuroendocrine
|
|
Which cells types in the posterior pituitary produce oxytocin and ADH?
|
supraoptic - ADH… paraventricular - Oxytocin
|
|
What separate base of the brain from the pituitary?
|
diaphragm sella
|
|
What are the names of the vascular connections that carry blood from the median eminence to the down the stalk and into the pituitary?
|
primary plexus and the portal hypophyseal vessels, which together make up the portal system leading to the anterior pituitary
|
|
Between primary plexus and the portal hypophyseal vessels, which has fenestrated capilaries and lacks a blood brain barrier?
|
primary plexus
|
|
Name for major phsiologic functions critical to survival that are integrate by the hypothalamus? (hint: WET-B)
|
Water balance, Energy balance, Temperature regulation, and Biological clock
|
|
T/F: All specialized receptors for the control of temperature, Osmo, and Chemo are leading to the hypothalamus are located in the hypothalamus?
|
False some are on the periphery
|
|
What type of feedback controls cortisol production and how is this done?
|
Negative feedback, where cortisol inhibits ACTH production in the pituitary
|
|
Besides cortisol, what else controls ACTH secretion?
|
1) the episodic dirunal rhythm and 2) increased stress
|
|
Does estrogen have a negative or positive feedback effect on LH?
|
both, depending on the stage of the reproductive cycle
|
|
Where does feedback regulation of hormones occur, at the pituitary or the hypothalamus?
|
both
|
|
What type of molecular structure is LH? Glycoprotein, Single chain protein, or a peptide arising from POMC?
|
Glycoprotein
|
|
What type of molecular structure is PRL? Glycoprotein, Single chain protein, or a peptide arising from POMC?
|
Single chain protein
|
|
What type of molecular structure is GH? Glycoprotein, Single chain protein, or a peptide arising from POMC?
|
Single chain protein
|
|
What type of molecular structure is TSH? Glycoprotein, Single chain protein, or a peptide arising from POMC?
|
glycoprotein (dimer)
|
|
What type of molecular structure is ACTH? Glycoprotein, Single chain protein, or a peptide arising from POMC?
|
peptide arising from POMC
|
|
What type of molecular structure is PRL? Glycoprotein, Single chain protein, or a peptide arising from POMC?
|
sinchain protein
|
|
What type of molecular structure is FSH? Glycoprotein, Single chain protein, or a peptide arising from POMC?
|
Glycoprotein
|
|
What type of molecular structure is 3-LPH (13-lipotopin)? Glycoprotein, Single chain protein, or a peptide arising from POMC?
|
Peptide arising from POMC
|
|
What type of molecular structure is MSH (Melanocyte stimulating hormone)? Glycoprotein, Single chain protein, or a peptide arising from POMC?
|
simple peptide arising from POMC
|
|
Which type of cells produce the peptide (ranginng from 1-44 amino acids) hormones that are secreted in the hypothalamus and influence the pituitary?
|
neurons
|
|
Name the 5 hypothalamic hypophysiotropic hormones
|
thyrotropin releasing hormone (TRH), Gonadotropin releasing hormone (GnRH), Corticotropin releasing hormone (CRH), Somatostatin (SRIF), Growth hormone releasing hormone (GHRH) and Dopamine
|
|
Which are the three trophic hormones and what do they produce?
|
Thyrotropin releasing hormone (TRH): TSH an PRL… b) Gonadotropin releasing hormone (GnRH): LH and FSH… c) Corticotropin releasing hormone (CRH): ACTH (which is incresed with sympathetic nervous system)
|
|
What pituitary effect does the release of Somatostatin have?
|
Inhibits GH and TSH release from the pituitary…
|
|
Which hormone has a widespread distribution and actions including the GI tract and pancreas
|
Somatostatin
|
|
Which hypothalamus hormone releases GH from the pituitary?
|
GHRH
|
|
Which hypothalamic hormone stimulates PRL release and which inhibits it?
|
Stimulates: TRH… Inhibits: Dopamine
|
|
Which hypothalamic hormone inhibits both GH and TSH?
|
Somatostatin
|
|
Besides GH and TSH inhibition, what other function does somatostin have?
|
Somatostatin produced in the pancreas inhibits insulin and glucagon by paracrine action
|
|
Episodic function is often seen in which hypothalamic releasing hormone?
|
GnRH
|
|
What is the relationship between the struture of LH, FSH and TSH?
|
They each share a common alpha chain, and differ in the beta chain
|
|
In general, what do gonadotropin do?
|
stimulate ovaries and testes
|
|
What is the function of LH?
|
stimulates hormone production
|
|
What is the function of FSH?
|
It regulates ovulation and spermatogenesis
|
|
What is the function of TSH?
|
stimulate the thyroid
|
|
The is the direct function of GH?
|
Stimulates IGF-1 productio in the liver and other tissues and has CHO metabolism
|
|
What is the direct function of PRL?
|
Stimulates lacation
|
|
What is the direct function of ACTH?
|
Stimulates the adrenal cortex, but it's not a direct effector
|
|
What is the direct function of 3-LPH?
|
Direct effector
|
|
What is the direct function of Melanocyte stimulating hormone (MSH)?
|
Direct effector of the mypothalamus
|
|
T/F: MSH circulates systemically
|
false: only in pituitary
|
|
Characterize primary hypothyroidism
|
absence of a functional thyroid
|
|
Characterize secondary hypothyroidism
|
lack of thyroid function due to TSH not being released by the pituitary
|
|
Characterize tertiary hypothyroidism
|
TSH is deficient secondary to TRH deficiency
|
|
Besides primary, secondary and tertiary hypothyroidism, what can cause clinical manifestations of hypothyroidism?
|
Thyroid hormone resistance due to mutation in the thyroid hormone receptors
|
|
What type of hypothyroidism would low T4 in the presence of high TSH
|
primary
|
|
What type of hypothyroidism would low TSH in the presence of high TRH?
|
secondary
|
|
What type of hypothyroidism would low TSH in the presence of low TRH?
|
tertiary
|
|
Can GH stimulate growth in the absence of the target gland hormones, i.e., thyroid, gonads, adrenal cortex?
|
No… but the target gland hormones cannot stimulate growth without GH
|
|
What do GH , thyroid hormone, cortisol, sex steroids, and insulin have in common
|
They are all growth hormones
|
|
What must be provided to children with hypopituitarism?
|
GH
|
|
What are some symptoms of adults that have GH deficiency
|
reduction in muscle mass and bone density as well as an increase in adiposity
|
|
Which two hypothalamic hormones control GH?
|
GHRH and somatostatin
|
|
What does GH stimulate?
|
Insulin like growth factor (IGF-1)
|
|
What effect does excess IGF-1 have on GH
|
negative feedback
|
|
when is GH secretion highest?
|
non REM sleep
|
|
Besides GHRH and somatostatin, which other 2 ligands can inluence GH levels?
|
TRH stimulates, and Ghrelin stimulates
|
|
Where is Ghrelin produced?
|
it is a peptide produced in the stomach
|
|
Besides stimulating GH secretion, what effect does Ghrelin have?
|
stimulates appetite, causing weight gain
|
|
What effect do the following have on GH? Sleep, Exercise, Stress, hypoglycemia, Hyperglycemia, Amino Acids (Arginine), Estrogen, ß-adrenergic agonist (propranolol), and ∂-agonists (phentolamine)?
|
Sleep: GH pulse at onset of sleep… Exercise: stimulate… Stress: increase secretion… hypoglycemia: increase secretion… hyperglycemia: inhibit secretion… Amino Acids: stimulate secretion… Estrogen: enhance GH action… ß-adrenergic agonist: inhibit secretion... ∂-adrenergic agonist:stimulate secretion.
|
|
How do you test for GH deficiency?
|
dynamically, because levels are low, i.e., 1) induce hypoglycemia w/insulin… 2) give ß-blocker + ∂-adrenergic agonist… 3) Give GHRH directly to test the function of the anterior pituitary directly… 4) check IGF-1, since low levels indicate GH deficiency. 5) check after exercise, 6) Give Gherlin
|
|
How does hypoglycemia increase GH secretion?
|
it's thought to decrease somatostatin and increase GHRH.
|
|
How do you test the anterior pituitary directly for GH deficiency?
|
Give GHRH
|
|
What is somatomedin C synonymous with?
|
IGF-1
|
|
What happens to IGF-1 levels in nutrient deprived people?
|
IGF-1 is decreased
|
|
Is IGF-II regulated by GH?
|
no
|
|
What effect does GH have with respect to insulin?
|
it counters insulin, thus raises blood glucose levels, especially in muscle and fat
|
|
When GH deficiency exists, when is hypoglycemia more likely to exist?
|
when other counterregulatory hormones deficiencies are present
|
|
What effect does GH deficiency have on the adult?
|
reduced lean, decreased bone density and increased fat
|
|
If GH is present at birth, what is suspected?
|
GHRH deletions in hypothalamus… autosomal recessive trait
|
|
What is the most common cause of deficient GHRH?
|
hypothalamic infiltrative disease or tumors
|
|
What is the most common cause of GH deficiency?
|
pituitary lesions, turmor… while, GH gene deletions are rare autosomal recessive disorders… GH receptor mutations have been characterized in GH deficiency
|
|
A) What is primary cause of GH excess? B) what generally accompanies the rise in GH?
|
A) pituitary adenoma producing GH… B) Prolactin production
|
|
Besides pituitary tumors, what are some other causes of GH overproduction?
|
tumors that produce GHRH found in the pancreas and hypothalamus (rare)
|
|
What is the cause of acromegaly?
|
overproduction of GH
|
|
Why doesn't hyperglycemia suppress GH?
|
because the somatotrophs in the pituitary are no profused by the hypphyseal pit-portal venus system
|
|
What are the Rx for acromegaly?
|
resection of tumor, radiation, somatostatin analog… or GH antagonists, which bind to only one receptor of the dimer receptor (Pegvisomant)
|
|
What is prolactin tonically inhibited by?
|
dopamin
|
|
Why do prolactin levels rise during pregnancy?
|
estrogen causes hyperplasia of lactotrophs.
|
|
What inhibits lactation during pregnancy?
|
high levels of estrogen and progesterone
|
|
Why do PRL levels increase after pregnancy?
|
rapid fall of estrogen and progesterone
|
|
What maintains high levels of PRL after pregnancy?
|
suckling
|
|
What effects do you see with elevated PRL?
|
galactorrhea and hypogonadotropic hypogonadism
|
|
What are the functional causes of Hyerprolactinemia?
|
hypothyroidism and renal failure
|
|
What are the pharmacological causes of Hyerprolactinemia?
|
Anti-dopaminergics
|
|
What are the Tumoric causes of Hyerprolactinemia?
|
Suprasella lesions, microprolactinomas, macdroprolactinomas,
|
|
what are causes of diminished dopamine synthesis and release in the hypothalamus? And what the consequences?
|
Tumors, arteriovenous malformation or inflammatory lesions, as well as drugs like ∂-methyldopa and reserpine which can deplete central dopamine store… consequences are Hyperprolactinemia
|
|
What are 4 causes of hyperprolactinemia
|
1) diminished synthesis and storage of dopamine in the hypothalamus… 2) interuption of the portal system… 3) Pituitary insensitivity due to drugs (antipsychotics, e.g., dopamine blockers)… 4) Prolactinomas (most common)
|
|
What is the size limit for a microadenoma?
|
< 1 cm
|
|
What is the cause and presentation of Cushing's disease from pituitary tumors?
|
small microadenoma --> ACTH excess
|
|
What is the hormonal effect of hyperthyroidism from pituitary tumors?
|
TSH excess, very rare
|
|
T/F FSH secreting tumors from pituitary tumors are rare
|
false, they are common silent clinically
|
|
Name 7 causes of hypopituitarism.
|
1. Pituitary tumors, 2. parapituitary tumors, 3. Post partum infarction (Sheehan's syndrome), 4. Infiltrations (sarcoidosis, histiocytosis, hemochromatosis), 5. Hypophysitis, 6. Infections, 7. Trauma.
|
|
What is Sheehan's syndrome and what causes it?
|
Hypopituitarism in women who experienced a difficult birth, who suffer post partum infarction of the pituitary… attributed the vulnerability of the pituitary to a drop in blood pressure caused by blood loss
|
|
What is hypophysitis?
|
hypopituitarism caused by a rare autoimmune disase of the pituitary
|
|
Give 2 infections that can cause hypopituitarism
|
tuberculosis and syphilis
|
|
what is idiopathic hypopituitarism thought to be caused by?
|
absent hypothalamic control of the anterior pituitary
|
|
Which hormonal deficiency is seen in the Amish population?
|
GH deficiency
|
|
What Kallman's syndrome?
|
the association of LH deficiency and anosmia (loss of sense of smell)
|
|
What do low levels of target organ hormones in the absence of elevated pituitary hormones indicate?
|
Hypopituitarism… because the pituitary should be compensating
|
|
Besides looking for ow levels of target organ hormones in the absence of elevated pituitary hormones, how can you diagnose hypopituitarism? Give 4 examples.
|
stimulate hormone secretion to see if there are pituitary reserves present: 1) Insulin induced hypoglycemia --> should stimulate GH and ACTH… 2) TRH should increase TSH… 3) GHRH should stimulate GH… 4) GnRH should stimulate FSH and LH
|
|
What is the order of loss of pituitary hormones in hypopituitarism?
|
GH… LH, FSH… TSH, ACTH
|
|
How do ADH and Oxytocin begin?
|
as prohormones: Neurophysin, which chaperones ADH and Oxytocin through the axons from the hypothalamus to the pituitary
|
|
Are ADH deficiencies seen with pituitary lesions? Why or why not?
|
No, because ADH is synthesized in the hypothalamus and can be secreted as long as the axon is long enough.
|
|
Where are ADH deficiencies seen?
|
With hypothalamus lesions
|
|
What is the cause of the rare Familial ADH deficiency?
|
mutation in the neurophysin portion of the gene
|
|
What function does Oxytocin serve?
|
contraction of mammary ducts and mild ejection (secretion caused by suckling)… not… causes contraction, but it's not required for this.
|
|
What effect does ADH have?
|
1) ADH augments CRH effects on ACTH, 2) ADH is responsible for free water readsoption by the kidney and 3) ADH is a vasoconstrictor.
|
|
When is ADH critical?
|
major injury
|
|
a)What do the following ADH receptors mediate, b) what effect do they have and c) where are they found? V1, V2, V3
|
V1: Phospholipid mediator, vasoconstriction, vascular smooth muscle… V2: cAMP, increase H2O permeability through aquaporin 2, renal collecting tubule… V3: Phospholipid mediator, ACTH secretion, Anterior pituitary
|
|
Characterize ADH and water regulation
|
Increasing plasma osmolarity is communicated to the hypothalamus from baroreceptors that measure volume in the atria and great vessels--> ADH secretion & increased thirst,
|
|
What is central diabetes insipidus?
|
absence of ADH
|
|
What is Nephrogenic Diabetes Insipidus?
|
ADH action is impaired
|
|
Name 8 causes of central diabetes insipidus?
|
1. Pituitary tumor, 2) parapituitary tumor, 3) infiltrative diseases of the hypothalamus (sarcoids), 4) Metastic dises oto the hypothalamus, 5) Basal skull fractures, 6) Idiopathic, 7) Familial, 8) Vasopressinase (produced in the placenta and cleaves ADH) treated with DDAVP
|
|
See pages 49 and 50 for graph interpretation
|
|