Endocrine System- Week 1 Slides Flashcards
where do hormones travel
bloodstream
Roles of endocrine system
- Differentiation of the reproductive and central nervous systems
- childhood growth
- male and female reproductive systems
- Maintenance of an optimal internal environment
- Initiation of corrective and adaptive responses when emergency demands occur
Three basic hormone secretion patterns
- circadian/diurnal patterns (cortisol)
- pulsatile/cyclic patterns (female hormones)
- patterns that depend on levels of circulating substrates
occurs because the changing chemical, neural, or endocrine response to a stimulus negates the initiating change that triggered the release of the hormone.
negative feedback
which hormones are water soluble and circulate in free (unbound) forms
Peptide or protein hormones (pituitary, hypothalamic, and parathyroid hormones; and insulin)
which hormones are transported bound to a carrier or transport protein and can remain in the blood for hours to days
Lipid-soluble hormones, such as cortisol and adrenal androgens
The sensitivity of the target cell to a particular hormone is related to what?
the total number of receptors per cell:
-the more receptors, the more sensitive the cell.
up-regulation
Low concentrations of hormone increase the number of receptors per cell
down-regulation
High concentrations of hormone decrease the number of receptors
which types of hormones can bind to an intracellular receptor
fat soluble hormones (can pass the lipid bilayer of the cell membrane)
-vitamin D, retinoic acid, and thyroid hormones
water soluble hormones have short or long lasting effects
short
Lipid-soluble steroids
- vitamin D
- retinoic acid
- thyroid hormones
do water or lipid soluble hormones have long-acting AND rapid-acting responses
Lipid-soluble steroids
The hypothalamus is connected to the anterior pituitary by way of ________
blood vessels.
The hypothalamus is connected to the posterior pituitary by way of _________-
a nerve tract
______ and _______ are synthesized in hypothalamic neurons but are stored and secreted by the posterior pituitary.
Antidiuretic hormone (ADH) and oxytocin
other name for posterior pituitary gland
neurohypophysis
hormones of posterior pituitary
- Antidiuretic hormone (ADH)
- oxytocin
leads to an increase in water reabsorption into the blood and the production of more concentrated urine
ADH
contraction of the uterus and milk ejection in lactating women and may affect sperm motility in men
oxytocibn
Characterized by high levels of ADH in the absence of normal physiologic stimuli for its release
Syndrome of Inappropriate Antidiuretic Hormone (SIADH)
what causes SIADH
- ectopic tumor secreting ADH
- pulmonary disorders
- neurological disorders
- surgeries
- medications.
with SIADH enhanced water retention leads to what?
-dilutional hyponatremia (low serum sodium concentration)
-hypoosmolarity (solutes diluted with water)
-urine concentrated
SIADH symptoms
-caused by the drop in soultes
-Severe gastrointestinal symptoms, including vomiting and abdominal cramps
-confusion, lethargy, muscle twitching, and seizures may occur
-neuro damage
Diagnosis of SIADH requires documentation of the following manifestations
- low serum hypoosmolality and hyponatremia
- urine osmolarity > serum osmolarity (urine is concentrated)
SIADH treatment
IV hypertonic saline
-resolves in 2-3 days
-if infusion given too rapidly, a severe neurologic syndrome called central pontine myelinolysis can occur
An insufficiency of ADH, leading to polyuria (frequent urination) and polydipsia (frequent drinking).
Diabetes Insipidus (DI)
2 types of Diabetes Insipidus (DI)
- Neurogenic/ central (not enough ADH)
- Nephrogenic (insensitivity of the renal collecting tubules to ADH)
cause of neurogenic diabetes insipidus
-brain tumor
-TBI
-pregancyn
what type of DI usually has an abrupt onset, and many individuals can specifically recall the date of onset of their symptoms
Idiopathic neurogenic DI
hypernatremia and hyperosmolality are associated with
Diabetes Insipidus (DI)
Signs and symptoms of DI include
polyuria, nocturia, continuous thirst, and polydipsia.
To differentiate between nephrogenic and neurogenic DI, they give what drug
desmopressin (synthetic ADH)
-neurogenic respons well
-nephrogenic doesn’t respond to the ADH
the secretory cells of the adenohypophysis/anerior pituitary
chromophils
hormones of anterior pituitary
- ACTH
- Melanocyte-stimulating hormone (MSH)
- Luteinizing hormone (LH)
- Growth hormone (GH)
- Prolactin
- Follicle-stimulating hormone (FSH)
- TSH
causes of Hypopituitarism
-tumor
-pregnancy
-TBI
-pituitary infarction resulting from severe shock
-sickle cell disease
panhypopituitarism
all hormones are deficient of pituitary gland
does ACTH Deficiency occur on its own usually
no
Symptoms of cortisol insufficiency
nausea, vomiting, anorexia, fatigue, and weakness
-hypoglycemia
in women of reproductive age is associated with amenorrhea and with atrophic changes in the vagina, uterus, and breasts. In post-pubertal males, atrophy of the testes and decreased beard growth occur.
FSH and LH deficiency
causes of GH growth hormone deficiency in children
- gentic
- tumor
symptoms of GH xu in adults
increased body fat, decreased muscle bulk and strength, reduced sweating, dry skin, and psychologic problems, including depression, social withdrawal, fatigue, loss of motivation, and a diminished feeling of well-being
Pituitary adenomas are usually benign slow-growing tumors that arise from cells of the anterior pituitary, most commonly those that secrete _____ and _____
GH and prolactin
adenomatous tissue secretes the hormone of ______________, without the check of negative feedback
the cell type from which it arose
mptoms of pituitary tumor
nonspecific complaints as headache and fatigue. Visual changes produced by pressure on the optic chiasm include visual field impairments
high levels of growth hormone in adults and concomitant elevation of IGF-1
Acromegaly
high levels go GH in children leading to growth of long bones
Gigantism
at what age does acromegaly occur
40 and 50 mostly women
-Results in cardiac hypertrophy, hypertension, atherosclerosis, and type 2 diabetes mellitus that lead to coronary artery disease.
since all epiphyseal plates have closed in adults what happens with excessive GH in adults
connective tissue proliferation and bony proliferation that results in the characteristic appearance of acromegaly.
does acromegaly lead to high or low blood sugar
high
glucose testing for acromegaly
During OGTT, GH should be suppressed by rise in glucose and insulin levels as GH and insulin are antagonistic of one another. If GH stays elevated → acromegaly**
Pituitary tumors that secrete prolactin are called
prolactinomas
main treatment for prolactanomas
opaminergic agonists (bromocriptine, cabergoline, and pergolide)
-then surgery to remove adenoma if needed
microprolactinomas (<1 cm in size) or macroprolactinomas(>1cm in size).
microprolactinomas (<1 cm in size) or macroprolactinomas(>1cm in size).
Prolactin levels more than _____ ng/ml are usually associated with a prolactinoma and are an indication for MRI scanning of the pituitary.
200
