Endocrine Flashcards
Hyposecretion
too little secretion of a hormone
Hypersecretion
too much hormone secretion
hyporesponsiveness
occurs when the receptors on target cells are under-responsive to a hormone
hyperresponsiveness
occurs when the target cells over-respond to a hormone
Primary disorder
the disorder is located primarily in the end-organ
secondary disorder
the source of the disorder is somewhere besides the end-organ
Thyroid
- sits in the anterior neck
- consists mainly of follicles, lined by follicular cells and containing colloid
- has C cells that make calcitonin
- the 4 parathyroid glands sit on the posterior side
what do follicle cells do?
- make thyroglobulin and secrete it into the colloid space
- facilitate absorption of iodide and it diffuses to the colloid space
2 types of thyroid hormones?
T3 (3 iodide groups) and T4 (4 iodide groups)
- both are nonpolar - this makes it act like a steroid hormone (easily crosses plasma membrane)
- both are carried in blood stream by carrier proteins
Metabolic actions of thyroid hormones?
speeds many metabolic processes
Permissive actions of thyroid hormones?
greatly magnifies the effect of other hormones
growth and development actions of thyroid hormones
acts in conjunctions with GH and other hormones
Adrenal=
your endocrine and neuroendocrine response to stress
how does the adrenal respond to stress?
release of cortisol from the adrenal cortex and epinephrine from the adrenal medulla
what does and medulla make and when?
epi when its stimulated by the nervous system, thus its neuroendocrine
what does the cortex make?
cortisol and other steroids, thus its purely endocrine
3 zones of the cortex
outer cortex, middle cortex, inner cortex
what steroid does the outer cortex produce?
glomerulosa=aldosterone
what steroid does the middle cortex produce?
fasciculata=cortisol
what steroid does the inner cortex produce?
reticularis=androgens
permissive functions of cortisol?
for the action of epinephrine and norepinephrine on muscles and blood vessels
function of cortisol maintaining glucose
ensures that there are adequate concentrations of the enzymes required to produce glucose between meals
function of cortisol decreasing inflammation
mediates events that are associated with the inflammatory response, such as capillary permeability and production of prostaglandins
what else is a function of cortisol?
important for fetal development
Metabolic function of cortisol?
-Increased catabolism in bone and muscle and more
-Liver brings in and burns ore amino acids
Elevated glucose
-Stimulates breakdown of adipose
Vascular function of cortisol?
- Enhances how blood vessels react to epi/ norepinephrine
- Inhibits inflammation and the immune system
Stress related functions of cortisol?
Activates protective mechanisms within the body in response to stress, like:
- Elevating white blood cell count
- Elevating blood glucose levels
- Increasing plasma volume
- Sometimes, catabolizing muscle to be burned as fuel
other functions of cortisol?
-Inhibits anything it sees as “non-essential” (growth, reproduction, inflammation)
what is it called when plasma levels of cortisol are chronically low?
adrenal insufficiency
Symptoms of adrenal insufficiency?
weakness, lethargy, and loss of appetite
Exam for someone with low cortisol may reveal what?
low blood pressure (in part because cortisol is needed to permit the full extent of the cardiovascular actions of epinephrine) and low blood sugar, especially after fasting (because of the loss of the normal metabolic actions of cortisol).
Primary adrenal insufficiency is also know as?
Addison’s disease
Cushings Syndrome
disease in which there is excess cortisol in the blood, even when no stress is present.
-can be primary or secondary defect
Secondary Cushing’s Syndrome (called Cushing’s disease)
increased blood levels of cortisol tend to promote uncontrolled catabolism of bone, muscle, skin, and other organs.
Cushing’s Syndrome problems
- Osteoporosis
- Muscles weakness
- Blood sugar increases to diabetic levels
- Immunosuppression
- Redistribution of fat (“buffalo hump” and “moon facies”)
- Hypertension (high blood pressure)
Treatment of Cushing’s Syndrome depends on the cause
- Surgical removal of the pituitary tumor
- Adrenalectomy
