Endocrine lecture EXAM 3 Flashcards
Is the endocrine system positive or negative feedback
Negative feedback
Anterior pituitary hormone production (just the stuff for the lecture)
-ACTH )Adrenocorticotropic hormone
-TSH , Thyroid stimulating hormine
Thyroid hormone production
T3: Tri-iodothyronine
T4: Thyroxine
Calcitonin
Parathyroid hormone production
-PTH: Parathyroid hormone
Adrenal gland hormone production (For this lecture)
-Cortisol (Glucocorticoid)
-Aldosterone (Mineralcorticoid)
Endocrine pathway for hormones
-Hypothalamus -> Pituitary -> hormone site
Hypothalamus
-Primarily maintains homeostasis in the body
-Links the nervous system with the endocrine system via the pituitary gland
-Secretes inhibiting or releasing hormones which stim/inhibit the anterior pituitary
Adrenocorticotrophic hormone (ACTH)
-Stims the adrenal cortex, making cortisol
-If there isnt enough cortisol in circulation, ACTH levels will rise
Thyroid stimulating hormone (TSH)
Stimulates the thyroid gland to make t3 and t4
-Negative feedback system
-Iodine is needed too, for the production of TH
-Thyroid hormone controls metabolic activity
-TH is made in the follicular cells in the thalamus
Calcitonin
-Made in C cells
-Secreted when there is a high plasma calcium level, leading to a reduction in Ca in the blood
-Works opposite to PTH
-Moves the Ca back into the bone
Hypothyroidism
-Inadequate amounts of T3/T4
-Decreases the metabolic rate of all body systems
-Primary secondary and tertiary
Primary hypothyroidism
-Dysfunction of the thyroid gland
-Caused by:
-Autoimmune
-Surgical removal of part or the entire thyroid gland
-Radiation to thyroid gland
-Meds
-Thyroiditis, viral infection, iodine (too much too little), congenital
Hashimoto’s thyroiditis
Auto immune attack of the thyroid causing primary hypothyroidism
Meds causing hypothyroidism
-Amiodarone
-Lithium
-Interferon, Interleukin-2, Immunotherapy (Cancer drugs)
Secondary hypothyroidism
-Failure of ant pituitary to stimulate the thyroid gland by inadequate secretion of TSH (tumor or radiation)
Tertiary hypothyroidism
-Hypothalamus doesnt produce Thyroid release hormone (TRH)
Hypothyroidism S+S
-Everything slows down
-Fatigue (Most common)
-Forgetful
-Depression
-Thinning of hair
-Dry flaky skin and brittle nails
-Constipation
-Intolerance to cold (feel cold all the time)
-Abnormal menstraual cycles
-Weakness
-Bradycardia
-Hypotension
-Edema
-Accelerated atherosclerotic disease
Hypothyroidism diagnostics
-Radioisotope I-123: Uptake will be slow in hypothyroidism (Slow absorption=low thyroid)
-EKG: Sinus brady, cardiac dysrhythmias (Later sign)
What labs are decreased in hypothyroidism
T3/T4
TSH in SECONDARY hypothyroidism
What labs are increased in hypothyroidism
-TSH in primary
-Antibody test if there is a disease process involved
Hypothyroidism treatment
-Meds: Essentially TH
-Need to take meds for life
-Take in the morning on empty stomach with water (8 oz)
-NPO except water for 60 min after taking thyroid meds, no other meds at the time
-No supplements (Ca, vitamin D, Mg, minnerals, iron) for at least 4 hrs from levothyroxine
-Take at the same time every day
-Start dose low and titrate up based on blood work
-Can affect levels of digoxin, warfarin, and may need increased insulin (Increased blood sugar)
Hypothyroidism in elderly
-Only treat if symptomatic, with lowest dose possible
-Huge risk of A-fib, Tachycardia
Hypothyroidism meds (T4)
-Levothyroxine (Synthroid, Euthyrox, Euthyroid)
-Synthetic T4
Amour Thyroid
-Dried pig thyroid
-Contains T3+T4, hard to regulate serum levels as a result