Thyroid Gland Hormones Flashcards
Thyroid Gland specs
Large gland in the neck, where it is attached to the trachea just below the larynx (voice box)
Two lobes (on either side of the trachea)
Thyroid hormones increases the metabolic rate, and stimulate all body cells to metabolize and use energy at a faster rate
Thyroxine (T4) specs
Produced & released in the thyroid
Increases the rate at which the body metabolizes fats proteins & carbs for Energy
No specific targets, but stimulates heart, skeletal muscles, liver & kidneys to increase cell resp.
Important for growth and development of children (making tissues into organs)
What happens when there are excessive amounts of Thyoxine?
Hyperthyroidism
Overactive Thyroid
Jittery, weight loss, increased HR, warmer temp., mood swings, hair loss, bulging eyes
What is Graves Disease?
Caused by Hyperthyroidism
Can be deadly, as the immune system is attacking the thyroid
Is treated by removing a portion of the thyroid gland (surgically or chemically)
What happens when there is an insufficient amount of Thyoxine?
Hypothyroidism
In children if the thyroid fails to develop it leads to cretinism
Stocky & shorter build, without injections, mental development delays will occur
As adults it leads to Myxedema
Tiredness & slow pulse, weight gain & puffy, cold & dry skin, hair loss,
What does the Thyroid Stimulating Hormone (TSH) do?
It causes the Thyroid to release Thyroxine (T4)
Thyroxine Negative Feedback Loop
The HP detects the low levels of Thyroxine, and sends a signal to the anterior pituitary gland to release TSH
TSH targets the thyroid causing it to release T4
Cell respiration will increase
HP detects this & stops releasing RH - the AP stops secreting TSH
What is needed to synthesize Thyroxine?
Iodine
What happens if there are inadequate amounts of Iodine in one’s diet?
The thyroid swells in an effort to make more thyroxine, causing goiders
What is Calcitonin?
It’s a Thyroid gland hormone that helps to lower Ca levels in the blood (it’s needed for clotting, bones, teeth, nerve conduction & muscle contraction)
Stimulates the uptake of Ca into the bones & lowers conc. in the blood
Primary effect is to bring about the deposit of Ca in the bones
It also plays a minor role in calcium homeostasis
Calcium -> Bones = lower conc.
Calcitonin Negative Feedback Loop?
The HP detects the low levels of Calcium, and sends a signal to the Thyroid gland to release Calcitonin
Calcitonin targets the Blood/Bones
Causes Ca2+ to move from blood to the bones & lowers blood Ca conc.
HP detects this and stops releasing RH
What is Parathyroid Gland Hormone (PTH)?
It causes the breakdown on bone material to reabsorb Ca into the blood to increase Ca conc.
PTH stimulates the kidneys to reabsorb Ca from urine, activating Vitamin D in the process
Vitamin D stimulates the reabsorption of Ca into the blood
PTH Negative Feedback Loop
The HP sends a signal to the Parathyroid gland to release PTH
PTH targets the kidneys to get them to reabsorb Ca into the blood
Blood Calcium levels will increase
HP detects this & stops releasing RH so the PTG stops secreting PTH
