Lecture 38: Thyroid and parathyroid glands Flashcards
What cells in the thyroid gland make thyrogloubin TGB?
- follicular cells which secrete iodised TGB into the follicle
What cells secrete calcitonin
- Parafollicular cells - C cells
How is TGB converted to TH?
Iodised TGB moves into follicle where is reacts with tyrosine ——> creates storage form of TH
What stimulates the release of thyroid hormones from the thyroid gland?
1) Hypothalamus releases TRH
2) Anterior pituitary releases TSH
3) Thyroid gland releases T3 or T4
Thyroid hormones have two forms which are?
T3 - active form
T4 - plentiful form
What effect does TH have on the body?
- metabolism
- increases BMR
- increases glycogenolysis & gluconeogenesis
- stimulates breakdown of fatty acids
What effect does TH have on the body?
- growth
- stimulates growth in fetus and early childhood
How are Ca+ levels regulated?
- Calcitonin = lowers Ca+
- PTH = increased Ca+
How does Calcitonin lower Ca+?
- decreases bone breakdown
- Decreases osteoclast activity
- Increases osteoblast activity
- Decreases osteoclast activity
Where is Calcitonin secreted from?
Thyroid gland
How does PTH increase Ca+?
- bone
- increased bone breakdown - releases Ca+
- increase osteoclast activity
- decrease osteoblast activity
-
How does PTH increase Ca+?
- kidneys
- increased Ca+ reabsorption
- decreases Ca+ lost in urine
What is graves disorder?
- High TH level = “ drug addict”
- increased BMR & HR
- nervous
- decrease in weight
- high temperature tolerance
What is Myxedemia disorder?
- low TH level
- low BMR & HR
- increased weight gain
- lethargy
- decrease temperature tolerance
What is cretinism?
low TH level which impairs brain development in children
