Term
| the thyroid gland is ~34g, well vasculated and of a butterfly shape. what joins the thyroid gland together in the middle? |
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Definition
| The Isthmus of the thyroid gland |
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Term
| which amino acid does the thyroid gland need in order to make T3 and T4? |
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Definition
tyrosine.
the thyroid gland makes the protein Thyroglobulin |
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Term
| what is the stuctural difference between T4 and T3? |
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Definition
T4 has 4 iodides
T3 has 3 iodides
the rest of the structure is the same |
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Term
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Definition
in the protein thyroglobulin.
thyroglobulin is a long protein with a lot of tyrosine side chains dangling off it. |
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Term
| calcitonin is a peptide hormone involved in calcium regulation. which cells of the thyroid produce calcitonin? |
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Definition
c cells baby!
c cells stand for 'clear' cells because they dont stain so well
c cells c cells on the c shore =P |
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Term
| name the enzyme that oxidises iodides and attactches them to thyroglobulin |
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Definition
Thyroid peroxidase
then all is exocytosed to the colloid and sits there until your body needs it |
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Term
| which hormone released from the hypothalamus regulates release of thyroid stimulating hormone (TSH) |
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Definition
| Thyrotropin releasing hormone (TRH) this is carried through the hypophyseal portal veins to the anterior pituitary glands and stimulates the release of TSH by thyrotrophs |
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Term
| name 4 effects TSH stimulates |
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Definition
iodide uptake
thyroglobulin uptake
thyroglobulin synthesis
thyroid peroxidase synthesis |
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Term
true or false?
T3 is more active than T4? |
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Definition
| True. however 90% of production is T4 |
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Term
| describe functions of thyroid hormones in development in frogs, bone formation and the brain |
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Definition
frogs - needed for metamorphosis
bone formation - stimulates osteblasts
brain - causes embryonic nerve cells to branch |
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Term
| describe the role of thyroid hormones in metabolism (4) |
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Definition
> metabolic rate
> ATP production (mitochondrial receptors)
stimulate glycolysis to make more ATP
increase HR and BP |
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Term
| name the congenital thyroid deficiency condition that arises due to poor skeletal and nervous development |
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Definition
Cretinism
-low metabolic rate and mental retardation-
affects 1 in 5000 live births |
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Term
| what is hypothyroidism in adults known as? |
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Definition
myxoedema - not having enough T3 and T4
symptoms include
lethargy, muscle weakness, low body temp, dry skin, hair loss, enlarged thyroid (goiter), subcutaneous swellings.
may be due to low dietary iodine |
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Term
| what is another name for hyperthyroidism? |
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Definition
Graves' disease
characteristics include:
high metabolic rate, high body temperature, sweating, high HR and BP, mood swings, excitability, restlessness
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Term
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Definition
| it lowers blood Calcium levels and stores it in your bones |
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Term
| when blood calcium level is low which hormone stimulates osteoclasts to release Calcium from bones and stimulates Calcium uptake from kidneys? |
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Definition
Parathyroid Hormone from the parathyroid gland. it also reduces blood phosphate levels
extra info : the uptake of calcium in the kidneys activates vitamin D which increase uptake of Ca2+ in intestines.
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Term
| name the 2 epithelial cells found in the parathyroid gland |
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Definition
Principal Chief Cells - produce PTH
Oxyphil cells - function unknown |
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Term
| which two hormones are made in the medulla of the adrenal glands? |
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Definition
adrenaline and noradrenaline
AKA
epinephrine and norepinephrine |
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Term
| where are corticosteroids made? |
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Definition
| in the cortex of the adrenal glands |
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Term
| name the 3 layers of the adrenal cortex starting from the base of the adrenal medulla |
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Definition
| Zona reticularis, Zona fasciculata, Zona glomerulosa |
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Term
| which layer of the cortex are androgens eg. testosterone made? |
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Definition
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Term
| which layer of the cortex are glucocorticoids eg, cortisol made? |
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Definition
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Term
| in which layer of the adrenal cortex are mineralocorticoids eg. aldersterone made? |
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Definition
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Term
| what does aldersterone do? |
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Definition
| it increases absorbtion of Na+ from the distal tubules. H20 follows by osmosis. |
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Term
| name some functions of glucocorticoids |
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Definition
stimulate glucose and glycogen synthesis
stimulate release of fatty acids
cause tissue to break down fatty acids and proteins
immunosuppresive
anti-inflammatory |
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Term
true or false?
Glucocorticoids inhibit phagocytosis, cytokine release and white blood cell production? |
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Definition
true.
they are immunosupressive and anti-inflammatory.
they also inhibit histamine release from mast cells |
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Term
| the hypothalamus activates the adrenal medulla via ...... impulses |
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Definition
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Term
| what are the short term effects of stress and the adrenal gland? |
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Definition
| the adrenal medulla secretes epinephrine and norepinephrine |
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Term
| what are the long term effects of stress and the adrenal gland? |
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Definition
| the adrenal cortex secretes mineralocorticoids and gluccocorticoids |
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