Thyroid gland Flashcards
Vertebral levels of the thyroid
C5 to T1
Tracheal rings which the thyroid isthmus covers
Tracheal rings 2 and 3
At which week does the thyroid begin to migrate from the floor of the foregut
3-4 weeks
The site from which the thyroid originated persists as the ______
foramen cecum
At which week does the thyroid begin secreting hormone
18th week
Where would a thyroglossal cyst be located
In the midline of the neck
Where would a branchial cyst be located
Anterior to the sternocleidomastoid
Where would a lingual thyroid be seen
At the back of the tongue
TSH stimulates which cells
Thyroid follicular cells
TSH stimulates follicular cells by which second messenger system
Gs
TSH stimulates the production of which protein
thyroglobulin
Functions of thyroid peroxidase
- oxidation of iodide to iodine
- Addition of iodine to tyrosine residues on thyroglobin
- coupling of DIT and MIT
T3 and T4 can only be transported in the blood bound to which molecule
Thyroxine binding globulin
Where us thyroxine globulin synthesized and what is its function
TBG is synthesized in the liver and is needed to transport T3 and T4 in the blood
Which enzyme is needed to convert T4 to T3
5’ iodinase
During starvation there is an upregulation of which thyroid hormone
rT3
Which transporter is need to for enter of iodide into the thyroid follicular cells
sodium-iodide symporter
Apart from TBG which other molecules can T3 and T4 be bound to to be transporter
Albumin and pre-albumin
Which thyroid hormone has a longer half life
T4
Which thyroid hormone is more biologically active
T3
How is the autoregulation of thyroid hormone production done
low iodide levels increase iodine transport into follicular cells while high iodide levels decrease iodine transport into follicular cells
In Primary hypothyroidism what happens to levels of :
T4
TSH
TRH
T4 - decreased
TSH - inceased
TRH - increased
In Pituitary hypothyroidism what happens to levels of :
T4
TSH
TRH
T4 - decreased
TSH - deceased
TRH - increased
In hypothalamic hypothyroidism what happens to levels of :
T4
TSH
TRH
T4 - decreased
TSH - deceased
TRH - decreased
In pituitary hyperthyroidism what happens to levels of :
T4
TSH
TRH
T4 - increased
TSH - inceased
TRH - decreased
In Graves’ disease what happens to levels of :
T4
TSH
TRH
T4 - increased
TSH - deceased
TRH - decreased
Any condition that increases body energy requirements ______ (stimulates/inhibits) the hypothalamus to produce TRH
Stimulates the hypothalamus to produce TRH
Effects of Thyroid hormone
- increase basal metabolic rates
- increased HR and contractility by increasing beta 1 receptors
- increase RR
- increase renal blood flow and GFR
- increased O2 dissociation from Hb
- ovulation, maintenance of pregnancy, spermatogenesis, menstruation
- brain maturation
- CNS development ad emotion tone
- increase glucose absorption in gut
- growth of bones
- protein breakdown in muscles
True or false:
Goiter can be caused only by hyperthyroisism
False.
Goiter can be caused by both hyperthyroidism and hypothyroidism
