Physiology - Thyroid Flashcards
the thyroid gland is composed of lobules of ………… follicles filled with colloid
a.hexagonal
b.spherical
c.square
b.spherical
colloid centre inside round follicle many follicles make up lobule
what are the 2 components required for thyroid hormone synthesis
a.tyrosine and calcium
b.tyrosine and iodine
c.adenosine and iodine
d.adenosine and magnesium
b.tyrosine and iodine
tyrosine + iodine —> monoiodotyrosine (MIT)
how does iodide leave the interstitial fluid and enter the follicle cell of the thyroid gland?
a.diffusion
b.active transport
c.cotransport with sodium
c.cotransport with sodium
how does iodide travel from the follicle cell into the lumen of the follicle (colloid)
a.diffusion
b.active transport
c.co transport with sodium
d.I/Cl transporter
d.I/Cl transporter
Pedrin
what happens to iodide in the colloid
iodide oxidised and attached to rings of tyrosines in the thyroglobulin
iodinated ring of one MIT is added to a DIT
what happens after iodinated tyrosine ring is added to another ring
a.endocytosis of thyroglobulin containing t3 and t4 molecules
b.lysosomal enzymes release t3 and t4 from thyroglobulin
c.thyroglobulin protein synthesised in follicle cell then sent to colloid
d.t3 and t4 released into interstitial fluid
a.endocytosis of thyroglobulin containing t3 and t4 molecules
correct sequence of events above^
in order to exert full biological activity T….. needs to be converted to T…
a.3 -> 4
b. 4 -> 3
b. 4 -> 3
which enzyme is produced in the liver, kidney, thyroid, pituitary and heart and is responsible for local synthesis of t3 and 4 in thyroid, and peripheral synthesis of t3
a.type 1 deiodinase
b.type 2 deiodinase
c.type 3 deiodinase
a.type 1 deiodinase
which enzyme is produced in the pituitary, brain, skeletal muscle and brown adipose tissue and is responsible for regulating local t3 production and adding to systemic t3 production
a.type 1 deiodinase
b.type 2 deiodinase
c.type 3 deiodinase
b.type 2 deiodinase
which enzyme is produced in the placenta, uterus, brain, fatal tissue, thyroid, kidney and adult liver and is responsible for inactivation of t3 and t4-> rt3
a.type 1 deiodinase
b.type 2 deiodinase
c.type 3 deiodinase
c.type 3 deiodinase
what type of intracellular receptor do thyroid hormones bind to?
a.cytoplasmic
b.mitochondrion joined cytoplasmic receptor and nuclear receptor
c.nuclear receptor
b.mitochondrion joined cytoplasmic receptor and nuclear receptor
binding causes increased ATP
and change in gene activity
altering structural proteins/ enzyme activity
leading to target cell response
thyroid hormones affect ALL cells in the body
what effect do t3 and t4 have on oxygen consumption
a. increase
b.decrease
a. increase
what effect do t3 and t4 have on Basal metabolic rate
a. increase
b.decrease
a. increase
what effect do t3 and t4 have on carbohydrate metabolism
a. increase
b.decrease
a. increase
increase absorption of glucose
increase glycogenolysis
increased gluconeogenesis
what effect do t3 and t4 have on lipid metabolism
a. decreased lipolysis
b.increased lipolysis
b.increased lipolysis
more circulating FFAs, increased FFA oxidation , decreases cholesterol and increases LDL receptor number
what effect do thyroid hormones have on the heart
a.increase HR,CO, increase blood flow to skin
b.decrease HR,CO, decrease blood flow to skin
a.increase HR,CO, increase blood flow to skin
what effect do thyroid hormones have on the heart
a.increase HR,CO, increase blood flow to skin
b.decrease HR,CO, decrease blood flow to skin
a.increase HR,CO, increase blood flow to skin
what effect do thyroid hormones have on the nervous system
a. increases synaptic activity , enhances effects of sympathetic NS
b.decreases synaptic activity , reduces the effects of the sympathetic nervous system
a. increases synaptic activity , enhances effects of sympathetic NS
what regulates the circulating levels of thyroid hormone ?
a.hypothalamus
b.pituitary
c.hypothalamus and pituitary
c.hypothalamus and pituitary
what substance released from the hypothalamus stimulates the release of TSH from the anterior pituitary whih in turn stimulates the thyroid gland to release T3 and T4
a.CRH
b.FSH
c.TRH
d.TSH
c.TRH
is released from the anterior pituitary in response to TRH from the hypothalamus
a.TSH
b.CRH
c.T3 and T4
d.TRH
a.TSH
what effect does stress have on secretion of t3 and t4 from the thyroid gland
.a. increase
b.decrease
b.decrease
what effect does cold have on secretion of t3 and t4 from the thyroid gland
.a. increase
b.decrease
a. increase
what effect does TSH have on iodine binding at the thyroid gland
a.increase
b.decrease
a.increase
what effect does TSH have on thyroglobulin synthesis and secretion into colloid at the thyroid gland
a.increase
b.decrease
a.increase
what effect does TSH have on t3 and t4 synthesis at the thyroid gland
a.increase
b.decrease
a.increase
what effect does TSH have on number and size of follicular cells at the thyroid gland
a.increase
b.decrease
a.increase
what effect does TSH have on blood flow at the thyroid gland
a.increase
b.decrease
a.increase
a disorder at the level of the hypothalamus would be referred as
a. primary
b.secondary
c.tertiary
c.tertiary
a disorder at the level of the pituitary would be referred as
a. primary
b.secondary
c.tertiary
b.secondary
a disorder at the level of the endocrine gland would be referred as
a. primary
b.secondary
c.tertiary
a. primary
the failure of the thyroid gland to respond to TSH is known as
a. primary hypothyroidism
b.secondary hyperthyroidism
c.tertiary hypothyroidism
d.primary hyperthyroidism
a. primary hypothyroidism
caused by
Thyroiditis
severe iodine defficinecy
severe deficiency of synthesis hormones
removal or destruction of thyroid gland
reduced negative ffedback in primary hypothyroidism causing elevated TSH in primary hypothyroidism causes which symptom
a.short height
b.goitre
c.impaired brain development
b.goitre
thyroid enlarges
defficient TSH production is known as
a. primary hypothyroidism
b.secondary hypothyroidism
c.tertiary hypothyroidism
d.primary hyperthyroidism
b.secondary hypothyroidism
in which type of hypothyroidism does thyroid atrophy occur
a. primary hypothyroidism
b.secondary hypothyroidism
c.tertiary hypothyroidism
d.primary hyperthyroidism
b.secondary hypothyroidism
deficient TSH production
in which type of hypothyroidism is there deficient TSH secretion due to deficient TRH secretion
a. primary hypothyroidism
b.secondary hypothyroidism
c.tertiary hypothyroidism
d.primary hyperthyroidism
c.tertiary hypothyroidism
what are the consequences of hypothyroidism
short stature
brain, bone and other development seriously impaired
what is the most common cause of hyperthyroidism
a.thyroiditis
b.severe iron defficiency
c.graves disease
d.thyroid adenoma
c.graves disease
graves disease pathophysiology
antibody producing cels produce thyroid stimulating antibodies
the thyroid rleases excess t3 and t4
hyperthyroidism
cold intolerance, dyspnea , fatigue, weakness, weight gain are symptoms of ..
a.hypothyroidism
b,hyperhtyroism
a.hypothyroidism
hyperactivity, sweating , palpatations, diarrhoea weight loss are symptoms of ..
a.hypothyroidism
b,hyperthyroidism
b,hyperthyroidism
increases sympathetic
bradycardia , goitre, dry skin, peripheral edema, and puffy face are signs of
a.hypothyroidism
b,hyperthyroidism
a.hypothyroidism
tachycardia,tremor,goitre, moist skin, proximal muscle weakness are signs of
a.hypothyroidism
b,hyperthyroidism
b,hyperthyroidism
what condition has high TRH and TSH but low T4
a.primary hypothyroidism
b.secondary hypothyroidism
c.tertiary hypothyroidism
d.graves disease
a.primary hypothyroidism
problem at level of thyroid gland
what condition has high TRH but low TSH and T4
a.primary hypothyroidism
b.secondary hypothyroidism
c.tertiary hypothyroidism
d.graves disease
b.secondary hypothyroidism
problem at level of pituitary
what condition has low TRH TSH and T4
a.primary hypothyroidism
b.secondary hypothyroidism
c.tertiary hypothyroidism
d.graves disease
c.tertiary hypothyroidism
provblem at level of hypothalamus
what condition has low TSH and TRH but high T4
a.primary hypothyroidism
b.secondary hypothyroidism
c.tertiary hypothyroidism
d.graves disease
d.graves disease
hyperthyroidism antibodies stimulate thyroid to produc t4
