mnsr 37 Flashcards

1
Q

thyroid gland is attached to the — and downgrowth is from the floor of the — and it weighs — and its highly —

A
  • larynx
  • pharynx
  • 25 grams
  • vascularised ( which has greater blood supply than kidney and is 2nd only to adrenal gland in blood flow )
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2
Q

a — is a bi-lobed structure with one love either side of the trachea

A

thyroid gland

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3
Q

each follicle consist of fluid filed spaces surrounded by a layer of — and these spaces are filled with jelly like substance called —- and it consist of — , surrounded by highly vascularised connective tissue lightly stained with — , they are held together by — which is a connective tissue supporting the follicles

A

follicular cells , colloid ,thryoglubin which is a protein prosecutor to the thyroid hormone , follicular cells , stroma

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4
Q

TRS is released by —
TSH is released by —

A

hypothalamus
anterior pituitary which promotes the release of T3 , T4

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5
Q

T3 + T4 :
has +ve effect on :
-ve effect on :

A
  • +ve on the target organ and -ve on hypothalamus and pituitary
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6
Q

Acumalation and storage of — is essential for the production of thyroid hormone .
Active — are located — membrane of the —

A
  • iodine and its ingested in small quantities in our diet ( 150 ug is suffiencet in diet )
  • idoine pump is located outside the membrane of the follicular cells
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7
Q

the uptake of iodine is partially under the control of the —-

A

pituitry hormone TSH ( thyroid stores 4,000 ug of iodine )

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8
Q

– stimulates follicular cells to increase the uptake of — from the bloodstream , the follicular cells pumps the iodide into the —-

A

TSH , idoide , follicular spaces

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9
Q

Iodide (I -) is oxidised by — to from —

A

TPO ( thyroid peroxidase ) , Iodine (I2)

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10
Q

— is a prosecutor to thyroid hormone and produced within the follicular cells and forms —

A

thyroglobulin (Tg) , homodimers
( each thryroglobulin has 140 tyrosine amino acids)

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11
Q

hormone formation process :

A

1- the oxidation of iodide to iodine by the enzyme TPO
2- after they get released into the follicular cells they iodine binds to tyrosine amino acid residue of the thryoglibulin folicule
3- each tyrosine has two or one iodine attached to form MIT ( monoiodotyroxine ) or DIT ( diiodotrysoine ) , these remain attache to the Tg protein
4- peroxide combines 2 DIT and produce T4 more than T3
5- throyglobin remains in the colloid until TSH stimulates the endocytosis of the colloid back to the follicular cells
5- protease will cleave T3 and T4 and hormones will be released into the bloodstream
5- the rest of Tg protein will be degraded and any iodinated tyrosine not incorporated in T3 or T4 is recycled

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12
Q

Peroxide is more efficient at combining — which makes — generation more easily thus the thyroid gland produces more – -than —

A
  • 2 DIT
  • T4 more readily
  • T4 more than T3
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13
Q

thyroid also contains smaller amount of — which are also called – and they produce —

A
  • parafollicular , c-cells , calcitonin
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14
Q

peroxidase will form — between iodanated tysoine

A

covelant bonds

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15
Q

2 DITS forms

A

T4

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16
Q

1 MIT and 1 DIT forms

A

T3

17
Q

I2 + tyrosine froms

A

monoiodotyrosine or diiodotrysoine ( T1 or T2 )

18
Q

– is more potent of two hormones up to 40 times

A

T3

19
Q

plasma half life of T4 is – while T3 is —

A
  • 6 days
  • 1.3 days
20
Q

T3 enters the cells of the — and causes direct activation of —-

A

target organs , dna transcription in the nuclease

21
Q

once inside the cells most of the thryroxine will be de-iodinated to — (80%) or reverse – which is — (20%)

A
  • T3 , T3 , inactive
22
Q

up to 90% of the biologically active thyroid hormone is —

A

T3

23
Q

the ratio of hormones in the blood stream is —
majority of these hormones are bounded to —

A
  • 10:1 , 90: thyroxine and 10% T3
  • serum proteins including thyroxine , globulin , and albumin
24
Q

Bound T3/T4 is — only free thyroxine and T3 can —-

A

inactive , enter the target cells

25
Q

the protien-bound thyroxine serves as a —

A

reservoir in blood

26
Q

carrier proteins have higher affinity to – which is why the proportion of T3 ion the plasma is in free/unbounded state has — times greater than —-

A
  • T4 than T3
  • 10 times than T4 in free state
    ( final circulation will have 90 ug and 40-60 ug of T3 since thyroxine will be de-ionated to t3)
27
Q

the effect of thyroid hormones :

A
  • increase the basal metabolic rate (amount of energy expended in rest)
  • promotes growth and mutaration
  • specific physological effects
28
Q

the effects of thyroid hormones of metabolic rate:

A
  • increase it from 60 to 100% where hormones will be released
  • increase 02 consumption
  • increase protein synstheis , rna sythesis so more rna and mrna , metbabolic enzymes will increase and mitochondria increase the ATP levels
29
Q

thyroid gland works synergically with —- on the bone growth
low level of the enzyme will lead to — but parodixally high levels of the enzyme will lead to —

A
  • insulin like growth factor ( IGF-1 )
  • poor growth and retarted sexual development in puberty
  • rapid pardoxally growth at first buy stops at younger bc because of early closure of epiphysis
30
Q

the normal development of the CNS before and after birth depends on the aduquent level of —

A

thyroid hormones

31
Q

physiological effects of thyroid hormone

A
  • carbs and fat metabolism is increased so increased levels of lipids
  • may decrease body weight but enhanced apetite
  • cardiac output increases so high systolic pulse pressure
  • GIT secretion increased and enhanced mobility
  • CNS as: nervousness , irratibilty, muscle tremor , constant tiredness and unable to sleep
32
Q

under active thyroid is — and produces insufficient levels of thyroid caused by — iodine and in children it may lead to — and in adults —
causes: —
treatment for primary :
treatmenr for secondary :

A
  • hypothyroidism
  • low idoine
  • cretinism aka congenital iodine deficney syndrome ( poor growth and dwarf stature , decreased thyroid activity before and after birth due to failure of development of the CNS )
  • myxoedema : thickens skin , hair loss m conga in facial appearance , goitre , muscle stiffness
  • iodine defecincy, yo-yo diet m overactive adrenal gland , hasmimoto thyroiditis , autoimmune which causes self destrcuture of thyroid cells , more common in females (80%)
  • primary : thryoid hormone
  • secondary : aleviate symptoms
33
Q

– refers to 5-10 higher than normal and most symptoms are under —- as: —–
causes are: —
(CHECK SLIDE 32)

A
  • hyperthyroidism
  • physiological effects
  • hypertension , raised body temp, weight loss and may be accompanied by protrusion of eyeballs called: exophthalmos
  • cause includes: graves disease 70-80% etology , toxic multidular goitre , toxic thyroid adenoma which is the hyper functioning follicle due to adenoma
34
Q

Graves disease is a cause of — and it occurs due to —–

A
  • hyperthyroidism
  • auto bodies to TSH , antibodies stimulates receptor and leads to increase secetion of T3 and T4
35
Q

— is enlargement of thyroid and may occur in ——

A
  • goitre
  • hypo, hyper, normal thyroid
36
Q

— is the bulging of the eye anteriorly out of orbit and retro-orbital oedema and fat demposition

A

exophthalmos

37
Q

exophthalmos is symptom of —

A

graves diseases and not hyperthrydosim