mnsr 37

Question 1

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

Answer 1

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

Question 2

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

Answer 2

thyroid gland

Question 3

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

Answer 3

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

Question 4

TRS is released by —
TSH is released by —

Answer 4

hypothalamus
anterior pituitary which promotes the release of T3 , T4

Question 5

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

Answer 5

• +ve on the target organ and -ve on hypothalamus and pituitary

Question 6

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

Answer 6

• 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

Question 7

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

Answer 7

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

Question 8

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

Answer 8

TSH , idoide , follicular spaces

Question 9

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

Answer 9

TPO ( thyroid peroxidase ) , Iodine (I2)

Question 10

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

Answer 10

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

Question 11

hormone formation process :

Answer 11

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

Question 12

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

Answer 12

• 2 DIT
• T4 more readily
• T4 more than T3

Question 13

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

Answer 13

• parafollicular , c-cells , calcitonin

Question 14

peroxidase will form — between iodanated tysoine

Answer 14

covelant bonds

Question 15

2 DITS forms

Answer 15

T4

Question 16

1 MIT and 1 DIT forms

Answer 16

T3

Question 17

I2 + tyrosine froms

Answer 17

monoiodotyrosine or diiodotrysoine ( T1 or T2 )

Question 18

– is more potent of two hormones up to 40 times

Answer 18

T3

Question 19

plasma half life of T4 is – while T3 is —

Answer 19

• 6 days
• 1.3 days

Question 20

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

Answer 20

target organs , dna transcription in the nuclease

Question 21

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

Answer 21

• T3 , T3 , inactive

Question 22

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

Answer 22

T3

Question 23

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

Answer 23

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

Question 24

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

Answer 24

inactive , enter the target cells

Question 25

the protien-bound thyroxine serves as a —

Answer 25

reservoir in blood

Question 26

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 —-

Answer 26

• 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)

Question 27

the effect of thyroid hormones :

Answer 27

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

Question 28

the effects of thyroid hormones of metabolic rate:

Answer 28

• 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

Question 29

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 —

Answer 29

• 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

Question 30

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

Answer 30

thyroid hormones

Question 31

physiological effects of thyroid hormone

Answer 31

• 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

Question 32

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 :

Answer 32

• 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

Question 33

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

Answer 33

• 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

Question 34

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

Answer 34

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

Question 35

— is enlargement of thyroid and may occur in ——

Answer 35

• goitre
• hypo, hyper, normal thyroid

Question 36

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

Answer 36

exophthalmos

Question 37

exophthalmos is symptom of —

Answer 37

graves diseases and not hyperthrydosim