Physiology - Thyroid

Question 1

thyroid gland tissue secretes what?

Answer 1

thyroxine (T4)
tri-iodothyronine (T3)
calcitonin

Question 2

the 4 parathyroid glands secrete what?

Answer 2

parathyroid hormone (PTH)

Question 3

the thyroid is situated between the _th cervical and _st thoracic vertebrae

Answer 3

the thyroid is situated between the 5th cervical and 1st thoracic vertebrae

Question 4

what is sometimes absent from the thyroid?

Answer 4

isthmus

Question 5

thyroid innervation:

sympathetic -
parasympathetic -

Answer 5

sympathetic - sup. inf. and middle ganglia of sympathetic trunk

parasympathetic - vagus (CN X)

Question 6

thyroid blood supply?

Answer 6

superior and inferior thyroid arteries

Question 7

nexus drainage of thyroid?

Answer 7

3 pairs:

superior/middle thyroid vein

Question 8

what is the other name for the posterior suspensory ligament?

Answer 8

berry ligament

Question 9

what nerve is at risk of damage in surgery of the thyroid?

Answer 9

recurrent laryngeal nerve

Question 10

the colloid contains ________ enclosed by __________ cells

Answer 10

the colloid contains TYROSINE enclosed by FOLLICULAR cells

Question 11

what do parafollicular C cells secrete?

Answer 11

calcitonin

Question 12

what element is used to synthesise thyroid hormone?

Answer 12

iodine

Question 13

thyroxine hormone has how many iodines attached to it?

Answer 13

4

Question 14

what drug is used to prevent active hormone being produced?

Answer 14

carbimazole

Question 15

1. iodine taken up by ________ cells
2. _______ attached to tyrosine residues on thyroglobulin to form MIT and DIT
3. coupling of MIT and DIT (T_) and 2 DITs (T_)
4. stored in colloid thyroglobulin till required

Answer 15

1. iodine taken up by FOLLICLE cells
2. IODINE attached to tyrosine residues on thyroglobulin to form MIT and DIT
3. coupling of MIT and DIT (T3) and 2 DITs (T4)
4. stored in colloid thyroglobulin till required

Question 16

T3 or T4?

90% of secreted thyroid hormone

10% of secreted thyroid hormone

T_ is 4 times more potent than T_

T_ is converted to T_ in any cell

major biologically active thyroid hormone

Answer 16

90% of secreted thyroid hormone -T4

10% of secreted thyroid hormone - T3

T3 is 4 times more potent than T4

T4 is converted to T3 in any cell

major biologically active thyroid hormone - T3

Question 17

T3 and T4 are _____phobic so bind to plasma proteins

Answer 17

T3 and T4 are HYDROPHOBIC so bind to plasma proteins

Question 18

name the 3 major binding protein that T3 and T4 bind to

Answer 18

thyroxine binding globulin - TBG

thyroxine binding prealbumin - TBPA

albumin

Question 19

bound or unbind is the biologically active form?

Answer 19

unbound

Question 20

only the ________ hormone is available to tissue

Answer 20

only the UNBOUND hormone is available to tissue

Question 21

what increases the total binding globulin but has no effect on free?

Answer 21

pregnancy

Question 22

name the effects of thyroxine

Answer 22

moist skin
anxiety
tachycardia
palpitations
loose bowels
lose period
muscle wasting

Question 23

what hormones increase basal metabolic rate, thermogenesis, carbohydrate, lipid and protein metabolism

Answer 23

thyroid hormones

Question 24

you need thyroid hormone for ____ production and so for growth

Answer 24

you need thyroid hormone for GHRH production and so for growth

Question 25

what drug is used to treat sympathetic symptoms in initial stages of hyperthyroidism?

Answer 25

propanolol

Question 26

___ from hypothalamus stimulates ___ release from _________ pituitary TSH is the major stimulant to release T3 and T4 from the ________ gland T3 and T4 exert ________ feedback control of TRH and TSH release

Answer 26

TRH from hypothalamus stimulates TSH release from ANTERIOR pituitary TSH is the major stimulant to release T3 and T4 from the THYROID gland T3 and T4 exert NEGATIVE feedback control of TRH and TSH release

Question 27

in babies: cold stimulates ___ release which stimulates ___ release so increases __ and __ release from thyroid

Answer 27

in babies: cold stimulates TRH release which stimulates TSH release so increases T3 and T4 release from thyroid

Question 28

what inhibits TRH and TSH release?

Answer 28

stress

Question 29

thyroid hormone is highest at _____ and lost in the ________

Answer 29

thyroid hormone is highest at NIGHT and lost in the MORNING

Question 30

name the important family of enzymes important in the activation an deactivation of thyroid hormone name the particularly important member of this family

Answer 30

delodinase enzymes Type 3

Question 31

__ activates T4 to T3 in tissues

Answer 31

D2 activates T4 to T3 in tissues

Question 32

name the location of the following de-iodinase enzymes: type I - type II - type III -

Answer 32

type I - liver and kidney type II - heart, muscle, CNS, fat, thyroid, pituitary type III - fetal tissue, placenta and brain - NOT pituitary

Question 33

primary thyroid gland failure may result in the presentation of what?

Answer 33

a goitre (enlarged thyroid)

Question 34

goitre or no goitre: secondary to TRH or TSH

Answer 34

no goitre

Question 35

goitre or no goitre: lack of iodine in diet

Answer 35

may be associated with goitre

Question 36

hypothyroidism symptoms?

Answer 36

``` reduced BMR slow pulse rate fatigue, lethargy, mental sluggishness cold-intolerance put on weight ```

Question 37

name the condition in adults associated with puffy face, hands and feet

Answer 37

myxoedema

Question 38

name the condition in babies associated with dwarfism and limited mental functioning due to deficiency of thyroid hormones at birth

Answer 38

cretinism

Question 39

name the common disease associated with hyperthyroidism

Answer 39

grave's disease

Question 40

is graves disease autoimmune?

Answer 40

yes

Question 41

what is bulging of the eyes called in graves disease called?

Answer 41

exophthalmos

Question 42

is there a goitre in graves disease?

Answer 42

yes

Question 43

graves disease symptoms?

Answer 43

``` increased BMR fast pulse increased nervousness insomnia sweating heat intolerance lose weight ```

Question 44

what is the main regulator of thyroid hormone release?

Answer 44

TSH

Question 45

what is the most biologically thyroid active hormone?

Answer 45

T3