T1 L7 :Thyroid Hormone Physiology

Question 1

what is the thyroid gland composed off in terms of cells

Answer 1

Follicles

Question 2

What is colloid

Answer 2

A reservoir of thyroid hormone

Question 3

what is the name of T3 and T4

Answer 3

T3= triiodothyronine
T4=
Tetraiodothyronine

(thyroxine )

Question 4

What does Di and monoiodotyrosine combine to form (MIT and DIT)

Answer 4

Forms T3 and T4

Question 5

where is iodine derived from

Answer 5

Plants

Question 6

What is T4 converted into in the tissues

Answer 6

T3

Question 7

what can Fe deficiency cause

Answer 7

It can disrupt iodine absorption leading to dysfunction of the thyroid gland

Question 8

what can radioactive iodine cause

Answer 8

Deficiency of iodine absorption in the thyroid gland (as radioactive iodine absorbed kills of the thyroid glands cells)

Question 9

what is the thyroid hormone made up of predominately?

Answer 9

T4

Question 10

hat is the active form of the thyroid hormone

Answer 10

T3

Question 11

what form of the thyroid hormone is given as medication

Answer 11

T4

Question 12

what converts T4 to T3

Answer 12

Deiodinase enzymes

Question 13

what other product is produced from T4

Answer 13

reverse T3

Question 14

is reverse T3 active ?

Answer 14

No it’s inactive

Question 15

what causes the secretion of the thyroid hormone (from a centre in the brain)

Answer 15

Hypothalamus- TRH

Pituitary -TSH

Thyroid gland - T3 and T4

Question 16

what is the negative feedback of T3/4 release

Answer 16

The inhibition of TSH (and assume therefore the inhibition of TRH)

Question 17

what cause Derbyshire neck

Answer 17

A loss of I2 causes an increase in the release of TSH which causes hypertrophy of the thyroid gland

Question 18

what metabolic effects does the thyroid hormone cause (3 effects)

Answer 18

Carbohydrate metabolism

Protein synthesis

Lipolysis

Question 19

what does thyroid hormone cause in the foetus

Answer 19

It causes the myelination of the nerve fibres

Question 20

how is albumin transported in the blood

Answer 20

10% albumin

20% TBPA(thyroxine-binding prealbumin)

75% T4 bound to thyronine-binding globulin

Question 21

what occurs when thyroxine travels across cells

Answer 21

Binds to intracellular receptors at the nucleus and influences gene transcription and thus protein synthesis

Question 22

what happens after gene transcription

Answer 22

More mitochondria and increased activity

Question 23

what are the effects of an increased carbohydrate metabolism

Answer 23

• glycogenesis and glucose uptake by muscle cells and adipose cells
• potentiation of the effects of insulin
• potentiation of the effects of the catecholamines
• increase in glucose absorption by the gastrointestinal tract.

Question 24

Which organs does the thyroid hormone not cause an increase in metabolism for

Answer 24

Brain
Uterus
Testes
Spleen
Thyroid gland
Anterior pituitary gland

Question 25

You can live as an adult without your thyroid gland but u need it as a kid, If so what are thyroid hormones essential for

Answer 25

Normal growth development

Question 26

what does a decrease in iodine cause or humans

Answer 26

Puberty inhibition so you don't grow and always remain looking like a child

Question 27

CORE DRUG: LEVOTHYROXINE

Answer 27

Its used to treat thyroid deficiency Suppresses TSH secretion and can be given by mouth or injection overdoes: Palpitations and arrhythmias

Question 28

Lithium does what to the thyroid hormone

Answer 28

It inhibits its secretion

Question 29

CORE DRUG : What does propylthiouracil do to the thyroid gland

Answer 29

prevents the peripheral conversion of T4 to T3. which normally acts in thyroid hormone synthesis. PTU also acts by inhibiting tetraiodothyronine deiodinase which converts T4 to T3. Drug of choice to treat hyperthyroidism in first trimester CAUSES- pruritus

Question 30

what does K+ perchlorate do

Answer 30

Potassium perchlorate acts by competing with iodide for the active iodide uptake pump.

Question 31

CORE DRUG :what does Carbimazole (methimazole) do

Answer 31

act by inhibition of the synthesis of thyroid hormones by preventing the incorporation of the iodide into the thyroglobulin. which prevents peroxidase iodinating the tyrosine residues on thyroglobulin, hence reducing the production of the thyroid hormones T3 and T4. can cause Pruritus

Question 32

what drugs can reduce goitre and how do they work

Answer 32

Lithium Iodides These ions are selectively concentrated within the thyroid gland where they interfere with iodide incorporation and hormone release.

Question 33

what is an alternate to using carbimazole in pregnant women and why

Answer 33

Propylthiouracil: it has a short half life and so its better than carbimazole for breastfeeding mothers