Physio Ii Test 4 (5): Endocrine - Thyroid Hormones

Front 1

The 4 Thyroid hormones

Back 1

1) Thyroid Hormones (TH)
2) Thyroxine (T4)
3) Triiodothyronine (T3)
4) Calcitonin
Thyroid Hormone production is regulated by the hypothalamus via TRH and the anterior pituitary hormone, thyrotropin (TSH)

Front 2

What glands and hormones regulate hormone production and secretion in the thyroid gland?

Back 2

Thyroid Hormone production is regulated by the hypothalamus via TRH and the anterior pituitary hormone, thyrotropin (TSH)

Front 3

What type of thyroid cell produces calcitonin?

Back 3

Parafollicular cells

Front 4

What cells of the thyroid gland secrete thyroglobulin into the lumen of the thyroid follicles where it is stored in colloid.

Back 4

The Follicular cells

Front 5

what cellular structure in the thyroid gland stores colloid?

Back 5

thyroid follicles

Front 6

Stimulates Thyrotrophs of the anterior pituitary to secrete TSH
Feedback inhibition – TSH, T3 & T4

Back 6

Thyroid hormone (T4 & T3) secretion is regulated via the hypothalamic-pituitary axis
CNS-Hypothalamus - TRH.
Anterior pituitary - thyroid stimulating hormone (TSH)
TSH signals the thyroid gland to produce & secrete the thyroid hormones (T3 plus T4).

Front 7

since T3&T4 are bound to transport proteins does this mean they are steroid hormones?

Back 7

NO NO NO!!!!!
T3&T4 are bound to transport proteins because they are insoluble in H2O and would precipitate out of the blood without they help of transport proteins.

Front 8

Is Thyroxine or triodothronine the major thyroid hormone produced under normal conditions?

during I- deficiency?

Back 8

major thyroid hormone produced

under normal conditions: Thyroxine(T4)

during I- deficiency: Tri-iodo-tyronine (T3)

Front 9

Thyroxine

Back 9

Thyroxine(T4)

Front 10

Tri-iodo-tyronine

Back 10

Tri-iodo-tyronine (T3)

Front 11

The Wolff-Chaikoff effect

Back 11

The Wolff-Chaikoff effect: inhibition of T3&T4 synthesis by high iodine

Front 12

What are the 3 transport proteins that are associated with T3&T4?

Back 12

1) Thyroxine-binding globulin (TBG binds ~70-75% of T4)

2) Transthyretin (~20% of T4)
3) Albumin (~5-10% of T4)

Proteins produced by the liver
TBG synthesis increased during pregnancy (estrogens)
TGB decreased by corticosteroids & liver disease

Front 13

most T4 is bound to what transport protein?

least?

Back 13

Thyroxine-binding globulin

TBG binds ~70-75% of T4

Albumin (~5-10% of T4)

Front 14

In comparison to other endocrine hormones the half-life of T3&T4 is ___

Back 14

T3&T4 have a longer half-life than other endocrine hormones.

days vs. hours or min

Front 15

TBG synthesis increased during pregnancy (estrogens).

Why is this important?

Back 15

physicians sometimes misdiagnose pregnant women as having hyperthyroidism.

false positive

Front 16

Allan-Herndon-Dudley syndrome

Back 16

brain thyroid hormone transporter problem

Front 17

T4 is converted to T3 inside target cells by ______?

Back 17

T4 is converted to T3 inside target cells by selenodeiodinases

Front 18

Which TH is more biologically active?

Back 18

T3 (tri-iodo-thyronine) is more biologically active.

T3 is 4x more potent than T4

Front 19

Thyroid Hormone Actions

Back 19

TH regulates metabolic rate
Virtually every tissue effected
↑oxygen & fuel consumption
↑heat production (calorigenic)
↑Na - K ATPase
↑Number of mitochondria

Front 20

Thyroid Hormone Actions

Back 20

1) Stimulates carbohydrate metabolism

2) Stimulates fat mobilization

3) Enhances vasodilation and tissue blood flow

Front 21

Thyroid Hormone Actions: Stimulates carbohydrate metabolism

Back 21

Stimulates carbohydrate metabolism
1) enhanced insulin-dependent entry of glucose into cells

2) increased gluconeogenesis and glycogenolysis

Front 22

Thyroid Hormone Actions: Stimulates fat mobilization

Back 22

Stimulates fat mobilization
1) increased plasma fatty acids

2) enhanced oxidation of fatty acids

3) Decreased plasma cholesterol and triglycerides

Front 23

TH insufficiency can cause Cretinism. What is Cretinism?

Back 23

Cretinism = growth & mental retardation due to lack of TH during development

Front 24

How does TH affects gluconeogenesis?

Back 24

T3&T4 stimulate carbohydrate metabolism.

T3&T4 stimulate gluconeogenesis

Front 25

How does TH affects glycogenolysis?

Back 25

T3&T4 stimulate carbohydrate metabolism.

T3&T4 stimulate glycogenolysis

Front 26

glycogenolysis

Back 26

Glycogenolysis (also known as "Glycogenlysis") is the conversion of glycogen polymers to glucose monomers.
Glycogen is catabolized by removal of a glucose monomer through cleavage with inorganic phosphate to produce glucose-1-phosphate.
This derivative of glucose is then converted to glucose-6-phosphate, an intermediate in glycolysis.

Front 27

Gluconeogenesis

Back 27

Gluconeogenesis (GNG)

generation of glucose from non-carbohydrate carbon substrates such as lactate, glycerol, and glucogenic amino acids.
1 of 2 pathways for maintaining blood glucose levels

Front 28

What pathways are used to maintain blood glucose levels to avoid hypoglycemia?

Back 28

1) gluconeogenesis glucose from non carbohydrate substrates

2) glycogenolysis: lysis of glycogen to get glucose.

Front 29

glycogenolysis

Back 29

is through the degradation of glycogen

lysis of glycogen to get glucose.

Front 30

What is a goiter?

Back 30

enlarged thyroid gland

Front 31

If there is elevated TSH do you have Hyperthyroidism or Hypothyroidism?

Back 31

elevated TSH appears in both Hyperthyroidism and Hypothyroidism

Hyperthyroidism with elevated TSH
pituitary tumor:

Hypothyroidism with elevated TSH
thyroid gland failure of dietary deficiencies:

Front 32

Graves’ disease

Back 32

Hyperthyroidism

Thyroid-stimulating antibody (TSI)

Front 33

pituitary tumor

Back 33

Hyperthyroidism with elevated TSH
TSH over production

Front 34

Iodine deficiency

Back 34

Hypothyroidism with elevated TSH

Dietary (elevated TSH)

Front 35

Thyroid gland failure

Back 35

Hypothyroidism with elevated TSH

Front 36

Hypothyroidism with elevated TSH

Back 36

Hypothyroidism
1) Dietary (elevated TSH)
-Iodine deficiency
-goiterogens
2) Gland failure (elevated TSH)

Front 37

Primary Hypothyroidism

Back 37

Primary Hypothyroidism failure of the gland
- Autoimmune (Hashimoto’s disease)
- Infection
- Other – genetic, toxins

Front 38

Secondary Hypothyroidism

Back 38

Secondary Hypothyroidism
TRH &/or TSH deficiency

Front 39

Dietary Hypothyroidism

Back 39

Dietary - Iodine deficiency

Front 40

Hashimoto’s disease

Back 40

Primary Hypothyroidism failure of the gland

Front 41

TRH &/or TSH deficiency

Back 41

Secondary Hypothyroidism

Front 42

Iodine deficiency

Back 42

Dietary Hypothyroidism

Front 43

Primary Hyperthyroidism

Back 43

Primary Hyperthyroidism:
TH producing tumor
Initial stages of thyroiditis

Front 44

Secondary Hyperthyroidism

Back 44

Secondary Hyperthyroidism:
Autoimmune (Graves disease)
TSH producing tumor

Front 45

Thyrotoxicosis

Back 45

Thyroid hormone excess – also called Thyrotoxicosis

Front 46

Grave’s disease

Back 46

Hyperthyroidism caused by antibodies that bind the TSH receptor and mimic TSH effects

frequent in older women

Goiter, weight loss, nervousness, tremor, exophthalmos (edema behind eyes), complaint of feeling hot, hair loss

Front 47

Myxedema

Back 47

Myxedema - puffy appearance common in hypothyroidism

Front 48

cretinism

Back 48

Hypothyroidism during infancy results in dwarfism & mental retardation called cretinism

Front 49

Hypothyroidism in adult produces

Back 49

Hypothyroidism in adult produces fatigue, sensitivity to cold, low body temp. weight gain & mental dullness
Drooping eyelids from decreased sympathetic tone to the levator palpebrae superiorus muscle

Front 50

patient has thyroid stare. What type of thyroid disease is indicated

Back 50

Graves disease

secondary hyperthyroidism, autoimmune problem with very low TSH due to T3 feedback inhibition

Front 51

What are the autoimmune thyroid disorders?

Back 51

1) graves disease: secondary hyperthyroidism due to thyroid stimulating antibody

2) Hashimotos disease: primary hypothyroidism due to antibodies targeting the thyroid or bind to TSH receptors and block binding.

Front 52

elevated blood levels of thyroid hormone and Thyroid stimulating immunoglobulin. Which of the following test results would you expect for her TSH levels?

Back 52

very low levels of TSH

Front 53

Mrs. Smith has elevated thyroid hormone blood levels with low levels of TSH. Which of the following conditions does she likely have? ↑TH ↓TSH
1) Graves disease
2) Pituitary tumor
3) Thyroid tumor
4) Hashimotos disease
5) Iodine Deficiency

Back 53

1 and 3 are Hyperthyroidism, 2 can be if it is a TSH secreting pituitary tumor: Pituitary tumor ↑TSH ↑TH


1) Graves disease ↓TSH ↑TH
3) Thyroid tumor ↓TSH ↑TH

TSH will be feed back inhibited by T3, while in TSH secreting pituitary tumors it will not.

Front 54

Mrs. Jones has low thyroid hormone blood levels with elevated levels of TSH. Which of the following conditions does she likely have? ↓TH ↑TSH
1) Graves disease
2) Pituitary tumor
3) Thyroid tumor
4) Hashimotos disease
5) Iodine Deficiency
Thyroiditis with gland failure

Back 54

Hypothyroidism 4-5

4) Hashimotos disease ↓TH ↑TSH
5) Iodine Deficiency ↓TH ↑TSH

Front 55

Autoimmune thyroid disease are primary or secondary?

Back 55

Graves disease: secondary hyperthyroidism

Hashimotos: primary
hypothyroidism

Front 56

Tumor causing thyroid disease are primary or secondary?

Back 56

TH producing Thyroid tumor: primary

TSH producing Pituitary tumor: secondary hyperthyroidism

Front 57

Following Surgery to remove Mr. Blind's Pituitary tumor, Which of the following replacement hormones should he receive?Insulin
TSH
Thyroid hormone
Cortisol
Calcitonin

Back 57

Thyroid hormone. monitored to keep TSH at normal levels

Front 58

Calcitonin

Back 58

Calcitonin
-Protein hormone that causes a decrease in blood calcium levels
-Produced by parafollicular cells of the thyroid gland
-Release is regulated by blood calcium ion levels
High calcium ion increases release
Low calcium ion decreases release
Inhibits osteoclasts

Front 59

Calcitonin is produced by ____ cells of the thyroid gland

Back 59

Produced by parafollicular cells of the thyroid gland

Front 60

Calcitonin is a protein hormone that causes a ___in blood calcium levels

Back 60

Calcitonin is a protein hormone that causes a decrease in blood calcium levels

Front 61

Calcitonin is a protein hormone that is secreted when there is ___ blood calcium levels

Back 61

Calcitonin is a protein hormone that is secreted when there is high blood calcium levels (hypercalcemia).

Front 62

Calcitonin ____ osteoclasts

Back 62

Calcitonin Inhibits osteoclasts