MLT 230: Final Cumulative Review

functions of thyroid hormones

- increase metabolic rate

- growth/maturation of body and brain

essential component of thyroid hormones

iodine

two hormones produced by thyroid

T3/T4 and calcitonin

responsible for calcium homeostasis

calcitonin

effects of thyroid hormone (T3/T4)

- tissue growth

- brain maturation

- increased heat production

- increased O2 consumption

- increased # of beta-andrenergic receptors

3-4 times more potent than T4

T3

active form of thyroid hormone

T3

amount is 50 times greater than T3

T4

can be converted to T3

T4

problems occur more frequently with this hormone vs. calcitonin

thyroid hormone (T3/T4)

transports thyroid hormone through plasma

protein

70-75% of T3 and T4 are transported by this protein

TBP/TBG

remainder of T3 and T4 transported by this protein

pre-albumin/albumin

pre-albumin and albumin transport this thyroid hormone

T4

only alternative to TBP/TBG for T3 transport

albumin

too much thyroid hormone (acute)

thyrotoxocosis

lack of TSH or TRH

secondary hypothyroidism

lack of T3/T4

primary hypothyroidism

insufficient free T3 and T4

myxedema

lab results in primary hypothyroidism

low T4 and high TSH

primary hypothyroidism disease (congenital)

cretinism

chronic lymphocytic thyroiditis

Hashimoto's thyroiditis

abnormal thyroid function due to anti-peroxidase

Hashimoto's

most common auto-antibody in Hashimoto's

anti-peroxidase

asymptomatic

euthyroid

lab results for hypothyroidism - primary

TSH increased

lab results for hypothyroidism - secondary

TSH decreased

amioderone-induced thyroid disease causes

hypothyroidism

example of secondary hyperthyroidism

Toxic adenoma

lab results in toxic adenoma

pituitary produces too much TSH

substance that toxic adenomas may secrete

HcG

most common antibody in Grave's disease

TSab

symptom of Grave's disease

diffuse toxic goiter

example of primary hyperthyroidism

Grave's disease

lab results in Grave's disease

undetectable TSH

lab results in primary hyperthyroidism

decreased TSH

lab results in secondary hyperthyroidism

increased TSH

guideline testing for thyroid evaluation

sTSH and FT4

sTSH is a ____________________ immunoassay

sandwich

reason sTSH is so sensitive

2 monoclonal antibodies to TSH are used

immunoassays for sTSH

EIA, RIA, FIA or chemiluminesensce

TSH reflex testing

If TSH is high, then FT4 performed. If FT4 is low, then T3 is performed.

FT4 is a _________________ immunoassay

competititve

to calculate the FTI, you need...

TT4 and TBG values (THBR/T-Uptake)

helps determine if disease is a true thyroid disease or just a protein problem with TBG

FTI

FTI formula

TT4 x TBG/THBR/T-Uptake

FTI must be increased or decreased for disease to be...

true thyroid disease

TT4 is affected by

amount of TBG

TBG is increased in

pregnancy and contraceptive use

TBG is decreased in

liver and kidney disease

The THBR/T-Uptake is

a percent inversely proportional to TBG

indirect measurement of available binding sites

THBR/T-Uptake

THBR/T-Uptake is decreased in

hypothyroidism

THBR/T-Uptake is increased in

hyperthyroidism

If THBR/T-Uptake is increased

then TBG is decreased.

If THBR/T-Uptake is decreased

then TBG is increased

used to screen newborns for thyroid disease

rT3

thyroid tumor marker test

thyroglobulin

TSH antibodies occur in

Grave's disease

TPO antibodies occur in

Hashimoto's disease

elevated TBG, low T-Uptake, and increased TT4 are consistent with

patient taking estrogen

T-Uptake is increased in

hyperthyroidism and TBG decreased

The old T3 resin uptake test has been replaced by a direct assay for:

bound T3

True or false?

Individuals taking recurring regimens of androgens or anabolic steroid drugs may exhibit increased TBG levels.

false

A 65-year-old woman presents with fatigue, hypothermia, pericardial effusions, and hair loss. Her thyroid function tests show a significantly elevated TSH and a low free T4. All of the following laboratory test abnormalities may be associated with her underlying condition EXCEPT:

a. An elevated cholesterol level

b. Elevated WBC

c. Elevated CPK levels

d. Anemia

b. Elevated WBC

A 26-year-old man presents with a 3-cm right lobe thyroid nodule and a normal TSH. What is the next test that should be performed?

a. Free T4 level

b. FNA of the nodule

c. Thyroid scan

d. Thyroid ultrasound

b. FNA of the nodule

lab results with increased TBG

- Decreased T-Uptake

- Increased TT4, FT4, FTI and TSH

lab results with decreased TBG

- Increased T-Uptake, FT4, FTI and TSH

- Decreased TT4

primary antibody in Hashimoto's

anti-peroxidase

primary antibody in Grave's

TSab

If a patient has a low level of TBG due to liver or kidney disease, then

FTI will be low.

If a patient has a low level of TBG due to liver or kidney disease, then

TT4 will be low.

The T Uptake test will be elevated when

the patient is producing to much thyroid hormone.

True or False

FSH affects all cells in the body.

False

2 examples of water soluble hormones

epinephrine and adrenaline

an example of lipid soluble hormone

testosterone

when does the body secrete melatonin and from what gland?

at night when eyes are closed and from the pineal gland

role of hypothalmus

- connection between the brain and the endocrine system

- influences the pituitary gland

True or False

The anterior pituitary only produces growth hormone.

False

ADH secreted in the

posterior pituitary gland

Role of thyroid gland

regulates metabolism

gland where insulin and glucagon come from

pancreas

secretions of the adrenal cortex

glucocorticoids

a secretion of the adrenal medulla

epinephrine

6 functions of hormones

1. Homeostasis

2. Growth and development

3. Sexual maturation

4. Energy production and stabilization

5. Stressful circumstances

6. Promote or inhibit other hormones

hormones that promote secretion of other hormones

releasing hormones

hormones that suppress the secretion of other hormones

inhibitory hormones

hormones that stimulate growth and activity of other glands

tropic hormones

hormones that act directly on target tissues

effector hormones

Endocrine cascade

Hypothalamus releases hormones with directions (from the brain) to the pituitary glands.

Pituitary glands release hormones to other endocrine glands. (4 tropic and 2 effector)

Endocrine glands release effector hormones.

4 tropic hormones produced by the anterior pituitary

TSH, ACTH, FSH & LH

2 effector hormones produced by the anterior pituitary

Growth hormone and prolactin

hormones of the anterior pituitary that work on a negative feedback system

effector hormones - growth hormone and prolactin

GnRH from hypothalamus causes

FSH & LH to be released by anterior pituitary

CRH (cortico-releasing hormone) from they hypothalamus causes

ACTH to be released by anterior pituitary

TRH from the hypothalamus causes

TSH and prolactin to be released from anterior pituitary

ACTH from anterior pituitary causes

adrenal glands to secrete hormones

FSH & LH from the anterior pituitary causes

gonads to release hormones

TSH from the anterior pituitary causes

thyroid to release hormones

GHRH from the hypothalamus causes

anterior pituitary to release effector growth hormone