ENDOCRINE DISORDERS-THYROID DISORDERS 1.1 (AB) Flashcards
Which glands are interrelated in thyroid physiology during pregnancy?
Maternal and fetal thyroid glands.
What hormone does the hypothalamus secrete to stimulate TSH production?
Thyrotropin-releasing hormone (TRH).
Which cells in the anterior pituitary secrete TSH?
Thyrotrope cells.
What is the central hormone in screening and diagnosing thyroid disorders?
Thyroid-stimulating hormone (TSH).
Does TSH cross the placenta?
No, TSH does not cross the placenta.
What hormone stimulates TSH production during pregnancy, particularly at 12 weeks AOG?
Human chorionic gonadotropin (hCG).
What secretes hCG?
The placenta.
When does hCG production start?
During implantation, after trophoblastic invasion.
Does hCG production start immediately after fertilization?
No, it begins during implantation.
Why does the thyroid gland enlarge during pregnancy?
Due to granular hyperplasia and increased thyroid hormone production.
What causes an increase in thyroid-binding globulin (TBG) concentration during pregnancy?
Increased hepatic synthesis due to elevated estrogen production.
What effect does elevated TBG have on thyroid hormones?
Increases total T3 and T4 concentration.
What is the role of free T4 in TSH secretion?
Free T4 suppresses TRH, limiting TSH secretion via negative feedback.
When does total serum T4 regress sharply during pregnancy?
At 6-9 weeks AOG.
What organ produces TBG?
The liver.
What happens if circulating T3 and T4 levels are high?
Negative feedback to the hypothalamus suppresses TSH production.
How many thyrocyte components are targeted by autoantibodies in autoimmune thyroid disease?
Approximately 200.
What are the effects of autoantibodies in thyroid disease?
Stimulation, blocking, or inflammation of thyroid function.
What can thyroid inflammation lead to?
Follicular cell destruction.
What is another name for thyroid-stimulating autoantibodies?
Thyroid-stimulating immunoglobulins (TSIs).
What is the primary function of thyroid-stimulating immunoglobulins (TSIs)?
Bind and activate TSH receptors, leading to hyperfunction and growth.
In which disease are thyroid-stimulating immunoglobulins (TSIs) predominantly found?
Graves’ disease.
What are thyroid-stimulating blocking antibodies?
Antibodies that counteract TSIs and may blunt their effect.
What enzyme do thyroid-peroxidase (TPO) antibodies target?
Thyroid-peroxidase (TPO), essential for hormone production.