Thyroid And TSH Flashcards
What is the Thyroid gland?
It is one of the largest highly vascular endocrine glands
What is the histology of the thyroid gland?
It has follicles,and parafollicular cells that secrete calcitonin
What is the purpose of calcitonin?
Reduces calcium concentration in body fluids when levels of Ca are elevated
What are the two lobes of the thyroid gland connected by?
The isthmus which is in front of the trachea
What do the follicular cells of the thyroid gland secrete?
Thyroglobulin
What is thyroglobulin composed of?
Thyroxine and diiodothyronine
What are some follicular cells associated with?
C cells which are at the basement membrane of the follicles
What do the thyroid hormones include?
Triiodothyronine and Thyroxine
What happens yo the thyroid hormones?
They are transported in the blood and bind with intracellular receptor molecules and initiate new protein synthesis and increase rate of glucose,fat and protein metabolism in many tissues
What is the source of T3(Triiodothyronine)?
The thyroid gland and the conversion of T4 to T3,enzymes in the liver,kidneys and other tissues
What is the purpose of T3?
It mediates the effects of thyroid hormone on peripheral tissues and exerts negative feedback on the pituitary gland and hypothalamus
What are the effects of Thyroid hormones?
Regulation of metabolism
Growth and Development
The neuronal system
How does TH regulate the metabolism?
It stimulates carbohydrate and lipid catabolism
Increases rate of protein synthesis
Increases the Basal metabolic rate
Increases the number of mitochondria
Increases the membrane transport activity
What is the calorigenic effect?
Heat realesed by the Basal metabolic rate which will cause an increase in body temperature
How does TH affect growth and development?
Regulates tissue growth and development in children
Together with the GH,TH will accelerate body growth
How does TH affect the neuronal system?
It will increase blood flow,heart beat,blood pressure,the motility of the GIT and nervousness increases
TH assists in development and myelination of neurons
What happens when there’s a shortage of TH?
Fewer and smaller defective myelination of neurons and mental retardation
What causes hypothyroidism?
Iodine deficiency
What causes secondary hypothyroidism?
Low concentrations of TSH from the anterior pituitary or hypothalamic TRH deficiency
What us Cretinism?
Inadequate skeletal and nervous development and metabolic rate below normal levels
What are some symptoms of hyperthyroidism?
Weight loss
Rapid heart rate
Bp increase and HR increases
Shifts in mood
What is Graves disease?
Goiter and protruding eyes due to excess hormone caused by TSI
What is thyroid stimulating immunogloubulins?
An antibody that acts like TSH
