Term
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Definition
| glandular and release secretions into the ECF |
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Term
| What are glands of the endocrine system? |
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Definition
hypothalamus pituitary gland thyroid gland pancreas thymus gonads
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Term
| Endocrine glands release ____ |
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Definition
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Term
| There are no ___ involved in the release of hormones |
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Definition
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Term
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Definition
organic molecules and chemical messengers |
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Term
| hormones are released in one tissue and ____ |
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Definition
| transported in the bloodstream to reach specific cells in other tissues |
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Term
| each hormone has ___ that are_____ |
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Definition
target cells specific and respond accordingly |
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Term
| ___ have receptors that can "read" hormonal messages |
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Definition
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Term
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Definition
| a number of functions in the body, e.g., digestion, reproduction |
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Term
| hormone function is closely linked to ______ |
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Definition
| nervous system function and the immune system |
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Term
| a hormone can exert various effects _____ |
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Definition
| on different tissues, e.g., estradiol. |
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Term
| a ___can be regulated by several hormones. |
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Definition
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Term
| _____ takes place between cells |
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Definition
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Term
| Hormones act ___ where concentrations are relatively high |
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Definition
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Term
| ____ occur within cells from where they were produced, e.g., insulin. |
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Definition
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Term
| _____ occurs between hormones bound on plasma membrane of cells and receptors of adjoining cells. |
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Definition
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Term
| What are two types of cell receptors? |
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Definition
(i) cell surface receptors (ii) intracellular nuclear receptors. |
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Term
What are characteristics of Cell surface receptors? |
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Definition
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Term
| What are characteristics of Intracellular receptors? |
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Definition
lipid-soluble cross cell membranes of target cells directly The receptors are in the cytoplasm and bind with the hormone. The bound-hormone then moves to the nucleus where a response occurs.
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Term
____ cross the cell membrane by diffusion or by a carrier mechanism. |
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Definition
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Term
Explain Thyroid hormone diffusion. |
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Definition
Once inside the cell cytoplasm, these hormones bind to receptors within the nucleus and on the mitochondria. The hormone-receptor complexes in the nucleus activate specific genes. Thyroid hormones bound to mitochondria increase the mitochondria's rates of ATP production.
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Term
| Describe control of hormone levels. |
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Definition
Hormones have specific rates and rhythms of secretion, e.g., diurnal, or cyclic. Thyroid hormone requires days for its full effect to take place. Hormones operate within a feedback system, either positive or negative.
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Term
| In ____, the hormone increases steadily until a required level is reached |
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Definition
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Term
| With ___, if a hormone level increases to a certain level, it triggers its own decrease. |
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Definition
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Term
| For negative feedback, the feedback is a _____ |
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Definition
regulatory mechanism and preserves homeostasis. |
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Term
Where are Thyroids located? |
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Definition
| two lobes on either side of the trachea. |
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Term
Describe Thryoids and their functions: |
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Definition
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Term
| Follicles are cells that surround substances called ___ |
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Definition
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Term
| Follicular cells synthesize a globular protein called ___ and secrete it into the colloid |
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Definition
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Term
| Each thyroglobulin molecule contains the amino acid ___ which is the building block of thyroid hormones |
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Definition
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Term
| ___ absorbed in the diet is transported from the digestive tract by blood. |
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Definition
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Term
| _______ to form the thyroid hormones |
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Definition
| Iodine ions bind tyrosine |
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Term
| ____ is known as tetraiodothyronine, or,T4 (four iodide ions). . |
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Definition
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Term
| ______, or T3, has three iodide ions |
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Definition
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Term
| What three glands are involved in thyroid hormone secretion: |
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Definition
hypothalamus pituitary thyroid.
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Term
| ____ in the hypothalamus initiates release of TSH. |
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Definition
| TRH (thyrotropin releasing hormone) |
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Term
| ____ in pituitary leads to release of ______ in thyroid gland. |
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Definition
- TSH (thyroid stimulating hormone)
- TH (thyroid hormone)
TRH (hypothalamus) à TSH (pituitary) à TH (thyroid gland) |
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Term
What are the functions of TSH? |
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Definition
(i) It causes TH to be released from thyroids (ii) causes iodide uptake (iii) increases thyroid hormone synthesis (iv) increases prostaglandin by thyroid gland. |
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Term
| if TH is secreted by thyroid, it suppresses TSH and TRH production. This lowers TH production and is a _____. |
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Definition
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Term
| The inadequate production of thyroid hormones is called _____ |
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Definition
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Term
| Hypothyroidism produces ___ in infants (inadequate skeletal and nervous development) and in later childhood retards growth and mental development. |
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Definition
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Term
| ___ occurs when thyroid hormones are produced in excessive amounts |
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Definition
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Term
| Describe symptoms of hyperthyroidism. |
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Definition
| Metabolic rate climbs, and skin becomes flushed and moist with perspiration. |
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Term
Hyperthyroidism occurs due to ___ |
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Definition
| increase in level of circulating T 3 and T 4 ( i.e.,TH) with heat intolerance. |
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Term
What are two causes of why there is excessive TH? |
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Definition
(i) Graves disease (ii) toxic multilocular goiter |
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Term
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Definition
autoimmune disease; abnormal stimuli of thyroid by thyroid stimulating antibodies; normal regulatory mechanism is overridden by abnormal immunological mechanism; may be associated with myasthenia gravis or pernicious anemia
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Term
___ results from diffuse thyroid enlargement |
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Definition
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Term
___ results from fibroblasts becoming activated behind the eyeballs |
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Definition
| ophthalmopathy (protruding eye balls) |
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Term
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Definition
| T lymphocytes become sensitized to antigens within thyroid gland; |
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Term
| Sensitized T lymphocytes stimulate ___ to synthesize antibodies to these antigens |
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Definition
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Term
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Definition
are known as thyroid stimulating immunoglobulins bind to TSH receptors in follicular cells and stimulate them to release TH are not under feedback control system.
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Term
| In Graves disease the ____ is disrupted because the thyroid releases large amounts of thyroid hormones (TH) and will not stop. |
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Definition
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