endocrine Flashcards
(101 cards)
Are gonads considered endocrine glands or endocrine tissues?
endocrine glands
Define hormones.
Hormones are chemical regulators of various body functions such as growth and reproduction
How are hormones transported?
They’re secreted into the blood and transported by the blood to affect the functions of their target cells.
What is the general scheme of hormone function?
stimulus–> gland with hormone in it–> hormone secretion–> to the blood–> blood transports hormone to the target cell–> action
Compounds acting as hormones are classified according to their chemical structure. What are the three divisions?
Steroids, amines, proteins & polypeptides
What are hormones made of 100 or more amino acids called?
proteins (less than 100 is a polypeptide)
Where do steroid hormones bind?
to cytoplasmic receptors and increase protein synthesis by mitochondria and ribosomes
Where do thyroid hormones bind?
to nuclear receptors and increase gene transcription in the cell nucleus
Where do hormones other than steroid or thyroid hormones bind?
to cell membrane receptors and activate cAMP, DAG, or inositol triphosphate second messanger systems
When blood level of the endocrine gland hormone reach an optimum value, it inhibits secretion of the hypothalamic and anterior pituitary hormones that stimulate the gland. What is the control of secretion called?
Negative feedback secretion
When the response to an endocrine gland hormone reach an optimum level, it increases secretion of the hormone that stimulate the response. What is the control of secretion called?
Positive feedback
Where is the hypothalamus?
central area of the basal brain limbic system (back of the head, towards the bottom)
What are the hypothalamic hormones?
they makes the endocrine system work
What are the 9 hypothalamic hormones?
GHRH, GHIH (somatostatin), PRH, PIH (dopamine), CRH, GnRH, TRH, ADH, OT
Where are OT and ADH secreted from?
Posterior pituitary
What ar ethe two parts of the pituitary gland?
anterior (adenohypophysis) and posterior (neurohypophysis)
What is the posterior pituitary?
derived form neural brain tissue and connects to the hypothalamus by the hypothalamic hypophyseal tract (secreteds ADH and OT)
What is the anterior pituitary?
derived from ectodermal tissue in the roof of the embryonic mouth and connects to the hypothalamus by the hypophyseal portal blood vessels
Both nuclei of the hypothalamus, paraventricular and supraoptic nucleus, produce both OT and ADH but whihc produces which dominantly?
paraventricular- OT
supraoptic- ADH
A polypeptide hormones of 9 amino acids. Target tissue are kidneys, sweat glands and the blood arterioles, what hormone am I?
ADH (vasopressin)
- causes kidneys and sweat glands to conserve water to increase blood volume
- causes vasoconstriction of arterioles to increase blood pressure
A polypeptide hormone of 9 amino aicds. Target tissues are the smooth muscles of reproductive system of both sexes. What hormone am I?
OT
male- contraction of smooth muscles during ejaculation
female- labor contractions and release of milk from mammary glands
Somatotropes
human growth hormone (hGH)
Corticotropes
Adrenocortecotropin (ACTH)
Thyrotropes
Thyroid Stimulating Hormone (TSH)