Chapter 12: The Endocrine System
The Endocrine System, Hypothalamus, & Pituitary and Pineal
Glands
Secretes hormones directly into the bloodstream
Glands of ES:
o Pineal
o Pituitary
o Thyroid
o Parathyroid
o Thymus
o Adrenal
o Pancreas
o Gonads & ovaries
Endocrine cells found in tissues:
o Cells in upper GI tracts: secrete gastrin – stimulates
gastric secretions
o Cells in kidney: secrete erythropoietin – stimulates red
blood cell production
o Fat cells: secrete leptin – suppresses appetite, lack of
this leads to overacting obesity
o Cells in tissue throughout body: secrete prostaglandins
– dilate blood vessels, relax airways, stimulate uterine
contractions in menstrual cramps or labor, lower acid
secretion in the stomach
Hypothalamus
Located in brain above pituitary gland and connects brain to
the endocrine system through blood vessels between the
hypothalamus and pituitary gland
Oxytocin: hormone that stimulates uterine to contact
ADH: decreases uterine output
Pineal Gland:
, Near top of the brain’s 3rd ventricle, posterior to the
hypothalamus
Secretes the feel-good hormone serotonin
Serotonin: neurotransmitter; converts to melatonin
Melatonin: helps to regulate sleep and wake cycles
Pituitary Gland
Suspended from the hypothalamus and has two
components:
o Large anterior lobe
o Small posterior lobe
There are 6 anterior lobe hormones
o Follicle-stimulating hormone (FSH): stimulates target
cells in the ovaries to develop eggs as well as sperm
production in the testes
o Luteinizing hormone (LH): stimulates ovulation and
estrogen and progesterone production; stimulates
testosterone production in males
o Thyroid-stimulating hormone (TSH): thyrotropin;
stimulates the growth of the thyroid gland and the
production of the chief thyroid hormone, thyroxine
o Adrenocorticotropic hormone (ATCH): stimulates the
adrenal glands to produce hormones called
corticosteroids (hydrocortisone and cortisone)
o Prolactin (PRL): encourages the mammary glands to
produce milk after pregnancy
o Growth hormone (GH): somatropin; stimulates cells to
enlarge and divide
Thyroid Gland
Lies beneath the skin of the neck and below the “Adam’s
apple”
Two lobes extend up on either side of the trachea and are
joined by an isthmus
Thyroid Hormone:
The Endocrine System, Hypothalamus, & Pituitary and Pineal
Glands
Secretes hormones directly into the bloodstream
Glands of ES:
o Pineal
o Pituitary
o Thyroid
o Parathyroid
o Thymus
o Adrenal
o Pancreas
o Gonads & ovaries
Endocrine cells found in tissues:
o Cells in upper GI tracts: secrete gastrin – stimulates
gastric secretions
o Cells in kidney: secrete erythropoietin – stimulates red
blood cell production
o Fat cells: secrete leptin – suppresses appetite, lack of
this leads to overacting obesity
o Cells in tissue throughout body: secrete prostaglandins
– dilate blood vessels, relax airways, stimulate uterine
contractions in menstrual cramps or labor, lower acid
secretion in the stomach
Hypothalamus
Located in brain above pituitary gland and connects brain to
the endocrine system through blood vessels between the
hypothalamus and pituitary gland
Oxytocin: hormone that stimulates uterine to contact
ADH: decreases uterine output
Pineal Gland:
, Near top of the brain’s 3rd ventricle, posterior to the
hypothalamus
Secretes the feel-good hormone serotonin
Serotonin: neurotransmitter; converts to melatonin
Melatonin: helps to regulate sleep and wake cycles
Pituitary Gland
Suspended from the hypothalamus and has two
components:
o Large anterior lobe
o Small posterior lobe
There are 6 anterior lobe hormones
o Follicle-stimulating hormone (FSH): stimulates target
cells in the ovaries to develop eggs as well as sperm
production in the testes
o Luteinizing hormone (LH): stimulates ovulation and
estrogen and progesterone production; stimulates
testosterone production in males
o Thyroid-stimulating hormone (TSH): thyrotropin;
stimulates the growth of the thyroid gland and the
production of the chief thyroid hormone, thyroxine
o Adrenocorticotropic hormone (ATCH): stimulates the
adrenal glands to produce hormones called
corticosteroids (hydrocortisone and cortisone)
o Prolactin (PRL): encourages the mammary glands to
produce milk after pregnancy
o Growth hormone (GH): somatropin; stimulates cells to
enlarge and divide
Thyroid Gland
Lies beneath the skin of the neck and below the “Adam’s
apple”
Two lobes extend up on either side of the trachea and are
joined by an isthmus
Thyroid Hormone:
