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Ch 26 - Chemical Regulation
1) the nervous system controls the body's activities,
while the endocrine system makes the chemicals; the nervous system decides
when and where the chemicals will be distributed
2) exocrine gland - secretes hormones through ducts
endocrine gland - secretes hormones
directly into blood
hormone - chemical produced
by the body to regulate an activity
3) the endocrine glands are the: pituitary, thyroid,
parathyroid, adrenal, pineal, and thymus
4) some organs contain some endocrine & exocrine
tissue; these include the pancreas, gonads (ovaries & testes), and
hypothalamus
5) the hypothalamus is a neuroendocrine organ
I. Pituitary gland (hypophysis) - in the middle of the
brain, sitting in the sella turcica; it consists of a posterior lobe (neurohypophysis)
and an anterior lobe (adenohypophysis)
A. four tropins (tropic hormones)
in the anterior lobe regulate the secretory action of other endocrine glands
1. TSH
(thyroid stimulating hormone) -stimulates thyroid,
2. ACTH
(stimulates adrenal glands,
3. LH
(luteinizing hormone) - involved with gamete production and release,
4. FSH
(follicle stimulating hormone) - stimulates gamete production
B. the other two hormones produced
in the anterior lobe affect nonendocrine targets
1. GH
(growth hormone controls body growth,
2. PRL
(prolactin) - milk production
C. the posterior lobe stores
a couple of hormones produced by the hypothalamus
1. ADH
(antidiuretic hormone) - controls reabsorption of water
2. oxytocin
- stimulates uterine contractions in childbirth
II. Thyroid gland
A. in the neck, just below the
larynx
B. produces thyroxine to regulate
metabolism
C. produces calcitonin to regulate
blood calcium level
III. Parathyroid gland
A. usually 2 pairs of small
glands embedded in the thyroid
B. makes parathormone (PTH)
to regulate calcium and phosphate metabolism
IV. Adrenal glands
A. on top of the kidneys; each
consists of two parts ... the medulla and the cortex
B. the medulla makes epinephrine
(adrenalin) and norepiniphrine (noradrenalin) to stimulate the body
C. the cortex makes corticosteriods
... a collection of over two dozen steriod hormones
V. Thymus
A. near the heart; shrinks as
you get older
B. aids in the immune system
of children by producing peptide hormones that are necessary for the production
of T cells
VI. Pineal gland
A. hangs from the roof of the
3rd ventricle in the diencephalon
B. produces melatonin; melatonin
concentrations in the blood go up at night and decrease during the day
VII. Pancreas
A. behind the stomach
B. islets of Langerhans produce
the hormones
C. the more numerous beta cells
make insulin (to lower blood glucose level)
D. alpha cells produce glucagon
(to raise blood glucose level)
VIII. Ovaries - produce estrogen and progesterone to
control primary and secondary female sex characteristics
IX. Testes - produces testosterone to control primary
and secondary male sex characteristics
Prostaglandins - "local hormones" that affect a small
area
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