Bio1152
Chapter
45
Hormones and the Endocrine System
Hormones are chemical
signals
secreted into the
system to target
cells,
and often act by
feedback.
The
and
integrate many functions of the vertebrate
system.
The pituitary is composed of
pituitary
and
pituitary
lobes.
The thyroid gland produces two
-containing hormones,
(T3) and
(T4), which are regulated by two
feedback
loops.
The parathyroid gland regulate calcium
homeostasis
by secreting
hormone (PTH).
The pancreas secretes two hormones from clusters in the islets of
to regulate glucose
levels.
The adrenal
glands
are adjacent to the
and comprise 2 types of secretory cells.
The
gonads
-
testes
and
ovaries
- produce most of the body's sex hormones, which are
derived from
cholesterol.
The
gland, located within the brain, secretes
, mainly at night, which may be involved in biorhythm
regulation.
Review:
Human Endocrine Glands and Hormones