Endocrine System
- Consists of collection of cells located
in tissues scattered throughout the
body that produce substances
released into the blood (hormones) to
ultimately affect the activity and
metabolism of target cells.
- Made up of the cells, tissues, and
organs that secrete hormones into
body fluids.
- Endocrine derived from the Greek
word ENDO means WITHIN and KRINO
means TO SECRETE
- One of the important control systems
of the body
Endocrinology – study of endocrine
system
FUNCTION OF ENDOCRINE SYSTEM
1. Metabolism and tissue maturation
2. Ion regulation
3. Water Balance
4. Immune system regulation
5. Heart rate and blood pressure
regulation
6. Control of blood glucose and other
nutrients
7. Control of reproductive function
8. Uterine contractions and milk release
COMPARISON OF NERVOUS VS
ENDOCRINE
=
OVERVIEW OF THE ENDOCRINE SYSTEM
Hormones are carried in blood stream=
But only certain cells can be affected
by hormones=
These target cells have 1000’s of
receptors specific for a
particular=hormone.=
Response determined by responding
cell: different cells may respond
differently=to the same=hormone.
Cell may have > 1 type of receptor, so
can respond to more than
one=hormone
Negative-feedback mechanisms, which
maintain homeostasis, control=the
secretion of most hormones=
Hormone secretion from an endocrine
tissue is regulated by one or=more of
these three mechanisms:=
a. Changes in the extracellular
concentration of a non-hormone
substances=
b. Stimulation by the nervous system=
c. Stimulation by a hormone from
another endocrine tissue
Hypothalamus
- The hypothalamus regulates
pituitary gland activity
through=hormones and action
potentials
- Production of ADH, OXYTOCIN,
and REGULATORY HORMONES
- Makes hormone that control the
pituitary gland
- It makes hormones that are
stored in the pituitary gland
Pituitary gland
- Also known as hypophysis
- Serve as major link between
nervous and endocrine systems=
- The pituitary gland secretes at
least nine hormones that
regulate=numerous body
functions and other endocrine
glands=
- Located in depression
in=sphenoid bone just inferior=to
the brain=
- Has 2 lobes:
oAnterior pituitary
(ADENOHYPOPHYSIS) -
Develops from the roof of
the mouth=
1. ACTH
2. TSH
3. PRL
4. MSH
5. LH
6. FSH
7. GH - Stimulates
protein synthesis
oPosterior pituitary
(NEUROHYPOPHYSIS)=Dev
elops from the floor of the
brain and connects to the
hypothalamus=by the
infundibulum:
1. Oxytocin - Smooth muscle
contraction of uterus
during childbirth=
- Causes
“letdown” of milk
from glands to
ducts=
2. ADH (Antidiuretic
Hormone) - Causes kidneys
to retain more water=
