Download Ch. 3 S. 3

Chapter 3 Section 3
The Endocrine System
Obj: Identify the hormones
secreted by the major glands of
the endocrine system and the role
each one plays.
Hormones and Effect on the
Body
The endocrine system
consists of glands that
secrete hormones into
the bloodstream.
Hormones stimulate
reactions. Psychologists
study hormones because
they affect behavior and
emotional reactions.
Hormones are produced by
several different glands.
• Pituitary Gland – lies
just below the
hypothalamus;
responsible for the
secretion of many
different hormones
that affect various
aspects of behavior
such as the growth
hormone.
Oxytocin and prolactin
affect females in
relation to pregnancy
and mothering.
• Thyroid Gland –
produces thyroxin
which affects the
body’s metabolism –
it’s rate of converting
food to energy. People
with too little thyroxin
have hypothyroidism
and are often
overweight. If too
much thyroxin, develop
hyperthyroidism, and
they are excitable,
unable to sleep, and
experience weight
loss.
• Adrenal Gland –
located above the
kidneys; the outer layer
of the adrenal gland, or
cortex, secretes cortical
steroids which increase
resistance to stress
and promote muscle
development. They
also release adrenaline
and noradrenaline
which enables a
person to cope with a
stressful situation.
• Testes and Ovaries
– produce the
hormones
testosterone,
estrogen, and
progesterone that
play an important role
in the development of
primary and
secondary sex
characteristics and
have psychological
as well as biological
effects.
• Testosterone – male sex
hormone, although females
have small amounts of it. It
is a kind of
steroid…affecting muscle
mass, etc. It also stimulates
the sex drive and raises
self-esteem. Primary sex
characteristics are involved
in reproduction, secondary
sex characteristics, such as
beard growth, distinguish
males and females but are
not directly involved in
reproduction.
• Estrogen and
Progesterone –
female sex hormones,
although low levels
are found in men.
Together, they
regulate the
menstrual cycle.
Changes in levels
have been linked to
PMS.