Download Endocrine System

E NDOCRINE S YSTEM
T HE F UNCTIONS OF THE
E NDOCRINE S YSTEM


Two systems regulate the
body

Nervous system

Endocrine system
Endocrine System

Controls daily activities

Controls development
 The endocrine system is
made up of glands
 Glands are organs that
produce and secrete
chemicals
 Hormones
 Secrete chemicals
into blood
H ORMONES

Chemical product of an endocrine gland

Chemical messenger

Can affect organs and tissues far away
from the gland

Hormones have many jobs

Turn off activities of organs and
tissues

Speed up activities of organs and
tissues

Slow down activities of organs and
tissues
H ORMONE
P RODUCTION

A stimulus occurs

A nerve impulse is sent to the
brain

The brain sends an impulse
back to an endocrine gland

Endocrine gland produced a
hormone and releases it into
the blood

Hormone travels to target
tissue and causes a response
H ORMONE A CTION

Nerve impulse has a
quick, short lasting
effect

Hormones have a
slower, longer lasting
effect

The effect lasts until the
hormone is out of the
blood
TARGET C ELLS

Cells that the hormone
effects

Each endocrine glands
produces one kind of
hormone

Each hormone effects a
certain kind of cell


Key in a lock
Hormones will not effect
cells that don’t fit
T HE
H YPOTHALAMUS

Nervous and endocrine systems
work together

The hypothalamus is the master
gland in the brain that
communicates between these
two systems

Nerve messages controlling
sleep, hunger, thirst and other
conditions come from the
hypothalamus

The hypothalamus plays a
major role in maintaining
homeostasis
T HE P ITUITARY

Also located in the brain

Communicates with the
hypothalamus to control many
body activities

The hypothalamus sends its
nerve impulses to the pituitary

The pituitary sends the signal to
other endocrine glands in the
body

Thyroid releasing hormone

Growth hormone
T HE P ITUITARY
E NDOCRINE
G LANDS
H ORMONE
PATHWAYS
F EEDBACK

Many systems in the
body maintain
homeostasis using
feedback loops

Negative feedback

Positive Feedback
N EGATIVE
F EEDBACK

System where the
product tells the body
when to stop making it

Once a hormone reaches
a certain level, a
message is sent to the
endocrine gland telling it
to stop production
N EGATIVE
F EEDBACK
P OSITIVE
F EEDBACK

When a reaction causes
more of the same effect

A stimulus causes an
effect

That effect creates more
stimulus
P OSITIVE
F EEDBACK
B ODY
SYSTEMS THAT
WORK WITH THE
ENDOCRINE SYSTEM ;

The reproductive system
works with the respiratory,
circulatory, and endocrine
systems.
W HERE
ARE THE
G LANDS ?
P ITUITARY
Pituitary
The pituitary gland
produces a growth
hormone which
controls growth and
homeostasis.
PARATHYROID
Parathyroid
The parathyroid gland
produces
parathormone which
controls calcium
levels in the body.
A DRENALS
TheAdrenals
adrenal glands
Adrenals
produce adrenaline in
response to physical
and emotional stress.
T HYROID
Thyroid
The thyroid gland
produces thyroxin to
regulate metabolism.
PANCREAS
Pancreas
The pancreas
produces insulin
which controls sugar
levels in the blood.
T ESTES ( IN
MALES )
The testes produce
testosterone
used
in
Testes
sperm production and
the development of
male traits.
O VARIES ( IN
F EMALES )
The ovaries produce
Ovaries
estrogen used in egg
production and the
development of
female traits.