educative

2. What is the endo
crine system?
The endocrine system is made up of glands and the
hormones they secrete. Although the endocrine gla
nds are the primary hormone producers, the brain,
heart, lungs, liver, skin, thymus, gastrointestinal mu
cosa, and placenta also produce and release hormo
nes.

3. What is the endocrine system?
The primary endocri
ne glands are the pit
uitary (the master gla
nd), pineal, thyroid, p
arathyroid, islets of L
angerhans, adrenals,
ovaries in the female
and testes in the mal
e.
The function of the endocrine system is the prod
uction and regulation of chemical substances cal
led hormones.

4. Hormones…
A hormone is a chemical transmitter. It is released in smal
l amounts from glands, and is transported in the bloodstr
eam to target organs or other cells. Hormones are chemic
al messengers, transferring information and instructions f
rom one set of cells to another.

5. Hormones… Hormones regulate growth, dev
elopment, mood, tissue function
, metabolism, and sexual functio
n.
Hyposecretion or
hypersecretion of
any hormone can
be harmful to t
he body. Controll
ing the pro
duction of ho
rmones can tre
at many
hormonal disorde
rs in the
body.

6. Hormones…
The endocrine system and nervous system work together
to help maintain homeostasis… balance. The hypothalam
us is a collection of specialized cells located in the brain, a
nd is the primary link between the two systems. It produ
ces chemicals that either stimulate or suppress hormone s
ecretions of the pituitary gland.
The pituitary gland has 2 lobe
s…

7. Secretions from the anterior pituitar
y gland…
Growth Hormone (G
H): essential for the
growth and develop
ment of bones, mus
cles, and other orga
ns. It also enhances
protein synthesis, d
ecreases the use of
glucose, and promot
es fat destruction.

8. Secretions from the anterior pituitar
y gland…
Adrenocorticotropin
(TRŌ pun) (ACTH):
essential for the gro
wth of the adrenal c
ortex.
Thyroid-Stimulating Hor
mone (TSH): essential fo
r the growth and develop
ment of the thyroid gland
.

9. Secretions from the anterior pituitar
y gland…
It stimulates the growt
h ovarian follicles in t
he female and the pro
duction of sperm in th
e male.
Follicle-Stimulating Horm
one (FSH): is a gonadotro
pic hormone.

10. Secretions from the anterior pituitar
y gland… Luteinizing Hormon
e (LH): is a gonadot
ropic hormone stim
ulating the develop
ment of corpus lute
um in the female ov
arian follicles and th
e production of test
osterone in the male
.
The yellow corpus luteum
remains after ovulation; it
produces estrogen and p
rogesterone.

11. Secretions from the anterior pituitar
y gland… Prolactin (PRL): sti
mulates the develop
ment and growth of
the mammary gland
s and milk producti
on during pregnanc
y.
The sucking motion of the
baby stimulates prolactin s
ecretion.

12. Secretions from the anterior pituitar
y gland…
Melanocyte-stimulating hormo
ne (MSH): regulates skin pigme
ntation and promotes the depo
sit of melanine in the skin after
exposure to sunlight

13. Antidiuretic Hor
mone (ADH): sti
mulates the reab
sorption of wate
r by the renal tu
bules. Hyposecr
etion of this hor
mone can result
in diabetes insip
idus.
Secretions from the posterior lobe of
the pituitary gland…

14. Oxytocin: stimulates
the uterus to contract
during labor, delivery,
and parturition. A sy
nthetic version of this
hormone, used to ind
uce labor, is called Pi
tocin. It also stimulat
es the mammary glan
ds to release milk.
Secretions from the posterior lobe of
the pituitary gland…

15. Secretions from the pineal gland…
The pineal gland is pine-cone-shaped
and only about 1 cm in diameter.
Melatonin: communicates
information about enviro
nmental lighting t
o various parts of the bod
y. Has some effect on s
leep/awake cycles and ot
her biological events con
nected to them, such as a
lower production of gastr
ic secretions at night.

16. Secretions from the pineal gland…
Serotonin: a neurotransmitte
r that regulates intestinal mo
vements and affects appetite,
mood, sleep, anger, and meta
bolism.

17. Secretions of the thyroid gland…
Calcitonin: influences
bone and calcium met
abolism; maintains a
homeostasis of calciu
m in the blood plasma
The thyroid gland plays a
vital role in metabolism a
nd regulates the body’s m
etabolic processes.

18. Secretions of the thyroid gland…
Thyroxine (T4) and triodothy
ronine (T3): essential to BM
R – basal metabolic rate (the
rate at which a person’s bod
y burns calories while at res
t); influences physical/ment
al development and growth
Hyposecretion of T3 and T4 = cretinism, myxede
ma, Hashimoto’s disease
Hypersecretion of T3 and T4 = Grave’s disease, go
iter, Basedow’s disease

19. Secretions of the parathyroid gland…
The two pairs of parathyroi
d glands are located on the
dorsal or back side of the t
hyroid gland. They secrete
parathyroid (PTH) which pl
ays a role in the metabolis
m of phosphorus. Too little
results in cramping; too m
uch results in osteoporosis
or kidney stones.

20. The islets of Langerhans…
The islets of Langerhans are small clusters of cell
s located in the pancreas.

21. Secretions from the islets of Langerhans
… Beta cells secrete the hormon
e insulin, which is essential f
or the maintenance of normal
blood sugar levels. Inadequa
te levels result in diabetes me
llitus.
Delta cells suppress
the release of gluca
gon and insulin.
Alpha cells facilitat
e the breakdown of
glycogen to glucos
e. This elevates the
blood sugar.

22. The adrenal glands…
The triangular-sh
aped adrenal gla
nds are located o
n the top of each
kidney. The insid
e is called the m
edulla and the ou
tside layer is call
ed the cortex.

23. Secretions from the adren
al cortex…
Cortisol: regulates carbohydr
ate, protein, and fat metabolis
m; has an anti-inflammatory e
ffect; helps the body cope du
ring times of stress
Hyposecretion results
in Addison’s disease;
hypersecretion result
s in Cushing’s diseas
e
Corticosterone: like
cortisol, it is a steroi
d; influences potass
ium and sodium met
abolism

24. Secretions from the adrenal cortex…
Aldosterone: essential in regulating
electrolyte and water balance by pro
moting sodium and chloride retentio
n and potassium excretion.
Androgens: several
hormones including
testosterone; they p
romote the develop
ment of secondary s
ex characteristics in
the male.

25. Secretions from the adrenal
medulla…
Dopamine is used
to treat shock. It di
lates the arteries,
elevates systolic b
lood pressure, inc
reases cardiac out
put, and increases
urinary output.

26. Secretions f
rom the adr
enal medulla…
Epinephrine is also called adrenalin. It elevates sy
stolic blood pressure, increases heart rate and car
diac output, speeds up the release of glucose from
the liver… giving a spurt of energy, dilates the bro
nchial tubes and relaxes airways, and dilates the p
upils to see more clearly. It is often used to counte
ract an allergic reaction.

27. Secretions from the
adrenal medulla…
Norepinephrine, like epinephrine, is released when
the body is under stress. It creates the underlying i
nfluence in the fight or flight response. As a drug,
however, it actually triggers a drop in heart rate.

28. Secretions of the ovaries…
The ovaries produce sever
al estrogen hormones and
progesterone. These horm
ones prepare the uterus for
pregnancy, promote the de
velopment of mammary gla
nds, play a role in sex drive
, and develop secondary se
x characteristics in the fem
ale.
Estrogen is essential for the growth, development,
and maintenance of female sex organs.

29. The testes produce
the male sex hormo
ne called testostero
ne. It is essential fo
r normal growth and
development of the
male sex organs. Te
stosterone is respo
nsible for the erecti
on of the penis.
Secretions of the testes…

30. During pregnancy, the place
nta serves as an endocrine
gland.
Secretions of the placenta…
It produces cho
rionic gonadotr
opin hormone, e
strogen, and pr
ogesterone.

31. The mucosa o
f the pyloric ar
ea of the stom
ach secretes t
he hormone g
astrin, which s
timulates the
production of
gastric acid fo
r digestion.
Secretions of the gastrointestinal mu
cosa…

32. The mucosa of t
he duodenum an
d jejunum secret
es the hormone
secretin, which
stimulates pancr
eatic juice, bile,
and intestinal se
cretion.
Secretions of the gastrointestinal mu
cosa…

33. The thymus gland has
two lobes, and is part
of the lymphatic syste
m. It is a ductless gla
nd, and secretes thym
osin. This is necessar
y for the Thymus’ nor
mal production of T ce
lls for the immune sys
tem.
Secretions of the thy
mus…