Endoceine System 03/05/2013

1. The Endocrine System
Mr. Hunter
Kennedy High School
www.mrhunterspage.blogspot.com

2. 03/14/2013
Anatomy and Physiology
• Objective(s)
• SWBAT
• Explain the function of the endocrine system
• Understand the function of posterior pituitary
gland hormones and the hypothalamus
• Bell Ringer : Where are PGs produced?

3. Endocrine System
• The endocrine system
performs the same general
function as the nervous
system.
• The nervous system
provides a more rapid
response than the
endocrine system.
•Nerve signals are sent via
electrical impulses while
the endocrine system (ES)
communicates via
circulating hormones.

4. Endocrine System
• Of the two types of
glands – exocrine and
endocrine, the endocrine
gland is part of the
endocrine system.
•These ductless glands
secrete hormone into the
blood or into fluid
surrounding cells.
•Exocrine glands secrete
substances through ducts
to specialized regions of
the body. – Sweat glands,
mucous and salivary
glands.

5. • Endocrine glands secrete hormones into
Endocrine System intercellular spaces.
• Hormones can diffuse into the blood
and be carried throughout the body.
• • Hormones may bind to cells that have
hormone specific receptors on their
surfaces.
• These cells are known as target cells.
The binding of the hormone with the
receptor initiates a chemical reaction.
• Hormones play an important role in
homeostasis and metabolism.
• Diseases may cause a gland to secrete
too much or too little hormone. –
Hypersecretion or Hyposecretion

6. • Two main classes of hormones are
Hormone Classes steroid and nonsteroid type
hormones.
• • Nonsteriod hormones are whole
proteins, shorter chains of amino
acids, or versions of a single amino
acid.
• Nonsteroid hormones act via a
second messenger system.
• Within this system hormones are
released from endocrine glands and
interact with receptors on target
cells. This interaction causes
chemical changes to occur within the
cell’s interior.

7. • Within the second messenger
Hormone Classes system ATP within side the cell is
turned into cAMP. Ex cAMP causes
the thyroid cells to respond to
• thyroid stimulating hormone by
secreting the thyroid hormone
thyroxine.
• Nonsteriod hormones are first
messengers that act on target cells.
• The interaction of the target cell
with receptors causes chemical
changes to occur within the cell. This
creates a second messenger within
the cell that causes other reactions
to take place.

8. Review 02/25/2013
1. Why does the nervous system produce a faster response
than the endocrine system?
2. Of the two types of glands, exocrine and endocrine, which
one is part of the endocrine system?
3. What is the difference between the two glands?
4. What protein structures on the surface of cells do
hormones bind to?
5. What are the names of the cells in which hormones act
upon?
6. What are nonsteroid hormones and how do they act on
target cells?

9. Steroid Hormones • The actions of lipid soluble steroid
hormones do not occur by second
messenger systems.
• Because they are soluble in lipids
they can pass directly through the
plasma membrane of their target
cells.
• Once inside the cell’s nucleus, the
steroid hormone can bind to
receptors – lock and key model.
• This hormone receptor complex acts
on DNA which causes the formation
of a new protein in the cytoplasm
that produces specific effects in the
target cell.

10. Steroid Hormones • An example of this type of hormone
class would be estrogen.
• Since the steps are quite involved for
steroid hormones, their hormone
response times are much slower
than nonsteroid hormones.
• Steriod hormones may also induce
membrane receptors to produce a
variety of secondary effects.

11. Hormonal Regulation • Negative feedback systems can
regulate hormone levels within the
blood.
• As you recall, positive feedback
systems amplify the condition
instead of reversing them to normal
levels.
• Oxytocin secretion during birth
increases muscle contractions for a
successful delivery.

12. Prostaglandins (PGs) • PGs are tissue hormones that are
found in a large variety of tissues.
• They perform many important
functions but are not like typical
hormones.
• PGs are produced within tissues and
diffuse a short distance to act on
cells within that tissue.
• PGs typically influence the activities
of neighboring cells. Hormones can
influence the activities of widely
separated targets.
• PGs can be divided into separate
classes – A, E and F.

13. Prostaglandins (PGs) • PGs can have influences on many
body functions such as:
• Respiration
• Blood pressure
• GI secretions
• Inflammation
• Reproductive Systems
• Most PGs regulate cells by the
production of cAMP.
• Play roles in the treatment of various
conditions including high blood
pressure, ulcers, and asthma.
• Aspirin cause their effects by altering
the functions of PGs in the body.

14. Review 03/06/2013
1. What is the difference in the mechanism of action between nonsteroid
hormones and steroid hormones?
2. Once inside the cell, what do steroid hormones interact with?
3. What is produced as a result of this interaction?
4. What is the name of a steroid hormone produced in substantial
quantities by females.
5. Why are the response times for steroid hormones much slower than
nonsteroid hormones?
6. Describe what occurs in a negative feedback system for high levels of
glucose.
7. What are PGs and where are their target cells located?
8. How do PGs produce effects on target cells?

15. • The pituitary gland is no smaller
Pituitary Gland than a pea in size but carries out
very important functions.
• It consists of two glands – each of a
different type.
• Anterior pituitary gland –
adenohypophysis
• Posterior pituitary gland –
neurohypophysis
• The anterior pituitary gland has the
structure of an endocrine gland.
• The posterior pituitary gland has the
structure of nervous tissue.

16. • Hormones released from the
Pituitary Gland adenohypohysis serve different
functions from those released from
the neurohypophysis.
• The pituitary gland is located in the
sella turcica of the sphenoid bone.
• The pituitary stalk attaches the
pituitary gland to the hypothalamus.

17. • The anterior pituitary gland secretes
Anterior Pituitary Gland
Hormones several major hormones.
• Tropic hormones stimulates another
endocrine gland to grow and secrete
its hormones.
• The anterior pituitary gland was
sometimes called the master gland
because it exerts control over
various structures including the
thyroid gland and the adrenal cortex.
• Thyroid Stimulating Hormone – TSH
stimulates the thyroid gland to
secrete thyroid hormone.

18. • Thyroid Stimulating Hormone – TSH
Anterior Pituitary Gland
Hormones
stimulates the thyroid gland to
secrete thyroid hormone.
• Adrenocorticotropic Hormone –
ACTH – acts on the adrenal cortex.
Stimulates the adrenal cortex to
increase in size and to secrete larger
amounts of cortisol.
• Follicle Stimulating Hormone – FSH
stimulates the growth and estrogen
secretion of primary ovarian follicles
in the ovary. - In the male FSH aids
in sperm production.

19. • Luteinizing Hormone – LH acts with
Anterior Pituitary Gland
Hormones FSH to perform various functions.
• Causes estrogen production increase
and ovulation.
• Stimulates the formation of the
corpus luteum and its production of
progesterone.
• Stimulates the interstitial cells of the
testes to secrete testosterone.
• Growth Hormone – GH Speeds up
the movement of amino acids out of
the blood and into cells to promote
anabolism of amino acids into tissue
proteins.

20. • GH also promotes fat catabolism and
Anterior Pituitary Gland
Hormones slows down glucose catabolism. Less
glucose leaves the blood to enter
cells. GH therefore increases blood
glucose concentrations.
• Hypersecretion of insulin produces
hypoglycemia.
• Hypersecretion of GH produces
hyperglycemia.
• Prolactin –PRL or lactogenic
hormone. Stimulates the
development of the breasts for
producing milk during pregnancy.

21. ES Review 03/07/2013
1. What are the names of the anterior and posterior pituitary
glands?
2. What structure does the anterior pituitary gland have?
3. What structure does the posterior pituitary gland have?
4. Where is the pituitary gland located and what is it attached
to?
5. What is the function of a tropic hormone?
6. What are the functions of TSH, ACTH and FSH?
7. How does hypersecretion of GH produce hyperglycemia?
8. What is the function of PRL?

22. • The neurohypophysis releases two
Posterior Pituitary hormones.
• Antidiuretic Hormone (ADH)
• Oxytocin (OT)
• ADH accelerates the reabsorption of
water from urine in the kidneys back
into the blood.
• More water moves out of the kidney
tubules into the blood, less water
remains in the kidneys and therefore
less urine is excreted from the body.
• ADH acts to decrease urine volume.
• Hyposecretion of ADH results in
diabetes insipidus – large volumes of
urine are produced - Dehydration

23. • OT is secreted by the posterior
Posterior Pituitary pituitary of a female before and
after she has a baby.
• OT stimulates uterine contractions to
initiate and maintain labor.
• It stimulates glandular cells of the
breast to release milk into ducts
from which the baby can obtain
nutrients.
• Production of ADH and OT occurs in
the hypothalamus.
• Two groups of neurons make the
posterior gland hormones and pass
them along axons to the
neurohypophysis. Release is
controlled by nervous stimulation.

24. • The hypothalamus produces
Posterior Pituitary Releasing hormones (RHs) and
Inhibiting Hormones (IHs).
• They travel to the adenohypophysis
via a specialized capillary system.
• They can cause the release of
anterior pituitary hormones or
inhibit their production and release
into the general circulation.
• The hypothalamus plays a dominant
role in regulating many body
functions including:
• Body temperature
• Appetite
• Thirst

25. • The thyroid gland is located in the neck just
inferior to the larynx.
Thyroid Gland
• The thyroid gland secretes two thyroid
hormones, thyroxine – T4 and
triiodothyronine – T3. It also secretes
calcitonin (CT)
• T4 is the most abundant thyroid hormone.
• T3 is the more potent and is considered to
be the principal thyroid hormone.
• In order for T4 to be produced, the diet
must contain sufficient amounts of iodine.
• The thyroid gland can store thyroid
hormone in its follicle cells until the
hormone is needed and secreted into the
blood.

26. • Thyroid hormones help to increase
Thyroid Gland cell metabolism.
• All body functions depend on thyroid
secretion.
• Calcitonin decreases the amount of
calcium in the blood by acting on
bone to inhibit its breakdown.
• Less calcium will move out of bone
into the blood. Concentration of
blood Ca+ levels will decrease.
• Calcitonin helps to maintain
homeostasis of blood Ca+ levels –
prevents hypercalcemia.

27. Review 03/12/13
1. Name two hormones produced by the posterior pituitary
gland.
2. What are the functions of ADH and OT?
3. Hyposecretion of ADH may result in what physiological
condition?
4. Where are ADH and OT produced?
5. What controls the release of ADH and OT into the blood?
6. What are some of the functions of the body that the
hypothalamus controls?
7. Where is the thyroid gland located?
8. Name and describe the functions of the hormones produced
by the thyroid gland.

28. • Small glands found on the back of
Parathyroid Glands the thyroid gland.
• There are usually four of these
glands.
• Secretion of Parathyroid Hormone
(PTH)
• PTH increases Ca+ concentration in
the blood.
• The opposite effect of Calcitonin.
• PTH stimulates osteoclasts (bone
resorbing cells) to increase their
breakdown of bone matrix. This
moves Ca+ out of bone into blood.

29. • Low levels of Ca+ in the blood can
Parathyroid Glands cause:
• Overactive nerve cells
• Muscle spasms resulting from
constant nervous stimulation
• High levels of Ca+ can cause :
• The death of brain and heart cells

30. • The adrenal glands are located on
Adrenal Glands the top of each kidney.
• The are composed of two glands :
• Adrenal Cortex
• Adrenal Medulla
• The two glands produce different
hormones.
• The adrenal cortex is divided into
three zones or layers.
• Hormones secreted by all three
layers are called corticoids.
• The outer zone secrete
mineralocorticoids – MCs.
• Main MC is aldosterone.

31. • The middle zone secretes
Adrenal Glands glucocorticoids – GCs
• Hydrocortisone or Cortisol is the
chief glucocorticoid.
• The innermost, deepest zone of the
cortex secretes small amounts of sex
hormones that resemble
testosterone.
• Mineral Corticoids - Aldosterone
help to control the amount of NaCl
in the blood. It increases the amount
of Na+ in the blood and decreases
the amount of K+ in the blood. More
K+ will be lost in urine.
• Aldosterone speeds up the kidneys
reabsorption of water.

32. • Glucocorticoids help to maintain blood
glucose concentrations by the process of
Adrenal Glands
gluconeogenesis.
• Amino acids or fatty acids are converted to
glucose within the liver.
• Glucocorticoids:
• Promote the catabolism of tissue proteins
into amino acids – transported to the liver
and turned into glucose and enters blood.
• Maintain normal blood pressure
• Produce anti-inflammatory effect –
example: hydrocortisone cream / ointment
• Production of ant-immunity or anti-allergy
effect. – Decrease in the production of
antbodies.
• Responding to stress
• Production of androgens in male and
females.

33. Review
03/14/2013
1. Where are the parathyroid glands located?
2. What is the function of PTH?
3. Where are the adrenal glands located?
4. What are the names of the two glands that the adrenal
gland is divided into?
5. How many layers is the adrenal cortex divided into?
6. What is the function of aldosterone?
7. How do glucocorticoids help to maintain blood glucose
concentrations?

34. Endocrine System 03/19/2013
Adrenal Medulla
• Adrenal Medulla is the
inner portion of the
adrenal gland.
• It secretes the hormones
epinephrine and
norepinephrine
• These hormones are
released directly into the
blood and are involved in
the body’s flight or fight
response.

35. Adrenal Medulla
• In response to stress the
hypothalamus causes the
anterior pituitary to release
ACTH.
• This causes the adrenal
cortex to release
glucocorticoids. In addition,
the adrenal medulla will
release norepinephrine and
epinephrine.
• Anti-inflammatory
responses can cause blood
vessel constriction and
promote the spread of
infections along with HBP.

36. Pancreatic islets – islets of Langerhans
• Glands are small clumps of
cells scattered among the
exocrine pancreatic cells.
• Alpha cells ( A cells )
secrete glucagon.
• Beta cells ( B cells ) secrete
insulin
• Glucagon accelerates
glycogenolysis in the liver
• Glycogen  Glucose in
liver
• Increase blood glucose
• Insulin decreases blood
glucose levels.

37. Pancreatic Islets
• Normal glucose levels = 70
to 100 mg per 100 ml of
blood.
• Hyposecretion of insulin =
type 1 diabetes mellitus
• Type 2 diabetes mellitus =
some decrease in insulin
and abnormalities in insulin
target cell receptors. Blood
glucose levels are
increased.

38. Other Endocrine Glands
• Pineal gland – production
• Thymus gland hormone = of melatonin – regulates
Thymosin for development onset of puberty and
and function of immune menstrual cycle.
system. • Timekeeping for the body –
• Placenta – Temporary internal clock
endocrine gland – hormone • Ghrelin –secreted by
= chorionic gonadotropins- stomach – boosts appetite
• Secreted in urine / and slows metabolism.
pregnancy Test • ANH atrial natriuretic
• estrogen and progesterone hormone – loss of Na+ ions
and water from kidney
• Antagonist to aldosterone