The Nervous System’s Cousin
 Differentiate
between endocrine and
exocrine
 Describe the structure and function of
various endocrine glands and their
corresponding hormones
 Determine how hormones are recognized by
receptors and can alter cellular function
 Differentiate between steroid and peptide
hormones
 Explain what negative feedback means
within the endocrine system
 2nd
greatest controlling
system of the body
 Works
closely with what
other system?
 Works
slowly by secreting
chemical messengers
called hormones
throughout the circulatory
system that tell the body
what to do
 Endocrine
glands- ductless glands that
produce hormones that release into blood or
lymph circulation

Pituitary, hypothalamus, thyroid, parathyroid,
adrenal, pineal, thymus, gonads, and pancreas
 Exocrine
glands- release their products at the
body’s surface or into body cavities through
ducts

Sweat and oil glands; pancreas; liver
 Chemical
messengers secreted by endocrine
glands that diffuse into the bloodstream and
act on target cells some distance away
 “Local
hormones” that function similarly to
hormones but are not technically hormones:


Paracrine – only affect neighboring cells
Autocrine – affect only the secreting cell (itself)
 Many




hormones, many functions
Reproduction
Growth and development
Metabolism
Nutrient, water, and ion balance
 Ongoing


processes
Equilibrium
Feedback loops
 What
does it mean to have a “hypo”
condition?
 What
does it mean to have a “hyper”
condition?
 Your
body wants to be in equilibrium to
function properly; when there are
hypo/hyper conditions, hormones are
released to bring the body back to normal!
 Disease/disordered
state
 http://www.pbs.org/wgbh/nova/body/obesit
y.html
 What


can cause this to happen?
Problems with synthesis or secretion of the
hormone
Problems with the hormone’s receptor protein
 How
blood levels of hormones are regulated
by maintaining homeostatic function
 Negative

feedback mechanism
If you have high levels of leptin in your body,
what happens?
 High
levels of hormone in the blood stream
will “feedback” to the source and tell the
gland to stop producing the hormone
 Turns
itself off
 If
negative feedback shuts down hormone
production after a large amount is detected
in the blood stream… what does positive
feedback do?

Process of amplification where an increase in
hormones causes an increase in the response

The body goes further away from equilibrium
 Hormone


known to exhibit positive feedback:
Oxytocin stimulates uterine contraction in
childbirth
Oxytocin promotes milk letdown in nursing
mammals
 Steroid
Hormones:
Made from
cholesterol
 Includes hormones
made in the
adrenal cortex
(cortisol &
aldosterone)
 Includes hormones
made in gonads
(testosterone &
estrodial/estrogen)

 Peptide
Hormones
Consist of amines,
peptides, proteins
 Made from amino
acids


What differences do
you notice between
peptide and steroid
hormone structure?
Steroid Hormones
Peptide Hormones
Steroid vs. Peptide Hormones
 Water
soluble?
 Lipid soluble?
 Ability to pass through cell membrane?
 Site of formation of hormone-receptor
complex? (where do they bind?)
 How does it work?
 Half-life?
Insoluble in water
(doesn’t dissolve)
 Soluble in lipids (does
dissolve)
 Can pass through the
phospholipid cell
membrane but cannot
travel in the aqueous
bloodstream without
a protein carrier

Steroid Hormones
Soluble in water
 Insoluble in lipids
 Cannot pass through
the phospholipid cell
membrane on its own
but can travel in the
aqueous bloodstream
alone

Peptide Hormones
Hormone-receptor
complex binds in the
nucleus
 This causes specific
genes to be activated
to make specific
proteins coded for by
the genes
 Long half-life

Steroid Hormones
Hormone-receptor
complex binds on the
cell membrane
(cannot pass through)
 This causes a cascade
of events triggering a
1st messenger protein,
which triggers a 2nd
messenger, eventually
activating proteins to
alter cell activity
 Very short half-life

Peptide Hormones
Broken down into 3 parts
 Describe
the structure of the pituitary and
label which hormones are released in each
section
 Describe the function of the pituitary
hormones
 Recognize various pathologies related to
pituitary hormone imbalances
 Located
at the base of the brain where the
pituitary stalk attaches to the hypothalamus
 1 cm in diameter
 Anterior
Pituitary
 Intermediate Pituitary

Not as functional in humans
 Posterior
Pituitary
 Produces
melanin stimulating hormone (MSH)
 Stimulates melanocyte cells to produce
melanin
 What does melanin do?

Pigment in the skin and in portions of the eye
and brain
 MSH
is increased in exposure to UV light
 Disappears
during fetal development, but its
cells become parts of the two remaining
lobes

Neuronal


Neural-endocrine hormones are produced in
hypothalamus and stored in posterior pituitary
Post. Pit. hormones are released upon
stimulation by hypothalamic neurons
Supraoptic nucleus (SON)
 Paraventricular nucleus (PVN)


Even though they are made in the hypothalamus,
the post. pit. hormones are named so because
that is where they enter the bloodstream
 Antidiuretic

hormone (ADH)
Sometimes called Vasopressin
 Oxytocin
(OT)

Background info:


Diuretic- chemical that increases urine production
Antidiuretic- chemical that decreases urine formation

Peptide hormone

Released by the Post. Pituitary when SON is
activated

How can ADH prevent urine production? What
organ may ADH target?


ADH produces an antidiuretic effect by reducing the
volume of water the kidneys excrete
Overall, regulates the water concentration of body
fluids
 Osmoreceptors
in the brain sense changes in the
osmotic pressure of body fluids
 When
dehydrated, concentration of blood
solutes (ions, salt, sugar) increases, which
increases osmotic pressure



Targets kidneys to reabsorb more water into the
bloodstream
Concentrates urine (low volume of urine, higher
blood volume)
Increases blood pressure by constricting
arterioles in kidneys to allow for more water to
be absorbed
 Drinking
too much water dilutes body fluids,
inhibiting ADH
 Diuretics
cause water to be flushed out of
the body through urine
 Can you think of any diuretics?
 Antagonists
 Thinking
of ADH
question: College students
typically drink excessive amounts of alcohol
and walk from bars back to their apartments.
Why is this dangerous in the winter? Think
about ADH!
 If
the SON is damaged lowering the secretion
of ADH…

What will happen?
 Pathology




called Diabetes Insipidus
Frequent urination; kidneys don’t reabsorb water
Excessive, continual drinking
Continual thirst
Not necessarily life threatening unless don’t
drink enough water
 Peptide
hormone
 Synthesized in the hypothalamus, released by
the Post. Pituitary when stimulated by the
paraventricular nucleus (PVN)
 Hormone involved in + feedback
 Made in significant amounts in childbirth and
nursing women
 Stimulates
uterine contractions in childbirth
& “milk letdown reflex” in nursing mothers
 Nursing mothers often get cramps while
nursing after childbirth due to high levels of
oxytocin released
 Synthetic oxytocin drugs are used to induce
labor by mimicing oxytocin (Pitocin)
 “Mother/Father Love hormone” or “Bonding
hormone”

For relationships?
Boyfriend blues?... Oxytocin is not the cure
 Women with less oxytocin receptors in their brain
show not as many affectionate behaviors toward
significant other


For anorexia


Anti-anxiety drug possibility; help fight food fixations
For autism



Helpful in boosting emotional recognition
Still in the research phase
http://www.scientificamerican.com/article/be-mineforever-oxytocin/
 Glandular
 Makes
tissue, purely endocrine function
many peptide hormones:
 Growth
Hormone (GH)
 Prolactin (PRL)
 Follicle Stimulating Hormone (FSH)
 Luteinizing Hormone (LH)
 Adrenocorticotropic Hormone (ACTH)
 Thyroid Stimulating Hormone (TSH)
 Function
in reproductive endocrinology
 FSH
(follicle stimulating hormone)stimulates follicle development in female
ovaries & stimulates sperm production in
males
 LH
(luteinizing hormone)- triggers ovulation
in female ovary monthly & stimulates
testosterone production in males
 Infertility
of males and females
 Some fertility treatments increase levels of
FSH or LH
 Multiple births due to increase in these
gonadotropic hormones causing multiple
ovulations a month
 Hormone
that controls metabolism, building
up muscles and uses glycogen & fats for
energy
 Anabolic function
 Plays role in bone and skeletal muscle
formation
 Hypo-GH


What does this mean?
Pituitary Dwarfism is hypo-GH in childhood

4 feet tall, proportional body
 Hyper-GH


What does this mean?
Gigantism is hyper-GH in childhood


8-9 feet tall, proportional body
Acromegaly is hyper-GH after long bone growth
has ended in adulthood; facial bones continue to
grow; non-proportional growth
 Gigantism
 Acromegaly
 Dwarfism
 Stimulates
and maintains milk production in
mother’s breasts after childbirth
 Inhibited
by dopamine (high levels of
dopamine = no milk production)
 Prolactinomas-
increase milk production; can
occur in males too
 Influences
the activity of the thyroid gland
by stimulating the release of T3/T4 (thyroid
hormones)
 Regulates
the endocrine activity of the
adrenal cortex
And the Parathyroid Glands
 Describe
the structure and function of the
thyroid gland
 Describe the function of the T3/T4 thyroid
hormones
 Describe the function of the C cell’s
Calcitonin hormone
 Explain the function of the parathyroid gland
and secreted parathyroid hormone
 Recognize thyroid and parathyroid hormone
pathologies
 Located
at the base of the throat below the
Adam’s apple around the esophagus
 Sticky colloid-filled follicles where thyroid
hormone is made
 C (parafollicular) cells is where calcitonin is
made
 T4

Thyroxine has 4 Iodines (the major form)
 T3

Triiodothryonine has 3 Iodines
 Both
T3 and T4 have similar functions
 T3 is five times stronger than T4
 Thyroid
collects iodine in order to make
T3/T4 hormones

Where do you get iodine?
 Function


Controls the rate at which glucose is used for
body heat and chemical energy
If a lot of thyroid hormones are made,
metabolism will increase
 Basal

in cellular metabolism
metabolic rate (BMR)
Determines how many calories the body must
consume at rest in order to maintain life
 Every
cell in the body is a target for T3/T4
(the thyroid hormones)
 Draw
it out

Anterior pituitary releases TSH
TSH goes to Thyroid
Thyroid releases T3/T4

How do they feedback?


 Hyperthyroid:
Goiter forms due to
overactive thyroid
 Swelling of eye socket
tissue  bulging eyes
 Irritable, hyperactive,
insomnia, high body
temp., ravenous
 Grave’s Disease
(autoimmune
disorder) can be a
cause of hyperthyroid

 Too




little T3/T4:
Possible cause is Iodine deficiency
Common before “iodized” salt
Goiter due to constant TSH in thyroid
Weight gain, lowered body temp., lethargy,
slower pulse
 Protein
hormone
 Made in the C cells in the connective tissue
between the thyroid follicles
 Decreases
blood calcium levels by putting
calcium deposits in bones
 If blood calcium levels increase, CT is
released to lower them again
4
tiny yellow glandular tissue masses on
outside of the thyroid gland
 Secretes parathyroid hormone (PTH), a
protein hormone, which is another regulator
of blood calcium levels
 PTH
works antagonistically with CT… what
does this mean?
 Functions in raising calcium levels in the
blood if they drop below a certain level by
causing osteoclasts in bone to break down
bone matrix to release calcium
 PTH also stimulates kidneys and intestines to
absorb more calcium from food
Severe hyperparathyroidism- breakdown of bone
matrix, increased osteoporosis, and broken
brittle bones
 Severe hypothyroidism results in death due to
low Ca2+ levels


Nervous system failure; uncontrollable spasms
(tetany)
Can actually remove parts of PTH tumors and
place remaining healthy parathyroid gland on
the skin and it will function normally!
 Low CT in elderly adults (possible link to
osteoporosis)


Take salmon calcitonin supplements
Consisting of the Adrenal Cortex and
Adrenal Medulla
 Located
on top of the kidneys
 Adrenal cortex- outer portion
of adrenals that is purely
glandular

Makes steroid endocrine
hormones
 Adrenal
medulla- inner region
consisting of neuroendocrine
tissue

Makes neurotransmitters
epinephrine and norepinephrine
 Makes
3 main groups of steroid hormones
called corticosteroids



Mineralocorticoids
Glucocorticoids
Sex steroids
Cannot survive
without adrenal
cortex
 ALDOSTERONE
 Functions
in regulating salt concentration in
the blood (Na+ and K+)

Higher aldosterone leads to increased absorption
of Na+ into blood and release of K+ into urine
 What
organ do you think this hormone
targets?

Kidneys- selectively absorb ions or allow them to
be flushed out in urine
 Help
regulate water and electrolyte balance
in blood
 Hyperaldosterone


water & Na+ retention
Abnormally high amount of water and sodium in
blood leads to HIGH blood volume and HIGH
blood pressure
Heart has to work harder!
Usually due to a tumor; must be removed
 Addison’s
Diseasehypoaldosterone




Sodium and water are lost,
electrolyte imbalance, weakened
muscles, tiredness, bronze skin
Low blood glucose, dehydration, low
blood pressure
Can lead to deficiency in
glucocorticoids (cortisol)
Lethal within days without
treatment of adolsterone and
cortisol hormone replacement shots
Excess unused ACTH
leads to buildup of
melanin
 CORTISOL,
sometimes called the stress
hormone
 Produced
in the middle adrenal cortex
 Without cortisol, a person will not survive
 Raises


blood glucose levels
Liver breaks down excess amino acids to glucose
Promotes fatty acid breakdown (rather than
glucose break down) for metabolism
 Suppresses
immune system by counteracting
inflammatory response


Hydrocortisone Cream- reduce swelling & itching
Steroid injections for extreme cases of
swelling/immune responses

Poison ivy, eczema, swollen/bulged disks in back, etc.
 Organ
transplant patients receive high doses
of cortisol-like steroids (dexamethasone) to
prevent immune response against foreign
organ
 Cushing’s





Disease- HYPERcortisol disorder
More likely to develop Diabetes due to high blood
glucose
High blood pressure (due to high blood glucose)
Fat deposits at waist, buffalo hump, moon face
Higher susceptibility to infection
Normally accompanied by an excess in
adolsterone as well

Swelling
 Extreme
Addison’s disease is also linked to
low cortisol

Usually when low in adolesterone, low in cortisol
too
 Hypoglycemia
(low blood glucose levels)
 Inability to deal with stress
 Both
male and female sex hormones
produced by innermost adrenal cortex
 Sometimes called sex steroids
 Androgens- male sex hormones are produced
in both males and females but at a higher
level in males
 Estrogens- female sex hormones produced in
both sexes but higher quantity in females
 Secretes

epinephrine and norepinephrine
Work together to do the same job
 Increase
heart rate, breathing rate, blood
glucose level, elevate blood pressure, and
decrease digestion
 Sympathetic nervous system stimulates
adrenal medulla
 Fight or flight
The Sex Hormones
 Most
of the androgens, like testosterone, is
produced by the testes in males
 Most of the estrogen and progesterone is
produced by the ovaries in females
 Made
in the testes
 Increase
primary and secondary sex
characteristics
 Testosterone plays role in building muscle

Anabolic steroids
 If
females overproduce androgens in adrenals
or can’t convert testosterone to estrogen,
can show characteristics of maleness

Masculinization regardless of the sex
 Made
in the ovaries
 3 types

Normal estrogen, 1 in pregnancy,
1 in menopause
 Primary
and secondary sex
characteristics in females
 Necessary for egg development
 Progesterone is necessary for
ovulation
 Synthetic
progesterone called progestin in
birth control pills
 Taken daily with makes the body think that it
is pregnant thus ovulation ceases


Near the end of monthly cycle, if egg is not
fertilized and implanted in uterus, progesterone
levels lower and the cycle starts again
If levels do not decrease, the cycle will not start
again
 Male



birth control by regulating hormones
Block FSH receptors?
Block FSH secretion?
Possibly interfere with inhibin

Another male hormone involved in sperm
development
A review from semester 1
 Exocrine-
releases
digestive enzymes
 Endocrine- releases
hormones
 Posterior
to stomach
and attached to first
section of small
intestine (duodenum)
 Pancreatic
islets- (Islets of Langerhans)
endocrine portion of the pancreas that
consists of two types of cells closely
associated with blood vessels

Alpha cells


Secrete glucagon
Beta cells

Secrete insulin
 Stimulates
liver to break down glycogen into
glucose to raise blood sugar

Epinephrine can also do this (not as efficiently)
 Low
blood glucose triggers the release of
glucagon
 Glucagon
prevents hypoglycemia between
meals and during exercise
 Stimulates
the liver to MAKE glycogen from
glucose and to uptake glucose from the blood
stream into cells
 Lowers blood glucose levels
 Prevents hyperglycemia
 High blood glucose levels trigger the release
of insulin
 Glucagon
antagonist
 Lack
of insulin or the inability of cells to
recognize it
 Insulin deficiency disrupts carbohydrate,
protein, and fat metabolism
 Symptoms- hyperglycemia leading to kidneys
excreting sugar in the urine; sweet breath;
polydipsia (extreme thirst); weight loss;
hunger increase; ketoacidosis (low blood pH)
 Usually
before the age of 20 and is
autoimmune where the immune system
attacks the beta cells of pancreas (so they
cannot make insulin)
 Insulin dependent- shots/pumps are required
 Islet

replacements can be placed in liver
Procedure is risky and rarely successful; thus
hormone replacement is the best choice for
treatment
 Beta
cells produce insulin but the body cells
lose the ability to recognize it
 85-90% of people with diabetes have Type 2
 Usually correlated with overweight people
over the age of 40
 Treatment: diet, exercise, oral drugs to
control glucose levels, possible insulin shots