Download Unit 6: Regulation

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 https://www.youtube.com/watch?v=9ZARPPQqU6
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 https://www.youtube.com/watch?v=4YM9wBIgY-Y
Unit 7: Regulation
CHEMICAL REGULATION
(ENDOCRINE SYSTEM)
Key Questions
1.
2.
3.
4.
5.
6.
What role does the cell membrane play in chemical
regulation?
What is a feedback mechanism?
What parts make up the endocrine system and what are
the functions of these parts?
What are examples of glands and hormones?
How do hormones influence male and female
reproduction?
What happens when hormones do not function as they
should? (disruption of cellular communication)
Regulation
 Remember:
Life function of REGULATION:
 Control
and coordination of all life
functions to maintain homeostasis.
Nervous System vs. Endocrine System:
FYI:
Characteristic
Response
time
Signals
travel…
Chemical
Secretions
Nervous
Endocrine
Responses are fast
Responses
and short in duration are slow and
longer lasting
On nerves
In blood
Neurotransmitters
Hormones
Endocrine System
 A. Endocrine System:
Role
– cellular communication through
chemicals
Composed
of glands that release hormones into
bloodstream.
Endocrine System
GLANDS:
• Organs made of specialized cells that
produce and release a secretion.
• Glands select and remove materials from
the blood, process them, and secrete the
finished chemical products into the blood
for use somewhere in the body.
Endocrine System
 HORMONES:
 Protein
molecules that act as chemical messengers
 Transported
blood.
throughout body to the target tissues in
 Control:
• Growth and development
• Metabolism - how your body gets energy from the foods you
eat
• Sexual function
• Reproduction
• Mood
Endocrine System
 Hormones continued:
Each
hormone affects only the cells that are
genetically programmed to receive and
respond to its message
Bind
to specific membrane receptors on
target cells
Hormone
Endocrine System
 Can stimulate (increase activity) or inhibit
(decrease activity) in target tissues.
 Hormone levels can be influenced by factors such
as stress, infection, and changes in the balance of
fluid and minerals in blood.
Endocrine System
Endocrine
system regulated by FEEDBACK
MECHANISMS to maintain HOMEOSTASIS:
Most
common is:
• Negative Feedback: An increase in any
substance “feeds back” to inhibit the process
that produced it in the first place.
Endocrine System
 Examples of Some Major Glands and the
Hormones they Produce:
1. Pituitary Gland: “Master Gland”
• Found at base of brain.
• Controlled by hypothalamus (produces
‘releasing factors’
• Secretes many hormones which affect
production of hormones of other glands.
Endocrine System
 Examples:
A.
GH = Growth hormone – regulates growth
of bone and cartilage.
B. TSH = Thyroid-Stimulating Hormone –
stimulates production and release of thyroid
hormone (thyroxin) by thyroid gland.
C. FSH = Follicle-Stimulating Hormone –
Stimulates development of egg cells in ovaries
of females.
Endocrine System
 2. Thyroid Gland:
Found
in neck – below larynx and in
front of trachea.
Has
major role in regulating body’s
metabolism through the hormone
thyroxine
Endocrine System
Secretes
THYROXINE
Increases
rate of protein, carbohydrate, and
fat metabolism and rate of cellular respiration
– rate can be increased in response to a low
body temp to increase blood temp
Negative Feedback and Thyroxine
Endocrine System
 3. Adrenal Glands:
2
small glands located at top of each kidney.
 Release
hormones (adrenalin) that helps body
prepare for and deal with stress.
Endocrine System
 Epinephrine
(adrenalin) and Norepinephrine–
causes an increase in blood sugar, heart rate, and
breathing rate.
“Fight
FYI
or flight response”
- epinephrine is a natural "antidote" to the
chemicals released during severe allergic reactions
triggered by drug allergy, food allergy or insect
allergy. When injected, it rapidly reverses the
effects of a severe allergic reaction by reducing
throat swelling, opening the airways, and
maintaining blood pressure.
Endocrine System
 4. Pancreas:
2
types of glands:
• Exocrine portion – makes digestive enzymes that
get secreted into pancreatic duct which leads into
small intestine.
• Endocrine portion of pancreas made of “islands” of
cells which secrete hormones called the islets of
Langerhans.
Endocrine System
Secretes:
• Insulin –
 Decreases
blood sugar levels:
• Increases rate of glucose transport into
cells.
• Makes liver store glucose as glycogen
Endocrine System
• Glucagon –
 Works
opposite to insulin – increases
blood sugar levels.
• Stimulates release of glucose from liver
into bloodstream.
Regulation of Blood Sugar Levels
Disruption in Homeostasis: Diabetes
 Person has high blood glucose levels
 Due to lack of enough insulin or problem with the
way cells respond to insulin
 Too much glucose damages most cells in body
 Glucose excreted in urine
Inheritance - Diabetes
 There are 20.8 million children and adults in the
United States, or 7% of the population, who have
diabetes.
 About 14.6 million have been diagnosed with
diabetes, unfortunately, 6.2 million people (or nearly
one-third) are unaware that they have the disease.
Inheritance - Diabetes
 Diabetes can come in several forms:

type I diabetes (which is usually diagnosed in children and
teenagers)

type II diabetes (which is usually diagnosed in adults).

gestational diabetes (during pregnancy)
Inheritance - Diabetes
 Type I:


thought to have genetic causes
body does not produce insulin (beta cells in liver have been
destroyed).


Insulin is a hormone that is needed to convert sugar (glucose),
starches and other food into energy needed for daily life.
need insulin shots to use glucose from meals
Inheritance - Diabetes
 Type 2 (most common form):
More strongly linked to lifestyle factors such as obesity,
lack of exercise and poor diet.
 Either the body does not produce enough insulin or the
cells ignore the insulin.
 When glucose builds up in the blood instead of going into
cells, it can cause two problems:

Right away, your cells may be starved for energy.
 Over time, high blood glucose levels may hurt your eyes, kidneys,
nerves or heart.

Inheritance - Diabetes
Symptoms of type 2 diabetes due to high blood
sugar may include:









Increased thirst
Increased hunger (especially after eating)
Dry mouth
Frequent urination
Unexplained weight loss (even though you are eating and
feel hungry)
Fatigue (weak, tired feeling)
Blurred vision
Headaches
Loss of consciousness (rare)
Inheritance - Diabetes
 Gestational Diabetes:

When pregnant women who have never had diabetes
before but who have high blood sugar (glucose) levels.

Gestational diabetes affects about 4% of all pregnant
women - about 135,000 cases of gestational diabetes in
the United States each year.
Diabetes (8:41)
 http://www.dnatube.com/video/2792/Animation-
about-diabetes-and-the-body
Endocrine System
 5. Gonads: Body’s Reproductive Glands
 A.
Female = ovaries
Produce
estrogen
Stimulates development of eggs
Responsible for development of secondary
sex characteristics.
Endocrine System
Produce
Works
progesterone
with estrogen to regulate menstrual
cycle and prepare uterus for embryo.
Endocrine System
 B. Male = testes
Produce
testosterone
Required
for normal sperm production
Responsible for development of secondary
sex characteristics.
FYI-New Hormone Discovered!!!
 Irisin is a hormone that is present in blood during
exercise
 Causes genes to ‘turn on’ that turn regular fat into
brown fat (zaps calories!)
 Also improves response to glucose
 http://www.psychologytoday.com/blog/the-
athletes-way/201402/irisin-the-exercise-hormonehas-powerful-health-benefits
Other disruptions in homeostasis
Poor Nutrition:
Goiter
 Goiter – due to lack of iodine in diet – results in
enlarged thyroid gland.



Iodine is necessary for the synthesis of thyroxin.
When thyroxin levels are low, the pituitary gland releases
thryoid stimulating hormone (TSH).
TSH acts to increase synthesis thyroxin, but it also causes the
thyroid gland to grow in size by increasing cell division.
Poor Nutrition – Goiter
Poor Nutrition - Goiter
 Treatment:
Removal may be necessary if it causes difficulty
with breathing or swallowing – but also
removes body’s ability to produce thyroxin.
 Alternative to surgery in large goiters:
Radioiodine therapy with or without the preinjection of a synthetic thyroid stimulating
hormone, TSH, can relieve obstruction and
reduce the size of the goiter by 30-65%.

1. Gigantism
2. Dwarfism
 Gigantism - Oversecretion of GH (due to pituitary
tumor)
 Dwarfism - Undersecretion of GH
Robert Wadlow (1918-1940):
Tallest man ever due to
gigantism! 8 feet 11 inches
tall!
http://www.guinnessworldre
cords.com/records/human_b
ody/extreme_bodies/tallest_
man.aspx
3. Hypothyroidism
4. Hyperthyroidism
 Hypothyroidism - Undersecretion of
thyroxine. Lower rate of metabolism – less
energy; weight gain
 Hyperthyroidism – Oversecretion of
thyroxin. Increased metabolic rate – weight
loss
Steroids
 Cause thyroid, which regulates the body’s
metabolic rate, to stop secreting the hormone
thyroxine.
 Steroids are necessary for many enzymatic
reactions.

Examples of steroid hormones:

Estrogen, testosterone, progesterone, auxins (plants)
Anabolic Steroids
 Imitate testosterone. Causes infertility in men,
menstrual problems in females. Increase muscle
mass.
 They are synthetic – man-made
 Cause an increase in protein synthesis and decrease
fat
 Video – on server “Acromegaly” 25 min.
 “The Disappearing Male” 44:18