CONTROL OF HORMONE RELEASE
Hormones regulate body functions by producing specific effects
in target cells. Disorders can develop if too much or too little
hormone is secreted.
How does the body determine when/how much hormones to
release?
The release of nearly all hormones occurs as part of negative
feedback mechanisms.
REVIEW: COMPARE AND CONTRAST NEGATIVE
AND POSITIVE FEEDBACK MECHANISMS
Negative feedback mechanisms maintain the levels of a variable (e.g.
body temperature) within a narrow range. If the variable becomes high,
the mechanism acts to bring it back down. If the variable becomes low,
the mechanism brings it back up.
 The output acts to change the direction of the stimulus.
 Example: Body temperature regulation
Positive feedback mechanisms dramatically increase a variable (e.g.
contractions) until a certain endpoint (e.g. childbirth) is reached.
 The output acts to increase the stimulus
 Example: labor contractions
EXAMPLE: BLOOD SUGAR REGULATION
EXAMPLE:
BLOOD
CALCIUM
REGULATION
STIMULUS OF HORMONE RELEASE
Even when glands are part of a negative feedback loop, there must be some
stimulus that triggers the release of hormones.
What was stimulus in the previous two examples?
Blood sugar level and calcium level. Non-hormonal chemicals like these are
called humoral stimuli.
There are three basic type of stimuli that cause the release of hormones.
1. Humoral stimuli (non-hormone chemicals in the blood and body fluids)
2. ?
3. ?
STIMULUS OF HORMONE RELEASE
Even when glands are part of a negative feedback loop, there must be some
stimulus that triggers the release of hormones.
What was stimulus in the previous two examples?
Blood sugar level and calcium level. Non-hormonal chemicals like these are
called humoral stimuli.
There are three basic types of stimuli that cause the release of hormones.
1. Humoral stimuli (non-hormone chemicals in the blood and body fluids)
2. Hormonal stimuli (other hormones – e.g. TSH, ACTH, FSH, LH, PRL)
3. Neuronal stimuli (e.g. release of ep. / nor-ep by adrenals)
Often there is just one stimulus that a gland
responds to. Occasionally there are
multiple stimuli (ex: release of aldosterol by
adrenal glands)
EXAMPLE OF
MULITIPLE
STIMULI:
ALDESTERONE
RELEASE
DIABETES MELLITUS
Diabetes is a disorder characterized by abnormally
high levels of blood sugar (hypoglycemia)
Facts
• 347 people world-wide have diabetes.
• 7th leading cause of death in the US
• Leading cause of kidney failure, non-traumatic limb amputation, and
adult-onset blindness in US
• Major contributor to heart attack and stroke
MAJOR TYPES OF DIABETES
Type I (juvenile-onset)
• Occurs when the immune system attacks the insulin-producing cells of the
pancreas, which means that little to no insulin can be produced
• Genetic risk factors and environmental triggers
• ~5% of cases
Type II (adult-onset)
• Too little insulin is produced and/or cells become insulin-resistant
• Obesity and inactivity are major risk factors, but genetics also play a role
• ~90% of cases
Gestational diabetes occurs in ~5% of
pregnant women. Disease usually disappears
when pregnancy is over.
SYMPTOMS OF DIABETES
Symptoms develop more
rapidly and are more severe
for Type I diabetes.
Additional symptoms found
with Type 1 diabetes include:
• Acetone smell to breath
• Lethargy
• Deep, labored breathing
COMPLICATIONS OF DIABETES
Hyperglycemia (high blood sugar) damages blood vessels and nerves,
leading to the major complications listed below.
Note: it’s the high blood sugar that causes the damage. The better blood sugar is
controlled, the less complications will arise.
TREATMENT OF DIABETES
Type I diabetes
• Healthy diet and exercise
• Blood glucose monitoring (multiple times a day)
• Insulin injections (multiple times a day) or pump
Type II diabetes
•
•
•
•
•
•
Weight loss
Healthy diet and exercise
Blood glucose monitoring
Medicines to increase the body’s production of insulin
Medicines to combat insulin resistance and help glucose enter cells
Insulin injections
Watch me!
Many new treatments in the development stage, including
• Pancreas transplants
• Stem cells
• More convenient glucose monitoring and insulin delivery
GAME!
Round 1:
Bet on 1, 2, 3, 4, 5, or 6
On your mark …
Round 2:
Bet on blue, yellow, gray, green, or red.
Ready, set, go!
CLOSURE
What were our objectives, and what did you learn about them?
What was our learner profile trait and how did we exemplify it?
How does what we did today address our unit question?