How negative feedback controls of blood pressure works

1
Blood Pressure
Hypertension Hypotension
Elie Moubarak Aftab Sandhu Rushd Khan
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How negative feedback controls of blood pressure
works

• Negative feedback mechanisms, called negative
  feedback loops control the bodys
  homeostatically cultivated systems.
• Any change from the normal range of function is
  resisted in negative feedback.
• The change initiates responses that bring the
  function of the organ back to its normal range.

3
Negative feedback loops require a Receptor, A
Control Center, and Effectors. 

• Receptors
• The receptor monitors internal conditions
• The human body has receptors in blood vessels,
  which monitor the pH of blood. Blood vessels
  have receptors which can measure the resistance
  of blood flow against vessel walls, thus
  monitoring blood pressure. Receptors then sense
  the changes in function and initiate the bodys
  homeostatic response.

4
Control Center

• Receptors are connected to control centers, which
  integrate information that is given to it by the
  receptors.
• The control center is also known as the brain.
• When the brain receives information about change
  in the bodys internal conditions it will send
  out signals along nerves.
• The signals will prompt changes in function that
  fix the deviation and bring in the internal
  conditions back to normal range.

5
Effectors

• Effectors are the muscles, organs, and other
  structures that receive signals from the brain or
  control center.
• After receiving a signal from the brain,
  receptors change their function in order to
  correct the deviation.

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Example

• A good comparison of negative feedback is like
  how a thermostat controls the temperature in your
  house.
• The temperature of the house will drop if it is
  cold outside, because the cold air will seep in
  through the walls
• After the temperature drops below the set
  thermostat point, it will turn on the furnace.
• When the temperature inside the house rises, the
  thermostat will sense this change and turn off
  the furnace when the internal temperature reaches
  the pre-set point

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Systolic Pressure

• Systolic pressure is the force of blood in the
  arteries as the heart beats
• For people who are 50 years of age, systolic
  pressure gives the most accurate diagnosis of
  high blood pressure. Systolic pressure is the top
  number in a blood pressure reading. High blood
  pressure is 140 mmHg or above.
• Systolic pressure is the most common form of high
  blood pressure for older people in North America
• Systolic blood pressure increases with age
• If high blood pressure is left uncontrolled, then
  the high systolic pressure may lead to stoke,
  heart attack, congestive heart failure, kidney
  damage, blindness, or other serious conditions.

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  Diastolic Pressure

• Diastolic pressure is the force of blood in the
  arteries as the heart relaxes between beats. It
  is shown as the bottom number in a blood pressure
  reading.
• Diastolic blood pressure is an important
  hypertension number for younger people.
• Diastolic pressure does not need to be high for
  you to have high blood pressure. When that
  happens, the condition is called "isolated
  systolic hypertension," or ISH.
• Higher diastolic pressure increases the risk for
  heat attacks, strokes, and kidney failure.
• Diastolic pressure increases until about age 55
  and then declines. About 65 percent of
  hypertensives over age 60 have ISH. You may have
  ISH and feel fine. As with other types of high
  blood pressure, ISH often causes no symptoms. To
  find out if you have ISH or any type of high
  blood pressure see your doctor and have a blood
  pressure test. The test is quick and painless.

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How is your blood pressure tested?

• In a blood pressure you should be seated with
  your arm resting on a table. Your arm should be
  slightly bent so that it is at the same level as
  your heart. The upper arm should be bare, with
  your sleeve comfortably rolled up.
• Blood pressure readings are measured in
  millimeters of mercury (mmHg) and usually given
  as 2 numbers.

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Hypertension (High Blood Pressure)

• Blood Pressure is the force of blood pushing
  against the blood vessel walls.
• Hypertension (High Blood Pressure) is dangerous
  because the heart has to pump harder to circulate
  blood throughout the body.
• Normal Blood Pressure Less than 120/80.
• Stage 1 Hypertension 140-159/90-99
• Stage 2 Hypertension 160/100 

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Causes and Symptoms

• No exact causes are known. Some factors include
• Smoking
• Being Overweight
• Lack of physical activity
• Too much salt in diet
• Too much alcohol
• Stress
• Old Age
• Genetics
• Family history
• Chronic Kidney disease
• Adrenal and Thyroid disorders
• Hypertension is dangerous because 1/3 of the
  people who have it dont know they do.
• Symptoms include
• Severe Headache
• Fatigue confusion
• Vision
• Chest Pains
• Difficulty breathing 

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Health Problems and TreatmentOf Hypertension

• Some health problems include
• Stroke
• Heart Failure
• Heart Attack
• Kidney failure
• Vision Problems
• Treatment of hypertension include
• Losing weight
• Quitting Smoking
• Healthy eating
• Exercising, more aerobic exercises 

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Hypotension (Low Blood Pressure)

• Hypotension is Blood pressure less than 90/60.
• Chronic low blood pressure is dangerous.
• Most common is Postural Hypotension which is when
  your Blood pressure drops suddenly when you stand
  up.

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Causes

• Like Hypertension no exact causes are known.
• Some causes include
• Pregnancy
• Hormonal problems such as under active and
  overactive thyroids
• Diabetes
• Low blood sugar
• Some medications
• Overdose of high blood pressure drugs
• Heart Failure
• Heart Arrhythmias (abnormal heart rhythms)
• Widening of the blood vessels
• Heart exhaustion/heat stroke
• Liver disease 

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Causes of sudden drops in Blood Pressure

• Some causes include
• Loss of blood from bleeding
• Low body temperature
• High body temperature
• Heart muscle failure
• Sepsis
• Severe dehydration
• Reaction to medication
• Sever allergic reaction 

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Treatments

• Some treatments and controls of hypotension
  include
• Eating a diet higher in salt
• Decrease intake of caffeine
• Drinking lots of nonalcoholic fluids like Sports
  drinks and water
• Having a doctor evaluate your prescriptions
• Sitting up right for a few minutes before
  standing up
• Avoiding heavy lifting
• Avoiding straining while on the toilet (LOL)
• Resting after eating
• Wearing elastic on calves or thighs to keep more
  blood in upper body (LOL)  

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References

• 
  References
• Science Encyclopedia. Negative Feedback. 12
  November 2007.
• http//science.jrank.org/pages/3365/Homeostasis.ht
  ml. Medline Plus Medical Encyclopedia. Blood
  pressure. 8 November 2007.
• http//www.nlm.nih.gov/medlineplus/ency/article/00
  3398.htm.
• NHLBI. What Are High Blood Pressure and
  Prehypertension? 8 November 2007.
• http//www.nhlbi.nih.gov/hbp/hbp/whathbp.htm.
• www.webmd.com, Hypertension/High Blood Pressure
  Health Center (2005-2007 WebMD), WebMD INC. Nov
  12, 2007
• www.webmd.com, Hypotension/Low Blood Pressure
  Health Center (2005-2007 WebMD), WebMD INC. Nov
  12,2007
• Elie Moubarak
• Rushd Khan
• 
  Aftab Sandhu