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How negative feedback controls of blood pressure works

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Title: How negative feedback controls of blood pressure works


1
Blood Pressure
Hypertension Hypotension
Elie Moubarak Aftab Sandhu Rushd Khan
2
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.

6
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

7
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.

8
  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.

9
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.

10
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 

11
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 

12
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 

13
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.

14
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 

15
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 

16
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)  

17
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
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