Post on 30-May-2018
transcript
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Regulating The
Internal Environment
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Learning Outcomes
At the end of the lesson, students should be able
to
1.State the meaning of internal environment
2. Identify 3 physical factors and 3 chemicalfactors affecting internal environment
3. Explain 2 necessity to maintain an optimal
environment4. Describe the involvement of various system in
maintaining an optimal internal environment
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What Is InternalEnvironment?
Pair and Share
Discuss with your partnerthe definition of internalenvironment and sharewith the class.
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Factors Affecting InternalEnvironment
What are they?
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Factors Affecting InternalEnvironment
Physical Factors Chemical Factors
Temperature
Blood pressure pH value
Salt
Osmotic pressure Sugar content
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Homeostasis
Rational Cloze
Read the text andfill in the blank
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Components ofHomeostasis Control
SystemComponent Function
Receptor a Receive message andgive appropriate
response
Control centre
b Detect changeEffector c Receive message and
process the information
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Control centre( brain )
Control centre( brain )
Normal 37 CNormal 37 C
Temperature
Temperature
Effector
E
Receptor
R
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Negative Feedback
Pair and Share
Discuss with your partner thenegative feedback mechanism and
share with the class.
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The Importance of RegulatingAn Optimal Internal
Environment
Enables the organism to live in a wider range of
habitatsMetabolic activities and physiological processes canstill continue even though the external environmentfluctuates substantially
A stable internal environment allows enzymes tofunction at an optimal rate
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The Importance of Homeostasis
=
The Importance of RegulatingAn Optimal Internal
Environment
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ACTIVITYIn your group, discus about the
regulation of the factor affecting
internal environment and the systeminvolved in the process.
1.Concentration of oxygen and carbon
dioxide2.The blood glucose level and pH level
3.Blood osmotic pressure and waste
products
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Presentation
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DISCUSSION
Regulation of body temperature
Body temperature is regulated by integumentarysystem, nervous system, circulatory system,
muscular system and endocrine system
When the body temperature rise above thenormal level, the receptors in the skin detect thechanges.
This information is transmitted to thehypothalamus, the temperature regulatorycentre in the brain.
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Hypothalamus activates various effectors suchas blood vessels and sweat gland.
Blood vessels dilate to allow more blood flow nearthe surface of the body. This will increase heatloss to the external environment.
Sweat gland produces more sweat that will lowerthe body temperature through evaporation.
The RESULT ???
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Normal 37
-Temperature increase
Hypothalamus
Skin receptors
Blood vessel
Sweat gland
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Regulation of concentration of oxygen andcarbon dioxide
Is regulated by respiratory, circulatory and nervoussystem.
Circulatory system transport oxygen from the lungsto the body cells.
Carbon dioxide is removed from the body cells intothe bloodstream and transported back to the lungs.
Changes in concentration of O2 and CO2 isdetected by nervous system.
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For example, decrease in O2 and increase inCO2 concentration during physical activities is
detected by nervous system.As a result, the breathing and pulse rates_______ so that the normal concentration ofO2 and CO2 is attained.
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Regulation of blood glucose level
Regulated by endocrine, circulatory and digestivesystem.
When the level of blood glucose rises,- pancreas secretes insulin into the
circulatorysystem to the liver.-insulin converts excess glucose intoglycogen
If the blood glucose level drops.- if the blood glucose level is below the setpoint,pancreas secretes glucagon to breakdown
glycogen into glucose .
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Other regulations
Blood osmotic pressure and the balance of waterand dissolved substances in body fluids is controlledby nervous, endocrine, excretory and circulatorysystem.
Chemical contents ( waste product of metabolismeg. urea ) is regulated by excretory, circulatory,nervous and endocrine system.
pH level is regulated by respiratory,circulatoryand exretory system.
pH level is maintained by controlling theconcentration of hydrogen ions, hydroxyl ions and
hydrogen carbonate ions.
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ASSESMENT
1. Maintenance of constant internal environmentis known as __________
2. Which are NOT included in chemical factorsthat affecting internal environment?
A.pH value
B.Blood glucose levelC.Body temperature
D.Salt content
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3.Which of the following are the physical factorsthat affect the internal environment of
organism?i. Temperature
ii. Blood pressure
iii. Osmotic pressureiv. pH
A.i and ii
B.ii and ivC.i, ii and iii
D.ii, iii and iv
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4.Which of the following systems are involved inregulating the concentration of oxygen and carbondioxide in the blood stream?
I respiratory system
II endocrine system
III circulatory systemIV nervous system
A.I and II
B.III and IVC.I, II and III
D.I, III and IV
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The systems involved in regulating blood glucoselevel are
A.Endocrine, circulatory and digestive system
B.Endocrine ,circulatory and nervous system
C.Respiratory, digestive and nervous system
D.Respiratory, endocrine and circulatory
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summary
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