class bio 1 feb

8/14/2019 Class Bio 1 Feb

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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

THANK YOU

class bio 1 feb

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