Question

Question 8 Differentiate between striated, unstriated and cardiac muscles on the basis of their structure and site/location in the body.

Class 9 - Science - Tissues Page 79

Answer 1

hello there!!!

Skeletal ( striated ) muscles are Voluntary muscles....

Cardiac and smooth muscles are Involuntary muscles...

Voluntary muscles
• These muscles function as per the direction of a conscious will..
• Brain can stop or start them...
• They get fatigued after some time..

Involuntary muscles
• they function on their own independence of conscious will
• brain can't stop or start them
• they don't get fatigued

Hope it helps you

Answer 2

Difference between Striated Muscle Fibres , Smooth Muscle Fibres and cardiac Muscle Fibres : 


♣ STRAITED MUSCLE FIBRES : 
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◆ They are long cyclindrical cells.

◆ The fibres have blunt ends.

◆ They possess striations or alternate light and dark bands.

◆ Intercalated discs and cross connections are absent.

◆ The muscle fibre is multinucleate . nuclei are oval in outline . They occur peripherally below the sarcolemna.

◆ They occur in bundles.

◆ Straited muscle fibres occur in limbs, hands, feet , body wall, tounge , pharynx and upper part of oesophagus.

◆ They are voluntary .

◆ They are able to perform fast and powerful contractions.

◆ They soon get fatigued.


♣ SMOOTH MUSCLE FIBRES : 
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◆The fibres are elongated and spindle shaped.

◆The fibres have pointed ends.

◆ Striations or light and dark bands are absent.

◆ Intercalated discs and cross- connections are absent.

◆ Smooth Muscle Fibres is uninucleate . nucleus is centrally placed , oval or elongated.

◆ They generally form sheets.

◆ The fibres occur in dermis, urinogenitical tracts, digestive tract , lungs, Iris, blood vessels, etc.

◆ They are involuntary.

◆ They perform slow but prolonged contractions.

◆ Fatigue is rare.


♣ CARDIAC MUSCLE FIBRES : 
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◆ The cells are small and cyclindrical.

◆ The fibres have broad ends. Striations are present but they are fainter than those of Straited muscle fibres.

◆ Intercalated discs and cross- connections are present.

◆ The cells are uninucleate . nucleus in oval- rounded . It is centrally placed.

◆ They form a network.

◆ The muscle fibres occur only in the wall of heart.

◆ They are involuntary.

◆ cardiac Muscle fibres performs powerful and rhythmic contractions.

◆ They seldom get fatigued.