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Slide 1

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Slide 2

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3 Types of Muscle
· Skeletal (striated)
· Smooth (visceral)
· Cardiac
· All three types have or do the following
· Artery
· Motor nerve
· Exert force when contracted
· Sheathed by connective tissue which can extend to
form tendons…read more

Slide 3

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Two types of skeletal muscle
· Slow twitch: mainly used in endurance
· Contain more protein called myoglobin which has
more affinity of O2 than haemoglobin
· Contain more mitochondria to produce ATP
· Fast twitch: mainly used in intensive
exercise explosive movement…read more

Slide 4

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Structure of Skeletal Muscle
· Sarcoplasm (cytoplasm)
filled by parallel myofibrils
· Sacrolemma (surface
membrane) forms deep
tubes (T tubules) into the
sarcoplasm along its
· Network of membranes
called sarcoplasmic
reticulum (ER)…read more

Slide 5

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Structure of Skeletal
· Actin filament / thinner than myosin
· Distance between 2 adjacent Z lines: sarcomere / actin filament is
attached to Z lines and extended into sarcomeres on either side
· Striation of actin alone I band
· Length of myosin A band
· Actin filament: 2 actin strands twisted around each other
­ Troponin-tropomyosin-actin complex blocks binding site for
· Myosin filament: bundles of myosin molecules
­ Bundle of myosin tails form a central stalk
­ Globular heads attach to specific sites on actin filaments
­ Myosin heads contain ATPase that hydrolyses ATP…read more

Slide 6

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Sliding theory of muscle
1. Sacrolemma depolarised
6. Myosin binding site on actin
2. Depolarisation spreads now exposed
across Sacrolemma
7. Myosin cross bridges bind
3. Depolarisation travels down to actin initiating muscle
T-tubules contraction
8. With the assistance of ATP
4. Sacrolemma reticulum
cross bridge cycling occurs
releases Ca2+ ions
9. Sarcomeres shorten
5. Ca2+ ions move troponin
molecules on actin filament
which moves tropomyosin out 10. Muscle fibres shorten
of the way…read more


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