Structure Of Skeletal Muscle Flashcards
What are the three types of muscle in body? And where they found
Cardiac muscle - heart
Smooth muscle- walls of blood vessels and gut
Skeletal muscle - it is attached to bone and acts involuntary, conscious control
What are muscles made up of
Millions of tiny muscle fibres called myofibrils
What’s within the sarcoplasm
Large concentration of mitochondria and endoplasmic reticulum
What do the muscle fibres share when separate cells have become fused together into muscle fibres
They share nuclei and cytoplasm, called sarcoplasm
What are the I bands ?
The light bands. They appear lighter because the thick and thin filaments do not overlap in this region
What are the A bands
The dark bands. They appear darker because the thick and thin filaments overlap in this region
What’s at the centre of each A band?
A lighter coloured region called the H zone
What’s at the centre of each I band
The Z line
What’s the distance between adjacent Z lines
A sacromere
What happens when a muscle contract to the sacromere
It shortens and the pattern of light and dark bands changes
What is tropomyosin
An important protein found in muscles
Which forms a fibrous strand around the actin filament
What are slow twitch fibres
These contract mite slowly than fast twitch fibres and provide less powerful contractions but over a longer period
What type of work are slow twitch fibres adapted for
Endurance work such as a marathon
How are they adapted for aerobic respiration to avoid build up of lactic acid
Large myoglobin stores ( stores oxygen)
Rich supply of blood vessels to deliver oxygen and glucose for aerobic respiration
Numerous mitochondria to produce ATP
What are fast twitch fibres
These contract more rapidly and produce powerful contractions but only for a short period
