muscles Flashcards
what are the three types of muscles
cardiac
smooth
skeletal
where is smooth muscle found
walls of the blood vessels and the gut
are smooth and cardiac muscle contraction under conscious control
no
which is thinner actin or myosin
actin
what are the two types of skeletal muscle fibres
slow twitch and fast twitch
what are properties of a slow twitch fibre
- higher concentration of myoglobin
- contract slowly
- slow to fatigue
lots of mitochondria to provide lots of ATP
- slow to fatigue
- lots of blood vessels to reduce diffusion pathway
- slow release of energy
what are properties of fast twitch fibres
- low concentration myoglobin #
- contract quickly
=energy is released quickly - few mitochondria and blood vessels
- quick to fatigue
what is contained in the sarcoplasmic reticulum
Ca2+ needed for muscular contraction
what is the sarcoplasm
cytoplasm
what is the sarcolemma
the cell membrane
what are adaptations of skeletal muscle
- multinucleate
- ## lots of mitochondria for release of ATP needed for muscular contraction
what is a sarcomere
short repeating units that make up the myofibril
what is the order of letter in the sarcomere
IAI
ZHZ
WHY IS THE A BAND DARK
because it contains both actin and myosin
why is the I band light
because it only contains actin
what is the M line in the sarcomere
middle of the H zone which only contains myosin
how does a muscle contract
an action potential from a motor neurone will depolarise the sarcolemma.
- this depolarisation will travel down the T-tubule to the sarcoplasmic reticulum
- this will stimulate Ca2+ ions to be released. this will stimulate ATP hydrolase to form ADP + Pi and energy from ATP. this will cause the myosin heads to bend. the actin and myosin filament will slide past each other. this will mean that the myosin head is no longer attached to the actin filament. then the myosin head will bend back to orignal position and will form a new bond with another actin filament further along
