13.9 Voluntary and involuntary muscles Flashcards
what are the 3 types of muscle?
skeletal
cardiac
smooth
function of skeletal muscle?
responsible for movement
function of cardiac muscle?
found in heart and contract without stimulus
ensures regular heart rhythm
function of smooth muscle?
INVOLUNTARY MUSCLE
found in blood vessels
skeletal muscle properties
cardiac muscle properties
smooth muscle properties
what is this?
skeletal muscle
what is this?
cardiac muscle
what is this?
smooth muscle
what are the units of muscle fibres?
sarcolemma
what is the cytoplasm of a muscle fibre?
sarcoplasm
what organelle is common in muscle cells?
mitochondria
to provide ATP
and glycogen granules
to provide glucose for respiration
what is contained in the sarcoplasmic reticulum?
Ca2+ ions
what are myofibrils?
protein organelles specialised for contraction
what is myofibril made out of?
actin
myosin
what is actin?
acTHIN
two strands twisted around eachother
what is myosin?
THICK
contains myosin heads
what is a light band or I-band?
regions of ONLY actin and NO mysoin
what is a dark band or A-band?
darker regions where actin and myosin DO OVERLAP
what is the Z-line?
line at the end of each light band
what is between 2 Z-lines?
a sarcomere
what happens to the sarcomere when contracted?
it shortens
what is the H-zone?
regions of only myosin
what happens to the H-zone when muscle contracts?
it decreases
what happens to the A-zone when muscle contracts?
it stays the same
what happens to the I-zone when muscle contracts?
it decreases
what happens to the H-zone when muscle contracts?
it decreases
cross section of H zone
contains only thick myosin
cross section of A zone
contains both myosin and actin
diagram of myofibril
