Muscles and Movement Flashcards
Bio 35
where is the ligament found in the elbow?
joint capsule
what are the four roles for skeletal muscles?
helps you move, supports the skeleton, protects organs, maintains body temp
name two fibrous connective tissues and their roles.
ligaments: connects bone to bone
tendons: connects bone to muscle
What signals muscle contractions?
the nerve via acetylcholine
what are the bones a site for?
muscle attachment
what do the bones act as?
levers
what is the role of the joint capsule (2)
seals the joint space and provides passive stability by limiting the range of movement
what is the role of the synovial fluid (2)
it contains oxygen, food and nutrients. it also provides lubrication to the cartilage
what does the radius act as? for what muscle?
acts as forearm levers for the biceps
what does the ulna act as? for what muscle?
acts as forearm levers for the triceps
what is bigger in a human body, the ulna or the radius?
the radius
what is the role of the cartilage? (3)
the cartilage absorbs shock and distributes the load. also allows for easy movement since it is a smooth surface.
what type of surface does the cartilage have?
a smooth surface
what muscle is the flexor? what muscle is the extensor?
flexor - biceps
Extensor-triceps
what is the role of the humerus?
the humerus anchors muscle
what bone acts as the muscle origin? what muscle attaches to this bone? what does muscle origin mean?
the humerus acts as a muscle origin. it is the site where triceps are attached and do not move during contraction
what bone acts as the muscle insertion? what does that mean?
the radius and the ulna act as muscle insertions. this is the attachment site that moves during contraction.
what are antagonistic muscle pairs? name an example
antagonistic muscle pairs perform the opposite function. ex. the flexor biceps muscle vs the extensor triceps muscles
why do muscles only pull and not push?
because of the way the sarcomeres work. the myosin will attempt to grasp the actin in a way that contracts the muscle.
describe the shape of the skeletal muscle? (2)
striated and tubular
how many nuclei does a skeletal muscle cell have?
many, more than one
what are skeletal muscles attached to?
to bone except in eye muscles
is the skeletal muscle voluntary or involuntary control?
voluntary
how do muscles move bones?
by contracting and relaxing. they can not push them back into position so they have to use the extensor/flexor pair
what are skeletal muscle cells called?
muscle fibre
what is the hierarchy of muscle structure?
muscle—> muscle fibre bundle—-> muscle fibre—>myofibrils—->myofilaments
what is the sarcolemma
the muscle fibre membrane
what are two types of myofilaments? describe them
actin- thin
myosin- thick
in a muscle, what contains large numbers of mitochondria?
the muscle fibre
what is the sarcoplasmic reticulum? what does it contain?
it is like the endoplasmic reticulum but specialized for the muscle. it contains calcium ions
what are fibres a bundle of?
myofibrils
what are the segments myofibrils are separated in called?
segments called sarcomeres
what is the z disc? what does it consist of? is it a dark or light area?
the z disc is the border of the Sarcomere and it consists of actin only. it is a light area
what is the I Band? what does it consist of? is it a dark or light area?
a section of the sarcomere that only consists of actin. this is a light section.
what is the A Band? what does it consist of? is it a dark or light area?
a section of the sarcomere that consists of both myosin and actin. This is the darkest area.
what is the h-zone? what does it consist of? is it a dark or light area?
in the middle of the sarcomere and it consists of only myosin. this is a dark area
what gets smaller on an electron micrograph when a muscle contracts?
the H-zone and the sarcomere width
what is the m-line? what binds to this line?
a line in the middle of the sarcomere that makes up the H-zone. the myosin binds here
what does an action potential from a motor neuron signal?
calcium release from the sarcoplasmic reticulum
what does calcium ion bind to when released
troponin
what is myoglobin?
carriers oxygen in the muscle
what is the protein covering the binding sites for myosin?
tropomyosin
what forms cross bridges with actin binding sites?
myosin
what is needed to break the cross bridge?
ATP
what is needed to change the myosin head’s shape to make it suitable for binding with the actin?
ATP
what two things pull together to shorten the sarcomere?
actin and myosin
how is calcium returned to the sarcoplasmic reticulum?
active transport
when is calcium returned to the sarcoplasmic reticulum?
when contraction ends
