13.9 Voluntary and Involuntary Muscles Flashcards
What are the three types of muscle in the body?
Skeletal (voluntary) , Cardiac, Involuntary (smooth)
What type of control is skeletal muscle?
Conscious control (voluntary)
What type of control is cardiac muscle?
Involuntary
What is the fibre appearance of skeletal muscle?
Striated
What is the fibre appearance of cardiac muscle?
Specialised striated (striped pattern isn’t as strong as skeletal muscle)
What is the fibre appearance of involuntary muscle?
Non-striated
What is the contraction speed of skeletal muscle?
rapid, used for speed and strength
(but some as slow, which are those used for endurance and posture)
What is the contraction speed of cardiac muscle?
Intermediate
What is the contraction speed of involuntary muscle?
slow
What is the length of contraction skeletal muscle?
short
What is the length of contraction cardiac muscle?
Intermediate
What is the length of contraction involuntary muscle?
can remain contracted for a relatively long time
How quickly does skeletal muscle fatigue?
Fatigue quickly
How quickly does cardiac muscle fatigue?
Does not fatigue
How quickly does involuntary muscle fatigue?
Doesn’t fatigue
Where is involuntary muscle found?
Walls of hollow internal organs
eg. gut, blood vessels, stomach, digestive tract
Where is cardiac muscle found?
Walls of heart only
What is the arrangement of skeletal muscles?
Regularly arranged so muscle contracts in one direction
What is the arrangement of cardiac muscle?
Cells branch and interconnect resulting in simultaneous contraction
What is the arrangement of involuntary muscle?
No regular arrangement, different cells contract in different directions
What is the structure of skeletal muscle?
-Striated, striped as contains cross striations
-Fibres are tubular and multi-nucleated
-Cross striations are regular
What is the structure of cardiac muscle?
-Striations but fainter than in skeletal muscle
-Fibres are branched and uninucleated
-Made of muscle fibres connected by intercalated discs which have low electrical resistance so nerve impulses pass easily between cells
-Fibres are branched to allow nerve impulses to spread quickly
What is the structure of involuntary muscle?
-Non-striated
-Fibres are spindle shaped with pointed ends and uninucleated (each fibre has one nucleus)
Which type of muscle is this?
Skeletal
Which type of muscle is this?
Skeletal
Which type of muscle is this?
Cardiac
Which type of muscle is this?
Involuntary
Which type of muscle is this?
Skeletal
Which type of muscle is this?
Skeletal
Which type of muscle is this?
Cardiac
Which type of muscle is this
Involuntary
Label this muscle fibre
What is the sarcolemma?
The plasma membrane of the muscle fibre cells
What are transverse (T) tubules?
Parts of the sarcolemma that fold inwards across the muscle fibres and stick into the sarcoplasm
What is the purpose of transverse (T) tubules?
Help to send electrical impulses throughout the whole scaroplasm, so that the whole of the fibres receives the impulse to contract as the same time
What is the purpose of the sarcoplasmic reticulum?
Stores and releases calcium ions required for muscle contraction
Why do muscle fibres contain lots of mitochondria?
To provide ATP needed for muscle contraction
Label this diagram of a muscle fibre
What are myofibrils?
Long cylindrical organelles found in muscle which are made of protein and specialised for contraction
What are the two protein filaments myofibrils are made up of?
Actin, myosin
Why are myofibrils lined up parallel to each other?
To provide maximum force when they all contract together
What is Myosin?
Thick filament, long rod-shaped fibres with bulbous heads that project to one side
What is actin?
Thinner filament, two strands twisted around each other
Label which protein filament in which in this transverse section through a myofibril
Myosin - thicker, pink
Actin - thinner, yellow
What do the dark bands of a myofibril contain?
Thick myosin filaments and some overlapping thin actin filament
What are dark bands knows as?
A-bands
What do the light bands of myofibrils contain?
Only thing actin filaments
What are light bands also known as?
I-bands
What is the Z-line?
The line found at the entire of each I-band (light band)
What is involuntary muscle controlled by?
Autonomic nervous system
What is the distance between each Z-line called?
A sarcomere
What is the H-zone?
The light coloured region found in the centre of each dark bands, where only myosin filaments are present
What happens to the sarcomere when the muscle contracts?
shortens
What happens to the H-zone when the muscle contracts?
decreases
Label this myofibril
Label this myofibril
Label this myofibril
Label this myofibril
What is the M-line?
The middle of each sarcomere
Label the features of this skeletal muscle
