13.9 Voluntary And Involuntary Muscles Flashcards
(16 cards)
What are the types of muscle in the body
Skeletal
Cardiac
Involuntary
What is skeletal muscle
Cells responsible for movement
It’s under conscious control
Regularly arranged so they contract in one direction
What is cardiac muscle
Involuntary control
Cells branch and interconnect
What is involuntary muscle
They have no arrangement and contract in different direction
They have slow contraction speed but remain contracted for a long time
What cells make up skeletal muscle and what is there structure
Muscle fibres - these are longer than normal cells as they are fused with one another making them stronger and share cytoplasm
What is the cytoplasm in muscle fibres
Sarcoplasm
What are muscle fibres surrounded by
Sarcolemma -
Parts fold inwards to help spread electrical impulses throughout the sarcoplasm ensuring all of the fibre receives the impulse
What do muscle fibres contain
Lots of mitochondria to provide ATP to contract
Sarcoplasmic reticulum - contains calcium ions for muscle contraction
Myofibrils
What are myofibrils
Long cylindrical organelles made of proteins and specialised for contraction
What are the two types of protein filament that make up myofibrils
Actin
Myosin
What protein filament in myofibrils is thinner
Actin
What are the light bands in myofibrils
Region where actin and myosin don’t overlap
What is the dark band in myofibrils
Here is where the thick myosin filaments are and the edges overlap with actin
What is the Z-line in myosin
Found at the centre of each light band
What is the sarcomere in myofibrils
The distance between adjacent Z-lines
It’s the functional unit of the myofibril
When a muscle contracts the savromere shortens
What is the H-zone of myofibrils
Lighter coloured region in the centre of each dark band
Only myosin filaments are present at this point
