Studied by 1 personKey information required for this part of the Neuronal Communication topic for OCR A Level Biology
What are skeletal muscles responsible for, what is the fibre structure, what type of control are they under, how are they arranged and why, how long is the length and speed of contraction
Movement; striated, multinuclear, tubular; voluntary; regularly so muscles can contract in one direction; short length, rapid speed
What are cardiac muscles responsible for, how are they myogenic, what is the fibre structure, what type of control are they under, how are they arranged and why, how long is the length and speed of contraction
Beating of the heart; they contract without need of the nervous system; branched uninuclear specialised striated; involuntary; cells branch and interconnect to allow simultaneous contraction; intermediate speed and length
What are smooth muscles also known as, what is the fibre structure, what type of control are they under, how are they arranged and why, how long is the length and speed of contraction
Involuntary muscle; spindle-shaped, uninuclear, non-striated; involuntary; non-regular to allow different cells to contract in different directions; long length, slow speed
What are the 4 features of muscle fibres (why is each present)
Made up of many embryonic muscle cells fused together (make muscles stronger); shared cytoplasm called sarcoplasm; shared membrane called sarcolemma; parts of sarcolemma fold inwards into T-tubules (help spread impulses through sarcoplasm so cells contract simultaneously)
What are the modifications on some of the organelles in muscle fibres (why are these present)
Lots of mitochondria (to provide enough ATP for contraction); specialised ER - sarcoplasmic reticulum extends through muscle fibre and contains calcium ions required for muscle contraction
What are myofibrils, where are they found and what proteins are they made up of (describe each protein)
Long cylindrical organelles made of protein, lined parallel to each other and specialised for contraction; actin (thinner, two strands twisted around each other), myosin (thicker, long rod-shaped fibres with bulb shaped heads that project on one side)
What is present in the light bands, dark bands and H-zone of a myofibril, what is a Z-line and sarcomere
Light band: actin only; dark band: myosin and actin; H-zone: myosin only; line found at the centre of the light band; distance between two Z-lines and the functional unit of a myofibril
Note
Flashcard