Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
19 Cards in this Set
- Front
- Back
|
what are skeletal muscles made up of
|
Myofibrils
|
|
|
what are the two types of protein filaments that myofibrils are made up of
|
actin - thinner and consits of two twisted strands
myosin - thicker and consists of longer rod shape fibres with a bulbous head |
|
|
what are the light and dark coloured bands called
|
light = isotropic
dark = anisotropic, are dark because the filaments overlapp |
|
|
Describe tropomyosin
|
a fibrous strand which wraps around the actin filament
|
|
|
describe troponin
|
a globular protein involved in muscle contraction
|
|
|
what are the two types of muscle fibre
|
slow twitch and fast twitch
|
|
|
When are slow twitch fibres used and why
|
for endurance work because they contract more slowly over a longer period of time
|
|
|
how are slow twitch fibres adapted
|
adapted for aerobic respiration by having a large store of myoglobin, glycogen, good blood supply, mitochondria
|
|
|
when are fast twitch fibres used and why
|
for intense excersise because contract more rapidly and produce powerful contractions but only over a short period of time
|
|
|
How are fast twitch fibres adapted
|
thicker and more numerous myosin filament
a high concentration of enzymes invovled in aerobic respiration |
|
|
What is a neuromuscular junction
|
where a motor neurone meets a skeletal muscle fibre
|
|
|
what is a motor unit
|
when all muscle fibres are supplied by a single motor neurone
|
|
|
What is the sliding filament mechanism of muscle contraction
|
when actin filament and myosin filament slide pas one another during msucle contraction
|
|
|
why is the evidence for the sliding filament mechanism
|
the changes seen in the band pattern of myofibrils
|
|
|
how are muscels stimulated
|
an AP reaches a neuromuscular junction causing Ca channels to open which cause synaptic vesicles to fuse with membrane etc
|
|
|
how does an action potential lead to muscle contraction
|
the ap travels through sacroplasm which are in contact with the endoplasmic reticulum which absorb calcium ions, the channels are opened and Ca floods into muscle
|
|
|
What does the influx of calcium ions in the muscle cause
|
the tropomyosin olefules that were blocking the binding sites on the actin fliament to pull alway
|
|
|
Once the actin fliament has moved, what happens
|
myosin head attaches, chaning angle and releasing ADP, ATP joins causing head to detach, resumes to normal position, binds to site further along
|
|
|
How is energy provided for the myosin head to resume normal position
|
hydrolysis of ATP to ADP by ATPase
|
