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;
17 Cards in this Set
- Front
- Back
|
What are muscles? |
- specialised tissue largely made of protein - good blood supply - mammals=40% body weight - responds to nervous system and chemical stimulation |
|
|
What are the types of muscles? |
- striated - smooth - cardiac |
|
|
What are striated muscles? |
- muscles attached to skeleton - striped under microscope - locomotion/rapid contraction - fatigues quickly |
|
|
What are smooth muscles? |
- Gut/blood vessels - not striped - move food through gut/involuntary control/slow contraction - fatigues |
|
|
What are cardiac muscles? |
- heart - striped - contracts spontaneously - doesn't fatigue |
|
|
What would happen if muscles were made of individual cells? |
- won't contract efficiently - junction between adjacent cells weak=reduce overall strength |
|
|
What is the structure of a muscle fibre? |
- made of myofibrils parallel to each other - each made of several sarcomeres - cytoplasm of myofibrils=sarcoplasm (mainly mitochondria - membrane network (sarcoplasmic reticulum) stores/releases Ca2+ |
|
|
What are the components of a sarcomere? |
- I band - A band - Z lines - H zone |
|
|
What is the I band of a sarcomere? |
- the gap between the end of the myosin filaments from neighbouring sarcomeres |
|
|
What is the A band of a sarcomere? |
- the length of the myosin filaments |
|
|
What are the Z lines of a sarcomere? |
- the join of actin filaments which defines the sarcomere |
|
|
What is the H zone of a sarcomere? |
- The gap between myosin heads where there's just filament |
|
Label the parts of this striated muscle. |
1. sarcomere 2. H zone 3. thin actin filament 4. thick myosin filament 5. Z line 6. A band 7. I band |
|
|
What is a neuromuscular junction? |
- point where motor neurone meets skeletal fibre (many along muscle) - one junction=long for contraction travel across muscle - not all fibres contract simultaneously=slow movement |
|
|
How does transmission across a neuromuscular junction work? |
- nerve impulse reaches neuromuscular junction - synaptic vesicles fuse with presyn=release ACh - diffuses to postsyn=change permeability to Na+ ions=enter/depolarise - broken down by acetylcholinesterase=muscle not overstimulated - choline/acetyl diffuse back into neurone=recombines |
|
|
What are the similarities between a neuromuscular junction and a synapse? |
- neurotransmitters transported by diffusion - receptors on binding with NT=influx Na+ - Na+/K+ pump=repolarise axon - enzyme breakdown NT |
|
|
What are the differences between a neuromuscular junction and a synapse? |
- only excitatory - only links neurones to muscles - only motor neurones involved - AP ends here - ACh binds to receptors on muscle fibre membrane |
