Module 5 Section 5/4 - Plant and Animal Responses Part 3
- Created by: RebeccaSmithySmith
- Created on: 15-12-18 20:21
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- Module 5.5 Plant and Animal Responses (Muscles)
- Antagonistic
- as one relaxes the other contracts
- Skeletal Muscle
- Fibres appear striated
- Control is conscious (voluntary)
- regularly arranged so muscles contract in one direction
- its rapid contraction
- contraction length is short
- Cardiac Muscle
- Fibres appear specialised striated
- Control is involuntary
- the cells branch and interconnect resulting in simultaneous contraction
- the speed of the contraction is intermediate as well as the length
- Involuntary Muscle
- Fibres appear non-striated
- Control is involuntary
- no regular arrangement meaning different cells can connect in different directions
- the contraction is slow and can remain contracted for a long period of time
- Structure of Skeletal muscles
- fibres bound together into a dascicle
- Fascicle's bind to form a muscle
- muscle fibres are multi-nucleate
- sarcolemma
- cell membrane of muscle fibres
- ER
- Sarcoplasmic reticullum
- cytoplasm
- sarcoplasm
- sarcolemma
- transverse tubules run through fibres
- Each fibre contains myofibris (contractile in the muscle)
- fibres bound together into a dascicle
- Sliding Filament model of muscle contraction
- contraction caused by myofibrils changing length
- myofibrils centain bundles of thick (myosin) and thin (actin) myofilaments)
- myosin and ctin are cytoskeleton components
- Sacromere
- a unit of thick and thin filaments.
- the distance between the two z-lines is about 2.5um long at rest
- a unit of thick and thin filaments.
- A - band
- length of a thick filament responsible for contraction
- M-line
- a disk in the middle of the sarcomere. formed of cross connecting elements of the sytoskeleton
- z - line
- holds together the thin filaments. forms the borders of one sarcomere
- h-zone
- area of thick filament where there is no overlap with the thin filament.
- the m-line would be at the centre of the -zone
- area of thick filament where there is no overlap with the thin filament.
- Energy supplies and ATP
- Myoglobin releases o2 when surrounding concentrations are low (emergency store)
- anaerobic respiration means you do not receive much ATP per glucose molecule
- Neuromuscular Junctions
- end of motor neuron synapses with a muscle
- neurotransmitter:Acetylchoine
- folded postsynaptic muscle cell
- e.g. motor end plate
- increases surface area so more can be present (receptors)
- threshold potential doesn't have to b reached for a contraction to occur
- single impulse needed
- Antagonistic
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