Topic 4 Flashcards
4.1
Label a diagram of a motor unit
Dentrites, cell body, nucleus, axon, motor end plate, synapse, muscle
Explain the role of neurotransmitters in stimulating skeletal muscle contraction
Neurotransmitters are chemicals that are used for communication between the neuron at the synapse and another cell. This process allows muscles to recieve nerve stimuli an react by moving
Explain the fliding filament theory
Hundreds of myofibrils make up a muscle fiber. Each one made up of wo protein filaments: actin and myosin. For the sliding filament motion to begin, an electrical signal in a motor neuron (action potential) causes the release of calcium ions from the sarcoplasmic reticulum. The calcium ions then bind to the troponin, causing the troponin and tropomyosin to move and uncover the actin binding sites for the myosin to attach to. The myosin head then attaches to the actinmyofilament forming a crossbridge. With the release of a phosphate, the powerstroke can occur, which slies the actin towars the M-line. The Z-lines are brought together, which shrinks the H-zone. THe ADP molecule is then released. As new ATP moleculesattach to the myosin head and link between the actin and myosin weakens an the cross brige etaches. As the ATP is split into ADP and P, the myosin head is energised and attaches to the actin, forming a crossbrige as the cycle repeats.
Explain how slow and fast twitch fibres differ in structure and function
Type 1 fibres - Slow twitch, low force and low speed, small and red
Type 2a fibres - Moderately fast, medium force and medium speed, moderate sized and red
Type 2b fibres - Fast twitch, high force and fest speed, large and white in colour, a ndd b both high in glycogen
4.2
Types of movement at synovial joints
Flexion/Extension Abduction/Adduction Pronation/Supination Elevation/Depression Rotation/Circumduction Dorsi flexion/Plantar flexion Eversion/Inversion
Types of muscle contraction
Isometric Isokinetic Isotonic - Concentric - Eccentric
Explain the concept of reciprocal inhibition
Reciprocal inhibition states that muscles work in pairs during movement, one being the agonist and one being the antagonist.
- The agonist is the muscle that is contracting
- The antagonist is the muscle that is extending
- E.g. Bicep annd Tricep, Quadriceps and Hamstrings
Analyse movements in relation to joint action and muscle contraction.
During the upwards motion of a bicep curl, the joint action of the elbow is contraction and the muscle conntraction is the bicep.
During the downwards motion of a bicep curl, the joint action of the elbow is extension and the muscle contraction is the tricep
Explain DOMS in relation to eccentric and concentric muscle contractions.
- Presents 12-24 hours after exercise annd can last between 12 - 72 hours
- Occurs mainly from eccentic movements and sometimes from isometric
movements - It is caused by microscopic tears in the muscle fibres which the body
reacts to with inflamation - It can be eased/prevented by reducing the eccentic components of
exercise, warming up and cooling down, massages and warm/cold baths
4.3
Force - Vector
The mechanical interaction that goes on between two objects.
Formula: Mass X Acceleration
Speed - Scalar
The rate at which someone or something is able to move or operate at.
Formula: Distance / TIme
Velocity - Vector
The speed of something in a given direction.
Formula: Displacement change / TIme
