MSK Muscle composition Flashcards
Give an example of a convergent skeletal muscle
Pectoralis major
Give an examples of a mulitpennate skeletal muscle
Deltoid muscle
What are the 4 muscle groups?
Agonists, Antagonists, Synergists and Fixators
What is the roles of agonists?
They are prime movers (main muscles responsible for a particular movement
What is the role of antagonists?
They oppose prime movers (agonists)
What is the role of synergists?
They assist prime movers (agonists)
What is the role of fixators?
Stabilises action of prime mover e.g fixes non mover when the prime mover is acting over 2 joints.
Give the analogies for each of the different types of levers within the body
1st class; A see saw
2nd class: wheel barrow
3rd class: Fishing rod
What is the most efficient type of lever?
1st class
What is the name given to the support around where a lever picots?
A fulcrum
What are a very large proportion of levers? Example?
3rd class. E.g the arm
What are the 2 different types of muscle contraction?
Isotonic and isometric
What is isotonic contraction? Subtypes?
Constant tension and variable muscle length.
Concentric - Muscle shortens
Eccentric - Muscle exerts force whilst being extended e.g walking down a hill.
What is isometric contraction/ Example?
Muscle stays the same length but exerts a force e.g hand grip (forearm muscle)
What are the two types of fibres in skeletal muscle? When are they used?
Fast/slow twitch muscle.
Fast = sprinting or jumping
Slow = postural muscle
What is the awareness of self within fibres called? What are these specialised units?
proprioception. Called muscle spindles
What is eectromyography? How is it carried out?
It is a medicine technique for evaluating and recording the electrical activity produced by skeletal muscles.
Electrodes are placed on the skin
What is electromyography? How is it carried out?
It is a medicine technique for evaluating and recording the electrical activity produced by skeletal muscles.
Electrodes are placed on the skin
Give on example of why electromyography may be a good diagnostic tool
For neurological diseases
How does the relaxation of muscles take place?
Calcium ions are pumped back into the sarcoplasmic reticulum OR calcium ions bind to calmodulin
What is muscle tone?
The force of contaction of a muscle
What is baseline tone and what is it due to?
It is present in muscles at rest. It is due to motor neurone activity and muscle elasticity
What is additional tone due to?
Via moon control centres in the brain and feedback from muscle signals
What is the difference between spatial and temporal summation?
Spatial - lots of pre synaptic neurones and one post synaptic neurone.
Temporal - one pre synaptic neurone but send signals may times in succession
What is serum creatine kinase a marker for?
Muscle damage (creatine kinase is a source of ATP)
Why does contraction occur?
Because ATP sources are depleted so myosin bridges are unable to detach from actin filaments
What is delayed muscle soreness an example of? Give examples of when this might occur
Example of eccentric isotonic contraction
Hill walking or ski-ing
What is hypotonia?
Low level of muscle tone
What may cause hypotonia?
Damage to brain or spinal cord
Damage to cerebellum (involved in feedback control)
Why are muscle relaxants used in surgery?
Because they make the surgeon’s job easier and less tissue damage is done is the muscle is relaxed.
What is tetanus? What is it caused by?
It is caused by bacterium-clostridium tetani in the soil.
It cases muscles to remain contracted because feedback control is interfered with.
What is the pain caused by in muscle cramp?
An increase in acidity (lactate) which acts on nerve endings
What may be the causes of muscle fatigue?
Depletion of muscle glycogen stores
Interrupted blood flow
How do muscle relaxants work?
They interfere with acetylcholinesterase
