The Muscular system Flashcards
What are the features of skeletal muscle?
-voluntary
-striated
-multinucleated
What are the features of cardiac muscle?
-involuntary
-striated
-single nucleus
What are the purpose of intercalated discs in cardiac muscle?
They help to boost nerve impulses so that it can contract efficiently.
What are the features of smooth muscle?
-involuntary
-non-striated
-single nucleus
What are the functions of muscle?
-movement
-position
-regulating organ volume
-moving substances into the body
-heat production (shivering, muscle contractions produce heat).
What are the characteristics of muscle?
-excitability
-contractility
-extensibility
-elasticity
What is the meaning of excitability?
The ability to respond to a stimulus.
What is the meaning of contractility?
The ability to contract when stimulated.
What is the meaning of extensibility?
The ability to be stretched or extended.
What is the meaning of elasticity?
The ability to return to the original length after stretching.
During muscle contraction, what is the origin of the muscle?
This is the end of muscle attached to a structure (usually bone) that remains stationary.
During muscle contraction, what is the insertion part of the muscle?
This is the opposite end to the origin and it is moved by the contraction.
What is a tendon?
Attached muscle to bone.
What is the gaster/belly of muscle?
This is the fleshy/ meaty portion of the muscle that contracts.
What are antagonistic pairs of muscles?
Opposing pairs of muscles working together to create movement.
What is the agonist muscle?
(prime mover) contracts to cause an action.
What is the antagonist muscle?
This stretches and yields to the action go the agonist.
What is the synergist?
This contracts to stabilise intermediate joints (against dislocation).
What is the fixator?
This stabilises the origin of the agonist.
What is the order of structures that make up a muscle?
Myofibrils-> muscle fibres-> fascicles-> muscle
What is a fascicle?
This is a bundle of muscle fibres.
What does the epimysium surround?
The whole muscle.
What does the perimysium surround?
The fascicle (bundle of fibres).
What does the endomysium surround?
The individual muscle fibres.
What are myofibrils made up of?
These are made of contractile proteins actin and myosin (myofilaments).
What gives the muscle a striated appearance?
The overlapping of thin (actin) and thick (myosin) filaments.
What is a sarcomere?
One section of myofibril- made of actin strands and myosin strands.
These sections are separated by a z- line.
What happens to sarcomere when muscle contracts?
These contracts and squash together, essentially bringing the z-lines closer together.
Why do muscles always pull (not push)?
The insertion is always brought towards the origin so always pulling.
What is a motor unit?
A group of muscle fibres that all get their signals from the same, single motor neuron (therefore, act together).
