The Muscles Flashcards
What are agonists?
They are the prime movers. The main muscles responsible for creating a particular movement at a joint.
What are antagonists?
The muscle opposite the agonist. The muscle that relaxes when the agonists contracts.
What are assistors?
They help the agonist muscle to perform work. They may not be a prime mover but are still involved.
What are stabilisers?
These are muscles that hold a joint in place so that the exercise can be performed. They are not necessarily moving during the exercise but provide stationary support.
What it is the muscle function?
Generates force.
Muscles can pull and push; true or false?
False, muscles can only pull.
What are the three types of contractions?
Isotonic, isometric and isokinetic.
Define Isotonic
Same tension, length changes
Define Isometric
Same length, tension changes
Define Isokinetic
Same velocity, length changes and tension changes
What are the different types of muscle contractions?
Isotonic: Concentric and Eccentric.
Define Concentric
Muscle shortens
Define Eccentric
Muscle Lengthens
What is the gross Muscle structure?
Made up of muscle fibres. Each fibre is made up of long cells. Cannot be seen from surface. Grouped into bundles. Covered in fascia.
What is the microscopic muscle structure?
muscle fibres= multineucleaic cells Striations Myofibril Sarcomere Filaments (thick and thin) Actin Myosin Cross bridges
What is a Sarcomere?
It is an organelle made up of a repeating structure, z line to z line.
What is the muscle as, an organ, made up of?
Many bundles of Fascicles all wrapped up in Epimysium fascia.
What are Fascicles made up of?
Made of bundles of fibres surrounded by Perimysium.
What are muscle fibres made up of?
Bundles of myofibrils. Each fibre wrapped in Endomysium.
What are Myofibrils?
The contractile element
What are Myofibrils made up of?
Actin filament (thin) Myosin filament (thick)
What is the theory called describing the movement within the muscle?
Sliding filament theory
How small are cross bridges?
There are >300 molecules of myosin in each thick filament.
Each molecule has 2 cross bridges (heads).
How many cross bridges per thick filament?
> 600 per thick filament
How are sarcomeres created?
Thick/thin filaments repeat.
What are the resting length of sarcomeres?
2-3um
How much force can a single cross bridge generate?
> 4 pN of force
