Musculoskeletal System Flashcards
What is the Agonist muscle?
The primary muscle that causes the movement e.g. Biceps Brachii during the lifting phase of a Bicep Curl
What is the Antagonist muscle?
The muscle opposite the Agonist muscle that lengthens and relaxes during a movement e.g Tricep Brachii during the lifting phase of a Bicep Curl
What is a Synergist muscle?
A muscle that assists the Agonist during a movement e.g. hamstring assisting the gluteals during hip extension
What is a Fixator muscle?
A muscle that contracts during a movement to keep a joint stable e.g. the mid trapezius and rhomboids stabilise the shoulder during a shoulder press
What are the 3 types of muscle?
Cardiac
Voluntary or Skeletal
Involuntary or Smooth
Where does Skeletal muscle attach to?
Bones
Why is Skeletal muscle sometimes called Striated?
Because under a microscope you can see striations of bundle like tissue
Why are Skeletal muscles Voluntary?
Because you consciously choose to use them during movement
Where is Cardiac muscle located?
The Heart
Is Cardiac muscle Striated?
Yes
Is Cardiac muscle voluntary or involuntary?
Involuntary
Does Cardiac muscle have any anaerobic capacity?
No
How much of the oxygen in the coronary arteries does the heart use at rest?
70-80%
Is smooth muscle striated?
No
Where is smooth muscle located?
In Viscera structures such as blood vessels and the digestive system
What is the function of smooth muscle?
To assist with the flow of blood and food
Is smooth muscle voluntary or involuntary?
Involuntary
How does the amount of fibres in a muscle change during its life?
It doesn’t change
What happens to the muscle fibres during Hypertrophy?
The fibres get bigger
What is muscular Atrophy?
A reduction in the size of muscle fibres
What are the three layers of connective tissue surrounding a muscle?
Outer Epimysium, Central Perimysium and Inner Endomysium
What is the Epimysium?
The Epimysium is the outer covering of the whole muscle
What is the Perimysium?
The perimysium is the tissue that covers a bundle of fibres within the epimysium
What is the Endomysium?
The sheath surrounding each muscle fibre/cell
What is a bundle of muscle fibres called?
Fascicle
What do the Perimysium, Epimysium and Perimysium form when they come together at the end of a muscle?
A Tendon or a broad sheet called an Aponeurosis
What do a Tendon or Aponeurosis connect to?
Bone (Periosteum)
What does each Muscle Fibre contain?
Myofibrils and a fluid called Sarcoplasm
What are the repeating units of Myofibrils called?
Sarcomeres
What smaller structures are the Myofibrils filled with?
Myofilaments
What are the two types of Myofilaments?
Myosin & Actin
Is Myosin a thick or thin filament?
Thick
Is Actin a thick or thin filament?
Thin
What are the 4 types of muscle depending on Fascicle arrangements?
Parallel muscles, Convergent muscles, Pennate muscles and Circular muscles
How are the Fascicles arranged in a Parallel Muscle?
Parallel to the long axis of the muscle
What makes a parallel muscle Fusiform?
Having a Tendon at one or both ends rather than Aponeuroses
What shape are Fusiform muscles?
Spindle shaped with a wider belly
How much can a muscle cell contract?
By about 30%, so a parallel muscle can also contract by 30% as the fibres are parallel to the long axis
How are the Fascicles arranged in a Convergent Muscle?
Spread over a broad area like a fan coming back to a common attachment e.g. Pectorals
Why is a Convergent Muscle versatile?
Because different sections can be contracted to pull in different directions
What negatives come with the versatility of a Convergent Muscle?
Because the fibres pull in different directions, when the whole muscle is contracted it produces less force than a parallel muscle would
How are the Fascicles arranged in a Pennate Muscle?
At a common angle to the tendon
How does the angle of fibres in Pennate Muscles effect muscular contraction compared to Parallel Muscles?
The muscle can’t contract as far as in a Parallel Muscle, however can produce more tension relative to its size
When is a Pennate Muscle Unipennate?
When all the fibres are on the same side of the tendon e.g. the extensor digitorum
When is a Pennate Muscle Bipennate?
When it has fibres both sides of a tendon e.g. the rectus femoris
When is a Pennate muscle Multipennate?
When the tendon branches within the muscle e.g. the deltoid
How does the muscle contraction take place?
ATP on the myosin head allows myosin to attach to actin forming a cross bridge
Then the myosin pivots and bends which pulls actin over the myosin
This allows muscle to shorten without actually shortening the muscle fibres
What is the role of Calcium in muscle contraction?
Calcium causes the molecules blocking the binding site on Actin to be moved, allowing the Myosin to bind
What is the role of ATP in muscle contraction?
ATP provides the energy for the contraction
Which molecules block the binding site on Actin?
Troponin & Tropomyosin