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
What are the 3 types of muscle fibre?
Type 1 (Slow Twitch) Type 2a (Fast Twitch) Type 2b (Fast Twitch)
In what manner do slow twitch fibres contract?
Smoothly and gradually
How long does it take slow twitch fibres to reach full contraction?
40-50ms
Do slow twitch fibres have a high or low capacity to generate force?
Low
Do slow twitch fibres generate ATP slowly or quickly?
Slowly
Which system do slow twitch fibres use to produce ATP?
Aerobic
How is the supply of capillaries in slow twitch fibre?
Good, to be able to supply enough oxygen for producing ATP aerobically
What protein do slow twitch fibres contain to make them very good at extracting oxygen from blood, and also gives them their red colour?
Myoglobin
Why do slow twitch fibres have lots of mitochondria?
Because this is the only place ATP can be generated aerobically
Why are slow twitch fibres good fat burners?
Because fat can only be used to create ATP in the presence of oxygen
What are waste products of aerobic ATP production in slow twitch fibres and why does this make them resistant to fatigue?
Water, Heat & CO2, these are dealt with easily and don’t inhibit and metabolic processes
Do slow twitch fibres need a large stimulus to contract?
No
What kind of activity recruits type 1 fibres?
Low to moderate intensity endurance type activities
What is the difference in the type of metabolism used in Type 2a and Type 2b fibres?
Type 2a use a mixture of aerobic and anaerobic and are referred to as fast oxidative glycolytic fibres
Type 2b use anaerobic only, and are referred to as fast glycolytic fibres
How do Type 2a fibres adapt to training?
The type of metabolism they use will improve depending on how they are trained. Endurance training will improve their aerobic capacity whereas high intensity training will improve anaerobic capacity
When are Type 2 fibres recruited?
During high intensity short duration activities
Which systems can Type 2 fibres use to create ATP?
Phosocreatine (PCr) & Lactic Acid systems
Do type 2 fibres need a large stimulus to contract?
Yes
How quickly do type 2 fibres reach full contraction?
About 5ms, this generates considerable power due to the added speed of contraction
Do Type 2 fibres generate ATP slowly or quickly?
Quickly
Why are Type 2 fibres useful for high intensity work?
Because they don’t need Oxygen to create ATP therefore they can produce ATP at near maximal heart rates
How do Type 2 fibres create higher tension compared to Type 1
They are thicker and contain more Actin & Myosin
How many Mitochondria do Type 2 fibres have?
None
Why do Type 2 muscles fatigue easily at high work rates?
Because using glucose as an energy source anaerobically produces Lactic Acid, which prevents further production of ATP until it is removed
Why would less fit people tire more easily even at lower work rates?
Because of the inefficiency to generate ATP aerobically Type 2 fibres get recruited even at lower work rates
In what order are muscle fibres preferentially recruited?
Type 1 -> Type 2a -> Type 2b
What happens when the cross bridges are damages at high workloads?
The muscle adapts and creates more myosin and actin for the muscle, this is Hypertrophy
Why can Type 2b fibres turn to Type 2a fibres even in anaerobic training?
Because paying back the oxygen debt to replenish energy stores at rest has an aerobic element to it
What is Hyperplasia theory?
The thought that instead of the fibres growing in size (Hypertrophy), they split to make more fibres
No conclusive evidence
What are Dense Connective Tissue?
They are a smooth, white tissue which massive tensile strength in one direction, formed almost entirely of collagen with also a small number of elastic fibres
What is a Tendon?
A connective tissue that joins the epimysium of a muscle to bone
What is a Ligament?
A connective tissue that joins bone to bone
How much elasticity do Ligaments have?
Only about 6% whilst being able to return to original length
Do Ligaments have much in the way of blood supply?
No
What is the role of Articular Cartilage & Ligaments?
They contain nerve endings that sense positional change, these proprioceptors signal that a joint is under pressure and cause muscles to be recruited that can change that
What are the properties of Cartilage?
is dense is tough is fibrous withstands compression can be worn or torn is very similar to plastic and is very durable does NOT have a blood supply has limited ability to repair itself is dependent on regular physical activity for health
What are the properties of Hyaline (Articular) Cartilage?
is tough, smooth and thin
is bluey white in colour
is found covering bone ends to form joints
becomes slippery when lubricated with synovial fluid thus reducing friction and allowing optimal joint movement.
What are the properties of Elastic Cartilage?
has a structure similar to hyaline cartilage
has more fibres than hyaline cartilage
has most of its fibres made up of elastin as opposed to collagen
has the ability to spring back into shape immediately due to the properties of elastin
can be found in the ear, the walls of the Eustachian tube (the tube that runs from the middle ear to the pharynx) and the epiglottis, all places that require maintenance of a specific shape.
What is the role of Fibrocartilage?
It is a thicker and stronger cartilage that acts as a shock absorber in joints e.g. Meniscus in the knee
Why are the core muscles important to stability?
Because unlike the thorax, the abdominal wall has no skeletal reinforcement
What role do the muscles involved in core stability play aside from stability?
Protect the abdominal organs and lumbar spine
Why are exercises such as stomach crunches ineffective to improving core stability?
Because the main muscles in core stability don’t bring about large movements, their job is mainly to restrict not to move
What problems can a weak core lead to?
Poor posture, incorrect spinal alignment, abdominal distension and spinal injuries
What is the location and role of the Transversus Abdominus?
It is the innermost muscle of the stomach wall, wrapping around like a corset
It protects the back and flattens the stomach
Where is the origin of the Transversus Abominus?
Thoracolumbar Facia
Which three bones fused together make up each side of the Pelvic Girdle?
The Ilium, Ischium & Pubic Bone
What is the main action of the Levator Ani pelvic floor muscle?
Supports pelvic viscera/organs and provides sphincter like action in the anal canal and vagina
Where is the Origin of the Levator Ani pelvic floor muscle?
Pubis & Ischium
Where is the Insertion of the Levator Ani pelvic floor muscle?
Coccyx
What is the main action of the Superficial Transverses Perinea pelvic floor muscle?
Supports pelvic viscera/organs
Where is the Origin of the Superficial Transverses Perinea pelvic floor muscle?
Ischium
Where is the Insertion of the Superficial Transverses Perinea pelvic floor muscle?
Central Tendon
What is the main action of the Bulbospongiosus?
Males: Assists in emptying ureathra
Females: Contracts vagina
Where is the Origin of the Bulbospongiosus?
Central Tendon
Where is the Insertion of the Bulbospongiosus?
Males: Penis
Females: Root of clitoris
What is the main action of the Ischiocavernosus?
Assists function of Bulbospongiosus
Where is the Origin of the Ischiocavernosus?
Ischium
Where is the Insertion of the Ischiocavernosus?
Pubic Arch
Which are the Deep/Local Muscles of the Core?
Transversus Abdominis Multifidus Internal Oblique Quadratus Lumborum Pelvic Floor Muscles Diaphragm
What kind of support does the Transversus Abdominis provide?
Anterior
What kind of support does the Multifidus provide?
Posterior
What kind of support does the Internal Oblique provide?
Lateral
What kind of support does the Pelvic Floor Muscles provide?
Inferior
What kind of support does the Diaphragm provide?
Superior
Which are the Superficial/Global Muscles?
Rectus Abdominis Erector Spinae (iliocostalis, longissimus, spinalis) External Oblique
What causes women to have greater pelvic instability?
A larger Q angle due to a wider child bearing pelvis
What are often seen hip dysfunctions in women?
IT band syndrome, femoral anteversion and pronation at the knee
What common lower extremity dysfunctions are often seen in women?
Over pronation of foot
Anterior pelvic tilt coupled with lengthening of abdominal wall (often a result of child bearing)
What injuries are female runners more prone to?
Knee, calf and ankle injuries
What environmental factors often affect female posture?
Added weight from long hair
Kyphotic posture, sometimes from spinal flexion trying to hide developing breasts due to self consciousness
High heeled shoes
What muscular changes can be caused by wearing high heeled shoes?
Shortening of the Soleus & Gastrocnemius
Hyperextension of the knee causing tightening in lumbar erectors & hip flexors
Posterior neck muscles shorten to lift head as a reaction to body being tipped forward
Do females generally have a higher or lower percentage of fat than males?
Higher
What are problems associated with females being more flexible than males?
Can cause joint pain, common around sacroiliac and knee joints
Why can pregnancy cause more flexibility problems?
The hormone Relaxin loosens joints and connective tissues in preparation for birth
How many thick, strong, short ligaments are there in each hip joint?
7
