[L3 Anatomy and Physiology] Section 2: The musculoskeletal system Flashcards
Explain the cellular structure order of skeletal muscle, starting from the Epimysium.
Epimysium, Perimysium, Fasculi, Endomysium, Muscle Fibres, Myofibril, Myofilaments (actin/myosin).
What is the Epimysium?
The tough membrane that surrounds the whole muscle belly and holds the smaller fasciculi
units together.
What is the Perimysium?
The membrane which surrounds the bundles of muscle fibres (the fasciculi).
What is the Endomysium?
The membrane that surrounds the individual muscle fibres, which contain the myofibrils.
What is a Tendon?
Tough, inelastic fibres which wrap around the end of the muscle and attach it to the outer layer
of the bone.
What is the Myofibril?
The smallest unit, or fibril, within the individual muscle fibers.
What is the Myofilaments?
The contractile proteins myosin and actin arranged within compartments in the myofibril
called sarcomeres.
The power to drive the myosin head in the sliding filament theory is what molecule?
ATP.
How does the ATP molecule prime the myosin for activity?
By binding and transferring energy with the head.
Although the myosin head may have been primed with energy from the ATP, it will be unable to bind with the
actin without the presence of what element in the body and why?
Calcium - In a relaxed state, the myosin-binding sites on the actin are blocked by a combination of other molecules (troponin and tropomyosin) and Calcium causes the blocking molecule to move away from the myosin binding site (thus allowing the
‘primed’ myosin head to bind with the actin)
What are some structural features of slow twitch/type 1 muscle fibres?
- Smaller diameter fibre size
- Large myoglobin content
- Many mitochondria (cells where aerobic energy is produced)
- Many capillaries to deliver blood and oxygen
- Red in colour
What are some functional features of slow twitch/type 1 muscle fibres?
- Increased oxygen delivery
- Produce less force
- Long-term contractions
- Resistant to fatigue
- Aerobic
What are some structural features of fast twitch/type 2 muscle fibres?
- Larger diameter fibre size
- Smaller myoglobin content
- Fewer mitochondria
- Fewer capillaries
- White (pale) in colour
What are some functional features of fast twitch/type 2 muscle fibres?
Decreased oxygen delivery • Produce more force • Short-term contractions • Less resistant to fatigue • Anaerobic
Explain the four main stages of the sliding filament theory.
COCKING PHASE:ATP is broken down, releasing energy to prime the myosin head into a ‘cocked’ position.
BINDING PHASE: Calcium ions are released from the SR and allow the myosin head to attach to the actin binding sites.
POWER STROKE: The myosin head rotates, pulling the actin towards the centre of the sarcomere to generate tension/muscle contraction.
RE-SETTING: ATP binds to the myosin head, releasing it from the actin binding site.
What are some effects aerobic/endurance exercise has on Type 1 and Type 2a/2b muscle fibres.
Type I or type IIa fibre changes: • Improved efficiency and work capacity. • Increased number and size of mitochondria. • Hypertrophy. • Increased aerobic enzyme levels. • Increased capillary density.
No change to type IIb fibres.
What are some effects anaerobic, heavy resistance exercise has on Type 1 and Type 2a/2b muscle fibres.
Type IIa and IIb fibre changes: • Increase in anaerobic enzyme levels. • Increased phosphocreatine stores. • Hypertrophy. • Increased contractile protein density.
No change to type I fibres except hypertrophy.
What is the frontal plane?
A vertical plane that divides the body into anterior
and posterior parts.
What is the saggital plane?
A vertical plane that divides the body into left and
right parts.
What is the transverse plane?
A horizontal cross-section through the body which
separates the upper and lower body
What is an axis, and at what angle is the axis of each plane associated with.
A theoretical point around which rotation occurs passes through each plane at right angles.
Which axis passes through the frontal plane?
The anterior-posterior axis
Which axis passes through the sagittal plane?
The medial-lateral axis
Which axis passes through the transverse plane?
The longitudinal axis
Whats plane and axis does a squat take place in?
Sagittal & Medial-lateral
Whats plane and axis doe side-stepping place in?
Frontal & Anterior-posterior
Whats plane and axis does throwing a ball take place in?
Transverse & Longitudinal
Name the three types of joints
FIBROUS, CARTILAGINOUS & SYNOVIAL
Name the 6 types of synovial joints and give an example of each
- Gliding joints, e.g. the mid-carpal and mid-tarsal bones of the wrist and ankle.
- Pivot joints, e.g. between the atlas and axis of the cervical vertebrae.
- Saddle joints, e.g. the thumb.
- Ball and socket joints, e.g. the hip and shoulder.
- Ellipsoid joints, e.g. the knuckles between the phalangeal bones of the fingers and toes.
- Hinge joints, e.g. the knee and elbow.
Plane of movement and axis for: Shoulder - Flexion/Extension
Sagittal & Medial-Lateral axis
Plane of movement and axis for: Shoulder - Ab/Aduction
Frontal & Anterior-Posterior axis
Plane of movement and axis for: Shoulder - Internal/External Rortation
Transverse & Longtuidinal
Plane of movement and axis for: Elbow - Flexion/Extension
Sagittal & Medial-Lateral axis
Plane of movement and axis for: Spinal - Flexion/Extension
Sagittal & Medial-Lateral axis
Plane of movement and axis for: Spinal - Lateral Flexion
Frontal & Anterior-Posterior axis
Plane of movement and axis for: Spinal - Rotation
Transverse & Longtuidinal
What do the rotator cuffs do, and where do they orginate and insert?
Stabilize and control movement at the shoulder joint.
They originate from the scapula and inserts on the
upper aspect of the humerus.
Name the four rotator cuff muscles
Teres minor, supraspinatus, infraspinatus & subscapularis
Where does the Teres minor run, and what joint movement does it help with?
This runs laterally from the scapula to the humerus and helps with adduction and external rotation.
Where does the supraspinatus run, and what joint movement does it help with?
This runs superiorly from the scapula to the top of the humerus and helps with shoulder abduction.
Where does the infraspinatus run, and what joint movement does it help with?
This runs laterally from the scapula (slightly higher than the teres minor) to the humerus. It helps with horizontal extension, external rotation and adduction.
Where does the subscapularisrun, and what joint movement does it help with?
This runs from the underside of the scapula to the front of the humerus and helps with internal rotation and adduction.
Whyat is the Shoulder Girdle comprised of?
Scapulae and Clavicles
The upper back of the shoulder girdle is occupied by what muscles?
The trapezius, rhomboids Major and minor
and levator scapulae muscles
The pectoralis minor and serratus anterior are part of the anterior musculature of the shoulder girdle.
Where do they originate and insert?
They originate from the costal bones and run to the anterior surfaces of the scapulae area.
The vertebral column is comprised of a series of what shape of vertebral bones, linked by what type of joints and separated by intervertebral what?.
The vertebral column is comprised of a series of irregular vertebral bones, which are predominantly linked by cartilaginous, slightly movable joints. These are separated by intervertebral discs.
Movement of the spine is achieved via which three major muscles of the trunk?
The rectus abdominis, obliques (internal/external) and erector spinae.
The musculature of the posterior section of the vertebral column tends to be more complex than elsewhere - Why?
Because of its need for multiple origins and insertions.
What are the two important muscles of the posterior musculature?
The multifidus and quadratus lumborum
What’s the differences between the shoulder and hips in terms of mobility and stability.
The hip joint sacrifices mobility for stability, whereas the shoulder joint sacrifices stability for mobility. The shoulder is, therefore, more prone to dislocation.
At the hip, what muscles are invloved with flexion?
The iIiacus or psoas and the rectus femoris
At the hip, what muscles are invloved with extension?
The gluteus maximus and hamstrings
At the hip, what muscles are invloved with adduction?
The adductor longus, brevis or magnus; the pectineus and gracilis
At the hip, what muscles are invloved with abduction?
The piriformis and tensor facia latae; the gluteus minimus or medius
What are the four quad muscles?
Rectus fermoris, vastus lateralis, vastus medialis, vastus intermedialis
What are the three hamstring muscles?
Biceps femoris, Semimembranosus, Semitendinosus
