Muscular-Skeletal system Flashcards
Anatomy, Physiology
interelationship
Study of the structures of the body and their relationships.
Study of the proper functioning and relationships between body structures and systems.
Understanding how anatomy and physiology connect helps in maintaining health and maximizing movement capacity
Skeletal system
The skeletal system consists of 206 bones and around 360 joints, along with connective tissues (ligaments and cartilage) that provide structural integrity.
Functions of Skeletal System
o Support: Enables movement, standing, and sitting.
o Protection: Shields vital organs (e.g., skull protects the brain, ribs protect the heart and lungs).
o Movement: Bones acts as levers that transfer forces generated by contracting muscles.
o Blood Cell Production: Bone marrow generates blood cells.
o Storage: Bones stores minerals like calcium and phosphorus.
Skeletal structure: axial and appendicular
- Axial Skeleton: 80 bones: Along the central ‘axis’ of the body. Part of the skeleton that comprises the head, vertebrae and rib cage and predominately protects vital organs
- Appendicular Skeleton: 126 bones: Part of the skeleton that comprises the shoulder, pelvic girdle, arms and legs and predominately designed for movement.
Long bone
Longer than wide; has a shaft with 2 ends consisting of spongy bone.
Function: function as levers when muscles contract facilitating movement, support body weight
Examples: Femur, humerus or phalanges
Short bone
Cube-shaped, as long as they are wide
Function: stability, little to no movement.
Example: carpals and tarsals
Flat bone
Thin, slightly curved
Function: Protect vital organs, muscle attachment
Examples: Cranium, sternum and ribs
Irregular bones
Varies in shape and includes sesamoid bones (round bone)
Function: protect organs, tendon attachment
Example: Patella
Joint
A junction of 2 or more bones aka an articulation
3 types: Fibrous, cartilaginous, synovial
Fibrous joint
Immovable connected by strong fibrous tissue e.g. skull sutures
Cartilaginous
Slightly moveable, connected by cartilage
Examples of this joint exist in the vertebral column, where fibrous cartilage between discs allows a limited range of movement.
Synovial joint
Highly moveable where 2 bones meet, tendons, ligaments articular cartilage and synovial fluid combine to provide support and reduce friction for movement efficiency
e.g. shoulder, knee
Ligaments
+ impact if damaged
Well defined fibrous bands that connect bone to bone in the joint. Assist joint capsule to maintain stability by restricting excessive movement and prevent dislocation. Can control the degree and direction of movement that occurs. E.g. ACL (anterior cruciate ligament) stabilises the knee joint restricting knee rotation
Relatively inelastic structures: can become permanently lengthened/torn when stretched excessively - joint instability – more prone to disolocation
Tendons
+ impact if damaged
Tough, inelastic cords of tissue that connect muscle to bone. Further strengthen joints that extend across it and help ligaments hold it closed. Protect joint by absorbing and transferring force, stabilise the joint, allow for full range of motion. E.g. Achilles tendon connects the gastrocnemius to the heel bone: the transfer of energy across this joint allows us to walk and run.
Weakness, restricted movement
Synovial fluid
+ impact if damaged
Thick, slippery fluid that lubricates and forms a cushion between the joint surfaces reducing friction during movement. nourishes cartilage, carries away waste products and
stiffness, may lead to osteoarthritis
Articular cartilage
+ impact if damaged
Firm slippery tissue that covers the end of bones acting as a shock absorber, reduces friction on bones during movement. E.g. articular cartilage in the knee joint allows for smooth and efficient joint movements like running.
Pain, decreased motion (can lead to osteoarthritis)
Ball and socket
Freely moving joints that can rotate on any axis: wide range of movement e.g hip and shoulder
Hinge joint
Move on just one axis: one-direction movement allowing for flexion and extension e.g. elbow, knee
Gliding (plane) joint
Move against each other on a single plane: sliding movement e.g. wrist, ankle
Condyloid (Ellipsoidal)
Two-direction movement: (backwards/forwards, sideways) circular motion, flexion and extension e.g. Wrist joint between the radius and the carpal bones.
Saddle joint
Two-direction movement: (sideways, backwards/ forwards) allow for flexion, extension and other movements but not rotation. e.g. thumb
Pivot joint
Allows one bone to rotate about another e.g. Top of the spine = pivot joint for rotation of the head.
Flexion
Decreasing joint angle between 2 bones e.g. bicep curl
Extension
Increasing joint angle e.g. kicking a ball
Abduction
Body part moved away from the centreline (laterally) of the body e.g. breaststroke
Adduction
body part is moved towards from the centreline (medially) of the body including movements that go past the centreline (only sideways) e.g. star jump
Circumduction
the distal end of a limb has a circular movement moving 360 degrees while the proximal end remains fixed e.g. bowling in cricket
Rotation
The motion of a bone moving around on a central stationary axis e.g. swinging a baseball bat
Pronation
rotation of the hand and forearm so that the palm faces backwards or downwards. e.g. tennis serve
Supination
rottion of the hand and forearm so that the palm faces upward e.g. basketball layup
Eversion
movement of the sole of the foot outward, away from the midline of the body e.g. skiing
Inversion
he action of turning the sole of the foot inward, towards the opposite foot or the midline of the body e.g. dodging
Dorsi-flexion
the action of raising the foot upwards towards the shin decreasing the angle of the ankle e.g. pedalling on a bike
Plantar flexion
the movement of the foot in a downward motion away from the body increasing joint angle e.g. kicking an AFL
Protraction
Forward movement of the shoulder e.g. netball pass
Retraction
Backward movement of the shoulder, the scapulae is pulled posteriorly and medially, toward the vertebral column. e.g. preparing to pass in netball
Musclular system
A body system containing of over 700 muscles consisting of skeletal, smooth and cardiac muscle that produces movement of the body, maintains posture and helps circulate various fluids throughout the body.
Skeletal Muscles
Voluntary (able to be consciously controlled).: made up of bundles of contractile muscle fibres surrounded by a layer of connective tissue fascia providing structure and support. Attach to bones via tendons and they primarily contract (shorten in length) to produce movement and maintain stability. controlled).
Cardiac muscles
Involuntary: Found in the heart, responsible for making the heartbeat to delivering blood around the body.
Smooth muscles
Involuntary: Found in the digestive system: line the walls of hollow internal organs such as the bladder.
Muscle fibres
Skeletal muscle is made up of thousands of muscle fibres, which are bundled together and wrapped in connective tissue called fascia. Inside each muscle fibre are myofibrils, which contain repeating units called sarcomeres.
Sarcomeres are the basic units of muscle contraction and contain two proteins: actin (thin) and myosin (thick). When a nerve signal triggers contraction, ATP provides energy for myosin to pull actin, causing the sarcomere to shorten and the muscle to contract, creating movement.
Skeletal muscle is also called striated muscle due to its striped appearance, caused by the overlapping of actin and myosin filaments.
Slow twitch fibres
**Energy release: **efficient, slow contraction releasing energy gradually as required by the body during sustained activity over longer periods of time: oxygen and stored carbs = help supply fuel for over long period of time (e.g., endurance type activities: marathons).
**Oxygen supply: **Red in appearance (good blood supply) because of this they are efficient in using oxygen to generate fuel (ATP) = resistant to fatigue. Unable to produce the power and force of fast twitch.
Example: Endurance activities such as triathlon
Fast-twitch fibres:
Energy release: contract quickly, reach peak tension quickly but fatigue rapidly (feature of anaerobic metabolism used to supply energy needs).
Oxygen supply: White in appearance (less oxygen hence blood): less reliant on oxygen supplied via blood 4 energy don’t need rich blood supply and can produce energy w/o oxygen.
Example: recruited for power and explosive movements
Fast twitch A
immediate fast twitch fibres that can produce a high output for longer periods that FTb -> ability to draw on aerobic and anerobic metabolism to support contraction. Moderate power, short bursts E.g. speed, strength and power activities lasting for up to 2 minutes (e.g., 400m run).
Fast twitch B:
Possess high levels of glycolic enzymes draw energy solely from anerobic sources. Contract extremely quickly, create forceful muscle contraction (but fatigue rapidly. E.g. speed, strength, power activities higher intensity and greater explosive power in very short bursts (approx. 10sec) (e.g., 100m sprint).
Proportions of red and white muscle fibres
Most people have a similar mix of red (slow-twitch) and white (fast-twitch) muscle fibres, but genetics can lead to a higher proportion of one type. More slow-twitch fibres suit aerobic activities, while more fast-twitch fibres suit anaerobic activities. However, training can develop both fibre types to enhance performance.
Muscle attachement: origin and insertion
- All skeletal muscles have 2 points of attachment: muscle origin, muscle insertion.
- Muscles can only pull in one direction along the muscle fibres towards the muscle origin
- The origin is the attachment site that doesn’t move during contraction, while the insertion site does. it is pulled to where the muscle origin is. The insertion is usually distal, or further away, while the origin is proximal
e.g. The origin of the biceps. brachii is the scapular and head of the humerus and the insertion in the radius in the forearm. As the biceps brachii contracts it creates elbow flexion bringing the forearm up to the shoulder.
Isometric contraction
form of static contractions where muscle fibre are activated and develop force but muscle length doesn’t change and movement doesn’t occur e.g. plank: core muscles are engaged and tension applied by length of muscles in rectus abdominis and erector spinae aren’t changing length
Isotonic contractions:
refer to a muscle to changing in length and include both concentric and eccentric contractions
- Concentric isotonic: contractions involve the muscle shortening, decreasing the joint angle e.g. Bicep curl: bicep contracting to lift a weight (upward phase)
- Eccentric isotonic: contractions involve the muscle lengthening increasing joint angle e.g. Bicep curl: biceps muscle fibres lengthening as weight is returned to its og position in bicep curl (lowering phase)
Agonist and antagonist
Muscle causing the major action and doing the most work often contracting to create movement.
Muscle that must relax and lengthen to allow movement helping control an action.
These two roles are interchangeable depending on the directions of the movement. e.g. During elbow flexion, the biceps (agonist) contracts to pull the forearm towards the humerus, while the triceps (antagonist) relaxes. In extension, the triceps (agonist) contracts to move the forearm away from the humerus, while the biceps (antagonist) relaxes.
Stabiliser
Contracts isometrically for stability giving muscles a fixed base. This permits the action to be carried out correctly allowing other joints to work more effectively e.g. When bending the elbow to do a dumbbell curl, the deltoid muscle in the shoulder acts as a stabiliser to allow the efficient working of the shoulder and elbow joint, biceps and triceps, and to reduce the possibility of damage to the joint.
Interrelationship of skeletal and muscular systems
Vital for helping our bodies to respond and move efficiently, they work together to: Provide body with shape and stability, protect vital organs, produce all voluntary movement necessary for daily activities e.g. eating and exercise
* Skeletal system: provides attachment points for muscles to connect to bones through tendons
* Muscle’s ability to contract enables them to pull on the bones which act as levers: bring movement throughout body: The skeleton provides the framework, while muscles enable movement.
* Joints allow different movements (e.g., flexion, extension).
* Connective tissues (ligaments & tendons) ensure stability and coordination.
Example of interrelationship of skeletal and muscular system
Kicking a soccer ball: To extend the knee, the quadriceps (agonist) contract while the hamstrings (antagonist) relax, pulling the tibia forward. The hip flexors contract to lift the leg, while the gluteus maximus stabilizes the pelvis. Tendons transfer force across the hip and knee joints, generating the kicking motion.
