Muskoloskeletal system Flashcards
What is a joint ?
Where 2 or more bones meet
What are the types of joints when classified by movement type ? Give an example for each.
- Synarthroses -No movement takes place (skull)
- Amphiarthroses -little movement (spine)
- Diathroses -Very moveable joints (hip and shoulder joint)
What are the types of joints when classified by soft tissue structure ? What is their characteristic feature ? Give an example.
- Fibrous -fibre connections between 2 bones. Does NOT allow very much movement. Sutures of the skull.
- Cartilaginous - if primary then hyaline cartilage (=Synchondrosis). If secondary then fibrocartilage (=Symphysis). E.g. epiphysael plate and pubic symphysis.
- Synovial- Surrounded by thick flexible membrane forming sac into which is secreted fluid lubricating joint. E.g. bone socket, hinge joint.
What are the different kinds of fibrous joints ?
- Sutures (joints between skull vault bones)
- Syndesmosis (fibrous membrane between bones. E.g. radioulnar interosseous membrane)
- Gomphosis (peg and socket)
What is the structure of synchondroses (type of cartilaginous joint) ? How moveable are they ? Give examples.
Bone-Hyaline Cartilage-Bone
Not moveable
Epiphyseal plate, first stenocostal joint
What is the structure of symphyses (type of cartilaginous joint) ? How moveable are they ? Give examples.
Bone-Hyaline cartilage-Fibrocartilage disc-Hyaline cartilage- Bone
Allows limited movement
Pubic symphysis, intervertebral discs, joints of sternum
What is the particularity of synovial joints?
Allow friction-less movement.
What are the characteristic features of synovial joints ?
Periosteum, fibrous capsule, synovial membrane, synovial fluid in articular cavity, articular hyaline cartilage
What does the fibrous capsule consist of ?
Collagen fibres. Bands of collagen might develop along lines of stress to form ligaments (restricts movement to protect joint from damage).
Which types of ligaments are there ?
Intrinsic ligament= Part of the capsule
Extrinsic ligament= outside of the capsule
What is the main function of the fibrous capsule ?
Preventing dislocation
What is a defining feature of articular cartilage (besides the fact that it is hyaline cartilage) ?
It has very poor blood supply and few chondrocytes so very long time to heal if damage.
What is the synovial membrane made of and what is its role ?
Collagenous vascular connective tissue.
Secrete synovial fluid to lubricate and nourish joints while removing waste
What is synovial fluid made of ?
Hyaluronic acid, lubricin, some phagocytic cells.
How does exercice affect viscosity of the synovial fluid ?
Alignment of glycoproteins changes with exercise. Hence, exercise decreases viscosity (thixotropic), and hence improves lubrication.
What is the function of intra-articular discs ? Which kinds of joints are they found in? What are they made of ?
Absorb shock and deepen the socket.
In joints where rotatory movement occurs.
Made of fibrocartilage
What is a bursae ? Where are they found ?
Closed sacs lined with synovial membrane and lubricated with fluid
Found where friction occurs
What are synovial sheaths ?
Specialised bursae surrounding tendons where subject to Pressure.
Which of ball and socket joints, or hinge joints, is more likely to be dislocated, and why?
Ball and socket, because they allow movement in 3 planes versus 1 plane for hinge joint.
What are the factors influencing the stability of joints ?
- Shape of bones (hence range of movements)
- Strength and position of ligaments (tight ligament prevents large range of movement so more stable)
- Tone and position of surrounding muscle (increase in tone = decrease in movement freedom)
How do we get proprioception ?
Thanks to nerve supply in the area of joint
What is osteoarthritis ?
Degenerative disease affecting weight bearing joints, especially articular cartilage.
Joint dissolves in some areas and builds up in others, causing abnormal structure and grinding.
What is Rheumatoid Arthritis ?
Autoimmune disease resulting in inflammation of synovial membrane.
This leads to destruction of articular cartilage.
What are the types of muscle which exist and what are their basic characteristics ?
Skeletal (voluntary and striated)
Cardiac (involuntary and striated)
Visceral (involuntary and smooth)
How much do muscle cells shorten in contraction ?
By 1/3 their length.
What is the deep fascia and what is its role ?
Fibrous tissue enclosing muscle. It divides them into compartments sharing a function (E.g anterior muscle of the forearm are flexors vs posterior muscle of the arm are extensors)
What are the different kinds of muscle within a functional group ?
Prime mover (main participants)
Synergists
Antagonists
What are bundles of muscle called ?
Fascicles.
What are the types of connective tissue coverings muscle and what is their function ?
Their function is to support nerves and capillaries of muscle. They are: -Endomysium (seperates muscle fibers) -Perimysium (lies between fasciculi) -Epimysium (dense sheath on surface)
What happens in skeletal muscle differentiation ?
Myosatellite cells give rise to myoblasts which mature into myocytes.
Myostatin inhibits this process
If gene for myostatin defective, excessive skeletal muscle growth
How does muscle attach periosteum ?
Some muscles attach directly via fleshy muscle fibers
Others attach indirectly via tendons
What are the min different types of synovial joints ?
Ball and socket, hinge, gliding joint, saddle, pivot
Ball and socket
1) Which movements are possible ?
2) What are some examples ?
1) Extension and flexion
Abduction and adduction
Circumduction and rotation
2) Shoulder and hip
Hinge
1) Which movements are possible ?
2) What are some examples ?
1) Extension and flexion (mainly)
2) Ankle, elbow, knee, humeroulnar joint, interphalangeal joint
Gliding
1) Which movements are possible ?
2) What are some examples ?
1) Gliding (some very slight rotations)
2) Acromioclavicular joint, sternocostal joint, costovertebral joint
Saddle
1) Which movements are possible ?
2) What are some examples ?
1) Flexion and Extension
Adduction and Abduction
Circumduction
2) Carpometacarpal joint of thumb
Pivot
1) Which movements are possible ?
2) What are some examples ?
1) Rotation
2) Proximal radioulnar joint, antlanto-axial joint
