Muskoloskeletal system

Question 1

What is a joint ?

Answer 1

Where 2 or more bones meet

Question 2

What are the types of joints when classified by movement type ? Give an example for each.

Answer 2

1. Synarthroses -No movement takes place (skull)
2. Amphiarthroses -little movement (spine)
3. Diathroses -Very moveable joints (hip and shoulder joint)

Question 3

What are the types of joints when classified by soft tissue structure ? What is their characteristic feature ? Give an example.

Answer 3

1. Fibrous -fibre connections between 2 bones. Does NOT allow very much movement. Sutures of the skull.
2. Cartilaginous - if primary then hyaline cartilage (=Synchondrosis). If secondary then fibrocartilage (=Symphysis). E.g. epiphysael plate and pubic symphysis.
3. Synovial- Surrounded by thick flexible membrane forming sac into which is secreted fluid lubricating joint. E.g. bone socket, hinge joint.

Question 4

What are the different kinds of fibrous joints ?

Answer 4

• Sutures (joints between skull vault bones)
• Syndesmosis (fibrous membrane between bones. E.g. radioulnar interosseous membrane)
• Gomphosis (peg and socket)

Question 5

What is the structure of synchondroses (type of cartilaginous joint) ? How moveable are they ? Give examples.

Answer 5

Bone-Hyaline Cartilage-Bone
Not moveable
Epiphyseal plate, first stenocostal joint

Question 6

What is the structure of symphyses (type of cartilaginous joint) ? How moveable are they ? Give examples.

Answer 6

Bone-Hyaline cartilage-Fibrocartilage disc-Hyaline cartilage- Bone
Allows limited movement
Pubic symphysis, intervertebral discs, joints of sternum

Question 7

What is the particularity of synovial joints?

Answer 7

Allow friction-less movement.

Question 8

What are the characteristic features of synovial joints ?

Answer 8

Periosteum, fibrous capsule, synovial membrane, synovial fluid in articular cavity, articular hyaline cartilage

Question 9

What does the fibrous capsule consist of ?

Answer 9

Collagen fibres. Bands of collagen might develop along lines of stress to form ligaments (restricts movement to protect joint from damage).

Question 10

Which types of ligaments are there ?

Answer 10

Intrinsic ligament= Part of the capsule

Extrinsic ligament= outside of the capsule

Question 11

What is the main function of the fibrous capsule ?

Answer 11

Preventing dislocation

Question 12

What is a defining feature of articular cartilage (besides the fact that it is hyaline cartilage) ?

Answer 12

It has very poor blood supply and few chondrocytes so very long time to heal if damage.

Question 13

What is the synovial membrane made of and what is its role ?

Answer 13

Collagenous vascular connective tissue.

Secrete synovial fluid to lubricate and nourish joints while removing waste

Question 14

What is synovial fluid made of ?

Answer 14

Hyaluronic acid, lubricin, some phagocytic cells.

Question 15

How does exercice affect viscosity of the synovial fluid ?

Answer 15

Alignment of glycoproteins changes with exercise. Hence, exercise decreases viscosity (thixotropic), and hence improves lubrication.

Question 16

What is the function of intra-articular discs ? Which kinds of joints are they found in? What are they made of ?

Answer 16

Absorb shock and deepen the socket.
In joints where rotatory movement occurs.
Made of fibrocartilage

Question 17

What is a bursae ? Where are they found ?

Answer 17

Closed sacs lined with synovial membrane and lubricated with fluid
Found where friction occurs

Question 18

What are synovial sheaths ?

Answer 18

Specialised bursae surrounding tendons where subject to Pressure.

Question 19

Which of ball and socket joints, or hinge joints, is more likely to be dislocated, and why?

Answer 19

Ball and socket, because they allow movement in 3 planes versus 1 plane for hinge joint.

Question 20

What are the factors influencing the stability of joints ?

Answer 20

• 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)

Question 21

How do we get proprioception ?

Answer 21

Thanks to nerve supply in the area of joint

Question 22

What is osteoarthritis ?

Answer 22

Degenerative disease affecting weight bearing joints, especially articular cartilage.
Joint dissolves in some areas and builds up in others, causing abnormal structure and grinding.

Question 23

What is Rheumatoid Arthritis ?

Answer 23

Autoimmune disease resulting in inflammation of synovial membrane.
This leads to destruction of articular cartilage.

Question 24

What are the types of muscle which exist and what are their basic characteristics ?

Answer 24

Skeletal (voluntary and striated)
Cardiac (involuntary and striated)
Visceral (involuntary and smooth)

Question 25

How much do muscle cells shorten in contraction ?

Answer 25

By 1/3 their length.

Question 26

What is the deep fascia and what is its role ?

Answer 26

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)

Question 27

What are the different kinds of muscle within a functional group ?

Answer 27

Prime mover (main participants) Synergists Antagonists

Question 28

What are bundles of muscle called ?

Answer 28

Fascicles.

Question 29

What are the types of connective tissue coverings muscle and what is their function ?

Answer 29

``` 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) ```

Question 30

What happens in skeletal muscle differentiation ?

Answer 30

Myosatellite cells give rise to myoblasts which mature into myocytes. Myostatin inhibits this process If gene for myostatin defective, excessive skeletal muscle growth

Question 31

How does muscle attach periosteum ?

Answer 31

Some muscles attach directly via fleshy muscle fibers | Others attach indirectly via tendons

Question 32

What are the min different types of synovial joints ?

Answer 32

Ball and socket, hinge, gliding joint, saddle, pivot

Question 33

Ball and socket 1) Which movements are possible ? 2) What are some examples ?

Answer 33

1) Extension and flexion Abduction and adduction Circumduction and rotation 2) Shoulder and hip

Question 34

Hinge 1) Which movements are possible ? 2) What are some examples ?

Answer 34

1) Extension and flexion (mainly) | 2) Ankle, elbow, knee, humeroulnar joint, interphalangeal joint

Question 35

Gliding 1) Which movements are possible ? 2) What are some examples ?

Answer 35

1) Gliding (some very slight rotations) | 2) Acromioclavicular joint, sternocostal joint, costovertebral joint

Question 36

Saddle 1) Which movements are possible ? 2) What are some examples ?

Answer 36

1) Flexion and Extension Adduction and Abduction Circumduction 2) Carpometacarpal joint of thumb

Question 37

Pivot 1) Which movements are possible ? 2) What are some examples ?

Answer 37

1) Rotation | 2) Proximal radioulnar joint, antlanto-axial joint