musculoskeletal system

Question 1

Characteristics of joints

Answer 1

• Excellent nerve supply, can detect pain, touch, temperature, and proprioception (awareness of where joint is)

Question 2

where do joints get their blood supply

Answer 2

• Arteries supplying joint arise from large named arteries near joints – ‘articular branches’. periarticular anastomoses are common

Question 3

what can be damaged in dislocation

Answer 3

arteries supplying blood to joints

Question 4

classification of joints

Answer 4

synovial, cartilaginous, fibrous. Each compromise between mobility and stability

Question 5

fibrous joints

Answer 5

limited mobility, most stable. 2 types

Question 6

2 types of fibrous joints

Answer 6

syndesmoses and sutures

Question 7

syndesmoses

Answer 7

unites bones with fibrous sheet fibrous membrane eg interosseous membranes

Question 8

sutures

Answer 8

between bones of skull, eg between fontanelles, highly stable

Question 9

what are fontanelles

Answer 9

wide sutures in the neonatal skull, anterior, posterior and lateral. Allow the bones to slide over each other to make the head fit in birth canal

Question 10

cartilaginous

Answer 10

fairly limited mobility, relatively stable. 2 types

Question 11

2 types of cartilaginous joints

Answer 11

primary ‘synchondroses’ and secondary ‘symphyses’

Question 12

primary. synchondroses

Answer 12

‘synchondroses’ bones joined by hyaline cartilage eg in long bone epiphyseal growth plate. Permit growth in length. Ossification and fusion

Question 13

secondary. symphyses

Answer 13

‘symphyses’ strong, slightly movable, fibrocartilage eg intervertebral discs. Made of outer annulus fibrosus (fibrous ring) and inner sort nucleus pulposus (soft center). Each disc allows small movements, but all together allow a wide range

Question 14

what can happen with a slipped disc

Answer 14

can compress spinal cord

Question 15

synovial

Answer 15

most mobile, least stable. 2 or more bones articulating with each other

Question 16

characteristics of synovial joints

Answer 16

• Surfaces covered in hyaline cartilage
• capsule wraps around the joint
• contains a joint cavity which contains synovial fluid (cushions, nourishes, lubricates)
• supported by ligaments, which associate with skeletal muscles and their tendons
• associated with bursae, extensions of joint cavity and prevent friction around joint
• often have special features eg articular disc in jaw

Question 17

5 subtypes of synovial joints

Answer 17

Pivot eg rotating head. Plane, minimal movement in one place. Hinge, reasonable movement in one place. Biaxial, range of movement in one plane and less in another. Ball and socket, good range, multi-axial movement

Question 18

mobility/stability

Answer 18

type of joint dictates. - In synovial joint. The shape and fit are important for mobility and stability
- Eg shoulder has a shallow socket = more movement but less stable
- While the hip socket has a deeper socket therefor a tighter fit = less mobility but more stable

Question 19

direction of movement

Answer 19

shape of articular surface determines this. Example, shallow socket of the glenoid fossa of the scapula – permits circumduction of the shoulder

Question 20

ligament injury/ slipped disc

Answer 20

• Ligament injury or slipped disc still allows normal anatomical relationship w each other

Question 21

subluxation

Answer 21

• Subluxation = reduced area of contact between surfaces but still kind of work

Question 22

dislocation

Answer 22

complete loss of contact between articular surfaces. Common = shoulder, elbow, interphalangeal. And sometimes during pregnancy under influence of hormone relaxin the pubic symphysis can too

Question 23

skeletal muscle

Answer 23

• They provide movement, found under deep fascia of skin they have a tough fibrous connective tissue covering

Question 24

types of skeletal muscle

Answer 24

circular, usually cover an opening. Pennate, feather like with fibers spreading out. Quadrate, have 4 sides eg the abs. flat, aponeurosis. Fusiform, spindle shape eg biceps

Question 25

attachment of skeletal muscle

Answer 25

usually at least 2 points of attachment to bone the “origin” on one side of a joint the “insertion” on the other side

Question 26

what happens during contraction of skeletal muscle

Answer 26

The skeletal muscle moves the origin and insertion closer together during contraction. The muscle fibers shorten along the long axis

Question 27

how are skeletal muscle attached to bone

Answer 27

Tendons attach muscle to bone; they don’t contract themselves but pass the power across to muscle. In aponeurosis tendons attach muscles to soft tissue instead

Question 28

direction of movement with skeletal muscles

Answer 28

Direction of movement depends on which side of the joint the muscle is attached to. the action(s) of any given muscle can be worked out: which joint is spanned, the long axis of the muscle fibres, the aspect of the joint that is spanned, the shapes of the articular surfaces of the joint.

Question 29

reflexes

Answer 29

protective and automatic. 2 main types, stretch and flexion withdrawal

Question 30

flexion withdrawal reflex

Answer 30

touch something potentially dangerous. The nerve connections are at spinal cord level so don’t involve the brain

Question 31

stretch reflexes

Answer 31

if tendon hammer is used, it applies sudden stretch to the muscle via tendon making the knee jerk

Question 32

what does a normal stretch reflex indicate

Answer 32

• A normal stretch reflex checks the muscle, its sensory nerve fibers, motor nerve fibers, spinal cord connection, neuromuscular junction and descending controls from brain are all working okay

Question 33

muscle paralysis

Answer 33

muscle without functioning motor nerve supply, cant contract = reduced tone

Question 34

spasticity

Answer 34

muscle has intact motor nerve; descending controls aren’t working = increased tone

Question 35

muscle atrophy

Answer 35

muscle fibers become smaller, develops as result of inactivity

Question 36

muscle hypertrophy

Answer 36

opposite to atrophy, muscles enlarge, each individual myocyte enlarges