Musculoskeletal system

Question 1

ligament

Answer 1

Connect the articulating bones at a joint

Question 2

CARTILAGE

Answer 2

Supports body structures
Connects bones
Maintains the shape of body structures
Resists compression
Has tensile strength

Question 3

FUNCTIONS OF BONES

Answer 3

support
protection
storage of minerals & triglyceride
blood cell production
movement

Question 4

axial skeleton

Answer 4

• skull
• vertebral column
• rib cage

Question 5

APPENDICULAR SKELETON

Answer 5

upper limb
lower limb
shoulder girdle
pelvic girdle

Question 6

bone shapes

Answer 6

long-humerus & clavicles
short-tarsals, carpals, patella
flat- sternum, ribs, scapula,
skull bones
irregular-vertebra, hip bones

Question 7

passageways for blood vessel, nerves and sounds

Answer 7

foramen & canal or meatus

Question 8

OSSEOUS TISSUE

Answer 8

Is a connective tissue - contains specialised cells and an
extracellular matrix

Question 9

matrix has ground substance, collagen fibres, and calcium
phosphate crystals

Answer 9

collagen fibres:
provide flexibility & tensile strength calcium phosphate crystals:
make our bones hard & provide compressive strength

Question 10

Specialised Cells

Answer 10

Osteoprogenitor cells-differentiate into osteoblasts
Osteoblasts-produce & secrete
collagen fibres & ground substance
Osteoclasts- break down the
matrix and release stored minerals
Osteocytes- mature bone cells that maintain the matrix

Question 11

compact bone

Answer 11

Osseous tissue is arranged
into osteons=heavy
shaft of long bones
Resists forces applied to the ends of a bone.

Question 12

spongy bone

Answer 12

Osseous tissue is arranged into trabeculae
can resist force in call direction and very light
found the proximal & distal epiphysis
Contains red bone marrow and is a site of haematopoiesis.

Question 13

interstitial growth

Answer 13

New cartilage forms at the top of the epiphyseal plate. Bone replaces old cartilage at the bottom of the plate
Diaphysis lengthens

Question 14

appositional growth

Answer 14

Osteoblasts occurs on bone
surface= compact
bone=bone widens
In long bones, osteoclasts occurs in inner surface= enlarges medullary
cavity= lighter bones

Question 15

REGULATION OF BONE GROWTH

Answer 15

bone growth requires GH, TH,
testosterone & estrogen= growth spurt
End growth [the rate of bone formation exceeds the rate of cartilage formation
cartilage eventually replaced entirely by bone epiphyseal plate becomes epiphyseal line

Question 16

BONE REMODELLING

Answer 16

rate of bone deposition
equals the rate of resorption However when u age resorption is higher

Question 17

fractures

Answer 17

closed fracture-broken bone does not break the skin
comminuted fracture- bone fragments into three or more pieces
compression fracture- bone is crushed
greenstick fracture-incomplete break
spiral fracture- excessive twisting
forces are applied to a bone
avulsion fracture-tendon or ligament pulls off a fragment of bone
pathological fracture- disease that weakens bone structure
Colles fracture- distal end of the radius
scaphoid fracture- carpal bone
Pott’s fracture- a break in the medial malleolus of the
tibia and/or lateral malleolus of the
fibula

Question 18

fracture repair

Answer 18

Haematoma forms- burst of blood
Fibrocartilaginous callus forms- fibroblast and chondroblasts
Bony callus of spongy bone form-spongy bone forms & bone ends firmly united
Bone remodelling- compact bone replaces spongy bone, osteoclasts.

Question 19

Osteomalacia (adults) and Rickets (children)

Answer 19

bones are poorly mineralised
- lack calcium phosphate crystals

Question 20

Osteogenesis imperfecta

Answer 20

disorder that affects
the quantity and/or quality of
collagen fibres

Question 21

Osteoporosis

Answer 21

bone resorption outpaces bone
deposition= bones are porous,
light, fragile & easily fractured

Question 22

CLASSIFICATIONS OF JOINTS
(functionally)

Answer 22

synarthrosis - immovable joint
amphiarthrosis - slightly movable joint
diarthrosis - freely movable joint

Question 23

structurally

Answer 23

Fibrous joints have connective tissue that unite articulating bones, Joint cavity absent
CARTILAGINOUS JOINTS cartilage unite articulating bones, Joint cavity absent
synovial joint articular cartilage cover Articulating bone ends, joint cavity present

Question 24

synovial joint features

Answer 24

Articular capsule:
- tough outer fibrous layer - stabilises articulating bones
- inner synovial membrane - produces synovial fluid
Joint cavity: separates articulating bones
& contains synovial fluid
Synovial fluid: shock absorption, reduces friction, supplies oxygen and nutrients to articular cartilage cells & remove waste
Articular cartilage: covers the ends of each articulating bone, shock absorption & reduces friction
Reinforcing ligaments stabilise joint
Sensory neurons detect pain and
monitor proprioception & blood vessels mainly supply synovial membrane
Menisci: shock absorption, reduces friction & stabilise joint
Muscle tendons: stabilise joint
Bursae and Tendon sheaths: bags of synovial fluid reduce friction
Fat pads: cushion & protect joint structures

Question 25

TYPES OF SYNOVIAL JOINTS

Answer 25

allows rotation proximal radioulnar &
atlas-axis joints]
Plane Joint allows gliding movements
[intercarpal & intertarsal joints]
Condylar joint allows flexion, extension, adduction, abduction & circumduction [metacarpophalangeal (knuckle) & wrist joints]
Saddle joint allows flexion, extension, adduction, abduction & circumduction
[carpometacarpal joint of the thumb]
Hinge Joint allows flexion & extension
[elbow, knee, ankle &
interphalangeal (finger) joints]
Ball and Socket joint allows flexion, extension, adduction,
abduction, circumduction &
rotation [shoulder and hip joints]

Question 26

SKELETAL MUSCLE STRUCTURE

Answer 26

Are surrounded by three connective tissue sheaths Endomysium, perimysium & Epimysium
Myofibrils: Extend the entire length of a muscle fibre. Composed of contractile units called sarcomeres
Sarcomeres: Composed of contractile proteins called thick and thin myofilaments
Thick myofilaments are composed of the protein myosin
¨ Thin myofilaments are composed of the protein actin

Question 27

SKELETAL MUSCLE CONTRACTION

Answer 27

-Somatic motor output, in the form of an action potential, travels along the axon of a lower motor neuron to the axon terminals
-Voltage-gated Ca2+ channels open and
Ca2+ enters the axon terminal.
-Ca2+ entry causes synaptic vesicles to
release ACh into the synaptic cleft.
-ACh, diffuses across the synaptic
cleft and binds to chemically-gated
ion channels (nicotinic receptors)
on the sarcolemma.
-Ion channels open influx of Na+ ions
sarcolemma depolarises graded potential produced.
-Graded potential opens
voltage-gated Na+ channels in
the sarcolemma action potential produced.
-The action potential travels along the
length of the sarcolemma.
-The action potential travels down the T tubules deep into the muscle fibre.
-Action potential stimulates sarcoplasmic
reticulum Ca2+ release channels to open.
-Ca2+ flows into the cytoplasm of the
Ca muscle fibre.
-The binding of Ca2+ to troponin pulls tropomyosin away from the actin active
sites.
-Myosin heads bind to the active sites, forming cross bridges and contraction
begins.

Question 28

THE PROCESS OF CONTRACTION

Answer 28

Myosin heads bind to actin active
sites on the thin myofilaments.
Myosin heads pull the thin myofilament
towards the center of the sarcomere (M-line)
and then detach.
ATP breaks the attachment
of myosin and actin
Cycle repeats:
Myosin heads bind to next actin
active sites on the thin myofilaments.
Myosin heads pull thin myofilament
closer towards the M-line and then
detach.