Chp.10 Introduction to musculoskeletal system

Question 1

Cells:
____________: mature bone cells
____________: immature bone cells that release organic
components of matrix and able to form osteocytes
____________: dissolve bone matrix and release minerals

Answer 1

Osteocytes; Osteoblasts; Osteoblasts

Question 2

Matrix
2/3: ___________________
1/3: ___________________

Answer 2

Hydroxyapatite crystals; Collagen fibres

Question 3

➢Osteon—Functional unit of a bone
➢Lacunae—small chambers occupied by _______
➢Canaliculi—small channels that interconnect the
lacunae; providing route for diffusion of nutrients and
waste products

Answer 3

osteocytes

Question 4

Periosteum (骨膜）
➢ a fibrous tissue surrounding the outer surface of the bone (except the articular sites)
➢ Inner layer is osteogenic (osteocytes help bone regeneration) , capable of differentiating into osteoblasts
➢ Richly furnished with capillaries and nerves (i.e. nutrients are provided)

Question 5

➢ Compact bone
❖ dense, solid mass (closely packed & _______ aligned osteons), forms the outer surface layer of all bones

➢ Spongy bone
❖ Lighter, less dense than compact bone
❖ Bones arranged in trabeculae (__________ aligned osteons)
❖ Irregular cavities containing red bone marrow
=> usually underneath the compact bone

Answer 5

regularly; irregularly

Question 6

❖ Red bone marrow
-long bones but only situated in the ends; central is occupied by the yellow bone marrow
➢ contains ____________________________ which can differentiate into RBC, WBC, and platelets
➢ red bone marrow gradually transforms into yellow bone
marrow
❖ Yellow bone marrow— contains adipose tissues and
___________________ that can develop into
cartilage, bone, fat, or muscle cells

Answer 6

hematopoietic stem cells; adipose tissues; mesenchymal stem cells

Question 7

//Bones for muscle attachment//

Process: Projection or bump
Ramus: extension of a bone that forms an angle
Sinus (鼻竇): lined with epithelial cells that secrete mucus for immune defence
Foramen: A hole
Fissure: Deep furrow
Meatus: A channel-like structure
Trochanter: only found in the femur (large, rough projections)
Tubercle: small round process
Tuberosity: large rough process

Question 8

Facet: a surface for articulation with bones
Condyle: a round process for articulation
Trochlea: A pulley-shaped of bones for articulation

Question 9

Long bones: tubular
Short bones: cubical
Flat bones: flat
Sesamoid bones: patella (膝頭位）: develop within tendons
Irregular bones: Not tubular, cubical or flat (just like facial bones)

Question 10

Bursae are sacs filled with synovial fluid:
-provide cushioning between
the bones and the muscles and tendons crossing the joint.
=> usually form between tendons and ligaments in which friction may occur

Question 10

_______________
➢Small, flat, irregularly shaped bones between the flat bones of the skull

Answer 10

Sutural bones

Question 10

_____________
➢Spongy (cancellous) bones are being absorbed and air sinus are present
➢certain skull bones

Answer 10

Pneumatic bones

Question 11

A)Functional (mobility) vs B)Structural (tissues that connected the bones):

A1) Immovable (Synarthrosis) B1) Fibrous (joint separated by fibrous tissues)

A2) Slightly movable (Amphiarthrosis)
B2) Cartilages
(joint separated by cartilages)

A3) Freely movable(Diarthrosis)
B3) Synovial (joints separated by fluid-filled cavity; within a fibrous capsule)

Question 12

Articular capsule
➢Cuff around joint close to the articular surface

➢Outer fibrous capsule (continuous with periosteum)

➢Inner synovial membrane (secrete synovial fluid for lubrication, shock absorption & joint nourishment)

➢Articular cartilages act like coatings on the bone surface to provide a wear-resistant, low friction lubricated surface

➢Fibrocartilage (meniscus) located between the articular bones serve to smooth the movement and reduce friction

Periosteum covers most sites of the bone, except for the articular site, because it is covered by the articular cartilages to reduce friction during movements.

Question 13

Nerve supply:
➢Nerves supplying a joint=
1) supply the muscles moving the joint
2) supply the skin covering the insertion of these muscles

➢Provide proprioceptive feedback (本體感覺=肌肉記憶)(reflex) for controlling posture and movements

Blood supply:
➢Receive vascular supply through a rich anastomosis (吻合) of arteries extending from either side of the joint
➢Articular cartilage is nourished by synovial fluid

Question 14

Uniaxial joint:
Hinge joints
➢allow angular movement
in one direction and in
one plane e.g. flexion and extension
➢e.g. elbow joint, ankle
joint, _________________
joint (finger)

Answer 14

angular; interphalangeal

Question 15

Pivot joint
➢allow ________ movement
in one axis
➢e.g. C1/2 joint, proximal
radioulnar joint

Answer 15

rotary

Question 16

Biaxial joints:
Plane joints (gliding joint)
➢permit _______ movement only
➢usually small joints
➢e.g. inter-carpal joints,
facet joint of spine, superior tibiofibular joint and acromioclavicular joint

Answer 16

gliding

Question 17

Condylar (ellipsoid) joint
➢__________ movement in two
directions
➢oval shaped head, elliptical
cavity
➢flexion/extension,
abduction/adduction,
circumduction
➢e.g. wrist joint,
metacarpophalangeal joint

Answer 17

angular

Question 18

Saddle joint
➢articular surface of each
articular bone is _________
in one direction and
__________ in another
➢e.g. carpo-metacarpal
joint of thumb

Answer 18

concave; convex

Question 19

Poly-axial joints:
Ball and Socket joints
➢allows angular movement in
____ directions and a pivot
movement
➢e.g. hip joint, shoulder
humeral joint

Answer 19

all

Question 20

Intracapsular/joint/intrinsic ligament
* Localized thickenings of fibrous connective tissue
* Help reinforce the joint capsule
* e.g. Anterior & posterior cruciate ligament

Accessory/extrinsic ligament
* Separate from joint capsule
* Help to reinforce the joint by attaching the
bones together
* e.g. Medial & lateral collateral ligament

Ligaments join bones together & stabilize the joints

Question 21

Cartilage
➢Belongs to a strong but
flexible connective tissue
➢Chondrocytes secretes
extracellular matrices

Functions to:
➢Absorbing shock
➢Reducing friction
➢Supporting structures

Question 22

Skeletal muscles
➢Motion results from the alternating contraction
and relaxation of skeletal muscles (the bones cannot move by themselves)

➢In musculoskeletal system, we study anatomy (gross and microscopic) and function of skeletal muscles (not smooth muscles or cardiac muscles)

➢Skeletal muscles are innervated by somatic motor
nerves, while smooth muscle and cardiac muscles, which are involuntary, are innervated and regulated by autonomic division.

Question 23

Functions of muscle
➢Produce skeletal movement
➢Maintain posture and body position
➢Support soft tissue
➢Control of body openings and passages
➢Maintain body temperature
➢Store nutrients

Question 24

The arrangements of filaments within a sacromere:

Question 25

Organization of muscle:

Question 26

Organisation of muscle fibres:

➢ Parallel—fascicles parallel to longitudinal axis of muscle;
terminate at either end in flat tendon.

➢ Fusiform—fascicles nearly parallel to longitudinal axis of
muscle; muscle tapers towards tendons.

➢ Convergent—fascicles spread over broad area converge at thick central tendon; gives muscle a triangular appearance.

➢ Circular—fascicles in concentric arrangements to form sphincter or opening.

➢ Pennate (short fascicles in relation to total muscle
length)

➢ Unipennate—fascicles arranged on only one side of
tendon.

➢ Bipennate—fascicles arranged on both sides of
centrally positioned tendons.

➢ Multipennate—fascicles attached obliquely from
many directions to several tendons.

Question 27

Structural unit of
skeletal muscle:
Muscle fibres
(= muscle cells)

Functional unit of
skeletal muscle:
Motor unit = Neuron + Muscle
fibres

Question 28

A motor neuron in leg muscle controls more muscle fibres than eye muscle.

Muscle Tones:
A low level of contraction contributed by small groups of _________________ (being active and inactive in a constantly shifting pattern i.e. or continuously partial contraction) even at rest

• Not strong enough to produce a movement but able to keep skeletal muscle _____
• Established by motor neurons in the brain and spinal cord→ if damage → muscle becomes __________ and ______________（萎縮的）

Answer 28

motor units; firm; flaccid; atrophic

Question 29

Muscle contraction:

Isometric contraction:
➢Muscle fibers do not change in length during contraction
=> during no movement

Isotonic (concentric) contraction:
➢Muscle fibers shorten during
contraction
=> during lifting up

Isotonic (eccentric) contraction:
➢Muscle fibers lengthen during contraction
=> during placing down

Question 30

Fiber types of skeletal muscle:

Slow-Twitch Type I:
➢ For marathon; endurance-related training
➢ Contraction speed: Slow
(∵ low ATPase level=>longer energy suppky to muscles)
➢ High (generate ATP by aerobic respiration)
➢ Myoglobin: High (i.e. red in appearance)
➢ Muscle fibre size: smaller

Question 31

Fast-Twitch Type IIA:
➢ Powerful-lifting sprinting
➢ All features are medium
➢ Muscle fibre size: large

Question 32

Fast-Twitch Type IIX
or IIB:
➢ Very powerful lifting
➢ Muscle fibre size: large
➢ Force production: very high
➢ Contraction speed: very quick (high ATPase level)
➢ Low (rely on anaerobic respiration)

Question 33

➢At both ends of muscle → connect to bones → transmit forces generated from muscle to the bone to elicit movement

➢Tough, dense fibrous connective tissue with
high tensile strength (synthesize ECM containing
collagen and proteoglycans)

➢Tendons have different shapes and sizes; muscle generating large power and force tend to have shorter and wider tendons; whereas those generating fine delicate movements are long and thin

Question 34

Osteotendinous junction: origin and insertion
➢ Myotendinous junction—point at which tendon attaches to muscles
➢ Osteotendinous junction—point at which tendon attaches to bone
* The origin (usually proximal) is the attachment site that does not move during contraction
* The insertion (usually distal) is the attachment site that move when the muscle contracts.