Musculoskeletal system

Question 1

what is bone composed of

Answer 1

bone is connective tissue wit a hard matrix (osseous tissue) made of 55% crystallised mineral salts, 30% collagen, and 15% water

Question 2

what crystals make up the mineral salts in bone

Answer 2

Hydroxyapatite crystals (calcium phosphate + calcium hydroxide)

Question 3

what provides bone hardness

Answer 3

crystallised mineral salts resist compression

Question 4

what provides bone flexibility and tensile strength

Answer 4

collagen fibres resist stretching and tearing.

Question 5

Name the 5 bone shapes and functions

Answer 5

Flat: protect organs, muscle attachment
Long: act as levers
Sesamoid: protect tendons
Short: provide stability and limited motion
Irregular: ligament attachment

Question 6

what are the organic components

Answer 6

Collagen fibres (1/3 matrix weight); give flexibility & tensile strength

Question 7

what are the inorganic components

Answer 7

minerals, give hardness & compression resistance

Question 8

Name the parts of the long bone

Answer 8

Diaphysis: shaft, compact bone
Metaphysis: joins diaphysis and epiphysis
Epiphysis: ends, spongy bone
Red marrow: blood cell production
Yellow marrow: fat storage
Articular cartilage: protects ends
Periosteum: outer layer
Endosteum: lines medullary cavity

Question 9

what are the 4 bone cell types

Answer 9

Osteogenic cells: stem cells
Osteoblasts: build bone
Osteocytes: maintain matrix
Osteoclasts: resorb bone

Question 10

why do we have both types of bone

Answer 10

balance of strength, support, protection and lightness

Question 11

Key features of compact bone

Answer 11

Osteons, diaphysis, strong under compression

Question 12

Key features of spongy bone

Answer 12

Trabeculae, epiphysis, resists multi-directional forces

Question 13

Name the 3 structural joint types

Answer 13

Fibrous: no cavity; dense CT (sutures, gomphosis, syndesmosis)
Cartilaginous: no cavity; cartilage (synchondrosis, symphysis)
Synovial: joint cavity, ligaments & capsule

Question 14

What are the main components of a synovial joint

Answer 14

Capsule (fibrous + synovial membrane), articular cartilage, synovial fluid, ligaments, joint cavity, meniscus, bursae

Question 15

what are the 3 functional joint types

Answer 15

Synarthrosis: Immovable
Amphiarthrosis: Slightly moveable
Diarthrosis: Freely moveable

Question 16

what are the main functions of muscles

Answer 16

movement, posture, support, substance transport, heat generation

Question 17

Name 3 types of muscle types

Answer 17

Smooth: Involuntary, non-striated, regenerates
Cardiac: Involuntary, striated, no regeneration
Skeletal: Voluntary, striated, limited repair

Question 18

Smooth muscle characteristics

Answer 18

Uni-nucleated, spindle-shaped, non striated

Question 19

Cardiac muscle characteristics

Answer 19

uni-nucleated, striated, branched, intercalated discs

Question 20

Skeletal muscle characteristics

Answer 20

Multi-nucleated, striated, cylindrical

Question 21

what triggers muscle contraction

Answer 21

Calcium presence & ATP

Question 22

What is the sliding filament theory

Answer 22

Actin & myosin slide past, shortening sarcomeres

Question 23

What are the 9 steps in muscle contraction

Answer 23

1. ACh release & receptor binding
2. Action potential in T-tubule
3. Ca release from SR
4. Cross-bridge formation
5. Contraction begins
6. ACh breakdown
7. Ca reabsorption
8. Contraction ends
9. Relaxation

Question 24

what is muscle tone

Answer 24

continuous partial contraction at rest, maintains posture & joint stability

Question 25

define hypertrophy

Answer 25

increased cell size - increased tissue size (e.g., skeletal muscle)

Question 26

Define hyperplasia

Answer 26

increased cell number - increased tissue size (e.g., smooth muscle)

Question 27

Define atrophy

Answer 27

decreased cell size, decreased tissue size (e.g., skeletal muscle with disuse)