The Skeletal System (week 3)

Question 1

state the 5 functions of the skeletal system

Answer 1

1. movement (muscle attachment, provides leavers)
2. support (shape)
3. protection (vital organs)
4. mineral storage + other material deposit
5. hematopoiesis (body cell production)

Question 2

state what it is meant by the key term - lever

Answer 2

a lever is a relatively ridged object that may be made to rotate about an axis by the application of force

Question 3

state the difference between mechanical advantages and mechanical disadvantages

Answer 3

1. MA - effort arm longer than load arm so can move a large weight with little effort
2. MD - load arm longer than effort arm so can move a large ROM very quickly

Question 4

talk about bone composition and structure

Answer 4

1. organic component (35%), matrix is mostly type 1 collagen (elasticity), cells: osteoblasts, osteocytes and osteoclasts
2. inorganic component (65%), mineral content: hydroxyapatite (rigidity)

Question 5

state what it is meant by the key term - hydroxyapatite

Answer 5

hydroxyapatite is a complex salt of calcium and phosphate

Question 6

state 2 facts about the general structure of long bone

Answer 6

1. long bones consist of a diaphysis (shaft) and two epiphysis
2. the metaphysis is where the epiphyseal line, or growth plate, resides

Question 7

state 3 facts about cortical (compact) bone

Answer 7

1. 80% of bone mass
2. situated on the external surface of bones (walls of diaphysis)
3. principally have a mechanical function

Question 8

state 5 facts about cancellous (spongy/trabecular) bone

Answer 8

1. 20% of bone mass
2. lattice of fine plates
3. situated in the epiphysis of long bones, vertebral bodies, and flat bones
4. spaces filled with bone marrow
5. reduces skeletal mass without compromising skeletal strength

Question 9

state the names of the two types of bone growth

Answer 9

1. longitudinal growth

2. circumferential/radial growth

Question 10

state 2 basic facts about longitudinal growth (2 things)

Answer 10

1. occurs at the epiphyseal plates

2. stops at approx. 18-20 years old (epiphyseal line)

Question 11

explain circumferential/radial growth (2 things)

Answer 11

1. diameter on bone increases throughout an individual’s lifespan
2. it is the most rapid form of growth before adulthood

Question 12

what is the role of the epiphyses/epiphyseal plates in bone growth and development

Answer 12

the growth centre of a bone that produces new bone tissue as part of the normal growth process until it closes during adolescence, or early adulthood

Question 13

state what it is meant by the key term - periosteum

Answer 13

the periosteum is a double covered membrane covering bone; muscle tendons attach to the outer layer, and the internal layer is the site of osteoblast activity

Question 14

what is the role of the periosteum in bone growth and development

Answer 14

the internal layer of the periosteum builds concentric layers of new bone on top of existing bone. at the same time, bone is reabsorbed or eliminated around the circumference of the medullary cavity, so that the diameter of the cavity is continuously enlarged

Question 15

state what it is meant by the key term - wolf’s law

Answer 15

bone elements place or displace themselves in the direction of functional forces, and increase or decrease their mass to reflect the amount of functional forces (the bone will adapt to the loads placed on it)

Question 16

state what it is meant by the key term - bone remodelling

Answer 16

bone remodelling is a balanced integration of osteocyte signalling, osteoblast bone formation and osteoclast bone resorption in response to load

Question 17

state 3 facts about osteocytes

Answer 17

1. cells imbedded in bone tissue
2. sensitive to changes in flow of interstitial fluid through pores that result from bone strain
3. trigger osteoblast and osteoclast activity In response to strain levels

Question 18

state what it is meant by the key term - bone remodelling, hypertrophy

Answer 18

an increase in bone mass due to the predominance of osteoblast activity

Question 19

state 2 facts about bone hypertrophy

Answer 19

1. a response to regular physical activity

2. the greater the habitual load, the more mineralization of the bone

Question 20

state what it is meant by the key term - bone remodelling, atrophy

Answer 20

a decrease in bone mass resulting from the predominance of osteoclast activity

Question 21

state 2 facts about bone atrophy

Answer 21

1. causes a decrease in bone calcium, bone strength and bone mass
2. seen in bed-ridden patients, sedentary elderly, and astronauts

Question 22

state 2 facts about the axial skeleton

Answer 22

1. includes the skull, vertebrae, sternum and ribs

2. 74 bones

Question 23

state 2 facts about the appendicular skeleton

Answer 23

1. bones composing the body appendages

2. 126 bones

Question 24

state what it is meant by the key term - flat bones

Answer 24

thin and curved bone, serves as a point of attachment or muscle and protects internal organs

Question 25

state what it is meant by the key term - short bones

Answer 25

cube shaped bone that is approx. equal in length, width, and thickness and provides limited motion

Question 26

state what it is meant by the key term - long bones

Answer 26

cylindrical shaped bone that is longer than it is wide and functions as levers

Question 27

state what it is meant by the key term - irregular bones

Answer 27

bone of complex shape; protects internal organs from compressive forces

Question 28

state the two functions of joints

Answer 28

1. to facilitate movement between bones

2. to transmit force from one bone to another

Question 29

state what it is meant by the key term - articular surface

Answer 29

the contact point between two bones

Question 30

state what it is meant by the key term - synarthroses

Answer 30

synarthroses - fibrous joints that can absorb shock (attenuate force) while permitting little/no movement of the articulating bones

Question 31

state the names of the two types of synarthrodial joints

Answer 31

1. satures

2. syndesmoses

Question 32

state what it is meant by the key term - satures (synarthroses)

Answer 32

satures - irregular grooved bone sheets are closely connected by fibres that are continuous with the periosteum (eg - skull)

Question 33

state what it is meant by the key term - syndesmoses (synarthroses)

Answer 33

syndesmoses - joints where dense fibrous tissue bind the bones together permitting extremely limited motion (eg - mid radioulnar joints)

Question 34

state what it is meant by the key term - ampiarthroses

Answer 34

cartilaginous joints that attenuate force and permit more motion of adjacent bones more than synarthroses

Question 35

state the names of the two types of ampiarthroses joints

Answer 35

1. synchondroses

2. symphyses

Question 36

state what it is meant by the key term - synchondroses (ampiarthroses)

Answer 36

joints where articulating bones are held together by a thin layer of hyaline cartilage

Question 37

state what it is meant by the key term - symphyses (ampiarthroses)

Answer 37

joints where a thin layer of hyaline cartilage separates a disc of fibrocartilage from the bone (eg - pubic symphyses)

Question 38

state what it is meant by the key term - diarthroses

Answer 38

joints at which articular bone surfaces are covered with articular cartilage, an articular capsule, which separates synovial fluid and are freely mobile (6 types)

Question 39

state what it is meant by the key term - gliding/plane joint

Answer 39

joints where articulating bone surfaces are nearly flat, and the only movement permitted is non-axial gliding (eg - joints between carpals + tarsals)

Question 40

state what it is meant by the key term - hinge joint

Answer 40

1. one convex and one concave articulating surface; strong collateral ligaments restrict to single axis hinge like movement (uni-axial)
2. eg - interphalangeal joints

Question 41

state what it is meant by the key term - pivot joint

Answer 41

1. joints where rotation is permitted around one axis (uni-axial)
2. eg - proximal + distal radioulnar joints

Question 42

state what it is meant by the key term - condyloid joint

Answer 42

1. an ovoid articular surface allowing movement around two axis (bi-axial)
2. eg - radioulnar joints, metacarpophalangeal joints

Question 43

state what it is meant by the key term - saddle joints

Answer 43

1. joint where articulating bone surfaces are both shaped like the seat of a riding saddle, with movement the same as a condyloid joint but with a greater range of movement
2. eg - carpometacarpal joint of the thumb

Question 44

state what it is meant by the key term - ball and socket joint

Answer 44

1. joints where articulating surfaces are reciprocally convex and concave, permitting movement in all 3 planes of motion (tri-axial)

Question 45

state 3 structural landmarks of a diarthrodial joint

Answer 45

1. articular cartilage
2. articular capsule
3. synovial membrane

Question 46

state what it is meant by the key term - articular cartilage

Answer 46

the articular cartilage is a protective layer of connective tissue covering the ends of articulating bones

Question 47

state the purpose(s) of articular cartilage

Answer 47

1. reduces stress by distributing force

2. reduces friction and wear

Question 48

state what it is meant by the key term - articular capsule

Answer 48

double layered membrane that surrounds every synovial joint

Question 49

state what it is meant by the key term - synovial membrane

Answer 49

lines the deep surface of the joint capsule; secretes synovial fluid

Question 50

state what it is meant by the key term - joint stability

Answer 50

joint stability refers to the ability of a joint to resist abnormal displacement of the articulating bones

Question 51

joint stability is provided by what 3 things

Answer 51

1. the shape of articulating bone surfaces
2. arrangement of muscles and ligaments
3. other connective tissue