Skeletal System and Joints

Question 1

What does the skeletal system consist of?

Answer 1

1. ligaments
2. tendons
3. cartilage
4. bones

Question 2

Function of the skeletal system (1)

Answer 2

Body support
: bears weigh
: cartilage proceeds firm yet flexible support within certain structures
: ligaments, strong bands of fibrous connective tissue; holds bones to bones

Question 3

Function of the skeletal system (2)

Answer 3

Organ protection

Question 4

Function of the skeletal system (3)

Answer 4

Body movement - contraction of muscles
: tendons, strong bands of connective tissue; attach bones to muscles
: joints, two or more bones come together; allow movement between bones
: ligaments; allow movement between bones but prevent excessive movement

Question 5

Function of the skeletal system (4)

Answer 5

Mineral storage
: decreased mineral in blood = bones released them (calcium & phosphorous)
: adipose tissue; lipids are released for energy if needed

Question 6

Function of the skeletal system (5)

Answer 6

Blood cell production

: cavities filled with red bone marrow = produces rbc and platelets

Question 7

what is connective tissue surrounded by?

Answer 7

matrix - produced by cells and then is trapped within & broken down by cells so new matrix can replace it

Question 8

what is collagen?

Answer 8

• fibrous protein

- provides flexibilty but resists pulling or compression

Question 9

what does the matrix ground substance contain?

Answer 9

proteoglycans - water-trapping proteins: help cartilage be smooth and resilient

Question 10

what is the bone matrix?

Answer 10

35% organic - collagen & proteoglycans

65% inorganic - calcium phosphate crystal

Question 11

what is the bone matrix responsible for?

Answer 11

for the major functional characteristics of bone

Question 12

what are the characteristics of bone?

Answer 12

1. collagen - flexibility of ligaments, tendons; lend flexible strength to matrix
2. mineral components - give metrix weight-bearing strength

Question 13

what are the 3 types of bone cells?

Answer 13

1. osteoblasts
2. osteocytes
3. osteoclasts

Question 14

what is the function of osteoblasts?

Answer 14

bone formation (ossification/osteogenesis) 
*new bone forms over existing bone & surrounds osteoblast cell bodies and extensions = new bone layer

Question 15

how is new bone formed?

Answer 15

osteoblasts release calcium and phosphate ions, forming hydroxyapatite crystals = stimulate production of more hydroxyapatite crystals and mineralization of matrix

Question 16

when can ossification/osteogenesis occur in life?

Answer 16

1. formation of fractures

2. growth

Question 17

what happens during ossification/osteogenesis?

Answer 17

appositional growth on surface of existing material (bone/cartilage)

Question 18

what is the function of osteocytes?

Answer 18

production of components to maintain bone matrix

Question 19

how are osteocytes formed?

Answer 19

once osteoblasts secretes sufficient bone matrix, it become osteocytes

Question 20

where are osteocytes housed?

Answer 20

lacunae that have cell extensions in canaliculi

Question 21

what are synovial joints?

Answer 21

most common type of joint; allow both simple & complex movements

Question 22

types of synovial joints (high to low mobility)

Answer 22

1. ball & socket
2. condyloid
3. saddle
4. plane
5. hinge
6. pivot

Question 23

what are the characteristics of a synovial joint?

Answer 23

joint (articular) capsule lined by a synovial membrane, joint cavity m articular cartilage

Question 24

what is a joint capsule?

Answer 24

connective tissue cuff that encloses the joint cavity

Question 25

how many layers does the joint capsule have?

Answer 25

2. - thick outer fibrous layer attaches to articulating bones (accessory/collateral ligaments + tendons reinforce the fibrous layer - delicate inner layer synovial membrane (produce & absorbs synovial fluid)

Question 26

what is a synovial fluid?

Answer 26

viscous substance that lubricates & nourishes the articular srufaces

Question 27

whats the function of articular cartilage?

Answer 27

covers the surface of adjoining bones

Question 28

what does the synovial fluis and articular cartilage do?

Answer 28

provides a low-resistance surface for joint movement

Question 29

an example of a joint with fibrocartilagenous specializations

Answer 29

knee joint; deepens articular surfaces to increase joint stability and efficiency, and acts as a shock absorber

Question 30

an example of a joint with fibrocartilagenous specializations

Answer 30

bursae of shoulder; lie between the joint capsule and several associated tendons = reduce friction between structures that cross a joint

Question 30

an example of a joint with fibrocartilagenous specializations

Answer 30

bursae of shoulder; lie between the joint capsule and several associated tendons = reduce friction between structures that cross a joint