Introduction to bone and soft tissue (20) Flashcards
1
Q
What are the 3 components of the musculoskeletal system?
A
- bone
- muscle
- connective tissue
2
Q
What is connective tissue?
A
anything that links bits of the body
3
Q
What is the purpose of a tendon?
A
connects muscle to bone
4
Q
What is the purpose of ligaments?
A
connect bone to bone
5
Q
What is the purpose of muscle?
A
allow movement
and give you posture
6
Q
What is the purpose of cartilage?
A
- structural support
- protect tissues
- attachment sites
7
Q
What are the functions of the skeletal system?
A
- movement
- support
- protection of vital organs
- calcium storage
- haematopoesis (in bone marrow)
8
Q
How do we classify bones by shape?
A
- flat bone
- sutured bone
- short bone
- long bone
- irregular bone
- sesamoid bone
9
Q
What is an osteogenic cell?
A
bone ‘stem cell’
10
Q
What is an osteoblast?
A
- ‘bone forming’
- secretes osteoid
- catalyses mineralisation of osteoid
11
Q
What is an osteocyte?
A
- ‘mature’ bone cell/’resting’
- formed by incorporation of osteoblasts into bone matrix
- sense mechanical strain to direct osteoblast and osteoclast activity
12
Q
What is an osteoclast?
A
- ‘bone breaking’
- dissolve and resorb bone by phagocytosis
- derived from bone marrow
13
Q
What cells occupy bone?
A
osteogenic stem cells, osteoblasts, osteocytes, and osteoclasts
14
Q
Where are osteocytes found?
A
embedded in the matrix
15
Q
Where are osteoclasts found?
A
bone surfaces and at sites of old, injured, or unneeded bone
16
Q
Where are osteogenic cells found?
A
deep layers of periosteum
17
Q
Where are osteoblasts found?
A
growing portions of bone, including periosteum and endosteum
18
Q
What are the components of the bone matrix?
A
- 40% organic component: 90% type 1 collagen, 10% ground substance
- 60% inorganic component: calcium hydroxyapatite and osteocalcium phosphate
19
Q
What is immature/ woven bone?
A
- first bone that is produced
- laid down in ‘woven’ manner= weak
- mineralised and replaced by mature bone
20
Q
What is mature/lamellar bone?
A
- mineralised woven bone
- lamellar (layer) structure= strong
- cortical (outer) and cancellous (inner) components
21
Q
What is cortical bone?
A
- type of mature bone
- compact + dense
- suitable for weight bearing
22
Q
What is cancellous bone?
A
- type of mature bone
- spongy- honeycomb structure
- not suitable for weight bearing
- volume w/out weight
23
Q
What is the structure of a long bone?
A
proximal epiphysis
physis (growth plate)
metaphysis
diaphysis (long bit)
24
Q
What is intramembranous ossification in the uterus?
A
- formation of flat bones of skull, clavicle, and mandible
- bone development from fibrous membranes
- mesenchymal cell template
25
What are the steps in intramembranous ossification?
1. condensation of mesenchymal cells, which differentiate into osteoblasts- ossification centre forms
2. secreted osteoid traps osteoblasts--> become osteocytes
3. trabecular matrix and periosteum form
4. compact bone develops- superficial to cancellous bone + crowded blood vessels condense into red bone marrow
26
What is echondral ossification?
- process of forming long bones from a hyaline cartilage precursor
- NOT in flat sheets
- takes longer than intramembranous ossification
- 1y ossification centre= diaphysis
- 2y ossification centre= epiphysis
27
What is interstitial growth?
- long bone lengthening in the epiphyseal plate (contains hyaline cartilage)
1. growth plate zone
2. resting cell zone
3. proliferative zone
4. maturation and hypertrophy
5. calcified matrix
6. zone of ossification
28
What is appositional growth?
- deposition of bone beneath periosteum (outside covering) to inc. thickness (width)
1. periosteum ridges create groove for periosteal blood vessel
2. ridges fuse, forming an endosteum-lined tunnel
3. osteoblasts in endosteum build new concentric lamellae towards centre, forming a new osteon
4. bone grows outwards as osteoblasts in periosteum build new circumferential lamellae- osteon formation repeats as new periosteal ridges fold over blood vessel
29
What is the effect of calcitonin on osteoclast activity?
decrease osteoclast activity
| so less eating up bone, so lowers plasma calcium
30
Where do we find type 1 collagen?
skin, tendons, ligaments and bone
31
Where do we find type 2 collagen?
cartilage
32
Where do we find type 3 collagen?
vessel walls and outside of skin
33
What is the microstructure of a tendon?
parallel arrangement of collagen fibres- closely packed together
- some elastin for spring
- some proteoglycans (a ground substance)
34
What are the functions of a tendon?
- transmit muscle forces to bone
- elastic energy storage
- proteoglycan resists compressive stresses
35
What are the functions of a ligament?
- connect bone to bone to stabilise joints
- contain proprioceptors- for balance
- transmit pain signals via type C fibres
36
What is the composition of a ligament?
- contain type 1 collagen
- also type 3
- fibroblast cells produce collagen
37
What are the functions of cartilage?
- shock absorber to reduce friction
- covers and protects long bones at joints
- structural component of ribs and intervertebral discs
N.B. made of chondrocytes- produce collagen
38
What are the 3 types of cartilage?
- elastic
- hyaline
- fibrocartilage e.g. meniscus
39
What are the 3 types of joints (structural classification)?
- fibrous e.g. skull
- cartilaginous e.g. spine
- synovial e.g. long bones
40
What is the function of synovial fluid?
- lubrication
- nutrition of joint
- hydrostatic pressure- shock absorber
41
What are the types of joints (functional classification)?
- ball and socket e.g. hip
- hinge e.g. elbow
- plane e.g. between tarsal bones
- condyloid e.g. between radius+carpal bones of wrist
- saddle e.g. between trapezium carpal bone+1st metacarpal
- pivot e.g. between C1+C2 vertebrae
42
What are synovial joints?
- most common and mobile type of joint
- joint capsule: articular capsule (outer) keeps bones together structurally...synovial membrane (inner) contains synovial fluid--> reduces friction during movement
43
What factors affect joint stability?
- joint shape e.g. hip vs shoulder
- ligaments
- tendons
- cartilage e.g. glenoid labrum
44
What is the function of ligaments?
to prevent excessive movement that could damage the joint
N.B. more + tighter ligaments--> more stable, but less mobile (vice versa)
- if joint = unstable--> risk of dislocation
- excessive ligament laxity--> hyper mobility--> greater risk of injury
45
What features of the shoulder joint make it more prone to dislocation than the hip joint?
- shallow socket
- weak joint capsule
- lack of strong ligaments
- greater mobility
