Bone & Soft Tissue Flashcards
1
Q
What there components comprise the musculoskeletal system?
A
Bone
Muscle
Connective tissue
2
Q
Give three examples of connective tissue in the msk system?
A
Tendon
Ligaments
Cartilage
3
Q
What are tendons?
A
Connects muscle to bone
4
Q
What are ligaments?
A
Connects bone to bone
5
Q
What is cartilage?
A
Structure support
Protects tissues
Attachment sites
6
Q
How is the Skeleton divided into two anatomical regions?
A
Appendicular and axial
7
Q
What does the appendicular skeleton contain?
A
Pectoral girdle, upper and lower limbs, and pelvic girdle
8
Q
What anatomical structures does the axial skeleton contain?
A
Cranium, vertebral column, and rib cage
9
Q
What are the five functions of the skeletal system?
A
Movement Support Protection Site of calcium storage Site of haemopoesis
10
Q
Which cells do osteogenic stem cells derive from?
A
Derive from mesenchymal stem cells
11
Q
Which cells do osteogenic stems differentiate into?
A
Osteoblasts and chondroblasts
12
Q
What is the function of osteocytes?
A
Capable of bone deposition and resorption, involved in bone remodelling by transmitting signals to other osteocytes in response to slight bone deformations caused by muscular activity, strengthens bone due to additional stresses.
Mature osteoblasts, that have been enveloped by the bone matrix, osteocytes continue to form bone to an extent (maintains strength of bone matrix).
13
Q
Where do osteocytes reside within the bone?
A
Reside within the lacuna off the bone
14
Q
How do osteocytes communicate with other cells?
A
Through surrounding canaliculi
15
Q
What is a lacuna?
A
Calcified matrix of bone
16
Q
What are canaliculi
A
Cytoplasmic processes of the osteocyte extend distally from the cell towards other osteocytes.
17
Q
What is the function of canaliculi?
A
Exchange of waste productions and nutrients exchanged to maintain the viability of the osteocyte.
18
Q
What is the main function of osteoblasts?
A
Responsible for synthesis and catalyses mineralisation of osteoids during bone formation and remodelling.
Arise from differentiation of osteogenic cells in the periosteum,.
19
Q
What enzymes are released by osteoblasts?
A
Alkaline phosphatase
Collagenase
20
Q
Which factors are released by osteoblasts?
A
growth factors
hormones
collagen
21
Q
Which hormone is released from osteoblasts?
A
Osteocalcin
22
Q
What types of cells are osteoclasts?
A
Large multinucleate cells responsible for the dissolution and absorption of bone
23
Q
What function is performed by osteoclasts?
A
Bone resorption, dissolution and absorption of bone ; mediators of one destruction, resorb bone by phagocytosis
24
Q
Where do osteoclasts reside?
A
Reside within the minor depression indented on the bone surface, referred as Howship lacunae
25
What is formed by osteoclasts during osteclastogenesis?
Ruffled border
26
What is a ruffled border?
Invaginations of the plasma membrane, defines the active region, whereby phosphatase enzymes are secreted to dissolve the organic collagen,
27
Which organic component of bone is resorbed by osteoclasts?
Organic collagen (Type 1)
28
Which inorganic component of bone is resorbed?
Inorganic calcium and phosphate
29
Which proteins form the sealing zone between the osteoclast and bone?
Sialoprotein
| Osteopontin
30
Which inorganic compound is removed bone?
Calcium hydroxyapatite are removed from the bone by acidification
31
Which part of bone is protected against osteoclastic resorption?
Osteoid
32
Where are osteocytes located?
Matrix lacunae
33
Where are osteogenic cells located?
Deep layers of periosteum
34
Where are osteoblasts located?
Growing portions of bone, including periosteum and endosperm
35
What are the three components of ground substance?
Proteoglycans
Glycoproteins
Cytokine and growth factors
36
What are the 2 inorganic components?
Calcium hydroxyapatite
| Osteocalcium phospahte
37
What are the two main bone type?
Immature woven bone
| Mature bone
38
What are the two types of mature bone?
Cancellous bone
| Cortical bone
39
How is mature bone arranged?
mineralised woven bone with a lamellar structure
40
How is cortical bon arranged?
Densely arranged osteons (Haversian systems)
Osteon consists of central canal, surrounded by concentric rings (laemallea) of the matrix.
Intermediate of the matrix rings are osteocytes, locate in lacunae. Canaliculi (contains extracellular fluid) radiate from lacunae to the Haversian canal to provide passageways through the hard matrix
41
What does one osteon contain?
Central canal
42
How are osteons arranged?
Concentric rings of matrix,
43
What are the purposes of canaliucli in cortical bones?
Contains extraceluar fluid radiate from the lacunae to the Haversian canal to provide passageways through the hard matrix
44
What doe osteonic canals?
Encapsulates vasculature that are parallel to long axis of the bone
45
How are osteonic canals linked?
Perforating canals with vessels on the surface of bone- Volkmann's canal
46
What are cortical bones?
Supports body weight, protects organs, provide levers for movement, store and release calcium
47
What is the structure of cancellous bone?
Trabecular
48
Where does cancellous bone predominant?
Predominates epiphysis of bones , and within the medullary canal
49
What are the distinctive comparisons between cancellous and cortical bone?
Higher surface area, less dense, softer, weaker and less stiff
50
What do the irregular cavities contain within cancellous bone?
Red bone marrow
51
Where is the site of haemopoesis within cancellous bone?
Red bone marrow within cancellous bone
52
How are adjacencies cavities of cancellous bone connected?
Canaliculi
53
How does the structure of trabecular change upon addition stress?
Realign in accordance to stress directions, resistant to mechanical stress
54
What are the functions of cancellous bone?
Greater surface area, ideal for metabolic cavity; change of calcium ions. Cancellous bone is highly vascular and bone marrow is site of haemopoiesis.
55
What two structures divide long bones?
Diaphysis
| Epiphysis
56
What is the diaphysis?
Tubular shaft that traverses between the proximal and distal ends of the bone.
57
What is considered in the hollow region within cancellous bone?
medulla cavity, encapsulates yellow marrow
58
What types bone is located diaphysis?
Compact dense bone
59
What is the point whereby the diaphysis meets the epiphysis?
Metaphysis
60
Within the epiphyseal line, which region is responsible for growth?
Epiphyseal plates
61
What type of cartilage is located within the epiphyseal plates?
Hyaline cartilage
62
How does the epiphyseal line form?
Hyaline cartilage is replaced by osseous tissue, and the plate becomes the line.
63
What is the membranous lining of the medially cavity?
Endosteum
64
What is the function of endosteum?
Bone growth , repair, and remodelling occurs.
65
What is outer surface of medulla cavity?
Periosteum
66
What does the periosteum contain?
Blood vessels, nerves, and lymphatic vessels that nourishes the bones
67
Which type of cartilage cover the epiphyses?
Articular cartilage
68
What are the functions and properties of articular cartilage?
Covers epiphyses, reduces friction
| Shock absorber.
69
What is the mesenchyme?
Forms within the cranium to form flat bones of the skull, Clavicle and mandible
70
What is the first step of intramembranous ossification?
Mesenchymal cells undergo differentiation and specialising into osteogenic cells, and ultimately osteoblasts
Clusters of osteoblasts form an ossification centre
71
What is the second step of intramembranous ossification?
Secrets osteoid, uncalcified matrix consists of collagen precursors and organic proteins which calcifies due to mineralisation, thereby entrapping the osteoblasts.
osteoblasts that are entrapped within the matrix become osteocytes
As osteoblasts transform into osteocytes, osteogenic cell synth surrounding connective tissue differentiate into osteblastex at the ends of the growing bone
72
What is the third stage of intramembranous ossification?
Clusters of osteoid unite around capillaries forming a trabecular matrix.
Osteoblasts on the surface of the newly formed bone form become the cellular layer of periosteum
Periosteum secretes compact bone superficial to the cancellous bone.
73
What is stage four of intramembranous ossification?
Cancellous bone aggregates near blood vessels, condensing into red bone marrow
74
What is endochondral ossification?
Bone develops through hyaline cartilage replacement. Cartilage does not become bone
Cartilage behaves as a template to become completely replaced by new bone
Process is longer than intramembranous ossification
75
How do bones at the base of the skull and long bones form?
Endochondral ossification
76
What are chondroblasts?
Cartilage cells.
77
What do chondroblasts secrete?
Hyaline cartilage precursor for bone
78
What is cartilage?
Cartilage is flexible semi-solid matrix produced by chondroblasts, and consists of hyaluronic acid, chondroitin, sulphate, collagen fibres, and water.
79
Is cartilage vascular?
Avascular (no vasculature supply nutrients, or removing metabolic wastes).
80
How are nutrients and metabolic wastes transported from cartilage?
Functions are performed by diffusion through the matrix from vessels surrounding perichondrium
81
What are 5 stages of endochondral ossification?
```
Cavitation
Periosteal bud invasion
Diaphysis elongation
Cartilage remains at the epiphyses
Secondary ossification centre
```
82
What is cavitation?
Formation of matrix increases cartilaginous model size. Blood vessels in perichondrium bring osteoblasts to the edges of the structure, arriving osteoblasts deposit osteoid in concentric formation around the diaphysis.
Bony edges of the developing structure present nutrients from diffusion into the centre of the hyalin cartilage = chondrocyte death
83
how does chondrocyte death occur during endochondral ossification?
Bony edges of the developing structure prevent nutrients from diffusing into the centre of the hyaline cartilage.
84
What occurs during periosteal bud invasion?
Without cartilage inhibiting blood vessel invasion, blood vessels penetrate the resulting space, enlarging the cavities and transferring osteogenic cells with them- forming osteoblasts.
Enlarging spaces become the medullary cavity. Bone is deposited within the structure creating the primary ossification centre.
85
What is diaphysis elongation?
Chondrocytes and cartilage continue to grow at terminal ends of the structure (Epiphyses), increases length, continued growth accompanied by remodelling inside the medullary cavity (osteoclastic activity), and overall lengthening of the diaphysis.
86
What is the secondary ossification centre?
Matrix mineralisation, death of chondrocytes, invasion of blood vessels from the periosteum and seeding with osteogenic cells occur in the epiphyseal regions. Hyaline cartilage between the diaphysis and epiphysis known as epiphyseal plate.
87
What is the first stage of endochondral ossification (simplified)?
Mesechymal cells --> chondrocytes (cartilage model)
88
Describe the 5 stages of endochondral ossification?
Mesenchymal cells --> chondrocytes
2) Blood vessels on surface transfer osteoblasts that deposit a bony collar
3) Capillaries penetrate cartilage and deposit bone inside model --> primary ossification centre
4) Cartilage and chondrocytes grow at epiphysis, medullary cavity expands
5) Secondary ossification centre
89
What is the epiphyseal plate?
Area of elongation in a long bone, layer of hyaline cartilage where ossification occurs in immature bones
90
What is epiphyseal side?
Hyaline cartilage cells are active, dividing and producing hyaline cartilage matrix
91
What is diaphyseal side?
Cartilage calcifies and undergo necrosis replaced by bone
92
What is the reserve zone?
Region closest to the epiphyseal end of the plate, containing chondrocytes within the matrix. Chondrocytes do not participate in bone growth , however secure the epiphyseal plate to the overlying osseous tissue of the epiphysis.
93
What is the proliferative zone?
Layer towards the diaphysis contains stacks of large chondrocytes. Mitotically dividing cells producing multiple chondrocytes replacing those that die at the diaphysral end of the plate.
94
What is the zone of maturation and hypertrophy?
Mature cells situated closer to the diaphyseal side of the plate. Longitudinal growth the bone is a result of cellular division the proliferative zone, and the maturation of cells in the zone of maturation and hypertrophy
95
What is the zone of calcified matrix?
Closest to the diaphysis, chondrocytes are dead (Calcification restricts nutrient diffusion). Capillaries and osteoblasts from the diaphysis penetrate this zone, and osteoblasts secrete bone tissue on the remaining calcified cartilage. Connects the epiphyseal plate to the diaphysis.
96
What appositional growth?
Appositional growth is the deposition of bone beneath the periosteum to increase diameter.
97
Where does appositional growth occur within the bone?
Occurs at the endosperm, osteoclasts resorb old bone that lines the medullary cavity.
Bone formation via osteoblasts with simultaneous bone resorption along the medially cavity, and bone deposition deep to the periosteum increases the diameter of the diaphysis
98
Which cells produce new bone?
Osteoblasts
99
What is the 4 stage process of appositions growth?
Ridges in the periosteum create groove for periosteal blood vessel
2) Periosteal ridges fuse, forming a endosperm lined tunnel
3) Osteoblasts in nostrum construct new concentric lamellae inward toward centre of new tunnel, new osteons.
4) Bone growth outwards as osteoblasts in periosteum build new circumferential lamellae
Osteon formation repeats as new periosteal ridges fold over blood vessel.
100
What do tendons attach?
Attach skeletal muscle to bone
101
What is the composition of tendons?
Fibroelastic composition provides strength required to transmit large mechanical forces.
Each muscle has two tendons one proximally and one distally
102
What is the function of tendons?
Transmit forces generated from the muscle to the bone to elicit movement
Elastic energy storage/recoil
103
What is the origin of the tendon?
Proximal attachment of the tendon
104
What is the insertion point of the tendon?
Distal tendon
105
which component of tendons resit compressive stresses?
Proteoglycans
106
Which cells comprise tendons?
Tendoblasts
| Tenocytes
107
What are the shapes of tenocytes?
Become elongated, spindle shaped
108
What is the function tenocytes?
Responsible for turnover of maintenance of the extracellular matrix.
Respond to mechanical load of the tendon, and thus make adaptations, arranged longitudinally
109
What are connexions?
Collection of six connexion protein subunits have a central pore, form of gap junction
110
What is the open state of gap junctions?
Allow metabolites and ions to pass freely between the gap junction
111
Which forms of proteins form a tendon?
Type 1 collagen
| Proteoglycans
112
What is the function of type 1 collagen.
Type 1 collagen are responsible for tensile strength of the tendon
113
What is the function of proteoglycan in a tendon?
Responsible for viscoelastic nature
114
What is the configuration of collagen?
Parallel configuration
115
What is collagen?
insoluble fibrous protein that givers strength tendons, ligaments and bone
116
What is the primary structure of collagen?
Tripeptide sequence , consisting of 3 repeated amino acids, glycine, proline and lysine, bonded together by peptide bonds/
117
What is the secondary structure of collagen?
Hydrogen bonding occurs by the amino and carboxyl groups of the amino acids to form a left handed helix
118
What is the quaternary structure of collagen?
3 polypeptide helices (homotrimers) bond together to produce a right handled triple helix, the helical structure is maintained through hydrogen bonding - forms collagen molecule
119
how are multiple triple helices bonded together?
Covalent bonding between amino and carboxyl group of the amino acids.
This causes cross linking and strong intermolecular forces to occur
120
Which type of trimer is collagen 1?
heterotrimer
121
what is the purpose of ligaments?
Connect bone to bone to stabilise joint , connective tissue that supports the internal organs, and hold bones together in proper articular at the joints
122
What composes ligaments?
Consist of functional subunits that tighten or loosen depending on joint position
Proprioceptors
Epilligament
Type C fibres
123
Which fibres transmit pain signals?
Type C
124
Which cells secrete collagen?
Fibrolasts
125
What is a synovial bursa?
Synovial membrane, present to secrete lubricating synovium.
126
What is the epiligament?
Containing blood vessels and nerves in outer covering
127
What is cartilage?
Flexible connective tissue, avascular and not innervated , relying on diffusion to obtain nutrients (slow healing)
128
What is the composition of cartilage?
Chondrocytes, ground substance is chondroitin sulphate, and the fibrous sheath is the perichondrium.
Chondrocyte produce collagen extracellular matrix and reside in lacunae
129
What is the function of cartilage?
Cartilage behaves a shock absorber to reduce friction
Covers and protects long bones adjoints
Forms structural component of ribs and IV discs
130
What are the 3 main examples of cartilage?
Hyaline cartilage
Elastic cartilage
Fibrocartilage
131
What is the hyaline avascular structure surrounded by?
Perichondrium
132
Which type of collagen is present in elastic cartilage?
Type II
133
Which type of collagen is present in hyaline cartilage?
Type II collagen, interacting with proteoglycans
134
What type of collagen is present in fibrocartilage?
Type 1 collagen
135
Where does fibrocartilage predominate?
IV discs
136
Which molecule is associated with elastic cartilage?
Elastin
137
What are sutures?
immovable joints
138
Which term describes an immovable joint?
Synarthrosis
139
Which type of joint is the pubic symphysis?
Cartilaginous
140
What are primary cartilaginous joints?
Synchondrosis, connected hyaline cartilage; epiphyseal plates are temporary cartilaginous joints that enable bone growth.
141
What are secondary cartilaginous joints?
Symphysis, connected by fibrocartilage, mainly in the midline of the body
142
What are synovial joints?
Articulation is surrounded by an enclosing synovial capsule, bones not directly connected at the joint surfaces.
143
Which type of cartilage is articular?
Hyaline cartilage
144
What are synovial joints encapsulated?
Articular joint capsule
145
What does the synovial membrane?
Synovia to provide lubrication
146
What is the purpose of synovial joints?
Friction between then bones at a synovial joint is prevented by the presence of the articular cartilage, a thin layer of hyaline.
147
What is the function of synovia?
To provide lubrication to reduce further friction between the bones of the joint.
Fluid nourishes the articular cartilage, avascular
Ability of bone to move smoothly against each other within the join cavity, and the freedom of joint movement
148
What is the term used to describe a movable joint?
Diarthrosis
149
What is outer joint capsule?
Articular capsule: bones structurally held together
150
What is the inner joint capsule?
Contains synovial fluid, reduces friction during movement
151
What are the three types of synovial joints?
Uniaxial
Biaxail
Multiaxial
152
What are uniaxial joints?
Movement is exclusively in one direction (Hinge joints)
153
What are biaxial joints?
Movement in two different plans, saddle joint
154
What are multiracial joints?
Movement on several axes, ball and socket joints
155
What is synarthrosis?
Minimum non mobility (fibrous joints including sutures)
156
What is amphiarthrosis?
Restricted mobility (Pubic symphysis)
157
What is diarthrosis?
Dextrously mobile
158
What are 6 types synovial joints?
```
Hinge
Saddle
Plane
Pivot
Condyloid
Ball and socket
```
159
What are hinge joints?
Permits movement in one plane-flexion and extension (elbow joint)
160
What is a saddle joint?
Named due to its resemblance to a saddle; characterised by opposing articular surface with reciprocal concave-convex shape.
161
How are joints stabilised?
Ligaments: prevents excessive movement that could damage joint
More ligaments + tighter ligaments --> Greater stability, less mobility
162
What are the risks with poor stability?
Contributes to an increased risk of dislocation
163
What effect does excessive ligament laxity have on joints?
Leads to hyper mobility and greater risk of injury
164
How is the glenohumeral joint stabilised?
Glenoid labrum
| Rotator cuff muscles
