Bones And Soft Tissues Flashcards
How many bones are in the adult human body?
206
What are 3 bones in the axial skeleton?
Cranium, vertebral column and rib cage
What is a joint?
Where two bones meet
What bones are part of the appendicular skeleton? - 4
Pectoral girdle, upper limbs and hands and legs
What are the five functions of the skeleton? MPMPS
Movement
Protection of vital organs
Mineral storage eg calcium
Produce blood cells
Support
What are the different shapes of bones? - 6
Flat, sutured, short, long, irregular, sesamoid
What are the four types of bone cells?
Osteogenic cell
Osteoblasts
Osteocytes
Osteoclasts
What is an osteogenic cell?
A bone stem cell found in deep laters of the periosteum
What is a osteoblasts?
A bone BUILDING cell which is found on the growing portion of the bone
What do osteoblasts secrete?
Osteoid
What do osteoblasts do?
Catalyze the mineralization of osteoid
What is an osteocytes?
A mature bone cell
How is an osteocytes formed?
When an osteoblasts becomes embedded in its secretions
What is an osteoclast?
Bone CHOMPING - breaks the bone, dissolve and reabsorb via phagocytosis
Where are osteoclasts found?
Bone surfaces and the sites of old, injured or unneeded bone
What do osteogenic cells differentiate into?
Osteoblasts
How are osteocytes formed?
When osteoblasts get trapped in the calcified matrix
How are osteoclasts made?
Made from bone marrow - monocytes and macrophages
Where are osteocytes found?
The lacunae
What is the chain order of bone cells?
Osteogenic, osteoblasts, osteocytes and osteoclasts
What are the two types of bone?
Woven and lamellar
What is the first type of bone to be produced?
immature/ Woven bone
How is immature woven bone made into mature lamellar bone?
It is mineralized
What are the two types of mature bones?
Cortical and cancellous
What are the properties of Cortical bone? - 3
compact, dense and suitable for weight bearing
what are the properties of cancellous bone - 2
spongy structure, not suitable for weight bearing
Cancellous is spongy, and not suitable for weight bearing
What are bones made up of ?
Cells and matrix
What does the bone matrix consist of?
Inorganic and organic component
What are the two components of inorganic bone matrix?
Calcium hydroxyapatite and osteocalcium phosphate
What is in the organic component of bone matrix?
Type 1 collage and ground substance which is proteoglycans, glycoproteins and cytokines
What is an osteon?
A repeated structural unit, concentric lamellar around a central Haversian
What is a Haversian Canal?
Canal containing blood vessels, nerves and lymphatic, with concentric lamellae of bone around it
In which type of mature bone are Haversian Canals found? - 2
Cortical, compact bone
What is on the outside of a long bone?
Cortical bone
What type of bone is on the inside of a long bone?
Cancellous bone
What is a growth plate called?
Physis
What is the structure of long bones in terms of physes (in order)? - 4
Epiphysis
Physis
Metaphysis
Diaphysis
What is Intramembranous Ossification?
The development of bone from within a membrane
What bones does intramembranous ossification form?
Flat bones of the skull, clavicle and mandible
Describe the process of intramembranous ossification - 7 steps
- Mesenchymal stem cells cluster and differentiate to form osteogenic cells which whn firther differentiate into osteoblasts
- Forms ossification center
- Osteoblasts start to secrete Osteoid inwards which traps osteoblasts in their own secretions
- The osteoblasts catalyse the mineralisation and thus calcification of the osteoid, forming the bone matrix
- Osteoblasts differentiate into osteocytes
- This leads to the dveelopment of the periosteum as well as the trabeculae
- Crowded blood vessels condense into red bone marrow
What traps osteoblasts in intramembranous ossification?
Osteoid
How does an ossification center form?
The condensation of mesenchymal cells that differentiate into osteoblasts
What is endochondral ossification?
Development of a long bone from a hyaline cartilage model
Which type of ossification is faster?
Intramembranous
What is the primary ossification center called?
The diaphysis
What is the secondary ossification center called?
Epiphysis
What are the two mechanisms of bone growth?
Interstitial and appositional growth
What is interstitial growth?
Long bones increasing in length
Where does interstitial growth occur?
At the growth plates
What is appositional growth?
increase in thickness and diameter of bones
Where does interstitial growth occur?
At the physeal plate
What occurs in the proliferation zone?
Mitosis
What are the zones the cell undergoes through growth? - 5
Reserve zone
Proliferation zone
Maturation and hypertrophy
Calcified matrix
Zone of ossification
Describe appositional growth
The deposition of bone beneath the periosteum to increase thickness
in interstitial growth, what happens on the diaphyseal side of the bone?
cartilage calcifies and dies, which then gets replaced by bone
in interstitial growth, what happens on the epiphyseal side of the bone?
hyaline cartilage is active and dividing to form hyaline cartilage matrix
what cartilage is involved in interstitial growth?
hyaline cartilage
How does appositional growth occur? - 4 steps
- Ridges in periosteum create groove for periosteum blood vessel
- Ridges fuse forming a tunnel which is now lined with periosteum but since it is inside it is called the endosteum
- Osteoblasts in endosperm build new concentric lamellae inwards towards the center of the tunnel, forming new osteon
- Bone grows outwards as osteoblasts in periosteum build new circumferential lamellae => osteon formation repeats as new periosteal ridges fold over blood vessel
What regulates calcium release from the bone?
Parathyroid hormone
What are the three types of joints?
Fibrous, cartilaginous and synovial
What separates bones in a fibrous joint?
Sutures
What are cartilaginous joints?
Has cartilage in between the bones
What are synovial joints?
Joints have synovial fluid
How can synovial joints be classified?
According to the direction they move
What are the 6 types of synovial joints?
Plane, hinge, ball and socket, pívot, saddle, condyloid
What is a joint called if it only moves in one plane?
Hinge
What type of joint is the knee?
Modified hinge joint = synovial
Despite having cartilage it is not complete and therefore doesn’t form a true junction
What is the purpose of the cartilage in the knee joint?
Reduce the pressure between the bones
What is the purpose of the inner synovial membrane?
Contains synovial fluid which reduces friction during movement
What is the purpose of the articular capsule?
Keeps bone together structurally
Where does synovial fluid come from?
Synovial membrane
What do ligaments do?
Prevent excessive movement that could damage the joint
What is the movement of the joint if you have more but tighter ligaments?
Greater stability but less mobility
What is the movement of the joint if you have less ligaments by laxer ones?
Greater mobility but less stability
What do you have a risk of with poor stability?
Risk of dislocation
What results from excessive ligament laxity?
Hypermobility
What are the four factors affecting joint stability?
Joint shape
Tendons
Ligaments
Cartilage
What do tendons do?
Attach muscles to bone, and transmit the force from the muscle to the bone
What are tendons made of?
Collagen
What is the microstructure of tendons?
Parallel arrays of collagen fibers packed closely together
What is the structure of collagen?
3 polypeptide chains wound around each other like a triple helix
What do ligaments do?
Join bone to bone in order to stabilize the joint
Do ligaments have many nerves / blood vessels?
No
What allows ligaments to tighten or loosen?
The functional sub units
What is the outer covering of ligaments called?
Epiligament
What part of ligaments transmits pain signals?
Type 3 fibres
What is the purpose of cartilage?
Shock absorber to reduce friction
What is cartilage made up of?
Chondrocytes which produce a lot of collagenour ECM
What are the 3 types of cartilage?
Elastic
Hyaline
Fibrocartilage
Compare the joint capsule of the hip and shoulder joint?
Shoulder = weak
Hip = strong
What is the strength of the ligaments in the shoulder?
Lacks strong ligaments
What are the ligaments like in the hip joint?
Strong
What is the stability of the shoulder joint?
Unstable
What is the stability of the hip joint?
Stable
What is the mobility of the shoulder like?
Extremely mobile
What is the motility of the hip joint like?
Less mobile
state the stages of endochondral ossification - 5
bone collar formation => cavitation => periosteal bud invasion => diaphysis elongation => epiphyseal ossification
what is the role of calcitonin
stimulates calcium uptake into the bone
what is the role of Vitamin D
helps body absorb and use calcium
