Skeletal- Histology Flashcards
Describe the process of the formation of the skeleton?
- Bone collar forms around the hyaline cartridge model
- Cartilage in the centre of the diaphysis calcifies and develops into cavities.
- The periosteal bud invades the internal cavities and spongy bone begins to form.
- The diaphysis elongates and a medullary cavity forms as ossification continues. Secondary ossification centre appears in the epiphyses in prep for stage 5.
- The epiphyses ossify when completed, hyaline cartilage remains only in the epiphyseal plate and articular cartilage.
What are the 6 functions of the skeleton?
Protects internal organs Stores and releases fats Produces blood cells Stores and releases minerals Facilitates movement Supports the body
Define Axial?
Involves skeletal structures within the CNS such as the brain and the spinal cord
Define Appendicular?
Involves skeletal structures such as the lower limbs and upper limbs.
What are the 3 main types of cartilage?
Hyaline
Fibrocartlidge
Elastic
Define Hyaline cartilage?
Translucent matrix which is the most common type.
Covered by dense perichondrium matrix contains closely packed collagen fibres.
Provides rough but flexible support.
Define Elastic cartilage?
Contains elastic fibres allowing it to be flexible
Tolerates distortion
Found in the outer ear and epiglottis.
Define fibrocartlidge?
Matrix dominated by large collagen fibres
Tough durable
Results in compression and absorption
Prevents bone damage
What are the two types of bone?
Compact
Spongy
What type of marrow is in bone?
Yellow bone marrow
Red bone marrow
What is the function of yellow and red bone marrow
Yellow bone marrow - stores fat
Red bone marrow- Produced red blood cells
Define and give an example of compact bone?
Osteons are an example of compact bone
Osteocytes are arranged in concentric circled layers around the central canal with blood vessels.
Lamellae of osteons form cylinders around central canal
Blood vessels supply blood to osteons
What is a osteon surrounded by?
Periosieum
Define and give an example of spongy bone?
Lamellae forms rods called TRABERCULAE.
Frequent branching causes thin trabecular creates an open network.
Nutrients via canaliculi
Red marrow is found between trabercuale.
Define the structures of the bone?
Diaphysis- Bone shaft
Epiphysis- Proximal and distal ends of the bone
Metaphysis- Region between the diaphysis and epiphyses
Periosteum- Tough connective tissue sheath and its associated blood supply that supplies the bone surface
Medullary cavity- Cavity within the diaphysis that contains the bone marrow and vessels.
Define what a long bone is?
Tubular structure e.g FEMUR
Define what a short bone is?
Cuboidal structure e.g TARSALS
Define what a flat bone is?
Protective function e.g CRANIUM
Define what an irregular bone is?
Various shapes such as a zygomater
Define a sesamoid bone?
Tendons e.g PATELLA
What are the 4 types of cells present in bone tissue and define them
- Osteoprogentior cells
Tissue from which almost all connective tissue are formed - Osteoblast
Secrete collagen fibres to build extracellular matrix of bone tissue. - Osteocytes
Maintain daily metabolism of bone tissue, such as exchange of nutrients with blood. - Osteoclasts
Releases powerful enzymes that digest the protein and mineral components of the extra cellular matrix.
OSTEOBLASTS BUILD BONE OSTEOCLASTS CONSUME BONE
Explain the vasculature of bone?
Nutrient arteries pass through the foramen
Blood reaches the osteoclasts in the compact bone by Haversian systems.
Ends of the bones supplied by metapheseal and epiphyseal arteries
How much calcium does the bone store
99%
What cells depend on a stable level of calcium ions in extracelluar fluid
Nerve and Muscle cells
How does bone regulate calcium homeostasis?
Regulates via blood plasma using osteoclasts when the levels decrease and absorbed calcium using osteoclasts when level rises.
Whats the general treatment for fractures
To realign and immobilise the bone fragments to restore functions.
Define what reduction is for a fracture?
Where the fracture ends must be brought into alignment.
What are the 2 types of alignment?
Closed reduction
Open reduction
Define the 2 types of reduction?
Closed reduction- Fractured ends of bones are brought into line alignment. My manual manipulation and skin remains intact.
Open reduction- Fractured ends of a bone are brought into alignment by a surgical procedure using fixative devices such as screws.
What are the 4 stages of healing?
- Hematoma formation
- Fibrocartildginous callus formation
- Bony callus formation
- Bone remodelling
What cells remove the dead and damaged tissue around the fracture hematoma.
Phagocytes and osteoclasts.
Define the entire process of heeling?
Blood vessels crossing the fracture line are broken
Mass of blood forms around the site of the fracture
Formation of a fibrocartilaginous callus, and a bony callus to bridge the gap between the broken ends of the bones.
Blood vessels grow into the fracture hematoma and phagocytes begin to clear up dead blood cells.
Fibroblasts from the periosteum invade the fracture site and produce collagen fibres.
osteoprogenitor cells develop into osteoblasts, which begin to produce spongy bone trabeculae.
the fibrocartilage is converted to spongy bone, and the callus is then referred to as a bony callus.
Dead portions of the original fragments of broken bone are gradually resorbed by osteoclasts.
Compact bone replaces spongy bone around the periphery of the fracture
What are the 3 types of joints?
Fibrous
Cartilaginous
Sinovial
What is a joint
Unison between two or more bones.
Define fibrous joint?
Sutures on the cranium are examples of this
are examples of fibrous joints.
These bones are held close together, either interlocking along a wavy line or overlapping.
Define Cartilaginous joint?
- United by hyaline cartilage or fibrocartilage.
- Primary cartilaginous joints are temporary unions, such as those present during the development of a long bone.
- Secondary cartilaginous joints are strong, slightly moveable joints united by fibrocartilage.
Define Synovial joint?
The most common type of joint.
•Provide free movement between the bones they join.
•Joints of locomotion.
Define plane joint?
Permit gliding or sliding movements in the plane of the articular surfaces. The opposed surfaces of the bones are flat or almost flat, with movement limited by their tight joint capsules.
•Example includes acromioclavicular joint
Define grade 1 fracture?
Grade I – AC sprain.
A slight displacement of the joint. The acromioclavicular ligament may be stretched or partially torn. This is the most common type of injury to the AC joint.
Define grade 2 fracture?
Grade II - A partial separation of the joint in which there may be some superior displacement of the clavicle that may not be obvious during a physical examination.
The acromioclavicular ligament is completely torn, while the coracoclavicular ligaments remain intact.
Define grade 3 fracture?
Grade III - A complete separation of the joint.
The acromioclavicular ligament, the coracoclavicular ligaments, and the capsule surrounding the joint are torn. Usually, the displacement is obvious on clinical exam.
Without any ligament support, the shoulder falls under the weight of the arm and the clavicle is pulled up by the trapezius and SCM, causing a bump on the shoulder.
Define a hinge joint?
- Permit flexion and extension only.
- The joint capsule is thin and lax anteriorly and posteriorly where movement occurs
- Bones are joined by strong lateral collateral ligaments
- (elbow joint)
Define a condyloid joint?
- Permit flexion and extension as well as adduction and abduction.
- Metacarpophalangeal joints
Define a pivot joint?
- Permit rotation around a central axis.
* Atlantoaxial joint is a pivot joint in which the atlas rotates around the dens of the axis during rotation of head.
What movement does ball and socket joint permit?
Allow movement in multiple axes and planes (flexion, extension, abduction, adduction, medial rotation, lateral rotation and circumduction.
•Spheroidal surface of one bone moves within the socket of another.
