Bone Formation and Joints Flashcards
Cellular structure of Cartilage
Chondrocytes embedded in an extracellular matrix
Is Cartilage vascularized?
Cartilage is Avascular.
Howw do chondrocytes receive Oxygen and nutrients?
via diffusion from the Perichondrium.
What is the Perichondrium?
A fibrous connective tissue layer that nourishes the cartilage, lays down new cartilage, and provides attachment for the tendons and ligaments
What are the 3 types of Cartilage?
Elastic Cartilage, Hyaline cartilage, and Fribrocartilage
What type of cartilage is made of mostly Elastin fibers and is stiff and elastic? )e.g. can be found in the ear)
Elastic Cartilage
This type of cartilage is blue/translucent, composed of few elastin fibers?
Hyaline Cartilage: occurs in external nose, larynx, costal cartilage, and articular surfaces of synovial joints.
Which type of cartilage has the highest proportion of Collagen fibers and occurs in areas requireing tensile Strength?
Fibrocartilage (found btwn intervertebral discs, pubic symphysis, and others)
What are Ligaments and tendons made of?
Dense connective tissue of parallel bundles of collagen fibers with fibroblasts
Tendons attach…
muscle to bone (or coartilage) via periosteum or perichondrium
Ligaments attach…
bone to bone (or coartilage) via periosteum or perichondrium
What are intrinsic ligaments?
Thickenings of joint capsules
Ligaments Function to…
Provide stability to joints and prevent excessive movement.
Bones are composed of…
Osteocytes (mature bone cells), with an extracellular matix composed of collagen, glycoproteins, and mineral salts of calcium and phosphorus
What is the outer connective tissue covering all non-articulating surfaces of the bone?
Periosteum — it also contains sensory fibers and arteries that nourish the bone (periosteal and nutrient arteries)
Remodeling
The periosteum can form new bone (osteogenesis) in response to injury or mechanical stress.
What is Compact Bone?
closely packed structural units called osteons, hard and dense. Provides strength and rigidity.
What is Cancellous bone?
It is spongy/ trabecular bone interspersed with marrow, less dense and more vascularized than compact
What bones in Adults contain Hematopoietic marrow?
Flat bones and (skull, illium, scapula, sternum, ribs) and ends of long bones
Wht type of Marrow is found in the medullary cavities of long bones?
Fatty yellow marrow
What type of bone tissue makes the cortical layer?
Compact bone
Bone (superficial to deep)
Periosteum–> Compact bone (cortical layer) –> Cancellous bone or medullary cavity
Examples of short bones…
cuboidal bones found only in the wrist and ankles
Examples of Irregular bones…
include vertebrae and bones of the cranial base and face, coxal bone
Sesamoid bones:
form within tendons where they cross joints, reduce friction and increase mechanical advantage.
What do Accessory (supernumary) bones result from?
result from an incomplete or abnormal fusion of ossification centers; common in cranial sutures.
Describe Intramembranous ossification (direct ossification)
mesenchymal cells give rise to bone forming cells –> bone formation proceeds outward from this primary ossification center.
Describe Endochondreal Ossification…
Mesenchyme gives rise to cartilage-forming cells, which replace the mesenchyme model with hyaline cartilage –> invading blood vessels then initiate ossification of the cartiliginous model. (Secondary ossification center)
In long bones, a Primary ossification Center forms in…
the diaphysis (shaft)
In long bones, Secondary Ossification Centers form later in the….
Epiphyses (ends) of the bone
What is the epiphysial plate?
A growth plate made of Hyaline cartilage connects each epiphysis to the diaphysis in long bones
What happens with the growth of epiphysieal cartilage?
the bone increases in length.
What happens when growth stops in a long bone?
When growth is complete, the epiphysieal plate ossifies and fuses with the rest of the bone leaving a faint epiphyseal line.
What are the major joint classes?
Fibrous joints, Cartilaginous joints, and Synovial Joints
What are types of Fibrous joints?
Suture (fontanelles in infants/ syntoses in adults)
and Syndesmosis & gomphosis
What is a Syndesmosis?
A type of Fibrous Joint where elements are united by a sheet of connective tissues (i.e. tibiofibular syndesmosis/ minimally flexible & radioulnar syndesmosis/ highly mobile)
Name the types of Cartilaginous joints…
Synchondrosis (united by hyaline cartilage i.e. epiphyseal growth plate; growth/ no mvmt) & Symphysis (united by fibrocartilage; some mvmt i.i. pubic symphysis)
What are Synovial joints?
The most mobile joint type and the most common. Elements are united by a fibrous connective tissue joint (articular) capsule, which encloses a joint cavity
What is a Joint capsule/ Articular Capsule?
An outer fibrous capsule that connects the joint elements
The Fibrous joint Capsule and all non-articular surfaces are lined by….
A Serous Synovial Membrane, which secretes slippery synovial fluid
What what type of cartilage covers the articular surfaces in a synovial joint?
Hyaline articular Cartilage ( lubricated by synovial fluid)
Synovial effusion results when…
inflammation causes excess fluid production in the synovial cavity.
Articular discs..
Fibrocartilage structures that unite elements and/ or facilitate mvmt in synovial joints
Fibrocartilaginous rings..
Deepen articular surfaces and increase stability (e.g. glenohumeral labrum) in a synovial joint
Bursae (bursa s.)
Synovial structures that protect tendons and facilitate their mvmt
What are the 6 major types of Synovial Joints?
Plane, Hinge, Pivot, Saddle, Condyloid, and Ball-and-socket joints.
Hinge joint ex
Uniaxial… elbow/ knee
Condyloid joint ex
Biaxial (flexion/extension & Abbduction/Adduction)
ex. metacarpal phalangeal joints and whrist
Saddle joint ex
Biaxial, but also permit circumduction-like motion. i.e. thumb and sternoclavicular joint
Pivot joint
Uniaxial
I.e. Dens freely rotates with Atlas
& proximal radioulnar joint
Ball and Socket joints
Multi-axial, spherical head rotates freely about all axes i.e Hip and Shoulder
What is the extra cellular matrix of cartilage made of?
Collagen, elastin, and proteoglycans
What bones in infants contain hematopoietic marrow?
All bones at birth
