Joints and connective tissue Flashcards
What are the 3 key features of connective tissue?
- Doesn’t occur in free surfaces
- Has nerve supply
- Highly vascular
What are the 3 classes of components that make up connective tissue?
Cells
Fibres
Ground substance
What cells are found in connective tissue?
Fibroblasts: migrate through connective tissues secreting fibres and ground substance
Macrophages: develop white blood cells and phagocytose
Mast cells- produce histamine
Adipocytes- fat cells, store triglycerides
WBCs- plasma cells, lymphocytes, leukocytes
What are the 3 different fibres found in connective tissue?
- Collagen- strong fibres, resist force, toughest type
- Elastic- narrower than collagen fibres, made of elastin, found in blood vessels, skin etc.
- Reticular- provide support for walls of blood vessels, net/mesh like structure, made of collagen with glycoprotein coating
What makes up ground substance?
Macromolecules and multi-adhesive glycoproteins that are between cells and fibres
What is the role of ground substance?
Supports cells and facilitates exchange between cells by providing an exchange medium
What are the 3 cartilage subtypes?
Hyaline
Elastic
Fibrocartilage
What are characteristics of hyaline cartilage?
Most abundant cartilage but weakest
Found at ends of long bones- cushions joints
What are characteristics of elastic cartilage?
Elastic and structural cartilage- found in external ear
Has thread like network of elastic fibres
Similar to hyaline with increased elastin
What are characteristics of fibrocartilage?
Stringiest but no perichondrium
Found in invertebrate disks
Visible bundles of collagen fibres
Shock- absorbing
What are the different types of collagen?
Type I- skin, tendon, organs, bone, ligament
Type II- cartilage
Type III- reticulate
Type IV- basement membrane
What are the 3 classifications of joints?
- Fibrous- bones connect by fibrous connective tissue
- Cartilaginous- bones connects with cartilage
- primary- synchondrosis: connected by hyaline cartilage
- secondary symphysis: connected by fibrocartilage - Synovial joints- articulation surrounded by synovial capsule. Bones do not directly connect at joint surfaces but are strengthened by surrounding structures
What are the different synovial joints?
Uniaxial- movement in 1 direction
Biaxial- movement in 2 directions
Multiaxial- movements in many directions
What are types of uniaxial synovial joints?
Hinge joint: only allows flection and extension
Plane joint: permit gliding or sliding
Pivot joint: rounded process of bone fits into bony ligament socket allowing rotation
What are types of biaxial joints?
Saddle joint: saddle shaped head
Condyloid: permits flexion, extension, abduction, adduction and circumduction
What are types of multiaxial joints?
Ball and socket: rounded head fits into concavity
How is joint mobility classified?
Synarthrosis- little or no mobility
Ampiarthrosis- limited mobility (often fibrocartillaginous)
Diarthrosis- freely mobile (mostly synovial)
What are tendons?
Join skeletal muscle to bone
Stiff and long bundles of collagen fibres
Transit muscle force to bone, store elastic potential energy and resist compressive stresses
Mainly water, collagen, elastin, proteoglycans and inorganic compounds
What are ligaments?
Connects bone to bone
Strong bundles of collagen fibres
Have functional units that tighten or loosen depending in joint position
Contain proprioceptors and some blood vessels
Prevent excessive movement damaging joints
How does the number of ligaments affect stability?
More ligaments and tight ligaments = more stability but less mobility
Less ligaments and looser ligaments = less stability but more mobility
What makes up cartilage?
Chondrocytes
Made up of collagenous ECM and ground substance
What is the role of cartilage?
Allows shop absorption to prevent friction and protects long bones
Worn down in osteoarthritis
What are 3 other structures which stabilise joints?
Retinaculum
Aponeurosis
Bursa
What is retinaculum?
Tickened band of deep facia close to a joint
Band holds down tendon during muscle contraction to prevent bow- stringing
