Intro to Rheumatology Flashcards
What are the 4 different types of connective tissue?
What is connective tissue and what are its different functions?
Bone, cartilage, blood and proper
Connective tissue is composed of many different components - variety of components allows for variety of functions:
Connective tissue binds together, supports and strengthens other body tissues. It is the main site of immune responses. It protects and insulates internal organs, compartmentalises structures such as skeletal muscle. Blood = major transport system in the body, adipose = site of stored energy reserves
What defines / unites connective tissue (as all 4 types are very different with a variety of functions) and separates it from other body substances?
How can the structure of connective tissue be divided into 2 parts?
What are the 3 classes of components found in the composition / structure of connective tissue ?
All have common embryological origin - the mesoderm; and its composition
Connective tissue contains cells and the ECM (extracellular matrix - contents outside the cells). The ECM is the larger component, and consists of fibres and ground substance
- Cells - fibroblasts, macrophages, mast cells, plasma cells, lymphocytes, leukocytes, adipose cells
- Fibres - reticular, elastic, collagen
- Ground substance (jelly like substance outside the cells) made up of starches proteins and water - macromolecules and multiadhesive glycoproteins = provides structural support
What is the purpose / function of ground sunstance in the connective tissue?
It is found between cells and fibres and acts to bind them together and support the cells. It also provides a medium through which substances are exchanged e.g. HA (hyaluronic acid)
What are the 3 types of fibres, what are their properties and where can they be found?
What is the prupose / function of fibres in connective tissue?
- Collagen - strongest, made of collagen = most abundant protein in the body, used in cosmetics
- Elastic - made up of elastin, smaller in diameter than collagen fibres, more flexible, found in blood vessels and skin
- Reticular - forms a network - mesh kind of structure, made of collagen with a glycoprotein covering on top, provides support for the walls of blood vessels
It strengthens and supports connective tissue
What are the different types of cells found in connective tissue and their functions?
- Fibroblasts - large flat cells with brnching processes, responsible for secreting more ground substance and fibres. Fibroblasts can be found in specific connective tissue e.g. cartilage contains chondroblasts (similar to fibroblast) - secretes ground substance that forms cartilage
- Macrophages - form the foundation of the innate immune system, develop from WBCs and engulf material by phagocytosis
- Mast cells - produce histamine (chemical that dilates blood vessels)
- Adipocytes - fat cells that store triglycerides
What is the most abundant protein in the body?
What is the main function of connective tissue matrix fibres?
Collagen
Provide strength and support
What are the 2 types of proper connective tissue?
What are the 3 most common forms of loose connective tissue?
What are the 3 most common forms of dense connective tissue?
Dense = more collagen so more tightly packed; and Loose = more ground substance
Loose = areolar (most common, has lots of ground substance and tends to line organs), adipose (stores triglycerides), reticular (reticular fibres, forms mesh structure for support of some organs e.g. spleen)
Dense = irregular (skin dermis - irregular formation of collagen fibres), regular (tight collagen fibres to withstand force - tendons and ligaments), elastic (vertebrae)
What is the function of proper connective tissue?
What cells is it made up of?
What is found in the ECM?
Binding tissue, resists mechanical stress e.g. tension
Fibroblasts, fibrocytes, defense cells, fat cells
Gell like ground substance, collagen, and reticular and collagen fibres
What is cartilage and how is it supplied by blood and nerves? What are its functions?
What are the 3 types of cartilage and their compositions? And which of these is most common? Where are they found?
Cartilage is avascular (no blood supply) and no nerve supply either - found at joints = shock absorber, keeps bones in place etc.
Hyaline = most common but weakest of the cartilages as it has no collagen fibres, found in many articular surfaces e.g. synovial joints, and at the growth plates
Fibro = contains thick collagen and so is the strongest, acts as a shock absorber, found in intervertebral discs
Elastic = similar to hyaline but more elastic fibres in its ECM, provides strength and elasticity, found in the external ear
What is the function of cartilage?
What are the different cells found in cartilage?
What is found in the ECM of cartilage?
Strengthen and support connective tissue, resists compression, cushions and supports body structures
Chondroblasts (in growing cartilage), chondrocytes
Gel-like ground substance, contains collagen fibres, and elastic fibres in some
What are the 2 types of bone connective tissue?
What is the function of bone?
What cells is it composed of?
What is found in the ECM?
Spongey and Compact
Resists compression and tension, protection and support
osteoblasts, osteocytes, osteoclasts
Gel-like ground substance, calcified with inorganic salts (Ca2+), contains collagen fibres
What is the function of blood as a connective tissue?
What different cells is it composed of?
What is the ECM made up of?
Important for transport around the body - O2, CO2, nutrients, wastes and other substances
All subtypes of WBCs included (for immune responses), RBCs (for O2 transport), platelets (for blood clotting)
Liquid, plasma but no fibres
What are rheumatological disorders? What are some common examples?
Characterised by inflammation that affects the connecting or supporting structures of the body - not just joint disorders, although joints are most commonly affected
Rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), vasculitis
What is RA?
How can it arise and who does it generally affect?
What causes the swelling and pain of the joints?
Autoimmune disorder primarily affecting the joints resulting in painful joints - an inflammatory response
Genetic predisposition, then environmental trigger activates it / makes it worse - autoimmune cascade of joint damage
Generally affects females, aged between 20 - 40 (when symptoms begin to arise)
Inflammation of the synovial membrane leads to bone erosion, erosion of the hyaline cartilage, this can narrow the joint space resulting in joint deformity - leads to clinical manifestations of RA
What causes the inflammation in the joints of someone with RA on a microscopic level?
Which enzymes contribute to the cartilage destruction?
What are 3 key symptoms of RA?
Which joints are more affected by RA, small (fingers, feet) or big joints (hips)?
Cytokines (involved in regulating immune repsonse) acting abberantly, common cytokines involved include - TNF-alpha, IL-1, IL-6, and possibly IL-17 too
Proteinase enzymes contribute to cartilage destruction
Joint pain, swelling and stiffness
RA = affects both, but more likely in small joints - helps differentiate between RA and asteoarthritis (OA) as OA is more likely to manifest in large, weightbearing joints
Fill out this table of RA VS OA:
CRP goes up due to inflammatory response in RA
What are common signs on an X-ray to indicate RA?
Soft tissue swelling, erosions of the bones, joint space loss, subluxation (partial dislocation). osteopenia etc.
What is UCTD? What are 3 common examples?
Undifferentiated connective tissue disease
- SLE, RA and scleroderma
