Locomotor Flashcards
What is comorbidity?
comorbidity is the presence of one or more additional conditions often co-occuring with a primary condition
What are the 3 parts of long bone?
metaphysics (head of the bone), epiphysis (growth plate) and diaphysis
What are chondrocytes?
They are the only cells found in healthy cartilage. They produce and maintain the cartilaginous matrix, which consists mainly of collagen and proteoglycans.
exclusively responsible for synthesis/breakdown of ECM components. Can synthesis. the full range of ECM proteins and can synthesis cartilage-specific ECM components such as collagen type II.
What happens in growth plates?
Areas of cartilage where growth takes place. Chondrocytes undergo dramatic growth and then die, leaving behind the basis of bone.
What are harris lines?
Also known as growth arrest lines- regions of increases bone density.
represents the position of the growth plate at time it was slowed down- possibly due to injury or malnutrition or possibly due to growth spurts
What is a recent technique used to fix leg length discrepancy in young aged patients?
The ‘8th plate’ is used, a high quality steel implant applied to leg growing too fast- letting the other catch up.
What is osteoporosis and what is the most common type?
Porous bones that are fragile to low impact trauma.
Most common type of OP is vertebral compression fractures
Symptoms of this are back pain and kyphosis (curvature of the spine)
What are the 3 types of connective tissue?
Connective tissue proper- loose and dense
Fluid connective tissues- blood and lymth
Supporting connective tissue- cartilage and bpne
What are the 3 types of cartilage?
hyaline cartilage, fibro-cartilage and elastic cartilage.
What is cartilage ECM made of?
Made of fibres, eg collagen, complex interstitial fluid and filling material known as proteoglycans.
What are the resident cells in cartilage, connective tissue and tendons?
chondrocytes in cartilage
fibroblasts in most CT
tenocytes (fibroblast-like) in tendons.
What are the basic functions of osteoclasts, osteoblasts and osteocytes?
OSTEOBLASTS= build new bone
OSTEOCLASTS= remove old bone
OSTEOCYTES= maintains bone matrix/ assists bone repair
How are the chrondrocytes arranged in collagen type 1 and type 2?
Type 1- rope like structure
Type 2- basket weave
What are fibroblasts and fibrocytes?
Two types of the same cell- fibroblasts are active, fibrocytes less active
They are connective tissue cells characterised by abundant rough endoplasmic reticulum and resposible for synthesis of fibrous matrix proteins particularly collagens.
Tissue damage stimulates fibrocytes to become fibroblasts
What are proteoglycans?
also called ground substance, unstructured material composed of negatively charged glycosaminoglycans which attract cations and swell and resist compressive forces.
What does the ‘modes of failure’ graphs look like for failure rate, wear and tare and random.
What occurs in red and yellow bone marrow?
Red bone marrow is where the production of blood cells takes place, a process known as haematopoiesis.
Yellow bone marrow contains adipose tissue, and the triglycerides stored in the adipocytes of this tissue can be released to serve as a source of energy for other tissues of the body.
What are the functions of bone?
Metabolism, producing RBC, structural, protective, facilitating respiration, storing of adipose tissue, and there are highly specialised bones, such as the bones in the middle ear as well.
Why and how have humans adapted to bipedalism?
- Freed the upper limb for other functions
- Enlarged hip and knee joints to cope with increased forces
- The foot has evolved to support entire body weight on one leg and so has lost its fine motor functions. Also have a highly stable tripod structure.
What are the phases of walking gate?
Heel strike is also known as initial contact
Gait cycle refers to the movement of one leg (two steps)
What is the structure of collagen?
3 polypeptide chains are wound together in a right-handed superhelix
there are H-bonds between chains
What is elastin?
Another ECM protein, which forms elastic fibres in lungs, arteries, skin and tendons.
What are glycosaminoglycans and proteoglycans?
These are major components of the extracellular matrix
GAGs are negatively-charged
Proteoglycans are formed of glycosaminoglycans (GAGs) covalently attached to the core proteins
Proteoglycans act as molecular sponges as they are associated with cations and water
What is cartilage made of?
80% water; the remainder is collagen (~2/3) and glycosaminoglycans (~1/3). GAG aggregates are maintained within a mesh of collagen fibrils. This confers elasticity and low friction in joints.
What is common in creation of collagen genes?
Because of the complexity of collagen genes, splicing errors are common.
There are many types of post-translational modification. Errors in these processes (caused by
mutations in genes encoding collagen itself or encoding processing enzymes) result in the failure of collagen secretion by fibroblasts.
What is hyaline cartilage?
Hyaline cartilage (e.g. articular cartilage) is found on articulating surfaces of moveable joints - adapted to withstand mainly compressive forces (i.e. load-bearing) although surface can withstand tensile (i.e. stretching) forces.
Contains chondrocytes
What is synovial fluid?
Primary source of nuticion and removal of waste for cartilage cells
Produced by synoviocytes of the synovial membrane
What is fibro-cartilage?
Fibro-cartilage (e.g. intervertebral disc, meniscus) adapted to withstand mainly tensile but also compressive forces.
Supports bone to bone contact
Collagen fibres thick and have clear parallel orientation.
Mainly fibroblasts but also some chondrocytes
What is elastic cartilage?
Contains elastin- highly and reversible deformable.
Similar to hyaline- chondrocytes synthesise some collagen but mainly elastin
Why are you taller after you have slept?
When cartilage is static, fluid builds up
How is cartilage able to withstand load?
- No blood vessels or nerves (fragile)
- No epithelium at the cartilage surface- this is delicate so would be damaged on movement
- Low cell density (1-10%)
- There is a complex ECM (fibre-reinforced gel) which is highly resiliant and adapted to compressive and tensile forces.
What are osteogenic cells?
Precursor cells that differentiate into various different lines of cells (includes adipocytes, myocytes, chondrocytes and osteoblasts) depending on the mechanical environment they exist in.
Also known as osteoprogenitor cells
They can be present within the bone marrow, the endosteum and the cellular layer of the periosteum.
What is the endosteum and periosteum?
The periosteum is a membranous tissue that covers the surfaces of bones
Endosteum lines the inner surface of the medullary cavity of all long bones.
What effects osteoprogenitor cell’s fate?
Their fate is determined by environment- when there is minimal movement in the environment, become osteoblasts. If there is more movement in the local tissues, they become chondrocytes.
What are osteoblasts?
Single nucleus cells. Functions- form bone by producing non-mineralised matrix.
When synthesised by PTH (parathormone) they produce type 1 collagen and enzymes which initiate the calcification of the matrix by laying down deposits of calcium phosphate
Also regulates osteoclasts by producing RANK-ligand which bonds to RANK nd stimulates osteoclast precursors to become active osteoclasts, thus stimulating bone resorption
What are the 4 main types of tissue?
Epithelia, neural, muscular and connective.
What is connective tissue?
Makes up roughly half of body weight, consists of widely seperated cells situated in a ECM.
Main components are cells- both resident and immigrant
ECM- cotains proteins eg collagen, ground substance eg proteoglycans and GAGs
there is also intersitial fluid
What immigrant cells are present in connective tissue?
Macrophages- specialised cells involved in the detection, phagocytosis and destruction of bacteria
Lymphocytes-a type of white blood cell, produce antibodies
Neutrophils- a type of white blood cell
What are the two types of resident cells in connective tissue? And what is their function?
Fibroblasts and chondrocytes
Active secretion and synthesis of ECM components, some degradadive enzymes
Fibroblasts synthesis and secrete collagen, elastin, fibrillin and PGs
Chondrocytes are collegen and PGs
What are the 4 main proteins of the ECM?
(A) collagen- rope like- determines tensile properties
(B) elastin- determines elasticity
(C) Fibrillin- forms microfibrils that act as scaffold for elastin
(D) fibronectin- attachment point for anchoring of cells
What are the two causes of Osteoporosis?
- Primary-* due to the effects of aging, post-menopausal and decreased renal function
- Secondary-* associated with other causes such as diabetes, Vit C deficiency ect
What occurs in osteoarthritis?
Progressive destruction of articular cartilage- fibrillation (splitting) or the cartilage occurs. Hydration increases and PG decreases. This pushes collagen fibres away from each other and the cartilage breaks down. This exposes the sub-chondral bone and the resulting friction can be painful.
What occurs in rheumatoid arthritis?
Inflammation of synovial fluid- instead of it being smooth it is covered
What are a few perinatal modes of failure?
Spinal scoliosis
congenital deficiences- disorders that result from failure of formation of a bony part of the body
Developmental deformity of the hip
Growth disorders- endocrine or genetically or nuticionally caused
Trauma to physis can cause abnormality
What are some examples of trauma modes of failure?
Ligament and tissue injury
Fractures
What are some examples of elderly modes of failure?
What is different about running gate from walking gait?
There is a float phase
Increased movement at all joints in the leg
Increased stride length and shorter cycle time
What is bone made of?
20% collagen, 70% inorganic salts and 10% water.
Major mineral is hydroxyapatite, but other ions also present in the crystal lattice
What does immobilisation of cartilage cause?
Thinning, however this is REVERSIBLE
What are the 4 principle components of articular cartilage?
Collagen
Proteoglycans (have GAGs attached to them)
Interstitial fluid (also known as ground substance)
Chondrocytes (only living cell)