Basics Flashcards
What are the 3 major tissue components of the muscleskeletal syste
Bones
Muscles
Connective tissues
From which of the germ layers do the 3 major components arise?
Mesoderm
What are the functions of bone
Support
Protetcion - viscera - eg heart and lungs in thorax
Metabolism - actively metabolising - calciumand phosphate metabolism - bone is a massive store of there
Storage - minerals, protein store, stores fat, bone marrow is quite a fatty substance
Movement - joints, levers,
Haematopoiesis - production of blood cells
What are the functions of skeletal muscle
Locomotion
Posture - maintain equilibrium
Metabolic - glycogen metabolism in skeletal muscles
Venous return - muscles in leg compress deep veins - compress venous blood back up to heart
Heat production - skeletal muscle important for haemogenesis
Continence
What are the functions of connective tissue
Bottom 2 aren’t technically connective tissue
• Tendon connects muscle to bone - force transmission from muscle to bone
- Ligament - supportive function - bone to bone
- Fascia - sheets of connective tissue - function is to provide compartment eg compartments around muscles, is also protective
- Cartilage articulated cartilage at the end of bones contributed to joints - hyaline - coefficient of friction between bony suraces is like ice on ice. Fibrocartilage ahas many more collagen fibres - shock absorption - increase bony congruity - soft surfact allows bones to form easy articulation - allows articulate surfact to envelop other bone eg in the knee
- Synovial memb - releases synovial lucid to lubricate
- Bursa - synovial fluid filled sacs to protect tendons ligaments eg from fiction - protective function - freq around joints
What gives rigidity in the bone?
CaPO4 in the ECM - compressive strength
Collagen - tensile stregth
What calls are present in the bone?
Osteoblasts lay town ecm and mineralise it
Osteoclasts - release acidic substance, eats away bone
Osteocytes - osteoblast embedded in the matrix
(Fibroblats
Macrophages
Mast cells
Adipocytes)
Is bone dynamic?
- Bone is an extremely dynamic tissue
- Co-ordinated cellular activity maintains bone shape
- Calcium and phosphate can be liberated or stored depending on blood levels
What are different classifications of bone?
Long bones eg femur - levers
Short bones - as long as they are wide - work together to give great range of movement eg in wrist
Flat bones eg sternum, skull - typically involved in protection
Sesamoid bones - eg patella - they form within tendons - protective and mechanical functions
Irregular boenes - eg vertebrae - most abundant in axial skeleton
What is the significance of bony prominences?
Every feature has functional significance
Greater trochanter - muscle attachments - powerful muscle pulls on bone - rceates bony prominence
Largebony attachments
Sometimes muscle attachments are reoughenings on the surface of the bone
What are some surface features of bone?
Some bones have grooves eg over the humerus
Groove - implies nerve or vessel running over surface of bone
Olecranon ftis into hollow on humerous called olecranon fossa
Notches eg in pelvis
Foreman - window/hole - another class of foramena - little holes where blood vessels enter
Describe the blood supply to bone
Long bones normally have 1 major blood supply - nutrient artery - supported by periosteal artery
Growth plates in long bones - new bone laid down here to lengthen bone
Epiphyseal artery supplies epiphysis at end of bone - runs undependently of areas of bone supplied by nutrient artery
Fractures through top region can interfere bld supply from epip art - death of bone - in a child this can stop bone growth - asymmetric growth - when plates fuse - collateral supply coming from nutrient artery
What is avascular necrosis?
Bone will die if deprived of its blood supply, a condition known as avascular necrosis, which is particularly important in fractures of the scaphoid and neck of femur
Why might the shape of a humerous be different in, for example, a cricketer and swimmer?
Skeleton able to respond to environment variations arise due to balanced activity to osteoporosis blasts and clasts - remodel skeleton in response to stress and trauma
How does range of movement relate to stability
Joints connect one bone to another
Balance between range of movement and stability - stability = the probability of dislocation
stable = less prob of dislocation
Trade off
Eg
Skull - low ROM but high stability
Shoulder - high ROM but low stability
What are 3 joint classifications
LEAST MOBILE Fibrous Cartilaginous Synovial MOST MOBILE
What are fibrous joints?
- Essentially collagen fibres joining bones
- Very limited mobility
- Found where great strength/stability are required e.g. in skull
What are cartilaginous joints?
Cartilaginous joints
• Cartilage acts as ‘glue’ holding bones together
• Limited mobility
• Typically found at the ends of growing bones or along the midline of the adult body
Primary cartilaginous joints = growth plates
Secondary = eg intervertebral disc - thin layer of hyaline cartilage - fibro between the 2 - normally in midline = cartilaginous
What are synovial joints?
- Separate bones are capped by smooth articular cartilage with a thin film of synovial fluid separating them
- Frequently highly mobile
- Found all over the skeleton
What are different types of synovial joint?
Plane - 2 flat suraces tat slide against each other - fair degree of movement -cant separate bones
Hinge eg elbow - only allow movement in 1 plane
Pivot - peg in hole - peg rotates around long axis
Saddle - flexiona nd extension - or movement in a perpendicular plane - 2 planes of motion
Condyloid
Balls and Socket
How do synovial joints develop?
Bones develop as a rod of cartilage which becomes mineralised
All cartilage surrounded by perichondrium
Kill of chondrocytes at the point where synovial joint its to be built
Forming an interruption halfway - cavity of synovial joint
Capsule around joint Continuous with periosteum of bone
Some cartilage remained as intra articulate ligaments holding bones within joint together - knee
What are the classes of levers?
See notes/slide
What is the relationship between force generation and ROM
Longer bony process = increased force BUT less ROM
Describe muscle attachment points
o The origin is usually the ‘stationary’ proximal anchor point
o The insertion is usually the ‘mobile’ distal attachment point
o Either way, muscle contraction is ‘symmetrical’ exerting equal force on origin and insertion
o Origin and insertion can be ‘inverted’ if insertion point is fixed
Can muscles push?
NO only pull
Which joints can muscles act on?
Only joints which they + their tendons cross
Describe the action of a muscle on a joint related to its structure
• The action of a muscle on a joint is a function of the orientation of its fibres and the relation of those fibres to the joint
• The action of a muscle is a function of the starting position of the joint (usually described as starting in the anatomical position)
• Muscles work together and almost never in isolation
– The central nervous system co-ordinates this complex task
What do muscles lie within
Fascial compartments (deep fascia) Muscles in each compartment share common innervation and share common function
Name types of muscle
Parallel Fusiform Circular (sphincter) Triangular Pennate
How can muscle action be predicted?
• By looking at their structure (to infer their function)
– Where does it attach?
– How many joints does it cross?
– How is it related to the joint (e.g. anterior/posterior etc)?
– What direction do the fibres run in?
Are connective tissues connected to each other?
Yes
There is continuity between periosteum, joint capsule, tendon, epimysium and bone collagen matrix
What are alternative names for superficial fascia and deep fascia/
– Superficial fascia = subcutaneous fat, subcutis,
hypodermis…
– Deep fascia = epimysium of muscle
What causes skin creases?
Adhesion of skin to underlying fascia
Why do tendons heal slowly?
High collagen low elastic heal slowly - relatively poor bald supply and low amount of water
Mostly collagen in parallel bundles
Describe ligaments
Strong ligaments connect strong bones of the ligament
Hormone called relaxin relaxes ligaments of ilium in pregnancy - joints unstable
Ligaments - arches of feeet
Ligaments surround joints - periatrciuar ligaments - thickenings of joint capsule
Periosteum continuous with joint capsule
What are aponeurosis?
Sheets of connective tissue (dense regular)
“Flat tendons” - connect muscle to muscle
Sometimes connect muscle to bone
What is Hilton’s law?
Hiltons law - if we consider the nerves that supply a joint - these nerves also supply the muscles that cross the joint and the skin that overlies the insertions of these muscles
What are HOx genes?
Regulate segmentation eg
Hox genes regulate number of lumbar vertebrae - normally 5
