Muscles, joints, tendons and ligaments Flashcards
Filaments in each myofibril are arranged into what? Thick filaments made of? Contains what act as molecular spring too? Dark bands called what?Proteins that link central region of A band?
Sarcomeres Myosin Titin A bands M line
Length and diameter of thick filament? How many per filament? How many heavy and light chains? Thin filament made of? Light band just actin called what?
1.6 micrometers long and 15nm diameter
300
2 heavy and 4 light chains
I band
I bands anchored to what? Length and diameter of thin filament? How many per filament? Filaments (F-actin) made of monomers of what? F-actin makes a chain of 2 what?
Z line 1 micrometer long and 8nm diameter 380 per filament Globular protein G-actin 2 alpha helices
What is tropomyosin and what does it do? 3 troponin types? What does each do?
Double alpha helix around actin- partially covers myosin binding sites on actin filament
Tn I- inhibitory
Tn T- binds tropomyosin
Tn C- binds calcium
Membrane AP propagates through what? Ca2+ in sarcoplasm combines with what causing what? Energised by what? What breaks link between actin and myosin? When does contraction end?
T- tubules
Troponin- allows tropomyosin to move away from myosin binding site on actin
ATP hydrolysis
Binding of new ATP molecule
When Ca2+ returns to ECF by Ca2+/ATPase pumps and Na+/Ca2+ counter transporters
What is needed for energy for muscle contraction? When is creatinine kinase released?
High energy from ATP and creatinine phosphate- short term energy store, replenished by creatinine kinase- released on muscle fibre damage
Functions of joints? 3 structural joint types? Examples of each?
Allows movement, weight bearing and transfers load evenly to MSK system
Fibrous, cartilaginous and synovial
Fibrous= teeth sockets, cartilaginous= intervertebral discs, synovial= metacarpophalangeal
3 functional joint types and examples?
Syntharthroses- immovable joints e.g. skull sutures
Ampiathroses- slightly moveable e.g. intervertebral discs
Diarthroses- freely moveable joints e.g. hip
What are sutures?
Between bones of skull- allow growth in development, adjacent ones interdigitate and filled with short connective tissue
What are syndesmoses?
Bones connected by a ligament/ sheet of fibrous tissue e.g. interosseous membrane between trivia fibula
What are gomphoses?
Peg in socket fibrous joint found inly in tooth articulation
What are 3 fibrous joint types? 2 types of cartilaginous types?
Sutures, syndesmoses, gomphoses
Synchondroses and symphyses
What are synchondroses?
Bones directly connected by hyaline cartilage e.g. costal cartilage of ribs
What are symphyses?
Connecting cartilage is a pad/ plate of fibrocartilage e.g. intervertebral discs
What are synovial joints known as? The 5 components of synovial joints?
Freely moveable joints
1) Articular cartilage 2) Joint capsule 3) Joint (synovial) cavity 4) Synovial fluid 5) Reinforcing ligaments
Features of articular cartilage?
Almost frictionless surface, resists compressive loads, high water content, low cell content, no blood supply
What is the inner layer of the joint capsule? What is the external layer? Features of the synovial membrane?
The synovial membrane
It’s continuous with periosteum (tough, fibrous)
Only few cells thick, can have villi and projections to increase SA, secretes synovial fluid components
What is the synovial cavity filled with? What does the synovial fluid cover, what is it modified from and what is in it?
Synovial fluid
Covers articulating surfaces with thin film- reducing friction during articulation
By plasma from synovial membrane
Fluid, proteins, charged sugars that bind water e.g. hyaluronate
3 types of reinforcing ligaments in synovial joints? What do ligaments do?
Intrinsic- thickened part of fibrous capsule
Extrinsic- outside capsule
Intracapsular- deep to capsule covered with synovial membrane
They connect bone to bone, stabilise joints and have less regularly arranged fibres than a tendon
What do tendons do and what do they have?
Connect bone to muscle, stabilise joints, allow muscles to be accommodated at a distance from their insertion, provides solid base on which muscles can pull
Dense, regular connective tissue
3 types of cartilage? Composition? What are proteoglycans made of and what do they do?
Elastic, fibrocartilage, hyaline cartilage
Water, proteoglycan, collagen and ions
PPC to which are covalently attached chains of sulphated disaccharide repeating units
High density of -ve charges allows binding of water, conferring properties of compressive stiffness and friction-free surfaces e.g. aggrecan
3 synovial joint lever types? Where is fulcrum, weight and resistance in 1st class levers?
1st, 2nd and 3rd class levers. Fulcrum in middle, force is at one end and resistance is at other e.g. elbow joint and triceps muscle
Fulcrum, weight and resistance in 2nd class lever?
Fulcrum at one end, force at other end and resistance in centre e.g. mandible joint
Fulcrum, resistance and force in 3rd class lever?
Fulcrum at one end, resistance at other end and force in middle e.g. below joint and biceps muscle