1.2 - Musculoskeletal System Flashcards
1
Q
What 3 components make up the musculoskeletal system
A
- Bones (and joints)
- Skeletal muscle
- Connective tissues
2
Q
Functions of bone
A
- Support (mechanical support structure)
- Protection (ie ribs for softer organs inside)
- Metabolic (calcium etc)
- Movement (joints)
- Storage
- Haematopoiesis
3
Q
Functions of skeletal muscle
A
- Locomotion
- Posture (maintaining good posture by low-level constant contraction)
- Metabolic
- Venous return (by squeezing the veins → increase pressure → transport blood back to the heart from the lower extremities)
- Heat production (thermogenesis via shivering)
- Continence (sphincters to prevent unwanted release of excretion)
4
Q
Different types of connective tissues + their functions
A
- tendons (involved in force transmission muscle–bone)
- ligaments (support bone-bone)
- fascia (sheets of connective tissue) for compartmentalisation and protection
-
cartilage
☞ articular: decrease friction
☞ fibrocartilage: shock absorbtion + increasing bony congriguity - synovial membrane secretes synovial fluid for joint and tendon lubrication
-
bursa are synovial fluid-filled sacs to protect tendons, ligaments etc from friction
note: synovial membrane + bursa are not always considered connective tissue
5
Q
What is the difference between tendon, ligaments and aponeuroses
A
Tendon: connects muscle + bone
Ligament: connects bone + bone
Aponeuroses: connect muscle + muscle (but sometimes to bone)
6
Q
What are the 3 main cells found in bones + what are their functions
A
- osteoblasts are the builders
- osteoclasts cells that destroy bone, liberating calcium + phosphates. Very similar to macrophages. Release acidic vesicles onto surface of bone to dissolve it
- osteocytes are osteoblasts that have become trapped within the extracellular matrix. These maintain the bones. Send out cytoplasmic projections, communicate with other osteoblasts + osteocytes and involved in bone remodelling.
7
Q
Classification of bones
A
- long ie humerus, tends to be levers
- short ie in wrist + ankels, act co-operatively in groups to perform functions
- flat ie sternum, act as shields to protect underlying structures
- irregular ie vertebrae
- sesamoid ie patella, form within tendons
8
Q
What are some surface features of bones
A
- grooves for nerves to run in
- notches eg greater sciatic notch, permitting the sciatic nerve to run by
- foramina are holes within the bone. These can be large or smaller, such as the smaller nutrient foramina that form on the surface, allowing blood vessels to travel through
- fossa are basin-like depressions
9
Q
Blood supply to bones
A
- The nutrient artery enters the diaphysis (shaft) of the bone and supplies blood to the inside of the bone. Most of the bone is dependent on this artery
- There are also periosteal arteries that supply the periosteum and outer third cortex of the bone
- In some bones there are the metaphyseal arteries and these enter the site of attachement of the capsuloe
- In children, these metaphyseal arteries do not cross the growth plate, so the epiphyseal artery supplies the secondary ossification centre in the epiphysis. When the growth plate disappears, an anastomosis is formed between the epiphyseal and metaphyseal arteries
10
Q
What is avascular necrosis
A
- When bone dies
- Occurs when bone is deprived of sufficient blood supply
- Particular important in fractures, where they could be cutting off blood supply to the bone
11
Q
Features + main classification of joints (more detail on other cards)
A
- Joints connect one bone to another
- There is a balance between the range of movement vs stability (ie probability of dislocation)
- Ie shoulder joints need good range of movement, whereas skull bones don’t
- They are classified as fibrous, cartilaginous and synovial
- Fibrous = most stable with lowest RoM
- Synovial = least stable with highest RoM
12
Q
Fibrous joints
A
- Most stable type of joint, but a low range of movement
- Essentially two adjacent bones glued together by collagen
- Found where great strength + stability are needed eg skull, teeth
13
Q
Cartilaginous joints
A
- Somewhere in the middle – somewhat stable and a fair range of movement
- Cartilage acts as a glue holding two adjacent bones together
- Typically found at the ends of growing bones or along the midline of the adult body
- primary are found in growing skeleton ie at growth plates
- secondary are found in pubic bones and in between vertebrae
14
Q
Synovial joints
A
- Separate bones that are capped with smooth articular cartilage, with a thin film of synovial fluid separating them
- Leads to a very low friction environment
- Feels like egg whites
- Often highly mobile, but not very stable
- Found all over the skeleton
- Joint capsule and periosteum surround the joint
- Around the synovial fluid is the synovial membrane (this also secretes the fluid)
15
Q
Types of synovial joint (probably also need to identify from photos
A
- Plane where two flat surfaces slide against each other, allowing for smooth movement in several directions along a single plane. Eg carpal bones of the wrist.
- Hinge allow for flexion + extension without sliding or deviation. Movement only occurs along a single plane. Eg elbow joint
- Pivot comprise a peg within a ring-shaped hole. Allow rotational motion without gliding. Eg atlanto-axial joint that allows the head to rotate whilst maintiaining the stability of the head on the neck
- Saddle two bones that fit together like a rider in a saddle. Allows motion in two different planes at the same time. Eg carpometacarpal joint at the base of the thumb
- Condyloid aka ellipsoid are similar to plane joints, but like two elliptical bowls nested together. Unlike B+S joints, they prevent rotation from occurring due to their shape. Eg atlanto-occiptal joint at the base of the skull
- Ball and socket allow stable movement in several directions without slippage. Most mobile type of synovial joints. Eg hip and shoulder joints
