The Skeletal System Flashcards
bone tissue
- made of protein collagen, hardened by calcium phosphate
- two types of tissue:
- compact (cortical) = hard outer layer, dense/strong/durable
- spongy (cancellous/trabecular) - internal, lighter, less dense, flexible. consists of network of rod like structures
cellular components of bone -> osteoblasts
responsible for making new bone/repairing older
produce protein mixture -> osteoid = mineralized = bone
also manufacture hormones
cellular components of bone -> osteocytes
inactive osteoblasts (trapped in bone created)
maintain connections to cytes/blasts
important for communication w/in tissue
cellular components of bone -> osteoclasts
large cells, 1+ nucleus = break down bone
release enzymes/acids -> dissolve minerals = resorption
help remodel injured bones
bone function - protection
give a supportive structure or framework for the body
bone function - movement
attachments for tendons and muscles = movement
muscle contracts -> pull on bone = movement
bone function - boundary
boundary to thoracic, pelvic, cranial cavities
protective role for vital organs (hold in place -> efficient functioning)
bone function - RBC production
haemopoiesis (RBC production) in red bone marrow (spongy inside)
also produces WBC -> immune response
bone function - storage
area for Ca, P, Na, K
calcium = healthy bones/bp regulation
phosphorous = healthy bone/teeth
sodium and potassium = fluid balance, nerve transmits, muscles contract
long bones
consist of 2 extremities + shaft
found in limbs as bone is longer than width e.g. femur, tibia
role = strength/structure/mobility
structure of long bone
diaphysis = compact bone/central medullary canal/composed of fatty yellow bone marrow
epiphysis = outer cover of compact present, spongy = inside
periosteum = complex vascular 2 layer membrane (outer - fibrous = protection) (inner = osteoblasts + osteoclasts)
short bones
no extremities or shaft, different shape/size = roughly cube (same width and length)
e.g. carpals of the wrists
role = stability/some movement
irregular bones
no regular shape of characteristics
e.g. vertebra and some skull bones
role = protection of vital organs
flat bones
provide flat areas for muscle attachment, usually enclose cavities for organ protection
e.g. some skull bones, sternum and ribs
sesamoid bones
small bones developed in tendons around some joints
e.g. patella/knee cap
role = reinforce/decrease stress on tendon
axial skeleton
forms long axis of the body, includes bones of skull/spine/ribcage, and the clavicle
axial skeleton -> spine bones
cervical (7) C1-C7 (C1 = atlas, sits on C2 = axis)
thoracic (12) T1-T12
lumbar (5) L1-L5
sacral (5 fused) S1-S5
coccygeal (4 fused)
appendicular skeleton
bones of the upper and lower limbs and their girdles that join to the axial skeleton
fibrous joints
structure -> tough connective tissue
function -> permit no movement + stability
e.g. joints between skull
cartilagenous joints
structure -> connected entirely by cartilage
function -> acts as a shock absorber
e.g. rib
synovial joints
structure -> space with a capsule between two articulating bones
function -> movement e.g. flexion and extension
e.g. shoulder
features of synovial joints (structure + function)
ligament: band of strong fibrous tissue, connect bone to bone (stability)
synovial fluid: slippery fluid contained within joint cavity, reduce friction between articular cartilage and joint (mobility)
articular cartilage: spongy, covers ends of bones in the joint, absorb shock and prevent friction between end of bone and joint (mobility)
joint capsule: tough fibrous tissue (2 layers), strengthen joint and secretes synovial fluid (stability)
types of synovial joints -> movements and examples
hinge = flexion/extension e.g. elbow
ball and socket = circumduction, flexion/extension, abduction/adduction e.g. shoulder
pivot = rotation e.g. atlas and axis
plane = gliding/sliding e.g. tarsals
saddle = rotation, circumduction, flexion/extension e.g. thumb
condyloid = flexion/extension, circumduction, abduction/adduction e.g. between radius and carpals
connective tissue
made of collagen and elastin fibers
connect muscular and skeletal system
cartilage/ligaments/tendons
cartilage - structure and function
specialized connective tissue present in joints/ears/nose/rib cage/bronchial tubes/invertebrate discs
avascular -> very slow healing
shock absorption/joint lubrication/reduce friction
types of cartilage
hyaline - smooth/lines articular surfaces of all long bones/found in ribs and trachea/glassy/no nerves or blood vessels
fibrous - tough and strong/lots of collagen
elastic - main protein = elastin (flexible)/found in pinnae (external ear flap)
ligaments - structure and function
regular collagen fibers, slightly elastic, strong fibrous band of connective tissue
connect bone to bone, control movement and stability of joints, support organs
tendons - structure and function
soft, connective tissue found throughout body, less elastic and arranged in parallel fibers
transfers force between muscle and bone to crease movement
osteopenia
condition of lower than normal bone density
osteoarthritis (OA)
degenerative, slow onset
affects fingers and weight bearing joints
severe cartilage destruction -> rubbing of bone on bone
rheumatoid arthritis (RA)
autoimmune disorder, rapid or gradual onset (week/month)
affects bilateral joint involvement e.g. wrist, hand, elbow, feet
accessories of synovial joints
bursa (pl. bursae) - fibrous sac lines with synovial fluids, function = prevent friction
meniscus (pl. menisci) - making the joint more stable and reducing wear and tear on joint surfaces.
pad of fat - provides cushioning between the fibrous capsule and a bone or muscle.
