Skeleton Flashcards
Function of the skeleton
- support
- muscle attachment surface
- protection of delicate organs
what type of tissue is bone
- mineralised connective tissue
*contains collagen and calcium
*calcium hydroxyapatite crystals give hardness
difference between cartilage and bone
bones are hard, inelastic and tough
cartilage is soft, elastic and flexible
What are the cells of bone
- osteoblasts = bone forming cells
- osteocytes = bone cells
- osteoclasts = break down + resorb bone
steps of endochondral ossification (long bones)
- cartilage model
- Bone formations - osteoblasts produce bone and ossify the cartilage, blood vessels enter
- marrow cavity forms - primary ossification occurs
- growth plates develop - bone formed in growth plates = secondary ossification
- mature bone and bone marrow
define endochondral ossification
bone formation in which cartilage models are gradually replaced by bone forming *mineralisation
Explain intramembranous bone formation
- bones forming directly within fibrous tissues
- e.g. dermal bones (skull and pelvis) - usually smooth
what are the 3 skeletal systems
- Axial
- appendicular
- heterotorphic
what’s included in axial skeleton
- skull and head bones
- vertebral column
- sternum and ribs
explain the groups of the vertebral collumn
- Cervical - neck, enable movement of head (7)
- thoracic - chest, attachments for ribs, support head (12)
- lumbar - connect to postural muscles/back - have larger spikes for muscle attachment (5)
- sacral - pelvic (5)
- candal - tail (variable)
what are the first two vertebrae called and their purposes
1st - Atlas = allow pivoting (nodding up and down), ring shaped/ gaps for spinal chord
2nd - Axis = allows head movement side to side
Explain what is included in the apppendicular system
limbs and gurdles
Basic structure of limbs (draw and label)
Front:
- humerus (larger)
- Radius (smaller) and Ulna
- carpals (wrist area), then metacarpals (first bone in finger), then phalanges (final finger)
Back:
-femur (large)
- patella (knee)
- Tibia (larger of the two), and fibula (skinny)
- tarsals (feet)
- metatarsals (back of toe)
- phalanges (toe)
what are girdles?
bones that support the attachment of limbs to axial skeleton
What’s included in the heterotorpic skeleton
- random bones e.g. penis bone
Different types of bones
- long bones - femur
- short bones - carpals
- flat bones - scapulla
- sesamoid - patella
- irregular - vertebrae
how does each type of bone form
long bones - endochondral ossification
short bones - EO
flat = intramembranous
sesamoid - within a tendon (ossification of tendon)
irregular - both or complicated
explain the shape of each type of bone
long - epiphysis (weird end shape), metaphysis (other end) and diaphysis (long thin middle)
short - single centre of ossification, cube/rectangular shape
flat - thin and flat in most areas
sesamoid - rounded, ball shaped (usually at joints)
irregular - weird shapes e.g vertebrae
what is a joint
where two or more bones are attached to enable movement
3 classifications of joints
tissue composition
degree of flexibility
movement permitted
what are the three catergories of joint flexibility
fibrous joint = immobile
cartilagenous = limited
synovial = freely mobile (have ligaments and tendons)
what are ligaments
fibrous connective tissue joining bone to bone
what are tendons
cord of strong flexible tissue connecting bone to muscle
compare and contrast EO and Intramembranous
bones formed - EO: long bones, I: flat bones
EO: catrilage model, I: no cartilage formation, direct formation of osteoblasts
Both involve mineralisation of osteoblasts into bone
speed- EO: slower, I: faster
differences between endo and exo skeleton
endo = internal, bone, grows over time with the organism
exo = external, rigid chitin, molting
what is a suture
rigid joint between two or more hard elements of an organism, with or without significant overlap of the elements.
