bones and movement - finish on laptop Flashcards
axial skeleton -
80 bones
protection of internal organs
appendicular skeleton -
126 bones
appendages and supporting bones
movement
how many bones in the body:
206
types of bones:
Late Students Fail In Summer
Long bones Short bones Flat bones Irregular bones Sesamoid bones
Long bones -
e.g. humerus, femur, tibia, fibula, fingers
- long shaft
- two articular surfaces
- mostly compact bone
Short bones -
e.g. trapezoid, wrist, ankle
- cube shaped
- thin layer of compact bone with spongy centre
Flat bones -
e. g. skull, sternum
- parallel layers of compact bone and spongy centre
Sesamoid bones -
e. g. patella
- bones embedded in tendon or muscle
red bone marrow =
production of RBC, platelets, most WBC
yellow bone marrow =
higher fat content
production of some WBC
at birth…
all bone marrow is red but with age there is a conversion of red to yellow marrow
in an adult…
50% of bone marrow is red - mainly flat bones and spongy proximal ends of femur and humerus
marrow adipocytes -
high levels of yellow marrow
- can restrict haemopoiesis and osteoblast activity
- marrow adipose tissue acts as an endocrine organ to increase serum adiponectin (also released from fat)
- adiponectin = detrimental metabolic and cardiovascular effects
magnetic resonance imaging of vertebral marrow shows -
exercise lowers vertebral fat fractions
exercise helps prevent the loss of re bone marrow (= less yellow marrrow)
80% of the skeleton is…
compact (cortical) bone
20% of the skeleton is…
spongy (trabecular) bone
- light, resists stress, transfers force, supports and protects red bone marrow
extracellular matrix (ECM) of bone:
25% water
25% collagen fibres - provides flexibility (less brittle = allows absorption of shock)
50% crystallised mineral salts - provides hardness
calcification -
crydstalised mineral salt deposits (calcium phosphate and calium carbonate) in framework formed by collagen fibres - provide hardness
osteogenic cells =
located in inner periosteum, endosteum, bone canals with blood vessels
cells divide to form osteoblasts
osteoblasts =
bone building cells
secret collagen for ECM
initiate calcification
become trapped in ECM and become osteocytes
osteocytes =
mature cells -
maintain metabolism
exchange nutrients and waste with blood
osteoclasts=
large cell formed from fusion of many monocytes
release enzymes and acids to break down ECM (break down bone - used in repair of damaged bones)
movement…
the appendicular skeleton - bones of limbs and girdles that attach limbs to axial skeleton
movement relies on joints
fibrous joints =
bones joined by fibrous connective tissue consisting of collagen fibres
immovable/fixed
e.g. skull bones are connected by fibrous joints called sutures
cartilaginous joints =
bones held together by cartilage
no synovial cavity = little/ no movement
e.g. pubic symphysis
synovial joints =
bones held together by connective tissue and often by ligaments
synovial joints are surrounded by a articular capsule
allow movement
articular capsule =
surrounds synovial joints
synovial fluid provides lubrication for movemnt
reduces friction and shock
effect of warming up on synovial joints:
encourages production and secretion of synivoal fluid = less stress on joints
ligments =
join bone to bone
tendons =
join muscle to bone
