How many bones does the skeleton have?
206
What two parts is the skeleton divided into?
Axial
Appendicular
Axial Skeleton
axis of the body
Appendicaular Skeleton
extremities
What is the axial skeleton function?
Support and Protect
Comprised of:
skull, vertebral column, rib cage
What is the appendicular skeleton function?
locomation and manipulation
Comprised of:
arms, shoulder, legs, hips
What are the 5 types of bones?
Long
short
flat
irregular
sesamoid
Long bones
longer then it is wide
shaft plus 2 ends
named for it shape
most bones of the extermities
Example of long bones
femur
phalanges
Short bones
cube shaped
Example of short bones
wrist
ankle bones
patella
Flat bones
flat, thin, can be curved
Example of Flat bones
sternum
scapula
ribs
skull bones
Irregular Bones
complicated, don't fits in other category
Example of Irregular Bones
vertebrae,
hip bones
Sesamoid bones
form in a tendon
Example of Sesamoid Bones
patella
What are the functions of the bones?
Support
Protection
Movement
Storage
blood cell formation
Support
lower limbs, ribs
Protection
vertebrae
ribs
cranium
pelvis
Movement
act as levers when combined with muscles
Storage
Minerals
Triglycerides
Minerals
Ca++, PO4 released into blood as needed
Triglycerides
Stored energy sources
Blood cell formation
(RBC only)
occurs in marrow cavity
(known as hematopoiesis)
Bone Markings
sites muscle and ligament attachments
pathways for nerves and vessels
3 Categories
Projections
Depressions
Openings
Projections
Bulges, outward growths
Indications of stress from the pull of muscles
Modifies surfaces to form joints
Depressions
Indentions in the bone
Openings
Passageway thru bone
What are the 12 Bone Marking Projections
Tuberosity
Crest
Trochanter
Line
Tubercle
Condyle
Epicondyle
Spine
Process
Head
Facet
Ramus
Tuberosity
large and rounded
ex. ischial tuberosity
Crest
Narrow and prominent ridge
ex. lliac crest (on hip bone)
Trochanter
large, blunt, irregular, shaped
ex. greater trochanter
Line
Narrow ridge
ex. Pectineal line (in femur)
Tubercle
Small and rounded
ex. lesser tubercle
Condyle
rounded articular(joints) projection
ex. mandibular condyle
Epicondyle
raised area, above a condyle
ex. medial epicondyle (humerus)
Spine
sharp, slender, pointed
ex. scapular spine
What are the 4 Bone Marking of Depressions
Groove
Notch
Fossa
Groove
furrow
ex. radial groove
Notch
indentation at the end of a bone
ex. sciatic notch
Fossa
Shallow, base-like
ex. Olecranon Fossa (is on Humerus)
What are the bone marking openings?
Foramen
Meatus
Sinus
Fissure
Foramen
Round oval opening
ex. vertebral foramen
Meatus
Canal like passageway
ex. external acoustic meatus (skull)
Sinus
Cavity within a bone
ex. ethmoid sinus
Fissure
Narrow and slit-like
ex. superior orbital fissure
Compact Bone- Microscopic
Functional unit of bone osteon
Central canal
contain nerves, vessels
Lamellae
Concentric rings-collagen
Conllagen fibers in adjacent lamellae run in different directions, help withstand
twisting forces
Lacunae
Small spaces, house osteocytes
Canaliculi
connect lacunae (tiny little cells)
Osteocytes
maintain bone matrix, send message to other cells
Name part A,B,C
A- Lamellae
B- Central Canal
C- Lacunae
What are the 2 Bone Textures
Compact and Spongy Bone
Compact Bone
Outlayer
Appears smooth and solid
Composed of ostoens so is also called Lamellar bone
Spongy Bone
internal
Honeycomb appearance
Trabeculae or empty spaces
Filled with bone marrow in living
What is known as Woven Bone
Trabeculae
Chemical Composition
Organic components
Inorganic components
Organic componenets
Cells: Osteoblasts, osteoclasts, osteocytes
Osteoid:
Gound substances, collagen fibers
Osteoid Functions
help with structure, give flexibility and strength
Inorganic componenents
hydroxyapatities: mineral salts
Hydroxyapatites Functions
give bone it hardness, resist tension
Long Bone Parts
Diaphysis
Epiphysis
Metaphysis
Diaphysis
Tubular shaft, long axis
thick collar of compact bone
Surrounds medullary cavity
Epiphysis
end of the bone
wider then diaphysis
covered with articular cartilage- hyaline
Metaphysis
where diaphysis and epiphysis meet
Epiphysial plate
active site of bone growth-kids
Epiphysial line
adult remnant of the plate
Periosteum
Covers exterior part of bone except the joint surface
-white double layer membrane
-rich with blood vessels,nerves, lymphatic vessels
Fibrous layer
outer layer, dense irregluar CT
Osteogenic layer
inner layer formed by cells
What are 2 osteogenic layers
osteoblasts
osteoclasts
Osteoblasts
secret bone matrix, bone forming
Osteoclasts
bone destroying cells
Medullary cavity
central core of shaft
In adults the medullary cavity contains
yellow marrow-fat
In children the medullary cavity contains
red marrow
Hematopoietic tissue
where red marrow is
Hematopoietic tissue is found
medullary cavity and some areas of spongy bone
Hematopoietic tissue is found in infants
diaphysis and all area of spongy bone
Hematopoietic tissue is found in adults
epiphysis of femar/humerus, sternum, hips
yellow marrow can turn to red marrow
Endosteum
covers internal bone surface
Endosteum contains both
osteoclasts and osteoblasts
Articular cartilage
covers epiphysis
Articular cartilage composed of
hyaline cartilage
Articular Function
Cushions end of bone during joint movements
Nutrients foramina
Allows vessels and nerves to enter diaphysis
Short Bones
similar structure but no significant marrow cavity