bones and associated cartilage, tendons and ligaments
Why are bones resilient?
because of their elastic protein matrix, and strong because of mineral salts deposited in this matrix
The skeleton works together with ____ to create movement
Bones are made of ______ _______
The stone like appearance comes from _________________
mineral salts like calcium phosphate
The 5 functions of the skeletal system are: ___________________
Support surrounding tissues Protect vital organs Provide levers for muscles to pull on generating movement Manufactures blood cells (hematopoiesis) Stores mineral salts (calcium, phosphorus) and fats
Poiesis means: __________
The skeletal systems connective tissues are: ___________
cartilage ligaments tendons
Environment in which bone develops in fetus found at ends of bones and in joints Provides smooth surface for bone to bone areas
attach bones to bones
attach muscles to bones
Bone develops from: _____________
Osteoblast cells originate in the: ___________________
periosteum and endosteum of the bone.
Osteoblasts mature to become: ____________
Deposition of bone depends on: ____________
strain or pressure on the bone (exersize)
Step 1: Broken Bones
A broken bone stimulates osteocytes (mature osteoblasts) to proliferate.
Step 2: Broken Bones
They secrete large quantities of protein matrix, to form new bone
Step 3: Broken Bones
Osteoclasts are present in bone cavities, derived from the immune system they cause bone reabsorbtion, and remodelling.
Step 4: Broken Bones
Osteoclasts remove bone from the inner side and so remodel bone as after a break and can make a crooked bone straight
The two types of ossification are: _______ and _______
Intramembranous Endochondrial (both result in cancellous and compact bone)
Maintaining Bone requires calcium whose concentration is controlled by 2 hormones of the endocrine system:
causes calcium release into blood
results in calcium storage in bones
What happens to excess calcium?
excreted by kidneys and digestive system
Cancellous bone means: _______
Dense connective tissue membrane is replaced by inorganic salts like calcium, forming bones. This connective membrane becomes the periosteum, over a layer of compact and a layer of spongy bone. Only cranial bones are formed this way, complete ossification of the skull is not complete until fontanels close after birth.
This is when bone develops inside cartilage environment. Osteoblasts become completely surrounded by protein matrix and become mature bone cells or osteocytes Produces all other bones of the body
forming new bones By end of 3 months fetus skeleton is completely formed but mostly cartilage Begins ossification and grows as osteoblasts invade cartilage
Dense and strong Contain "Haversian canals" Blood vessels run parallel to surface of the bone These are surrounded by concentric rings of bone (lamella) Between rings of bone are Lacunae cavities containing osteocyte connected to the central haversian canal by canaliculi. Horizontal open areas contain blood vessels and fluid that nourish bone cells (osteocytes)
Functions of havesian cannals:
dense and strong with Haversian systems of central canals surrounded by rings of bone. Rings separated by lacunae, connected by canniculi. Horizontally blood vessels run through these canals bathing osteocyte with 02 and food, excreting waste
. Cancellous or spongy bone
Found at ends of long bones and forms the center of all other bones Spongy appearance created by meshwork of bone (trabeculae) with spaces filled with bone marrow
What else does Cancellous bone do?
Function as open spaces where bone marrow filled with red bone marrow performs hemapoesis. In adults found in vertebrae, sternum, pelvis, end of humerus (upper arm) and femur (thigh). Areas decrease with age.
Bone Marrow is found in:
the spaces of certain spongy or cancellous bones
Red marrow whose functions is...
Hematopoiesis (formation of RBC, WBC & Platelets). Contains blood cells in all stages of development.
Red marrow is found in the:
ribs, sternum, vertebrae, and pelvis
Yellow Marrow is:
connective tissue containing fat cells.
Yellow Narrow is found:
chiefly in shafts of long bones.
Bones are classified by these 4 shapes:
Long Short Flat Irregular
Structure of a long bone includes:
Diaphysis Metaphysis Epiphysis Epiphyseal growth line
shaft filled with yellow marrow
Epiphyseal Growth Line
where longitudinal growth occurs
Longitudal growth of bones for girls stops at what age?
Longitudal growth of bones for boys stops at what age?
Maturation and remodeling of skeleton continues till _____ for women and men.
Lack a long axis- consist of spongy cancellous bone covered by thin compact layer.
Shaort bones have a:
Somewhat irregular shape.
Short bones are NOT:
merely shorter versions of long bones.
Thin bones found wherever need for extensive muscle attachment.
The shape of a flat bone is:
Where do you find flat bones?
sternum, ribs, scapula, parts of pelvic bones skull
What shape do irregular bones have?
Examples of irregular bones are:
vertebrae, ossicles of ear
Irregular bones are:
Spongy bone enclosed by thin layers of compact bone.