Skeletal System Flashcards
What is the skeletal system composed of
Bones, cartilage (Articulations), connective tissue (ligaments and tendons)
What are the functions of the skeletal system
Support, provide leverage for body movement, protection, store minerals and lipids And blood cells synthesis
What is Cartilage‘a function
Support, cushion, and absorb shock
Avascular
What are the components of cartilage
Ground substance which holds a lot of water and helps resist compression
Collagen fibers which provides strength and flexibility
Elastic fibers which allow for elastic recoil
Chondroblasts which form extra cellular matrix and give rise to the chondrocytes
Chondrocytes which maintain and repair matrix
What are the three types of cartilage tissue
Hyaline cartilage – firm matrix with collagen fibers
Elastic cartilage – for matrix with elastic fibers
Fibrocartilage – for matrix with extra thick collagen fibers
In embryos what is the skeleton first made up of (cartilage tissue)
Hyaline cartilage
Where is the cartilage that’s not replaced by bones in adults
Articular cartilage – cover ends of long bones
Articular disc – found in certain movable joints
Costal cartilage – connect ribs to sternum
Laryngeal cartilage- Found in voice box
Tracheal/bronchial Cartilage – support windpipe
Nasal cartilage – support external nose
Intervertebral disc – separate and cushion vertebrae
What are the four types of bone cells
Osteogenic cells – bone stem cells
osteoblasts– Immature bone cells
Osteocytes – mature bone cells
Osteoclasts- Bone dissolving cells
What are the functions of osteogenic cells
They are bone stem cells that give rise to osteoblast and osteocytes
What are the functions of osteoblasts
Immature bone cells that lay down new bone matrix
What are the functions of osteocytes
Mature bone cells that maintain bone matrix
What are Osteoclasts and their function
Bone dissolving cells that break down bone matrix
What are the two components of bone matrix
Collagen fibers and ground substance
What are collagen fibers And their function
Protein component of bone that provides Flexibility and tensile strength
Without collagen bone would be brittle and shatter underweight
What is ground substance and what is their function
It contains calcium phosphate which is a mineral component of the bone and makes bone hard and durable
Without calcium phosphate bone Would be too flexible and soft to carry weight
What is bone homeostasis
Maintenance of bone matrix
Bone is a living dynamic tissue, bone cells continually recycle the protein ______ And minerals ______ Of the bone matrix
Collagen, calcium phosphate
___ and ___ do this by dissolving the adjacent matrix and releasing the minerals into the bloodstream
Osteoclasts and osteocytes
__ and __ Then rebuild the matrix by redepositing calcium and phosphate obtained from the bloodstream
Osteoblasts and osteocytes
Osseous tissue
Bone tissue
What are the five classifications of bone
Long bone, short bone, flat bone, irregular bone and sesamoid bone
What is Diaphysis and function
Shaft
Long hollow to that provide leverage for muscles
The walls are made up of compact bone in the hollow shaft contains bone marrow
Why are bones highly vascular
Because blood supply is critical for bone formation and bone homeostasis
Name of hole in diaphysis that allows blood vessels to penetrate bone
Nutrient foramen
Metaphysis
Zone between diaphysis and ends of long bones
Where is Epiphysis and what is the function
 proximal and distal end of long bones
Shaped like enlarged knobby ends
Helps form joints and provide attachment site for tendons and ligaments
Spongy bone with outer shell of compact bone
What is articular cartilage
Thin layer of smooth hyaline cartilage that covers the epiphyses
Provide low friction service and articular 
 what are the six histological features of long bones
Compact bone, medullary cavity, spongy bone, Periosteum, endosteum and epiphyseal
What is compact bone
Dense Osseotissue 
Outer walls of Epiphysis and diaphysis
Medullary cavity
Hollow cavity within diaphysis
Contains bone marrow 
Spongy bone
Trabecular bone
Mainly in Epiphysis
Almost always enclosed by more durable compact bone
Periosteum
Connective tissue membrane that surrounds compact bone
Outer bone surface except joints where articular cartilage is found
Contains osteogenic cells osteoblast And osteoclasts
For bone growth remodeling and healing
What happens if periosteum is removed or damaged during injury
New bone cannot grow and fracture cannot heal
Endosteum
Connected tissue that lines the medullary cavity
Inner surface of diaphysis
Contains osteogenic osteoblasts and osteoclasts
For bone growth remodeling and healing
Epiphyseal plate
Epiphysis near the metaphysis
Hyaline cartilage tissue type
Longitudinal bone growth in children

What is the Epiphyseal line
When Long bone has stopped growing, Highland cartilage is replaced by bone
On x-rays bone appear light to radio opaque
Cartilage appears dark to radiolucent x-rays because they can pass through cartilage 
What are compact bones Consist of
Bone cells and bone matrix arranged in cylinder osteon
Another name for osteon
Haversian system
What is osteon
A basic functional unit of compact bone
Smallest structure capable of carrying out main function of system
Run along the long axis of bone
Resemble targets of a central canal as bull’s-eyes
Another name for central canal
Haversian canal
What is the function of central canal
Carry blood vessels and nerves to osteon
Generally run parallel to the surface of the bone
What is another name for perforating canals
Volkman canal
What is the function for perforating canals
Connect central canal of neighboring osteons
Generally run perpendicular to the surface of the bone
What is lamellae and the two types
Layers of bone matrix
Concentric lamellae and circumferential lamellae
Concentric lamellae
Layers arranged and rings around central canal
Osteocytes, lacunae, canaliculi
Circumferential lamellae
Layers of bone matrix that hold together multiple osteon
Found in inner and outer border of compact bone, It wraps around and hold together clusters of osteon
To resist twisting forces
What is the function of osteons in compact bone
Longitudinal orientation of multiple Osteons provide great compressive strength
What type of bone is loosely organized osseous tissue
Where the cells and bone matrix form trabeculae
Spongy/trabecular bone
What is trabeculae
Spike of bone matrix in multiple direction that form delicate web
Mainly in Epiphyses and metaphyses
What is the function of trabeculae
To provide some strength without adding additional weight
Houses bone marrow in between trabeculae
What are the two kinds of bone marrow
Red bone marrow and yellow bone marrow
Red bone marrow
Blood stem cells that produce red and white blood cells
What type of Bone marrow is found in almost all bones in infants
Red bone marrow
During development bone marrow turns into ___
Yellow bone marrow
Red marrow is found only in the medullary cavities of
Skull, vertebrae, ribs, sternum, headphones, proximal epiphyses of humorous and femur bone
Yellow bone marrow
Adiposites for energy storage
Where is yellow bone marrow found in adults
In all medullary cavities of extremities except proximal end of humerus and femur bones
Bone growth lengthwise
Growth along the long axis of bone
Responsible for elongation of limbs
Occurs during infancy through puberty
Grows in growth plate aka epiphyseal plate 
Bone growth widthwise
Growth along the short axis of the bone
responsible for increase in width and overall bone density
Occurs during infancy through puberty
Location of growth
In the __  (The sheath of connective tissue that covers outside of compact bone) ___ Form new bone matrix on outer surface
Periosteum, osteoblasts
Location of growth
In the ___ (The connective tissue that lines the medullary cavity) ___ Dissolve bone matrix on inner surface
Endosteum, osteoclasts
Location of growth
As a result the medullary cavity gradually enlarges as a bone increases in diameter which results in
Overall proportional bone growth
Bone remodeling
Responsible for bone maintenance and homeostasis
occurs in all stages
Bone cells continuously reshape bone matrix depending on patterns of use or disuse
What is a balance between mineral deposition in mineral resorption
Bone modeling
Mineral deposition
Osteoblast and osteocytes lay down new bone matrix by pulling Calcium and phosphate from the blood
Mineral resorption
Osteoclasts and osteocytes dissolve bone and release calcium and phosphate back into the blood
