Anatomy and Physiology Unit 2.5 Histology of Osseous Tissue Name:______
(Chapter 7-2) pg 217-220 Slides 11-24
Bone is actually a connective tissue that consists of ______, ______, and ______
Bone Cells: There are four principal types of bone cells:
Osteogenic (osteoprogenator ) cells
Osteoblasts
Osteocytes
Osteoclasts
1.Osteogenic cells:are ______that develop from fibroblast and give rise to most other bone cells. They are found in the______, ______and the______Since they are stem cells they multiple constantly and differentiate to become______.
Osteogenic means______
2. Osteoblasts are ______. They line up in a single layer on the bone surface, under the ______and the______. These cells synthesize______-__
which then hardens by mineral deposition. THESE CELLS ARE NON-MITOTIC.
Osteoblast means______
Bone Stress and Fractures stimulate ______cells to multiple rapidly to generate increased numbers of ______-which rebuild and reinforce the bone.
3. Osteocytes are former______that have become trapped in the matrix they deposited. They reside in tiny ______called______which are interconnected by slender channels called______. These cells have fingerlike projections (cytoplasmic processes) that connect to other osteocytes and sometimes to also to osteoblasts. They exchange nutrients,and ______to one another and can pass ______to the nearest blood vessel in this way.
Osteocyte means______
Multi-functionality of Osteocytes:
some re-absorb bone matrix and others______
This is important in maintaining the homeostasis of ______and blood concentrations of
calcium and ______. They are Strain Sensors!!!!! When load is placed on bone, extracellular fluid flows thru the ______and ______. This stimulates osteocytes to
secrete______that stimulate bone remoldeling which is ______
______.
1,2,&3 are all derived from stem cells, and one cell lineage……stem cells derived from fibroblasts (connective tissue cell)
Please illustrate the path of the development of an osteoblast and osteocyte: Reference page 217 in text book
osteoclastshave independent origin!!
Pg 218
4. Osteoclasts are bone ______cells found on the bone______, just on or below the periosteum. They develop from the fusion of several bone marrow stem cells. (the same cells that give rise to blood cells) They are usually ______and have 3-4 nucleui, some having up to 50!! Some are visible to the naked eye they are so big. These cells have sides..one facing the bone surface has a ______which increases the efficiency of______.
Bone remodeling is the result of bone dissolving______andbone depositing
______
Osteoclasts often reside in ______called : ______that have etched into the bone surface.
Please illustrate the path of development of an osteoclast cell: see page 217 or slide 15.
The Matrix: The matrix of osseous tissue is about 1/3 organic matter and about ______.
Organic matter : synthesized by ______is mostly collagen with some carbohydrates such as gylcoproteins.
Inorganic matter is about 85% ______(crystalized calcium phosphate salts and about 10% calcium carbonate). The matrix is made up of collagen and hydroxyapatite. When bones are depleated of the calcium salts, the bone matrix is very soft. These bones bend under the weight. (Rickets) Without the protein, collagen, bones are brittle and would shatter.
Is this what you noticed in the baked and acid treated bones?
The process of calcification occurs only in the presence of collagen fibers. – Mineral salts confer hardness on bone while collagen fibers give bone its great tensile strength.
Osteogenesis imperfecta: ______
______
Osseous tissue is adapted to different amounts of tension and compression exerted on different parts of the skeleton.!!
Compact Bone:
The Osteon(Haversian System) is the ______
It is formed by a ______and its ______connected to each other by ______. (basically a cylinder of concentric matrix tissue around a central canal)
Perforating (Volkmann) Canals are transverse or diagonal passages along the length of the osteon that allow blood vessels through.
Collagen fibers corkscrew down the matrix of the lamella giving it a ______. In the adjacent lamella, they angle in the opposite direction. This gives ______to the bone!
The skeleton receives about ______of blood per minute! Blood vessels along with ______enter the bone tissue thru nutrient foramina on the surface. These open into the ______canals that cross the matrix and feed into the central canals.
NOT all of the matrix is organized into osteons!
The inner and outer boundaries of dense bone (compact bone) are arranged in ______
______.These runparallel to the bone surface.
Spongy Bone: Has a ______appearance.
Consists of slivers of ______called ______and thin plates of bone called______. There are numerous spaces filled with ______
Spongy Bone ishard and calcified.
The matrix is arranged in ______like in compact bone but there are few______and central canals are not needed because______.
Osteocytes are close to the marrow so no need for central canals and the trabeculae are arranged along______. This provides strength with minimal weight.
Bone Marrow:
Marrow is ______that occupies the narrow cavity of a long bone and the smallo spaces within the trabeculae of ______.
There are 2 kinds, ______and ______.
In children almost every bone cavity is filled with ______(myeloid tissue). It is said to be ______and produces RBCs and is composed of multiple tissues in a delicate and intricate arrangement…an organ itself!
Red Marrow is found in adults in the ______, ______, ______,
______and the heads of humerus and femur.
Most of these bones are of what type??______
In adults, most of this red marrow turns to ______. This no longer produces blood, except in severe or chronic anemia.