Bone Tissues Flashcards
What are 5 parts of the Skeletal Structure?
Bone (osseous tissue)
Cartilage - at joint surfaces
Ligaments - collagenous bands that connects bone to bone
Tendons - similar to ligaments but connect muscles to bone
Bone marrow - Material in bone
What are 5 functions of the skeletal system?
Support - limbs, and vertebrae, think what holds your teeth
Protection - Brain and spinal cord, lungs and heart
Movement - Ventilation, leverage
Blood formation - Red blood cells and immune cells
Storage - Reservoir for minerals and fat
What is the function of long bones?
Most long bones are limb bone and are for leverage and movement.
What is the elongated midsection called of a long bone?
Dialysis (shaft)
What is the end of a long bone called?
Epiphysis (head)
Place where tendons and ligaments attach. Filled with spongy bone and bone marrow
What is articular cartilage?
It is hyaline cartilage that is 2-4 mm thick and found at the end of bones to ease joint movement. Does not have blood vessels or nerves
Where is the medullary cavity and what does it hold?
Found in the diaphysis of long bones and that is where the yellow bone marrow is found.
Periosteum
The outer sheath of the bone made up of a fibrous layer of collagen. The inner layer is osteogenic which is for growth.
Endosteum
Inner lining of bony wall, lines the walls of where the bone marrow is. Made of reticular CT
What are the two functions of flat bone?
Protective Plates - Sternum and heart , cranial bones
Attachment Surfaces for muscles - Scapula
How many layers of compact bone are in flat bone?
Two layers of compact bone surrounding the spongy bone.
What are the four types of bone cells?
What do they do and where are they found?
Osteogenic cells - Inner layer of the periosteum that is used to form more bone.
Osteoblasts cells - is a bone builder at the bone surface that is a single layer. Produces collagen and proteoglycans.
Osteocytes - Mature bone cells that are formed from osteoblasts. Most abundant type of bone cells.
Osteoclasts - bone crusher and re absorption.
Describe what an osteoclast looks like
Very large cell with multiple nuclei. Breaks down bone and reabsorbs is
What is bone matrix?
Found surrounding the osteocytes and lacunae. 1/3 organic matter (collagen to resist tension and bend without breaking)
2/3 inorganic used for strength and support.
What type of bone is arranged in cylinders?
Compact bone.
Each cylinder is called a osteon that run longitudinally though the shaft
Has blood vessels ad nerves
Concentric layers of deposited bone matrix
Lamellae (think individual tree rings)
What is found between the lamellae?
Osteoctyes
What is the difference between circumferential and interstitial lamellae?
Circumferential lamellae - Outer surface of the compact bone.
Intersititial lamellae - fills irregular region between osteons
What is the porous lattice?
Where is it found?
Made of trebeculae (thin plates) and spicules (rods or spines)
Makes up the hard part of spongy bone.
Describe the hard parts of spongy bone
Space where bone marrow and blood vessels are found. Lacks ostenons and central canals. Provides strength while also being light weight. They will arrange and compact more around stress lines.
What fills cavities of long bones?
Bone marrow that is made up of soft tissue.
What is the difference between the two different types of bone marrow?
Red marrow - hemopoetic tissue that produced red blood cells. Found in almost every child’s bones. Found in adults skull, ribs, sternum, pelvic girdle, and heads of large bones.
Yellow marrow - found in adults and is fatty marrow, does not produce blood like red marrow.
What are the three types of cartilage and their arrangements?
Hyaline - lines the joints and surrounded by pericardium fibrous dense irregular connective tissue.
Elastic - Ear and nose, Surrounded by the pericardium fibrous dense irregular connective tissue
Fibrocartilage - disc in the back found between the vertebrae.
What are the functions of cartilage?
Support, framework and attachments
Protection
Structural models for developing bones
What are the two cells of cartilage and what is their function?
Chondroblasts - Builds the cartilage and secretes matrix
Chondrocytes - Mature chondroblasts trapped within the lacunae
True or false
Cartilage has blood vessels that move nutrients and waste around.
False - There are no blood vessels so nutrients and waste must diffuse through the matrix
Osteogenisis
Formation of bone
What is mesenchyme?
Embryonic CT that is the starting point for bone muscle blood and other stuff
Ossification that happens to flat bone
Intramembranous ossification (skull, clavicle, mandible)
What happens during the formation of interamenbranous ossification?
Mesenchyme is made of CT and cartilage that developed fibrous sheets. The center of ossification expand and the parts that they are not touching is called fontanels (think the soft spots of the head)
What happens when mesenchyme condenses?
Fibrous sheets are formed and blood vessels permeated the membrane. Mesenchyme cells turn into osteogentic cells which then turn into osteoblasts. Osteoblast then secrete sheets of collagenous osteoid tissue that is pre-bone
What crystalizes the oteoid?
Minerals that then produce bone matrix.
Osteoblast produce then trapping them within the matrix which produces osteocytes. The end result of this is trabeculae.
Spongy bone formation of intermembranous ossification
- Osteoblasts are bone
- Trabeculae - larger, grow together
- Cells within spaces form red bone marrow
Compact bone formation of intermembranous ossification.
Mesenchymal cells surrounding outside of new bone condenses making the peritoneum. Osteoblasts continue to make bone matrix. This fills the space and creates an outside layer of compact bone.
What are the results of intermembranous ossification?
Outer compact bone surface
Spongy bone center
Remodeling woven bone –> lamellar bone
What is woven bone?
First type of bone formed
It is weak and collagenfibers are random
Osteoclasts breakdown
What is lamellar bone?
Mature bone
Thin layer of lamellae
All the collagen fiber are arranged in parallel lines for strength.
What is endochondral ossification?
Produced in most other bone (vertebrae, ribs, pelvic bones, limbs and parts of skulls)
What stage of development does endochondral ossification?
12-20 weeks of devolopment from preexisting model.
Mesenchyme first transformed into hyaline cartilage.
What are the two processes of endochondral ossification?
Chondrification : mesenchyme to hyaline cartilage
Ossification : hyaline to bone
What is model growth?
The approximate shape of future bone before bone is formed.
What are the six steps in endochondral ossification?
Mesenchyme to hyaline cartilage
Primary ossification center is where the chondryocyte inflate which means that the lacunae is large and the walls are calcified. This is when the bone collar formation. Blood vessels –> chondrocytes –> osteobalsts
Formation of medullary cavity - chondrocytes hypertorphy and die in both directions. Osteocytes and osteoblasts do work.
Secondary ossification center when spongy bone is formed.
Cavities separated by epithyseal plate and this is the growth zone.
Reserve cartilage in epiphyseal plate deleated.
True or false:
Ossification stops after the person is full grown
False - ossification continues throughout life (growth and remodeling)
How do bones elongate?
The epiphyseal plate is made of catilage and bone
Hyaline cartilage in the middle and transition zones on each side that is the cartilage turning into bone.
What is the metaphysis?
The zone of transition facing the marrow cavity
Interstital growth
Growth from within.
Zone of reserve cartilage
Normal hyaline cartilage
Zone of cell proliferation
Chondrocytes multiply and line up in columns of small flattened lacunae (interstital growth)
Zone of hypertrophy
Stopping of mitosis; enlargement of chondrocytes and thinning of the lacuna walls
Zone of calcification
Temporary calcification of cartilage matrix
Blood vessels enter the area
Zone of bone deposition
Bone deposition by osteoblast (appositional)
Forms trabeculae of spongy bone
What is appositional growth?
Occurs at bone surface and is the continual growth in diameter and thickness
Wolffs law of bone
Architecture of bone determined by mechanical stresses placed on it
