CH. 6 Bones and Skeletal tissue
soft callus
"Kalus; Hard skin" Splints the broken bone
Your patient is returning for follow-up 6 weeks after sustaining a nondisplaced fracture of his radius. He tells you that his forearm is no longer painful, but he is concerned that he can palpate a "lump" in the bone at the site of the healing fracture. What is your response?
"That bump is a normal part of bone healing at this stage. As your body completes the process, the cells in your bone will gradually remodel it to its previous shape."
Cleidocranial dysostosis
-partially/completely missing coller bone, top of head frontal failed to close, bones and joints are under developed. -Pushing to hard during labor can increase pressure in the abdomen of baby causing the clavicle to break
Stages of healing bone
1. Hematoma formation 2. Fibrocartilage callus formation 3. Bony callus forms 4. Bone Remodeling occurs
4 classifications of Bones
1. Long bones 2. Short bones 3. Flat bones 4. Irregular bones
epiphyseal plate consists of five zones
1. Resting ( quiescent) 2. Proliferation (growth) 3. Hypertrophic 4. Calcification 5. Ossification (osteogenic)
Seven important functions of bone
1. Support 2. Protection 3. Movement 4. Mineral growth and factor storage 5. Blood cell formation 6. Tryglyceride (fat) storage 7. Hormone Production
Five major cell types populate bone tissue
1. osteogenic cells 2. osteoblasts 3. osteocytes 4.bone lining cells 5. osteoclasts
Calcitriol
A hormone produced from vitamin D that acts in essentially the same manner as parathyroid hormone.
Ramus
Arm like bar of bone. An extension of a bone making an angle with the rest of the structure
Why are bones considered organs?
Because they are made up of different types of tissues
FACT:
Bone lining cells are flat cells found on bone surfaces where bone remodeling is not going on.
Osteon
Bone. contains osteocytes, lamellae, and a central canal, and is found in compact bone only.
Bone Function: Mineral growth and factor storage
Calcium and phosphorus, and growth factor reservoir
What fibers are found in this type of cartilage?
Collagen Fibers
The structure of bone tissue suits the function. Which of the following bone tissues is adapted to support weight and withstand torsion stresses?
Compact Bone
Epiphysis
End of a long bone compact bone externally spongy bone internally
Canaliculi
Hairlike canals that connect lacunae to each other and the central canal
Identify the cells required for fibrocartilaginous callus formation and list their functions.
Fibroblasts - produce of collagen fibers to connect the broken bone ends chondroblast- secrete a cartilaginous matrix that later calcifies that spans the break and connects the broken ends
What are the tree levels of structure for a bone
Gross Microscopic Chemical
epiphyseal plate
Growth plate, made of cartilage, gradually ossifies
canaliculi
Hairlike canals that connect lacunae to each other and the central canal provide nutrients and remove wastes from osteocytes in compact bone.
Bone Function: Blood cell formation
Hematopoiesis Occurs in red bone marrow cavities of certain bones.
which of the labeled parts of the adult long bone would hematopoietic tissue be located?
Hematopoietic tissue is found in the red bone marrow within certain body locations consisting of spongy bone. Examples include the diploe of flat bones and the proximal epiphyses of the femur and humerus (pictured).
Three types of cartilage
Hyaline Elastic Fibrocartilage
ossification with Hyaline Caartilage
In this type of ossification, the bone is first modeled from cartilage and then replaced by bone as blood vessels invade the model.
What physiological processes allow growing bones to acquire their unique features such as processes, tuberosities, condyles, and fossae?
It results from mechanical stress and remodeling. Bones develop their specific features according to the stresses placed on them as they grow and fit together, and as they are pulled on by muscles.
Long bones are for what
Limbs
calcitonin.
Lowers blood calcium levels in pregnant women and children
Hyaline cartilage
Most common type of cartilage; it is found on the ends of long bones, ribs, and nose Collagen fibers ONLY provides support, flexibility and resilience
FACT:
Osteoblasts secrete collagen and calcium-binding proteins.
Bone Function: Hormone production
Osteocalcin secreted by bones helps to regulate insulin secretion, glucose levels, and metabolism
Osteoclasts
Osteoclasts are the bone cells that break down bone. If they were activated more than normal, you should expect to see bone loss.
FACT:
Osteoclasts secrete digestive enzymes and hydrogen ions.
Osteoporosis
Osteoporosis refers to a group of diseases in which bone resorption outpaces bone deposit. The composition of the matrix remains normal but bone mass declines, and the bones become porous and light. The bones become so fragile that they can break from something as simple as stepping off a curb or a hearty sneeze.
PTH function in bone
PTH; indirectly stimulates osteoclast activity
Old Norse stories tell of a famous Viking named Egil, who lived around 900 AD. His skull was greatly enlarged and misshapen, and the cranial bones were thickened (6 cm, more than 2 inches, thick). He had headaches from the pressure exerted by enlarged vertebrae on his spinal cord. So much blood was diverted to his bones to support their extensive remodeling that his fingers and toes always felt cold and his heart was damaged through overexertion. What bone disorder did Egil probably have?
Paget's disease is characterized by excessive and abnormal bone remodeling. It results in irregular thickening of bone tissue and often affects the skull and spine, causing pain and deformity.
Which anatomical structures in compact bone house blood vessels?
Perforating and Central canal
endochondral ossification
Process of transforming cartilage into bone.
Foramen
Round or oval opening through a bone
Elastic Cartilage
Similar to hyaline, contains elastic fibers External ear and epiglottis
What is the weakest part of a developing, adolescent long bone?
The epiphyseal plate is a weak point because of the lack of calcification.
Fibrocartilage
Thick collagen fibers great tensile strength Menisci of knee vertebral disks
achondroplasia
This genetic disease can lead to shortening of the long bones due to premature closure of the epiphyseal plate.
periosteum
What covers and lines the bone by this protective tissue
Short bones are for
Wrist and ankle
Trochanter
a site for a muscle or ligament attachment Very large, blunt, irregularly shaped process..
Yellow bone marrow within the medullary cavity is composed primarily of
adipose tissue (fat).
bone process
any part of a bone that protrudes
In bone remodeling the release of minerals into the bloodstream called
blood resorption
compound fracture
bone breaks through the skin
Bone remodeling involves the process of storing minerals in bone tissue called
bone deposition
fossa
bone depression into which a condyle might fit.
displaced fractures,
bone ends are out of normal alignment
Osteoblasts
bone forming cells secrete bone matrix
During bone growth, which significant event occurs at the surface indicated by the letter D?
bone resorption
sesamoid bones
bones embedded in tendons example: patella Vary in size
Cells responsible for ossification
cells responsible are osteoclast and osteoblast
Osteoclasts are
cells that break down bone matrix (Bone destroying cells)
Three types of fibers
collagen, elastic, reticular
osteomalacia
disease marked by softening of the bone caused by calcium and vitamin D deficiency
In some cases, the epiphyseal plate of the long bones of children closes too early. What might be the cause?
elevated levels of sex hormones
Paget's disease
excessive and haphazard bone deposition and resorption
interstitial growth of cartilage
growth in length
epiphyseal line
growth plate
red marrow in adults is only found in the cavities between trabeculae of spongy bones in:
he flat bones of the skull, as well as the sternum, ribs, clavicles, scapulae, hip bones, and vertebrae The heads of the femur (thigh bone) and humerus (long bone of the arm)
cartilage forms what
he model for endochondral ossification?
What controls bone remodeling?
hormones and mechanical stress
Perforating (Sharpey's) fibers
hundreds of connective tissue fibers that secure the periosteum to the underlying bone
The articular cartilage at the ends of long bones is formed from
hyaline cartilage
FACT:
hyaline cartilage This tissue persists within the epiphyseal plate at the boundary between primary and secondary ossification centers until early adulthood.
appositional growth
increase in bone thickness
appositional growth?
increase in bone thickness the secretion of new matrix against the external face of existing cartilage
parathyroid hormone increases osteoclast for what
increases osteoclast activity to release more calcium ions into the bloodstream?
Ossification of the ends of long bones ________.
is produced by secondary ossification centers
Bone Function: Movement
levers for muscle action
At an archeological site you discover a bone that is cylindrical in shape, about one inch long and a quarter of an inch wide. Choose the correct classification.
long
Bones are classified as
long, short, flat, or irregular on the basis of their shape, and as axial or appendicular based on their body location.
Proteoglycan
major component of the ground substance secreted by bone-forming cells. Provide Feedback
Osteosarcoma
malignant tumor of the bone
Endosteum
membranous lining of the hollow cavity of the bone
What does a bone contain other than osseous tissue?
nervous tissue, cartilage, fibrous connective tissue, muscle cells, epithelial cells in its blood vessel
central (Haversian) canal
opening in the center of an osteon, carries blood vessels and nerves
bone tissue is also called
osseous tissue
What term is used to describe the addition of new bone tissue?
ossification
Bone deposition is accomplished by cellular activity of
osteblasts
Bone resorption is accomplished by the cellular activity of
osteoclasts
What is the structural unit of compact bone?
osteon, an elongated cylinder oriented parallel to the long axis of the bone.
The periosteum is secured to the underlying bone by ______
perforating (Sharpey's) fibers
secondary ossification center
region of bone development in the epiphyses
bone markings
reveal where muscles, tendons, and ligaments were attached and where blood vessels and nerves passed
Lamellae
rings around the central canal, sites of lacunae. layers of bony matrix synthesized by osteoblasts during bone growth and maintenance. bony matrix surrounding the vessels and nerve
condyle
rounded part of a bone that articulates with another bone
Diaphysis
shaft of long bone, composed of compact bone filled with yellow bone marrow (adults)
spine
sharp, slender, often pointed projection
tuberosity
site of muscle attachment that is large and rough
Lacunae
small cavities in bone that contain osteocytes
facet
smooth, nearly flat articular surface
Flat bones located in
sternum, scapulae, ribs and most skull bones
trabeculae
supporting bundles of bony fibers in cancellous (spongy) bone
nondisplaced fractures,
the bone ends retain their normal position.
Osteomyelitis
the medical term for an infection in a bone; it can occur if an injury exposes the bone to germs.
Hematopoietic (blood-forming) tissue found in infants is located where
the medullary cavity of the diaphysis and all areas of spongy bone contain red bone marrow
bone resorption
the removal of minerals and collagen fibers from bone by osteoclasts
Wolff's law is concerned with ________.
the thickness and shape of a bone being dependent on stresses placed upon it
Blood resorption occurs when
there is a decrease of blood calcium and mechanical stress and an increase of parathyroid hormone
Bone deposition specifically occur when
there is an increase of blood calcium and mechanical stress decrease of parathyroid hormone
Diploe
thin plates in spongy bone
osteoid
unmineralized bone matrix
Irregular bones located in
vertebrae, hip bones.
