Biology 227 Chapter 6 Review
The fibrocartilaginous callus is the first repair mass to splint the broken bone.
true
Tiny canals connecting lacunae.
D. canaliculi
Location of compact bone in an adult's bone.
A. diaphysis
Scientific name for bone shaft.
A. diaphysis
The following events apply to the endochondrial ossification process as it occurs in the primary ossification center.
1. Cavity formation occurs within the hyaline cartilage [this occurs before blood vessel invasion because the cartilage cells in the middle of the model cannot receive enough nutrients by diffusion to stay alive. When they die the hyaline protein they maintain breaks down]. 2. Perichondrium becomes vascularized to a greater degree [this increased vascularization stimulates the perichondrial cells to differentiate to become osteogenic cells (osteoblasts) that lay down bone; the perichondrium now covers bone so it can be renamed periosteum]. 3. Collar of bone is laid down around the hyaline cartilage model just beneath the periosteum. 4. Periosteal bud invades the marrow cavity. 5. Osteoblasts lay down bone around the cartilage spicules in the bone's interior. 6. Osteoclasts remove the cancellous bone from the shaft interior, leaving a marrow cavity that then houses fat [you need to lay down the bone in e above before it can be removed to form a complete cavity].
List and explain five important functions of bones.
1. They support the body by providing a rigid skeletal framework. 2. They protect the brain, spinal cord, lungs, and other internal organs. 3. They act as levers and provide attachments for muscles in movement. 4. They serve as a reservoir for fat and minerals. 5. They are the sites of formation of blood cells.
Identify each of the following bones as a member of one of the four major bone categories.
1. long bone: -humerus -radius -femur - metacarpal 2. short bone: -calcaneus 3. flat bone: -frontal -mandible -sternum 4. irregular bone -vertebra
The initial supporting structure for this type of ossification is a fibrous membrane formed by ________________ . The first recognizable event is a clustering of the _______________cells to form a(n) ______________ in the fibrous membrane. These cells then differentiate into ______________, which begin secreting ________________ around the fibers of the membrane. Within a few days, calcium salt deposit or ________________ occurs, producing true _________________ . The first network of trabeculae formed are arranged irregularly. This early membrane bone is referred to as _______________ bone. As it forms, a layer of vascular ________________ condenses on the external face of the bone structure, forming a ________________ . Eventually lamellar bone replaces ___________________ , and the vascular tissue within the _________________ differentiates into red marrow. The final result is a flat bone.
1. mesenchymal cells 2. mesenchymal 3. ossification center 4. osteoblasts 5. osteoid 6. mineralization 7. bone matrix 8. woven 9. mesenchyme 10. periosteum 11. woven bone 12. dipole
Most hyaline cartilage "long bones" show primary ossification centers by 8 weeks.
12 weeks
Disuse such as that caused by paralysis or severe lack of exercise results in muscle and bone _________.
A. atrophy
Longitudinal canal, carrying blood vessels and nerves.
A. central (haversian) canal
What single structural characteristic account for the resilience of cartilage and its ability to grow rapidly in the developing skeleton?
Although collagen fibers form cartilage's supporting framework, its proteoglycons and hyalouronic acid attract and organize huge amounts of water, which becomes the main component of cartilage. This water "saves space" for bone development and is responsible for cartilage's resilience throughout life.
_____________ causes blood calcium to be deposited in bones as calcium salts.
B. calcitonin
Layers of calcified matrix.
B. concentric lamellae
Composed of hyaline cartilage until the end of adolescence.
B. epiphyseal plate
Region of longitudinal growth in a child.
B. epiphyseal plate
Location of spongy bone in an adult's bone.
C. epiphysis
Site of hematopoiesis in an adult's bone.
C. epiphysis & D. red marrow
Astronauts must perform isometric exercises when in outer space because bones atrophy under conditions of weightlessness or lack of ______________.
C. gravity
Residences" of osteocytes.
C. lacunae
Immature, or matrix-depositing, bone cells are referred to as _____________.
D. osteoblasts
Nonliving, structural part of bone.
E. bone matrix
Bone cells that liquefy bone matrix and release calcium to the blood are called _____________.
E. osteoclasts
Site of fat storage.
E. yellow marrow cavity
Mature bone cells, called ______________, maintain bone in a viable state.
F. osteocytes
When blood calcium levels begin to drop below homeostatic levels, ___________ is released, causing calcium to be released from bones.
G. parathyroid hormone
Large tubercles and/or increased deposit of bony matrix occur at sites of _______.
H. stress and/or tension
Crest
projection
According to Wolff's law: Bones grow or remodel in response to the forces or demands placed on them. A bone's anatomy therefore reflects the most common stresses it encounters. This concept explains differences in bone structure found throughout the body ______________________.
and as seen in comparisons of active humans, bed-ridden people, and human fetus
At birth, bones generally lack ossification centers.
bone markings
The enzyme alkaline phosphatase encourages the deposit of collagen fibers within the matrix of developing bone.
calcium salts
Fossa
depression
Forming the epiglottis.
elastic cartilage
The skeleton of the external ear.
elastic cartilage
Membrane bones develop from hyaline cartilage structures.
endochondral
In appositional growth, bone reabsorption occurs on the periosteal surface.
endosteal
Cartilage is especially strong in resisting shear (bending and twisting) forces.
false
In the adult skeleton, cartilage regenerates faster than bone when damaged.
false
Neither bone nor cartilage contains capillaries.
false
Nutrients diffuse quickly through cartilage matrix but very poorly through solid bone matrix.
false
Osteocytes produce collagen fibers that span the break.
fibroblasts
Forming the intervertebral discs.
fibrocartilage
Knee menisci
fibrocartilage
At the ends of long bones.
hyaline cartilage
At the junction of a rib and the sternum.
hyaline cartilage
Epiphyseal plates are made of spongy bone.
hyaline cartilage
Most of the fetal skeleton.
hyaline cartilage
Supporting the trachea walls.
hyaline cartilage
Facet
projection
Head
projection
Ramus
projection
Spine
projection
Tuberosity
projection
When a bone forms from a fibrous membrane, the process is called endochondral ossification.
intramembranous
Large numbers of osteocytes are found in the inner periosteum layer.
mesenchymal cells (or osteoblasts)
Fissure
opening
Foramen
opening
Meatus
opening
Sinus
opening
Osteoblasts from the medullary cavity migrate to the fracture site.
periosteum (endosteum)
Nonbony debris at the fracture site is removed by fibroblasts.
phagocytes (macrophages)
Condyle
projection
Primary ossification centers appear in the epiphyses.
secondary
The bony callus is composed of compact bone.
spongy
"Maturation" of newly formed (noncalcified) bone matrix takes about 7-10 days.
true
A hematoma usually forms at a fracture site.
true
Appositional growth, which continues after the cessation of longitudinal long bone growth, means that long bones increase in diameter.
true
Bone tissue contains relatively little water compared to cartilage tissue, which contains a large amount of water.
true
Cartilage can grow faster than bone in the growing skeleton.
true
Cartilage is more resilient than bone.
true
Deprived of nutrition, osteocytes at the fracture site die.
true
During endochondral ossification, the periosteal bud invades the deteriorating hyaline cartilage shaft.
true
Long bone growth during childhood and adolescence is provided by persistence of the epiphyseal plates.
true
The embryonic skeleton arises from the mesoderm.
true
The longitudinal growth of long bones ceases when the epiphyses and the diaphyses fuse.
true
The organic bone matrix is called the osteoid.
true
When trapped in lacunae, osteoblasts change into osteocytes.
true