Ch. 6 The Skeletal System Flashcards
True or false
Cartilage has a flexible matrix that can accommodate mitosis of chondrocytes - this makes it an excellent scaffolding tissue upon which to build bone?
True
True or false
The three types of cartlidge are hyaline elastic and fibroblastic?
False
Fibrocartilage
True or false
The most abundant type of cartilage in the human body is elastic cartilage?
False
Hyaline
True or false
The embryonic skeleton is comprised mostly of hyaline cartridge?
True
True or false
Cartilage is highly vascularized and innervated?
False
Not vascularized or innervated
List of four classifications of bone by shape and given example
1) long bones— femur
2) short bones— wrist, or ankle bones
3) irregular— pelvic girdle
4) flat— sternum
List the seven functions of the skeletal system
Protection
Support
Movement
Storage of minerals and growth factors
Storage of fat (energy)
Production of hormones
Production of blood cells
Label the following structure
Label the following structure
Label the following structure
Mitotically, active stem cells found in the periosteum and endosteum give rise to another type of bone cells called?
Osteogenic cells
Bone forming cells that secrete the bone matrix
Osteoblasts
Mature bone cells that reside in the lacunae of osteons; serve to monitor and maintain the bone matrix
Osteocytes
Flat cells found on bone surfaces were bone remodeling is not going on; believe to help maintain matrix and support bone
Bone lining cells
Giant multinucleate cells, responsible for bone reabsorption, derived from the same hematopoetic stem cells that become microphage
Osteoclasts
What mature cells found within lacune of cartilage; serve to maintain the tissue?
Chondrocytes
Label the following structure
Label the following structure.
What three components make a bone (hint: two organic and one organic)
1) cells —osteocytes, etc
2) osteoid — Bone matrix; comprise about 1/3 of bone -include ground substance and collagen fibers
3) mineral salts (hydroxyapatite’s) — in organic part of bone; comprises 2/3 of bone, primarily calcium phosphate crystals
True or false
Hematopoiesis refers to the formation of blood cells within the red marrow cavities of certain bones
True
True or false
The structural unit of compact bone (osteon) resembles the growth rings of a tree trunk
True
True or false
The term osteoid refers to the organic part of the matrix of compact bones
True
True or false
65% of the mass of bone is a compound called hydroxyapatite
True
True or false
Our bones stop growing by the end of adolescence
False
Appositional growth occurs anytime
True or false
An osteon contains osteocytes, lamellae, a central canal and is found in compact bone only
True
True or false
The hormone that is primary involved in the control of bone remodeling is a parathyroid hormone
True
True or false
Each consecutive bone lamella has collagen fibers that wrap in alternating directions
True
True or false
Each consecutive bone lamella has collagen fibers that wrap in alternating directions
True
True or false
Closure of the epiphyseal plate stops all bone growth in the body
False
Appositional growth occurs anytime; remodeling (not really growth) occurs throughout our lifetime
True or false
Osteoid is secreted by osteoclasts
False
Secreted by osteoblasts
True or false
Osteoid is secreted by osteoclasts
False
Secreted by osteoblasts
True or false
Osteoid consists of ground substance and fibers
True
Layers of bone matrix
Lamellae
Small channels that radiate through the matrix of bone
Canaliculi
The lining of the marrow cavity
Endosteum
Spaces found between concentric lamellae
Lacunae
The matrix of bone tissue is called?
Osteoid
Area where bone longitudinal growth takes place
Epiphyseal plate
The growth pattern of bone in which matrix is laid down on the surface
Appositional growth
The lining of the marrow cavity
Endosteum
Increase in the length of long bones
Interstitial growth
Aspiration or bone tissue formation occurs in three general “phases” during life briefly describe what these three phases are and what kind of bone development occurs
1) pre-natal: formation of the bony skeleton, using cartilage “models” or fibrous membranes (in which bone replaces the models or fibrous membranes)
2) post-natal until adulthood: increase in length and width of bones; goes on until early adulthood
3) adulthood: ossification in adult serves mainly for bone remodeling and repair
Briefly describe the two types of ossification and what bones they produce
1) endochondral ossification: phone forms by replacing hyaline cartilage “models”; forms most bones of skeleton
2) intramembranous ossification: bone developes from fibrous membranes; forms flat bones, such as clavicles and cranial bones
Briefly describe the two types of ossification and what bones they produce
1) endochondral ossification: phone forms by replacing hyaline cartilage “ models”; forms most bones of skeleton
2) intramembranous ossification: bone developes from fibrous membranes; forms flat bones, such as clavicles and cranial bones
True or false
Interstitial growth requires the presence of cartilage at the epiphyseal plate
True
True or false
During interstitial growth, the epiphyseal plate maintains a constant thickness as new bone cells grow on the distal end (i.e. closer to the epiphysis) while new Cartlidge cells grow on the proximal end ( i.e. closer to the diaphysis) of the bone
False
bone and cartilage are reversed
True or false
Interstitial bone growth ends at the time of birth
False
Continues until the end of adolescence
True or false
During appositional growth, the buildup of new bones must be balanced by the degradation of old bone
True
True or false
The most important hormone in regulating bone growth during youth is the thyroid hormone
False
Growth hormone, thyroid hormone ensure correct proportions
Briefly what is Wolff’s law?
Wolff’s law states, bones grow or remodel in response to demands placed on them
In adult bones are constantly being remodeled. Remodeling is a two-step process.: bone ___1___and bone ___2__. The cells which do these processes are called ___3___ and ___4___ , respectively. Bone resurfacing occurs at two membranous surfaces, the___5___ and the ___6___. Bone reabsorption occurs first which is essentially the enzymatic breakdown of bone. ___7___. Osteoclasts have a specialized surface called a___8___ border, which cleans tightly to the surface of the bone. Osteoclasts are also capable of phagocytizing ___9___ and ___10___. Once degraded the osteoblasts secrete a new bone, which is ___11___. Mineralization occurs within a week or so, and is controlled and part by mechanical signals and endosteal cavity concentrations of ___12___ and ___13___ ions. Bone remodeling in adults is regulated by genetic factors and two feedback control loops; ___14___ homeostasis, and ___15___ triggers. The two most important hormones are regulating Ca2+ homeostasis are ___16___ and ___17___.
- Reabsorption. 2. Deposition 3. Osteoclasts 4. Osteoblasts 5.Periosteum 6. Endosteum 7. Matrix (osteoid) 8. Ruffled 9. Matrix. 10. Osteocytes. 11. Unmineralized. 12. Calcium. 13. Phosphate. 14. Ca2+ 15. Mechanical/Gravitational. 16. Parathyroid 17. Calcitonin
