Bones pt 1
Where does bone formation occur when bones grow in diameter?
Surface of the bones
What gives bones their hardness and strength?
hydroxyapatite crystals
Each trabecula forms along
lines of stress
How many bones are in the human body?
206
What is the most common cell type in yellow bone marrow?
Adipocytes
This bone marking is characterized by being rounded or cupped so the bones can come together at a joint
Articulation
What are the three general classes of bone markings?
Articulations, projections, and holes
Once the chondrocytes die, what fills the remaining spaces?
Blood vessels
What is found in the central canals?
Blood vessels, nerves, and lymphatic vessels
What part of the body stores calcium?
Bones
What bones form by endochondral ossification?
Bones at the base of the skull and long bones
What are the three components of the skeletal system?
Bones, cartilages, and ligaments
What chemical inhibits osteoclast activity and stimulates calcium uptake by the bones, but also decreases reabsorption of calcium by the kidneys?
Calcitonin
What type of cell secretes the fibrocartilaginous matrix?
Chondrocytes
What word describes spongy bone?
Diploë
The process in which bone develops by replacing hyaline cartilage
Endochondral ossification
Which region of long bone is composed of thin compact bone and a thick layer of spongy bone?
Epiphysis
True or False: During bone formation, once the calli have been created, the osteoblasts start creating new compact bone to replace the broken bone.
False
True or False: Hyaline cartilage becomes new bone in endochondral ossification.
False
What physical characteristic do collagen fibers give bones?
Flexibility
What step of fracture repair does this describe?: broken blood vessels bring blood to area that clots and forms fracture hematoma
Hematoma formation
What are the steps our body takes to repair a fracture?
Hematoma formation, internal and external callus formation, bone formation, and bone remodeling
What cellular process takes place in red bone marrow?
Hematopoiesis
What specific tissue type forms the template for long bones?
Hyaline cartilage
What type of cartilage is epithyseal plates composed of?
Hyaline cartilage
Is this the result of hypocalcemia or hypercalcemia? lethargy, sluggish reflexes, constipation and loss of appetite, confusion, and in severe cases, coma.
Hypercalcemia
Is this the result of hypocalcemia or hypercalcemia? blood has difficulty coagulating, the heart may skip beats or stop beating altogether, muscles may have difficulty contracting, nerves may have difficulty functioning, and bones may become brittle.
Hypocalcemia
The condition characterized by abnormally low levels of calcium is called
Hypocalcemia
In long bones, where is cancellous bone located?
In the epiphyses
These are the general steps to flat bone formation, which is called what?: 1. Mesenchymal cells group into clusters, and ossification centers form. 2. Secreted osteoid traps osteoblasts, which then become osteocytes. 3. Trabecular matrix and periosteum form.
Intramembranous Ossification
Osteocytes are located in the ________ surrounded by osseous tissue.
Lacunae
What is found at the borders of adjacent lamellae?
Lacunae
What happens to the chondrocytes as a result of matrix mineralization and causes them to die?
Nutrient loss
What two bone cell types are incapable of mitosis?
Osteoblasts and osteocytes
During bone formation, what type of cells reabsorb the dead bone tissue?
Osteoclasts
What bone cell creates osteoblasts?
Osteogenic cells
What chemical stimulates osteoclast proliferation and resorption of bone by osteoclasts, promotes reabsorption of calcium from the urine by the kidneys, and stimulates the synthesis of vitamin D
PTH
In a state of hypocalcemia, which hormones would be released?
PTH and vitamin D
What is one sesamoid bone found in everybody?
Patella
What is the girdle located at the shoulder called?
Pectoral girdle
What is the girdle located at the hips called?
Pelvic girdle
This bone marking is characterized by an area that projects off the surface of the bone
Projection
This bone marking serves as the attachment point for tendons and ligaments
Projection
Which interstitial growth zone has chrondrocytes going through rapid mitosis?
Proliferative zone
Which interstitial growth zone looks like stacked coins?
Proliferative zone
What substance is located in the porous, cancellous (or spongy) bone inside the epithysis?
Red marrow
What are the four zones of the epiphyseal plate in interstitial growth? (In order from epiphysis to diaphysis)
Reserve zone, proliferation zone, maturation and hypertrophy zone, and calcified matrix zone
What is the purpose of calli?
Stabilize the fracture
What is the function of tendons?
They attach muscles to bone
True or False: Calcium is a chemical element that cannot be produced by any biological processes.
True
True or False: It is important for bone cells to subtly reshape the bone.
True
What chemical is important for calcium absorption?
Vitamin D
What marking is an opening or groove in the bone that allows blood vessels and nerves to enter the bone.
a hole
What tissue makes up yellow bone marrow?
adipose tissue
What type of growth is necessary for bones to grow in width?
appositional growth
The layer of hyaline cartilage that covers surfaces of bone that form joints with other bones is called
articular cartilage
During appositional growth, where do osteoblasts create new bone tissue?
beneath the periosteum
What step of fracture repair does this describe?: replacement of cartilage by trabecular bone through endochondral ossification
bone formation
The endosteum is the location of
bone forming cells
Eroded lacunae in the zone of maturation and hypertrophy cause the cartilaginous matrix to
calcify
In a state of hypercalcemia, which hormone would be released?
calcitonin
What two minerals create hydroxyapatite?
calcium phosphate and calcium carbonate
What is the function of osteoblasts?
create new bone
__________ are canals that radiate perpendicular to the lamellae and contain processes of osteocytes, which allows them to transport nutrients and remove waste products..
canaliculi
Osteocytes communicate to other cells and receive nutrients through
canaliculi channels
Where do cannaliculi connect?
cannaliculi and central canal
Running down the center of each osteon is what canal?
central (Haversion) canal
What type of cells create external calli?
chondrocytes and osteoblasts
Having a cast on your broken arm is an example of
closed reduction
What do platelets do?
clot blood
Osteoblasts synthesize and secrete what?
collagen and calcium salts
What fiber type is present in the bone matrix?
collagen fibers
What gives bone its flexibility?
collagen fibers
What are the two types of bone tissue? (the third one is subchondral tissue, which is located underneath cartilage)
compact and cancellous
What always surrounds cancellous bone?
compact bone
These are the general steps to long bone formation, which is called what?: 1. Mesenchymal cells differentiate into chondrocytes. 2. The cartilage model of the future bony skeleton and the perichondrium form. 3. Capillaries penetrate cartilage. Perichondrium transforms into periosteum. Periosteal collar develops. Primary ossification center develops. 4. Cartilage and chondrocytes continue to grow at ends of the bone. 5. Secondary ossification centers develop. (f) Cartilage remains at epiphyseal (growth) plate and at joint surface as articular cartilage.
endochondral ossification
The delicate membranous lining of the medullary cavity is called the
endosteum
Where are the chondrocytes that form the internal callus?
endosteum
Where are osteogenic cells found?
endosteum, periosteum, and central canals
The following functions belong to which location in the bones? bone growth, repair, and remodeling
endostreum
What do osteocytes secrete during normal processes (not ossification)?
enzymes
Once one has reached maximum size in adolecense/early adulthood, the epiphyseal plate becomes the
epiphyseal line
What is the growth plate in the metaphysis called?
epiphyseal plate
Where are the secondary ossification centers located in endochondral ossification?
epiphyses
Internal calli are composed of what type of tissue?
fibrocartilage
Which bones form through the process of intramembranous ossification?
flat bones of the face, most of the cranial bones, and the clavicles (collarbones)
When blood vessels are torn by a fracture they form a
fracture hematoma
The appendicular skeleton is divided into which two groups?
girdles and limbs
What is the process of creating blood cells?
hematopoiesis
What controls bone growth?
hormones
External calli are composed of what type of tissue?
hyaline cartilage
What are inorganic salt crystals called?
hydroxyapatite
What is formed by calcium phosphate and calcium carbonate and incorporates other inorganic salts like magnesium hydroxide, fluoride, and sulfate as it crystallizes?
hydroxyapatite
The condition characterized by abnormally high levels of calcium is called
hypercalcemia
What adheres to collagen fibers?
inorganic salt crystals
What step of fracture repair does this describe?: secretion of fibrocartilage matrix to create internal callus, and secretion of hyaline cartilage and bone to create external callus
internal and external callus formation
These steps result in the lengthening of the bone. This process is called what?: 1. Chondrocytes in the reserve zone undergo mitosis in the proliferative zone. 2. Chondrocytes enlarge and mature in the zone of maturation and hypertrophy. 3. Most chondrocytes in the zone of calcified matrix die as a result of the calcification of the surrounding matrix. 4. New bone is formed as osteoblasts and capillaries invade the calcified tissue.
interstitial growth
Compact and spongy bone develops directly from sheets of mesenchymal (undifferentiated) connective tissue during
intramembranous ossification
Why aren't bones composed of only compact bone?
it would be too heavy
In cancellous bone, where are osteocytes located?
lacunae
Layers (rings) of calcified matrix that surround the central canal are
lamellae (singular = lamella)
During appositional growth, osteoclasts reabsorb old bone in the
medullary cavity
From which tissue type do flat bones form?
mesenchymal (undifferentiated) connective tissue
What forms osteogenic cells?
mesenchymal cells
Where does each epiphysis meet the diaphysis?
metaphysis
What is the name of the process of increasing the diameter of the diaphysis and medullary cavities?
modeling
When the doctor preforms surgery to reset a broken bone, it is called
open reduction
What type of tissue composes the epiphyseal line?
osseous tissue
In intramembranous ossification, early osteoblasts appear in a cluster called an
ossification center
What are the four types of cells found in osseous tissue?
osteoblasts, osteocytes, osteogenic cells, and osteoclasts.
What bone cell is derived from monocytes and macrophages (two types of white blood cells)?
osteoclasts
What bone cells break down bone?
osteoclasts
Mature bones are made of a calcified matrix, what type of bone cell exists within the calcified matrix
osteocyte
Once the matrix surrounding the osteoblast calcifies, it becomes what?
osteocyte
What is the most common type of bone cell?
osteocyte
What do lacunae contain?
osteocytes
When blood vessels invade the previously cartilaginous space, what type of cells do they bring with them?
osteogenic cells
During intramembranous ossification, osteoblasts secrete _____________ to create an uncalcified matrix
osteoid
The functional unit of compact bone tissue is the
osteon
Where is PTH produced?
parathyroid gland
PTH stands for
parathyroid hormone
Vessels and nerves branch off at right angles through what canal?
perforating canal
In endochondral ossification, what is the membrane that covers the cartilage and will be the future periosteum called?
perichondrium
Where are the chondrocytes that form the external callus?
periosteal
During ossification, osteoblasts congregate around the cartilage of the diaphysis to form the
periosteal collar
The membrane that covers the outside of a bone is the
periosteum
Where are osteoblasts found?
periosteum and endosteum
Where are immature osteogenic cells found?
periosteum and marrow
What three cell types are made in red bone marrow?
red and white blood cells and platelets
During intramembranous ossification, the trabecular bone crowds nearby blood vessels to form
red marrow
What fills the space around and between trabeculae?
red marrow
After the fractured bone is repaired, it undergoes
remodeling
What step of fracture repair does this describe?: return to normal of bone shape and thickness
remodeling
What is the interstitial growth zone closest to the epiphyseal end of the plate and contains small chondrocytes within the matrix?
reserve zone
Which interstitial growth zone of chrondrocytes serve the function of securing the epiphyseal plate to the osseous tissue of the epiphysis?
reserve zone
Where is vitamin D produced?
skin
During bone formation, osteoblasts create
spongy bone
What are the five functions of the skeletal system?
supports the body, facilitates movement, protects internal organs, produces blood cells (hematopoiesis), mineral storage
Where are sesamoid bones found?
tendons
Where is the primary ossification center in endochondral ossification?
the (future) medullary cavity
In which interstitial growth zone do chondrocytes die?
the calcified matrix zone
Which interstitial growth zone borders the ossification zone within the medullary cavity?
the calcified matrix zone
In flat bones, where is cancellous bone located?
the center
During endochondral ossification, the blood vessels invade the previously cartilaginous space to create what cavity?
the medullary cavity
Where is the human when intramembranous ossification starts?
the womb
What is the function of ligaments?
they connect bones to each other
Once chondrocytes lose access to nutrients, what happens to them?
they die
What happens to chondrocytes when the matrix around them calcify?
they die
As a result of enlarged chondrocytes, what happens to the lacunae?
they erode and become larger
Where is calcitonin produced?
thyroid gland
What are the hard, bony branches within spongy bone called?
trabeculae
Spongy bone, cancellous bone, or
trabecular bone
During intramembranous ossification, osteoid secreted around the capillaries results in a
trabecular matrix
In yellow bone marrow's adipose tissue, the adipocytes store what molecule?
triglycerides
Which interstitial growth zone has enlarged chrondrocytes?
zone of maturation and hypertrophy