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Anatomy & Physiology Exam 3 chapter 6 bone
Terms in this set (100)
of a long bone is its shaft or long main portion
of a long bone is its end. The two ends
together are called the epiphyses. Each epiphysis is covered with articular cartilage.
of a long bone is the region of mature
bones where the diaphysis meets the epiphysis
_____ In a growing bone, it formed of hyaline cartilage divided into four zones of cells. Under the influence of growth hormone, the plate continues to grow, giving length to the bone. When bone growth exceeds cartilage growth, beginning at puberty, the epiphyseal plate is slowly lost. Growth of long bones stops when the cartilage is completely gone.
is a thin layer of hyaline cartilage
covering the articular surfaces of the epiphysis at a joint.
(marrow) cavity is the space within the bone containing either red or yellow bone marrow. Red bone marrow consists of blood precursors while yellow marrow consists of adipose tissue.
is the double-layered connective tissue surrounding the bone except where the articular cartilage is present. It is divided into an outer fibrous layer and an inner osteogenic layer.
The outer fibrous layer of the periosteum is
composed of dense irregular connective tissue containing blood vessels, lymphatics, and nerves that pass into the bone.
The inner osteogenic layer of the
periosteum contains elastic fibers and various bone cell types, particularly osteoprogenitor cells, that give rise to new osteoblasts when stimulated.
functions in bone growth,
repair, and nutrition. In addition, it provides attachment points for skeletal muscles.
The endosteum is a single layer of osteoprogenitor
cells lining the medullary cavity.
consists of lamellae (layers) of bone matrix arranged in an
irregular latticework of thin plates of bone called trabeculae. The spaces between the trabeculae are a part of the medullary cavity of the bone.
contains very few spaces. The layers of bone matrix are
packed together tightly, forming osteons (Haversian systems). It forms the external layer of all bones, providing protection and support and helps the long bone resist the stress of weight applied to them.
are immature quiescent cells lining the bone surfaces. When stimulated, they enter mitosis, giving rise to a new cell type called the osteoblast.
once differentiated, lose their mitotic ability, and
begin producing new bone matrix in a process known as osteogenesis.
are mature bone cells completely embedded in
bone matrix, are incapable of mitosis, and probably do not secrete new matrix. Their role in bone homeostasis is poorly understood.
reside scattered along the endosteal surfaces.
They function in a process known as bone resorption, the destruction of bone matrix. This process is required for normal bone function.
Unlike the other connective tissues, the matrix of bone
contains an abundance of mineral salts embedded into an homogeneous frame work of extracellular materials.
Identify the three main components of bone matrix
1. Tricalcium phosphate (hydroxyapatite--50% of total matrix). 2.Ground substance (25% of total matrix is water) 3.Collagen fibers (25% of total matrix)
The predominant mineral salt
is tricalcium phosphate (hydroxyapatite) (50% of total mineral) (there is also calcium carbonate, magnesium hydroxide, fluoride, and sulfate). As these salts are deposited into the framework of ground substance and collagen fibers, they crystallize and the tissue hardens or ossifies.
Although the hardness of the bone depends upon the crystallized mineral salts, without the collagen
the matrix would be very brittle (ex: an egg shell).
Collagen fibers provide
pliability and tensile strength to resist being stretched or torn apart. The mineral salts are crystallized onto the collagen fibers, giving bone its hardness.
Did you ever see the experiment in which a chicken bone is placed into vinegar for a few weeks?
When the bone was pulled from the vinegar, it could be bent and twisted, even tied into a knot. Why? Because the acetic acid in the vinegar dissolved the mineral salts from the bone, leaving only the collagen framework.
We tend to think of bone as a solid mass of calcified matrix, but it is instead
riddled with microscopic spaces through which blood vessels pass and fluids percolate.
A Volkmann's canal
is a minute passageway by means of which blood vessels and nerves from the periosteum of a bone penetrate into compact bone
(central) canal is a circular channel
running longitudinally in the center of an osteon of mature compact bone. It contains blood and lymphatic vessels and nerves.
are rings of calcified bone
matrix surrounding the Haversian canals of compact bone.
("little lake") is a small hollow space within bone
matrix wherein resides an osteocyte. They are located between concentric lamellae
is a small channel or canal connecting two
lacunae in compact bone. Each canaliculus contains a cellular process of an osteocyte
(Haversian system) is the basic unit of structure in
adult compact bone. Each consists of a central canal with its concentrically-arranged lamellae of matrix, lacunae, osteocytes, and canaliculi
are fragments of older compact
bone found between newer osteons. They have been partially destroyed during bone replacement.
What is the process of bone remodeling?
Remodeling is the ongoing replacement of old bone tissue by new bone tissue. It occurs as a delicate balance between bone resorption by osteoclasts and bone formation by osteoblasts.
What does bone remodeling accomplish
1. Changes the way bone matrix resists stress
2.Removes worn or injured bone
3.Provides a reservoir for body calcium
PTH has three targets (effectors):
1. increase bone resorption 2. increase calcium reabsorption by the kidneys. 3. increased absorption of calcium by the gut (inconjunction with vitamin D). The response to these effects is an increase in blood calcium concentration
Consider the role of bone in calcium homeostasis. How is it hormonally-controlled to either store or release calcium dependent upon the body's needs at the moment.
Blood calcium levels are very tightly controlled between 9.5-10.5
The hormones parathyroid hormone (PTH) and calcitonin (CT), as
well as Vitamin D, are the principal regulators of blood calcium concentrations.
This control is regulated by negative feedback mechanisms that are related to the amount of calcium in the blood. What happens if blood calcium drops too low?
The controlled condition is blood calcium concentration. In this case it has dropped below 9.5 mg%.
Parathyroid gland cells detect the lowered calcium concentration. This serves as input into the control center for the feedback system.
The parathyroid gland cells respond to the input from the receptors by secreting parathyroid hormone into the blood. This is the output of the system.
The response to these effects is an increase in blood calcium concentration.
What is the axial skeleton?
consists of those bones that lie in the longitudinal axis of the body, running through its center of gravity
Name the axial bones.
include the bones of the skull, the hyoid, the ribs, sternum, and vertebrae,
What determines a joint's function?
structure determines its function(s).
Name the four factors that influence the range of motion allowed at any particular joint?
1.tightness of fit between bones
2.precise manner in which the bones fit together
3.tightness of the tissues that bind the bones of the joint together
4.position of the ligaments, muscles, and tendons surrounding the
Name the structural classification of joints
fibrous, cartilaginous, synovial
There is no joint cavity. the bones are held tightly
together by dense fibrous connective tissue.
There is no joint cavity. The bones are held
together by a bridge of cartilage.
There is a joint cavity present. the bones are held
together loosely by a surrounding capsule of connective tissue and by various ligaments
Name the functional classification of joints
synarthrosis, amphiarthrosis, diarthrosis
This is an immovable joint.
This is a slightly movable joint
This is a freely movable joint.
Joint cavity (synovial cavity)
The distinguishing anatomical feature of a diarthrosis
is the synovial (joint) cavity, a fluid-filled space that separates the articulating bones.
articular cartilage of synovial joint
(hyaline type) that
covers the surfaces of the bones at their point of articulation, but does not bind the bones together
Synoviocytes, lining the inside surface of the
synovial membrane, secrete synovial fluid into the joint cavity for lubrication of the articular cartilages and the nourishment of the cartilage cells
articular capsule of synovial joint
The sleeve-like articular capsule surrounds the
joint, uniting the two bones by forming a sac-like structure that incorporates the ends of each bone
The outer layer of the articular capsule
is the fibrous capsule. It is formed of dense irregular connective tissue that blends with the periostea of the two bones and provides flexibility with resistance to dislocation.
The inner layer of the articular capsule
is the synovial membrane. It is composed of synoviocytes, areolar tissue, and adipose tissue.
In addition to the ligaments formed by
thickenings of the fibrous capsule, most synovial joints have accessory ligaments as well. These are not an integral part of the fibrous capsule.
lie outside the articular capsule and bridge the two bones.
lie within the articular capsule and bridge the two bones. They are excluded from the joint cavity by wraps of the synovial membrane.
Describe the articular discs (menisci) of cartilage found in the knee and shoulder joints. What are their functions?
Inside the shoulder and knee joints are pads of fibrocartilage called the articular discs (menisci). these pads lie between the articular bone surfaces in addition to the articular cartilages and are attached to the fibrous capsule by ligaments. They serve to: 1.allow the ends of the articulating bones to fit more closely together; 2.give more stability to the joint by giving a better fit between the bones; and 3.direct the flow of synovial fluid to areas with greatest frictio
What are bursae?
are thin, lubricated cushions located at points of friction between a bone and the surrounding soft tissue, such as skin, muscles, ligaments and tendons. It lies between a bone and opposing surface (e.g. skin) like a tiny water balloon with only a few drops of fluid in it, wedged between two surfaces.
Where are bursae found?
are strategically located between moving parts. In general, they are found between skin and bone, tendon and bone, muscle and bone, ligament and bone, or articular capsule and bone.
What is burase function?
Their function is to reduce the great amounts of friction that are generated between moving parts during various motions.
CONTACT AT A DIARTHROSIS
Several factors contribute to keeping the articular surfaces of bones in a synovial joint in contact. These factors, in turn, determine the type and extent of motion that is possible at the joint. Several factors contribute to keeping the articular surfaces of bones in a synovial joint in contact. These factors, in turn, determine the type and extent of motion that is possible at the joint.
Identify these five factors.
1. structure or shape of the articulating bones
2. strength and tension of the joint ligaments
3. arrangement and tension of muscles around the joint
4. apposition of soft parts
5. hormones (relaxin)
Identify each of the four major movement types allowed by synovial joints and give a brief description of each
Gliding, Angular, Flexion, Extension, Hyperextension, Abduction, Adduction , Rotation, Circumduction
List the five pairs of special movements allowed by diarthroses and give a brief description of
is a layer of synovial membrane around a tendon. It permits the tendon to stretch and not adhere to the surrounding fascia. It has two layers: synovial sheath. fibrous tendon sheath.
Elevation vs depression -
_____is an upward movement of a
body part, while ____ is a downward movement. The mandible and the shoulder do these movements.
Protraction vs retraction
______is a movement forward on a
plane parallel to the ground, as in thrusting the mandible forward. The shoulders can also be protracted. _____ is the opposite movement.
Inversion vs eversion
Inversion is the movement of the sole of the
foot inward (medially) so that the soles face each other. Eversion is movement of the sole outward (laterally) so that the soles face away from each other.
Dorsiflexion vs plantar flexion
_____ involves bending the
ankle in the direction of the dorsum (top) of the foot, as in trying to stand on your heels. ____ is bending the ankle in the direction of the plantar surface (sole) of the foot, as in standing on your toes.
supination vs Pronation
____is a movement of the forearm
in which the palm of the hand is turned anteriorly (anatomical position). ____ is the movement that turns the palm posteriorly.
Due to compression and shear stress
Fragments may cause joint to lock or bind
Cartilage rarely repairs itself
Repaired with arthroscopic surgery
Sprains and dislocations
most common joint injuries
inflammation of a bursa usually caused by a blow or friction
inflammation of tendon sheaths typically caused by overuse
Cartilage provides a smooth, gliding surface for joint motion and acts as a cushion between the bones. In __, the cartilage breaks down, causing pain, swelling and problems moving the joint. As __worsens over time, bones may break down and develop growths called spurs. Bits of bone or cartilage may chip off and float around in the joint. In the body, an inflammatory process occurs and cytokines (proteins) and enzymes develop that further damage the cartilage. In the final stages of __, the cartilage wears away and bone rubs against bone leading to joint damage and more pain.
is an autoimmune disease in which the body's immune system - which normally protects its health by attacking foreign substances like bacteria and viruses - mistakenly attacks the joints. This creates inflammation that causes the tissue that lines the inside of joints (the synovium) to thicken, resulting in swelling and pain in and around the joints. The synovium makes a fluid that lubricates joints and helps them move smoothly.
What is an articulation?
(joint) is a point of contact between bones, between
cartilage and bone, or between teeth and bones
Which type of cartilage is most associated with bone? Where is it found?
hyaline cartilage is the type of cartilage most associated with bone. It is found lining bones and joints (articular cartilage). The other two are elastic cartilage and fibrocartilage.
Distinguish between appositional and interstitial growth
Interstitial growth-increases the length of long bones an appositional growth-increases the thickness and is responsible for remodeling of all bones.
What are bone markings?
are features visible on the surface of bones. Each marking has a specific function. it allow medical professionals to perform three general classes of bone markings
is a thin layer of hyaline cartilage
covering the articular surfaces of the epiphysis at a joint.
distinguish among osteomalacia, osteoporosis
In osteoporosis, the bones are porous and brittle, whereas in osteomalacia the bones are soft
What are the different types of fractures?
The different fractures are simple, compound, spiral, and compression
rheumatoid arthritis (RA)
is a chronic, autoimmune disease
Ligaments are _____.
fibrous bands that connect bones and cartilages
Fracture (compound or Open)
bone breaks and ruptures through the skin; creates an increased chance of infection
simple or closed fracture
complete break of the bone with no damage to the skin
fracture in which the bone is splintered or crushed
bending and incomplete break of a bone; most often seen in children
Bursitis means _____.
inflammation of a synovial-filled sac
The process in which mineral matter replaces previously formed cartilage is called ____________________.
Name the five functions of the skeletal system
protection, Mineral storage, Acid-Base Homeostasis, Blood cell formation, Fat storage, Movement, support.
Inorganic matrix of bone
- 65% of ECM
- Hydroxyapatite crystals (Ca & P) (strong & compression resistant)
organic matrix of bone
-Osteoid (fibers, proteoglycans, glycosaminoglycans)
____________________ is a joint disorder characterized by an acute inflammation commonly affecting the big toe.
The one cells that are thought to regulate the movement of calcium and phosphate into and out of the bone matrix are known as
Osteocytes within compact bone tissue are located in minutes capsules, or space, known as
What are the six fontanels:
Anterior, posterior, two anterolateral, and two posterolateral frontals
bones forming the orbit (eye socket)
frontal, zygomatic, maxilla, palatine, ethmoid, lacrimal, sphenoid
The mastoid process is a bony extension of the
The three components of the sternum l, listed from the superior to inferior in position, are
Manubrium, body, xiphoid, process
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