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58 Cards in this Set
- Front
- Back
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What are the 3 functions of bone?
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Structural support
mineral homeostasis hematopoiesis |
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Bone formation:
1. ... – cartilage model (long bones) 2. ... – flat bones (i.e. skull) |
endochondral
intramembranous |
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Bone investments:
... – covers entire bone ... – covers internal surfaces |
periosteum
endosteum |
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... have a well developed Golgi complex, many cisternae of rER and numerous mitochondria.
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osteoblast
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... produce bone matrix.
The un-calcified bone matrix made by these immature osteocytes is called .... |
osteoblasts
osteoid |
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Osteoblasts – also produce ... (first produced by osteoblasts) which appears to play a role in mineralization of bone.
... is a useful clinical marker for bone formation activity. |
alkaline phosphatase
Alkaline phosphatase |
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... – less active than osteoblasts.
... link the lacunae and serve as a means for the passage of nutrients and information. |
osteocytes
Canaliculi |
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... conform to the shape of the lacunae and send processes into canaliculi, where they form ... with the processes of adjacent cells.
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Osteocytes
gap junctions |
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Mature osteocytes have many ..., but a decrease in the number of other organelles listed above for osteoblasts.
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lysosomes
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...:
Large multinucleated cells with acidophilic cytoplasm that occupy Howship's lacunae etched, by enzymatic action, into the surface of bone that is being resorbed. erodes away part of bone --> releases Calcium into the blood These cells secrete acids, collagenase and other proteolytic enzymes. |
osteoclasts
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Osteoclasts:
In response to ..., osteoblasts secrete neutral proteases that expose the surface of bone (degrades osteoid). Parathyroid hormone acts ... to influence osteoclasts/osteolysis Calcitonin inhibits directly |
PTH
indirectly |
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Bone grows only ...
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appositionally
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BRC (bone remodeling compartment)
It is generally accepted that the coordinated actions of ... and ... control bone remodeling. |
osteoclasts and osteoblasts
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BRC
The ... seems to be the cell which initiates the response to stress by it’s apparent ability to respond to matrix deformation. |
osteocytes
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The osteocytes release ... which influence the activity of osteoblast (surface cells).
Osteoblasts in response increase their production of factors such as osteopontin, ... and ... |
chemofactors
PGE2 nitric oxide (NO). |
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Bone resorption is coupled with new bone formation. This paired process is called ....
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bone remodeling
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Bone:
... - Remnants of Haversian systems that were partially resorbed. |
interstitial lamellae
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According to Wolff’s law, bone is ... in areas where load bearing is high. In contrast, bone will be ... in areas not subjected to stress.
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deposited
resorbed |
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Articular Cartilage:
A layer of ... cartilage on the ends of bones forming an articulation. The cartilage and the ... provide a low friction, lubricated surface allowing smooth painless motion. |
hyaline
synovium (synovial membrane) |
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Four Zones of Articular Cartilage:
1. ... zone: smooth nearly frictionless surface. Thin collagen fibrils parallel surface, chondrocytes elongated, proteoglycan content lowest and water content highest. 2. ... zone: chondrocytes rounded, collagen fibers less organized. 3. ... zone: highest concentration of proteoglycans and lowest water content. Collagen perpendicular to surface. 4. ... zone: contains calcified cartilage next to subchondral bone. |
Superficial tangential
Middle (transitional) Deep Calcified |
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deep and calcified zones separated by the...
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tidemark
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... (synovial membrane): Secretes synovial fluid which lubricates surfaces, reducing friction.
Lines synovial joints, bursae and tendon sheaths. Made up of a double layer of mesenchymal cells Major component in synovial fluid = ... |
Synovium
hyuronic acid |
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The synovium (synovial membrane) is composed of 2 major cell types:
Type A synoviocytes are ...-like (remove particulate debris from joints); Type B synoviocytes are ...-like cells (secrete hyaluronic acid present in synovial fluid) |
macrophage
fibroblast |
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Synovial Tissue:
Articular surface does not have a .... Thus, synovial fluid acts to deliver and remove material from the articular cartilage. Synovial fluid does not contain ... and therefore will not clot. |
blood supply
fibrinogen |
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... are important in protecting joints from instability but at the same time allow normal movement with minimal resistance.
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Ligaments
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... - collagenous tissue which unites two or more bones
... - connective tissue attachment uniting muscle to muscle, cartilage or bone |
Ligament
Tendon |
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Ligaments and tendons are both ... regular connective tissue.
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dense
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1. ... are composed of very highly organized collagen fibers that are uniformly stiff and does not allow significant elongation of the fibers.
2. ... are not as highly organized into parallel bundles and at rest are somewhat crimped. This allows for a small amount of stretching to occur before the fibers tighten |
Tendons
Ligaments |
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Ligaments and tendons are highly ... and contain mechanorecetors important in ....
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vascularized
proprioception |
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... is the point at which a tendon or ligament inserts into bone.
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Enthesis
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A disease of the entheses is known as an "..." or "....".
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enthesopathy
enthesitis |
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Ligaments and tendons attach to bone in 2 ways:
A “direct” attachment involving ... (... entheses). This enthesis consists of four zones. An “indirect” attachment to the bone or periosteum (... enthesis; associated with Sharpey's fibers). |
fibrocartilage
Fibrocartilaginous Fibrous |
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Zones of a fibrocartilage enthesis:
1. the tendon or ligament (displaying ... oriented fibroblasts and a ... arrangement of collagen fibers); 2. ... fibrocartilage; 3. ... fibrocartilage (the uncalcified fibrocartilage and calcified cartilage are separated by a “...”); and 4. ... bone. |
longitudinally
parallel unmineralized mineralized tidemark lamellar |
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Fibrous entheses may be subdivided into two categories— ... and ....
At the former, the tendon attaches to the periosteum, which thus indirectly attaches the tendon to the bone. At the latter, the periosteum is absent and the tendon inserts directly into the bone itself. |
periosteal
bony |
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Fibrous Enthesis:
Fibrous periosteal attachments spread the force transmitted by the tendon over a broad area. In the limbs, fibrous entheses are characteristic of tendons that attach to ..., whereas fibrocartilaginous insertions are typical of .... |
diaphyses
epiphyses |
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Injuries:
... - injury of ligament causing some degree of damage to the ligament fibers or their attachments. –... degree-minimal tearing of fibers with histologic evidence of swelling and hemorrhage –... degree-partial tear of ligament with gross evidence of swelling and hemorrhage –... degree-complete tear with extensive edema and hematoma –... -point of origin or insertion pulls off of bone attachment ... - injury of muscle-tendon unit |
Sprain
first second third avulsion Strain |
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Healing process:
In ligaments that can heal such as the MCL, the process is divided into 3 stages: 1. ..., involving formation of a blood clot and release of attractants for inflammatory cells (day 0-10); 2. ..., involving increase of cell density in the ligament remnant and new collagen (types I and III [embryonic and elastic]) (day 10-21); 3. ..., involves alignment of the new matrix, cross-linking of collagen occurs, type III collagen is replaced with type I, and decrease cell proliferation (~ day 21 -52 weeks). *Some ligaments, especially ... ligaments such as the ACL fail to heal (due to blood failing to clot) after rupture. |
Inflammation
Proliferative Remodeling intra-articular |
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Connective Tissue Healing:
-... ligaments heal by forming a blood clot between the ruptured ends -The initial clot is remodeled by invading cells |
Extra-articular
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skeletal muscle fibers are described as being invested by an ..., a C.T. fiber coating that fills the spaces between muscle fibers.
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endomysium
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Groups of muscle fibers are termed ... and the C.T. capsule that separates or surrounds them is the ....
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fascicles
perimysium |
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The tough fibrous C.T. sheath of elastic, collagenous and reticular fibers that surrounds an entire named muscle is the ....
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epimysium
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The ... surrounding muscle is composed of densely packed collagen bundles and elastic fibers.
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deep fascia
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The area of the deep fascia adjacent to a muscle contains a high concentration of ....
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hyaluronic acid
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... – Contraction coupling:
This is an ordered process in skeletal muscle whereby a motor neuron that is stimulated to generate a propagated action potential from the perikaryon (nuclear) region sends its impulse (propagated action potential) distally on an axon where it is distributed to multiple separate nerve endings which are distributed to one or several skeletal muscle fibers. |
Excitation
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Excitation- contraction coupling:
The motor neuron and the skeletal muscle fiber(s) it innervates is called a .... |
motor unit
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...:
All muscle cells that are controlled by one motor neuron The ... the ratio of muscle fibers to neurons, the more precise the movement can be. Few cases 1: 1 relationship. Most cases: many muscle fibers (up to 2,000) : 1 motor neuron. |
Motor units
lower |
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The synaptic endings contain large numbers of round synaptic vesicles that contain ....
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acetylcholine
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The post synaptic surface of the muscle fiber is highly elaborated by multiple folds or grooves that are called synaptic ... or synaptic ....
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gutters
clefts |
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Excitation – contraction coupling:
The acetylcholine released from the presynaptic surface by the nerve action potential reacts with a membrane receptor and causes a graded ... of the muscle membrane which in turn if it reached threshold is propagated as an action potential in ... directions along the cylindrical muscle fiber. This depolarization is also distributed inward into the core of the muscle fiber from the immediate overlying surface by a minute system of transversely oriented tubules (...). |
depolarization
both T tubules |
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T tubules are in open communication with the extracellular space; and represent a continuation of the ....
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plasma membrane
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The t tubules in turn are the site of electrical activation of the surface of an internal closed, highly structured membrane system called the ... which surrounds the myofibrils in the sarcoplasm.
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sarcoplasmic reticulum (SR)
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Each T-tubule comes into close association with 2 dilated “... cisternae of the sarcoplasmic reticulum. *
This structure is called a .... |
terminal
triad |
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Activation of the terminal cisternae of the sarcoplasmic reticulum produces a large release of stored ... into the sarcoplasm adjacent to the thin and thick filaments where it catalyzes the interaction between adjacent thick and thin filaments that generates a physical movement of the thin filaments from each end of a sarcomere towards the center of the dark band which contains the thick filaments.
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calcium
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The movement of these cross bridges is powered by the breakdown of bound ....
This results in a ... of each individual sarcomere along the length of a myofibril. The net result is a physical ... of the length of a whole muscle fiber as all the individual myofibrils across the entire cross section of the muscle fiber act synchronously in this process. |
ATP
shortening shortening |
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As ATP is regenerated there is a simultaneous activation of the membrane of the longitudinal elements of the SR which then actively sequester the activating calcium to store it back in the ... until the next stimulus for contraction.
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terminal cisternae
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Striated Muscle Cell Adaptations:
A major skeletal muscle adaptation is the development of a system of small muscle fibers – the ..., made up of intrafusal (very small) muscle fibers. All of the ordinary skeletal muscle fibers outside of the spindle are known as ... muscle fibers. |
neuromuscular spindle
extrafusal |
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Extrafusal fibers are innervated by large ... myelinated motor fibers coming from anterior horn cells.
In contrast, the small intrafusal muscle fibers receive motor innervation from small nerve fibers called ... efferents. |
alpha
gamma |
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Striated muscle cell adaptations:
The muscle spindle has an extensive ... receptor innervation that directly measures the tension state of the ... muscle fibers, and because of their physical location among the ..., it indirectly measures the state of tension in the myriads of extrafusal muscle fibers that surround it. These fibers provide this information on the state of ... to the spinal cord and the cerebellum. This system is thus a major determinant of organized coordinate muscle control. |
sensory
intrafusal extrafusals tension |
