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The axial skeleton is the basic framework of the body, consisting of the ____________ , _____________, and _____________.
- Skull
- Vertebral column
- rib cage
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Cartilage
- composed of firm but elastic matrix called chondrin
- chondrin is secreted by specalized cells called chondrocytes
- cartilage is the principal component of embryonic skeletons in higher animals - hardens and calcifies into bone
- Cartilage reamins in external ear, nose, walls of the larynx, and trachea, and skeletal joints contain cartilage
- most cartilage is avascular - contains no blood or lymph vessels, and is devoid of nerves
- *receives nourishment from capillaries located in nearby CT and bone via diffusion through the surrounding fluid.
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Most cartilage is avascular, containing no blood or lymph vessels, and is devoid of nerves.
A. True
B. False
True
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Cartilage receives nourishment from capillaries located in nearby CT and bone via _______ through surrounding fluid.
Diffusion
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_______________, also called cancellous bone, consists of interconnecting lattice of bony spicules called ______________.
Trabeculae
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______________ bone marrow is inactive and infiltrated by adipose tissue.
Yellow bone marrow
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_____________ is involved in blood cell formation.
Red bone marrow
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The bones of the appendages are called _____________.
Long bones
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The shaft of the long bone is called a _________________.
Diaphysis
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The dilated ends of long bones are called epiphyses
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The diaphysis is composed primarily of __________________.
Compact bone surrounding a cavity containing bone marrow.
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The ______________ are composed of spongy bone surrounded by a thin layer of compact bone.
Epiphyses
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The ____________________ is a disk of cartilaginous cells separating the diaphysis from the epiphysis, and is the site of longitudinal growth.
epiphyseal plate
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A fibrous sheath called the _________________ surrounds the long bone, and is the site of attachment to muscle tissue.
Periosteum
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Some periosteum cells differentiate into ____________________.
Bone-forming cells
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Compact bone is composed of dense, hardened bone matrix, which contains both ___________ and _____________ components.
Organic and Inorganic components
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In compact bone, the organic components include ______________.
Proteins: collagen fibers, glycoproteins
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In compact bone, inorganic components include _________________.
- calcium, phosphate, hydroxide (which combine and harden to form hydroxyapatite crystals)
- sodium, potassium, magnesium ions
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The association of __________ and ____________ gives bone its characteristic strength
hydroxyapatite crystals and collagen fibers
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The bony matrix is deposited in structural units called ____________, also known as Haversian systems.
Osteons
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Each osteon consists of a microscopic channel called a _________________.
Haversian canal - surrounded by a number of concentric circles of bony matrix called lamellae
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The Haversian canal is surrounded by a number of concentric circles of bony matrix called _____________.
Lamellae
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There are _____________, ________________, and _____________ in the Haversian canals, vascularizing and innervating bone tissue.
- Blood Vessels
- Nerve fibers
- Lymph
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Radiating from each lacuna are a number of minute canals called __________________.
Canaliculi
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The _____________ interconnect with each other and with Haversian canals, allowing exchange of nutrients and wastes.
canaliculi
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________________ synthesize and secrete organic constituents of the bony matrix.
- Osteoblast - form bone
- *once they are surrounded by their matrix, they mature into osteocytes
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________________ are large multinucleated cells involved in bone resorption (destroy bone!)
Osteoclasts
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Bone formation occurs by either ___________________ or by ____________________.
- Endochondral ossification
- Intramembranous ossification
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In _____________________, existing cartilage is replaced by bone.
Endochondral ossification
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Long bones arise primarily through ______________________.
Endochondral ossification
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In ________________________, mesenchymal (embryonic, undifferentiated) connective tissue is transformed into and replaced by bone.
Intramembranous ossification
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During __________________, inorganic ions (i.e. calcium and phosphate) are absorbed from the blood for use in bone formation.
Bone reformation
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During ___________________, inorganic ions (i.e. calcium, phosphate) are released into the blood.
Bone resorption (degradation)
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______________, and hormones, ___________ and ______________, are all involved in the regulation of bone remodeling (forming, and destroying).
- Vitamin D
- Parathyroid hormone
- Calcitonin
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The freely movable _________ joints, the two bones are separated by a cavity.
Synovial joints
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An example of a synovial joint is ______________.
the knee.
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Synovial joints are subject to _____________.
Arthritis
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______________ ease friction between tendons and ligaments and between tendons and bones.
Bursae
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The knee and elbow are _______________ because they largely permit movement in one direction.
Hinge joint
knee-synovial joint
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_____________ joints allow movement in all planes and even rotational movement.
- Ball and socket
- examples: ball of femur, shoulder
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The skeletal muscle is innervated by the __________________.
Somatic nervous system
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The cytoplasm of a muscle fiber is called _____________.
Sarcoplasm
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The cell membrane of a muscle fiber is called the ____________________.
Sarcolemma
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The __________________ is capable of propagating an action potential, and is connected to a system of transverse tubules (T system) oriented perpendicularly to the myofibrils.
Sarcolemma
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The __________________ provides channels for ion flow throughout the muscle fibers, and can also propagate an action potential.
T system
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Skeletal muscles can be characterized as either red or white.
A. True
B. False
True
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Red skeletal muscle fibers are abundant in ___________ content, and _____________.
- Myoglobin - store oxygen
- mitochondria
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_______________ derive their energy from aerobic respiration and are capable of sustained and vigorous activity.
Red skeletal muscle fibers : "slow-twitch fibers"
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___________________ contain less myoglobin and fewer mitochondria.
White skeletal muscle fibers
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________ skeletal muscle fibers are anaerobic.
White fibers
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Which of the following has a greater rate of contraction?
A. White skeletal fibers
B. Red skeletal fibers
White skeletal fibers
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Which of the following fatigues more easily ?
A. White skeletal muscle fibers
B. Red Skeletal muscle fibers
white fibers
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The ______________ is composed of thin and thick filaments.
Sacromere
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The thin filaments of the sacromere are the ____________.
Actin filaments
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Actin filaments are associated with two proteins: _________________, ________________.
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The thick filaments are composed of organized bundles of ____________.
- Myosin molecules
- *each myosin molecule has a head region and a tail region.
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In the sacromere, the ________________ define the boundaries of a single sacromere and anchor the thin filaments.
Z lines
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______________ runs down the center of the sacromere.
M line
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In the sacromere, the ___________ is the region containing thin filaments only.
I band
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In the sacromere, the _______________ is the region containing thick filaments only
H zone
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In the sacromere, the _______________ spans the entire length of the thick filaments and any overlapping portions of the thin filaments.
A band.
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During skeletal muscle contraction, the ______________ is not reduced, while the H zone and are reduced.
A band. a
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During skeletal muscle contraction, the ____________, and ___________ are reduced in size.
H zone, and I band
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_________________ break down ATP and form cross bridges that attach to and pull the actin filaments toward the center of the sacromere.
Myosin filaments
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Muscle fibers rely on _______________, a storage form of high-energy phosphate for energy.
- creatine phosphate. - cannot participate directly in muscle contraction.
- It anaerobically regenerates ATP by :
- creatine-P + ADP -------> ATP + creatine
- *this is the speediest energy source available to muscles.
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Muscle contraction is stimulated by a message from the _________________ sent via a motor neuron.
Somatic nervous system
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During muscle contraction, the sarcolemma of the muscle fiber is called the _____________________.
Neuromuscular junction
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________________ of the motor neuron results in the release of neurotransmitters from the nerve terminal.
- Depolorization
- *The neurotransmitter diffuse across the synaptic cleft and binds to special receptor sites on the sarcolemma.
- *If enough of these receptors are stimulated, the permeability of the sarcolemma is altered and an action potential is generated.
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During muscle contraction, once an action potential is generated, it is conducted along the ____________, and the ____________, and into the inferior of the muscle fiber.
Sarcolemma, T system
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During contraction, the generation of the action potential causes the ______________ to release Ca2+ into the sarcoplasm.
sarcoplasmic reticulum
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The Ca2+ binds to the ______________.
a. troponin
b. tropomyosin
troponin
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ATPase Activity
5 steps:
- 1. resting stage - ATP is hydrolyzed when myosin head is unattached
- 2. Ca2+ binds to troponin; myosin binds to actin
- 3. powerstroke occurs; sacromere contracts
- 4. ADP and P are released
- 5. New ATP binds to myosin, causing detachment of myosin from actin;
- Relaxation
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What is the function of Ca2+ in muscle contraction?
Troponin-Ca2+ complex pulls tropomyosin away, exposing myosin binding sites
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Individual muscle fibers generally exhibit an ____________ response.
all or none response - only a stimulus above threshold value can elicit contraction.
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The strength of the contraction of a single muscle fiber cannot be increased, regardless of the strength of the stimulus.
A. true
b. false
true
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Whole muscle exhibits an all or none response.
a. true
b. false.
- false
- *although there is a minimal threshold value needed to elicit a muscle contraction, the strength of the contraction can increase as stimulus strength is increased by involving more fibers.
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A ______________________ is reached when all the fibers have reached the threshold value and the muscle contracts as a whole.
Maximal response
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__________ refers to the continual low-grade contractions of the muscle, which are essential for both voluntary and involuntary muscle contraction.
- Tonus
- *Even at rest, muscles are in a continuous state of tonus
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A ________________ is the response of a single muscle fiber to a brief stimulus at or above the threshold stimulus.
Simple twitch
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A simple twitch consists of 3 periods:
1. ________________
2. ________________
3. ________________
- 1. latent period
- 2. contraction period
- 3. relaxation period
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During a simple twitch, the time between stimulation and the onset of contraction is the ___________ period.
Latent period
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During the ____________ period in a simple twitch, the action potential spreads along the sarcolemma and Ca2+ ions are released.
latent period
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Following the contraction in a simple twitch, there is a brief relaxation period in which the muscle is unresponsive to stimulus, this is known as the ______________.
Absolute refractory period.
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Following the absolute refractory period in a simple twitch, a _____________ occurs, during which a greater than normal stimulus is needed to elicit a contraction.
relative refractory period
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When the fibers of a muscle are exposed to a very frequent stimuli, the muscle cannot fully relax.
A. true
B. false
- true
- *the contractions begin to combine, becoming stronger and more prolonged. This is known as frequency summation.
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A tetanus contraction is stronger than a simple twitch of a single fiber.
a. true
b false.
- true
- *If tetanization is prolonged, the muscle will begin to fatigue
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Smooth muscle is innervated by ________________.
Autonomic nervous system
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_____________ possess one centrally located nucleus.
Smooth muscle
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Smooth muscles also contain actin and myosin filaments.
a. true
b. false
- true
- *however, these filaments lack the organization of skeletal sarcomeres; thus, lacking striations.
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All muscle contractions by skeletal, smooth, and cardiac require Ca2+ for contraction.
a. true
b. false
true
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____________ muscle contains many nuclei per cell.
Skeletal muscle
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Smooth muscle contractions are slower, and are capable of being sustained longer than skeletal muscle contractions.
a. true
b. false
true
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________________ muscle typically have both inhibitory and excitatory synapses that regulate contraction via the nervous system.
Smooth muscle
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_______________ muscle also have the property of reflexively contracting without the nervous stimulation; this is called myogenic activity.
- Smooth muscle
- *also cardiac muscle !!!!!!! has myogenic activity
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Like skeletal muscle, ____________ muscle have actin and myosin filaments that are arranged in sacromeres, giving the striation look.
Cardiac
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___________ muscle contains 1-2 nuclei (centrally located) per cel.
Cardiac
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Cardiac muscle is innervated by the _________________.
- autonomic nervous system
- *cardiac muscle is also myogenic - has the property of reflexively contracting without nervous stimulation
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______________ has a high O2 affinity.
- myoglobin -binds to O2 from the bloodstream and holds onto it.
- *During strenuous exercise, when muscle cells rapidly run out of available O2, myoglobin releases its O2.
- *If the oxygen supply to muscles become insufficient to meet its energy standards, the muscle obtains additional energy via anaerobic respiration, resulting in the build-up of hte lactic acid.
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Connective Tissue:
________________ binds epithelium to underlying tissues and is the packing material that holds organs in place.
Loose connective tissue
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Loose connective tissue contains 3 types of fibers :
1. ________________
2. ________________
3. ________________
- 1. collagenous fibers
- 2. elastic fibers
- 3. reticular fibers
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Connective tissue:
______________ fibers are composed of collagen and have great tensile strength.
collagenous fibers
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Connective Tissue:
_______________ fibers are composed of elastin and endow connective tissue with resilience
Elastic fibers
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Connective tissue:
________________ fibers, which are branched, tightly woven fibers that join connective tissue to adjoining tissue.
Reticular fibers
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There are two major cell types in loose connective tissue:
1. _________________
2. _________________
- 1. fibroblasts
- 2. macrophages
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In loose connective tissue, ____________ secrete substances that are components of extracellular fibers
fibroblasts
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In loose connective tissue, _______________ engulf bacteria and dead cells via phagocytosis.
Macrophages
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_______________ is a connective tissue with very high proportion of collagenous fibers.
Dense connective tissue
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Connective Tissue:
_________________ fibers are organized into parallel bundles that give the fibers great tensile strength.
Dense connective tissue
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__________________ tissue forms tendons, which attach muscle to bone.
Dense connective tissue
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____________ attach muscle to bone.
Tendons
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___________ hold bones together at joints
ligaments
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A _________ muscle will contract to decrease the angle of a joint.
flexor muscle
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A __________ muscle will contract to straighten the joint.
extensor
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An _____________ moves a part of the body away from the body's midline.
abductor
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An ______________ moves a part of the body toward the midline.
adductor
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_______________ are bone cells involved in the secretion of bone matrix.
osteoblasts
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_______________ serves as the site of attachment of bone to muscle.
Periosteum
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Cells of the _______________ differentiate into osteoblasts
periosteum
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The ________________ is a fibrous sheath that surrounds long bones.
periosteum
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