Quizlet from Athena Flashcards
Greater number of muscle fibers per cross-sectional area=
more force
In the postmortem state of rigor mortis, actin and myosin are bound and unable to dissociate in the absence of ______
ATP
E and NE stimulate ____ receptors on the beta cells of the pancreas to decrease insulin secretion
alpha-adrenergic
What is the only cartilage remaining on mature bone
articular surfaces
Structure of Tropomyosin
composed of two polypeptide chains that sit within the grooves of thin filament, F-actin.
Isotonic contraction
lengthening of a contracting muscle or “lengthening contraction”. i.e. coactivation of antagonistic muscles used to brake a muscle movement
Cartilage is an _________ tissue. It receives nutrients from blood capillaries
avascular
Thick myofilaments composed of the protein myosin. Considered dark bands
A-bands
Hyperplasia of muscle
occurs by the formation of more muscle cells. This also increases the force generating capacity of muscle. However, the ability of differentiated muscle to form new cells is limited.
Which GAGs are found in cartilage and bone?
Chondroitin sulfates, keratan sulfate
External lamina
similar to basal lamina, surrounds all muscles fibers, Schwann cells, endothelial cells and adipocytes. Made of the same components as basal lamina.
Electromyography (EMG)
involves the detection and characterization of electrical activity recorded from the patients muscles.
What type of collagen fibers are found in the bone matrix
Type I
During bone modeling bone resorption occurs at the
endocortical surface
How does disproportional growth of distal bones affect speed?
improved stride distance and higher oscillation rate
Hypertrophy of muscles cells
Occurs by increasing the diameter of a muscle fiber through the synthesis of new myofibrils. Increasing the diameter will increase the force-generating capacity of the muscle
What causes increased ACh release associated with weakness due to continued depolarization of post-synaptic membrane
Hypercalemia
What connects thick myofilaments with the Z-line
Titin
___ is the principal structural protein of thin myofilaments
actin
Where all the cell bodies of motoneurons located
In the CNS within the ventral horns of gray matter of the spinal cord or motor nuclei of the brainstem. p
What is the limiting factor in the ATP-PC system
the substrate
Isometry
means k=1 and there is a linear relationship between the organ weight and body weight. The organ weight is a constant percentage of body weight throughout development
A globular protein bound to tropomyosin along the thin filament
Troponin
Formation of End-Plate potentials
two molecules of ACh reversibly bind to the ACh-receptor that results in increased permeability to sodium and potassium ions, creating a change in the local membrane potential, the EPP. They are sufficient to initiate muscle action potentials
Somitomeres turn into
striated (skeletal) muscle of head and branchial arches 1-3
Exercise’s effect on bone formation
increases it
Direct vs. Indirect bone healing
direct does not require a callus formation and occurs during conditions of fracture stability. Indirect requires formation of a callus doe to instability of fracture
What protein supports the sarcolemma on its sarcoplasmic surface?
dystrophin
The muscle stretch reflex is a ________ reflex
monosynaptic
Reasons why you should extract teeth
- Crowding of teeth
- Retained deciduous teeth
- Teeth in the line of a fracture
- Teeth destroyed by disease
- Endodontically diseased teeth
3-5 electron dense lines located in the middle of A-bands.Contain the enzyme creatine kinase
M-lines
Dense connective tissue
has relatively few cells but an abundance of thick fibers. Can be classified as dense irregular and dense regular connective tissue
Myosin makes up ____% of Total structural protein. Filaments are ____ and the general function is _____
55%, thick, contraction (activates myosin ATP-ase)
What happens to patients that lack the protein dystrophin
they develop muscular dystrophy
Moment arm
Perpendicular distance from an axis to the line of application of a force
What type of connective tissue do chondroblasts and chondrocytes make
Cartilage
Glycogenolysis is initiated by both the presence of _____ and increased ______ associated with contractile activity
epinephrine, increased intracellular Ca++ levels
Troponin-Tropomyosin complex during depolarization
Propagation of membrane potentials to the T-tubules. Calcium ions are released from the sarcoplasmic reticulum into the sarcoplasm elevating the calcium ion concentrations. The release of calcium ions are taken up by the Tn-C subunits. This results in a change in the Tn-1 subunit that in turn moves the tropomyosin molecules deeper into the actin grooves thus exposing the myosin binding sites on actin.
Type II collagen
Found in hyaline and elastic cartilage originates from chondrocytes
Somites differentiate into 3 critical regions
sclerotomes, myotomes, and dermatomes
At rest each myosin head has 2 molecules of ____ tightly bound to it. When myosin binding sites on actin are freed by action of the troponin-tropomyosin complex, myosin heads bind to _____
ATP, actin
Contraction time (Tc)
measure of ‘speed’ of contraction which is the time required for tension developed to reach maximum peak tension
If oxygen is not available pyruvate accepts 2 H+ ions and is converted to
lactic acid
What effect does interstitial and appositional cartilage growth have on the hyaline cartilage model
causes it to lengthen and broaden
Dense irregular connective tissue
irregular arrangements of fibers, makes it strong and able to withstand considerable stretching and distending forces
When EEP reaches critical level a ____ is generated from the end-pate and propagated out over the sarcolemma in all directions.
MAP muscle action potential.
Bone remodeling affect on bone shape
Does not change the shape
Myoblasts
myotomes becomes myoblasts by losing the ability to undergo further mitoses and acquiring specialized ability to synthesize myofibillar proteins. They then fuse together in a true syncitium losing cell memrbrane compnents that separate, them forming a myotube, or multinucleated muscle fiber.
Ligaments are ver resistant to ______ forces
tensile
What is the extracellular matrix of cartilage made up of
GAGs
Fasciae, tendons, and ligaments are classified as
dense, connective tissues. Fascia is considered irregular dense and tendons and ligaments are considered regular dense.
What happens when the calcium ions are removed from the sarcoplasm by the sarcoplasmic reticulum
The calcium content of Tn-C is reduced and the effects of troponin and tropomyosin are reversed, moving tropomyosin out of the groove to block the myosin binding sites on actin
The force that muscles can generate is a function of _____
total cross-sectional area
Vascular nonunion
Callus forms but fracture fails to heal.
Length of thick and thin myofilaments following contraction
unchanged
Fast-Twitch, Fatigable (FF, Type IIB)
cannot sustain tetanic tensions above 25% for more than 1-2 mins
What is high creatine in the blood indicative of?
degeneration of muscles
What is the cutter cone
Osteoclasts at the tip of a capillary bud that cross the fracture site. Behind the osteoclasts a cuff of osteoblasts lays down concentric lamellae of bone
Hematoxilin binds to
acidic substances. Acidic substances are considered basophilic i.e. nucleic acids
Antagonist muscles
muscles that produce oppositely directed movements at a joint
Elastic cartilage
ground substance contains elastin which gives it a yellow color. Chondrocytes are more closely packed. No isogenic groups. Less accumulate of glycogen and lipids than in hyaline cartilage. Does not calcify
Marfan’s Syndrome
mutation in FNB-1 (the gene that produces fibrillin). Ligaments may not be as effective at limiting joint movement, increased risk of aortic rupture.
Total ATP production from one molecule of glucose through aerobic metabolism
38 ATP
A reflex arc that passes through only a small segment of the CNS
segmental reflex
How does disproportional proximal distribution of muscle mass improve speed?
by changing the frequency of oscillation by changing the center of gravity
E and NE stimulate ____ receptor on alpha cells in the pancreas to increase glucagon secretion when plasma glucose levels are norma
beta-adrenergic
How does increased PTH affect osteoclasts
Increases activity=more bone resorption
The insertion
the most distal attachment of the muscle. The most moveable part and may have multiple insertions.
How does flexibility of the spine affect speed?
Flexibility of the vertebral column may increase stride length by providing an additional pivot point through the vertebral column . Rigid spine runners are limited by the limb
The belly of the muscle
usually a single one but may be multiples
What type of collagen fibers are found in Fibrocartilage
Type I
Gylcosaminoglycans (GAGS)
polysaccharide chains composed of repeating disaccharide units in which one of the sugars is always an amino sugar. The other sugar is either a uronic acid or galactose. They are highly negatively charged and attract sodium ions, which in turn draws water into the matrix thereby causing swelling or turgor which helps resist against compressive forces.
2/3 of cortical bone is supplied by the ________ artery
nutrient
The speed of contraction or the shortening of sarcomeres is directly proportional to the actin activated ATPase activity of ______
myosin
_____must be present for the transfer of energy from NADH and FADH to ATP
Oxygen
The matrix of Hyaline cartilage is rich in ______ fibers
Type II collagen
Interstitial growth
division of chondrocytes within lacunae and synthesis of new cartilage matrix so that cartilage expands from within
Negative allometry
means k
Synchondrosis joint
Mobility: Synarthrotic
Appendicular skeleton
thoracic and pelvic limbs
What are the complications of marginal gingivitis
Marginal gingivitis which can lead to: chronic gingivitis, pocket formation, loss of attachment, alveolar bone loss
Synostosis joint
Mobility: Synarthrotic
Osteoblasts
responsible for bone formation, produce bone matrix, initiate mineralization of the matrix. Ovoid to cylindrical in shape. Single and eccentric nucleus. Produce type I collage, proteoglycans, and bone specific proteins.
What is the principal funcition of the sarcoplasmic reticulum
control calcium ion concentration of the sarcoplasm surrounding myofibrils and myofilaments through its ability to concentrate and release calcium ions
Actin possesses a binding capacity for ____ and activates the _____
myosin, myosin ATPase
Exocytotic release of ACh from axon terminal is calcium ion dependent. In _______ there is a reduced ACh release that is associated with muscle weakness
Hypocalcemia
What gets excited by muscles spindle stretch and what happens once they do.
alpha motoneurons associated with those spindles. Results in a rapid contraction and the muscle shortens reducing the amount of stretch on the receptor.
Creating collagen precursors
synthesized in the rough ER of the fibroblasts where proline and lysine are hydroxylated. Pro-alpha chains are then assembled into procollagen and subsequently packaged in the Golgi apparatus for secretion by exocytosis into the extracellular space. In the extracellular space, the terminal peptides are enzymatically cleaved by peptidase to form collagen.
What happens to cartilage during calcification
chondrocytes hypertrophy/die. Blood vessels form around perichondrium. Osteoblasts differentiate.
Fast-twitch (F, Type II) Motor Units
Contraction times are relatively fast and tetanic fusion frequency is relatively high
articular cartilage
refers to hyaline cartilage on the articular surfaces of bones
Places where hyaline cartilage is found
growth plate, trachea, articular cartilage, larynx
What decreases the activity os osteoclasts
Calcitonin and E2
Normal pattern of healing of the extraction socket
clot formation after removal phase–> repair phase and initiation of bone formation–> woven bone–> lamellar bone
How does elongation of limbs affect speed?
If the frequency of oscillation remains constant, speed may be enhanced by merely increasing stride length through increasing the length of the pendulum (limb)
Amphiarthrotic
some mobility.
Nerve action potentials during neuromuscular transmission
originating at the motoneuron cell body. Are conducted along the axon to the axon terminals
Bone modeling
sculpting process that follows the elongation of growth. Process by which the overall shape is changed in response to physiolgic and or mechanical influences. Bone formation and resorption occur at separate bone surfaces
Phosphocreatine is available in _____ amounts in muscle. Therefore PC release of energy can only really be used for short term intense exercise
small
How do you treat Myasthenia Gravis (MG)
Through the use of cholinesterase inhibitor and/or suppression of immune response with steroids
What is the net production of glycolysis
2 or 3 ATPs and 2 NADHs
Where is synovial fluid produced
synovial fold
The osteoid seam, an unmineralized bone matrix is found between _______ and ______
active osteoblasts and bone surface
If a normal animal is laid on its side the crossed extension reflex is _____
absent.
Glycolysis is controlled by the activity of the rate limiting enzyme _____
Phosphofructokinase (PFK)
What are transverse T tubules
transverse invaginations of the sarcolemma that propagate changes in the membrane potential of these large cells
Maloclussion
failure of the upper and lower teeth to interdigitate properly. Leads to difficult mastication caused by Prognathia(protrusion of lower jaw) or Brachygnathia (shorter lower jaw)
_____ is the principal protein comprising thick filaments
Myosin
The origin
the most proximal attachment of the muscle and usually has no tendon or a small aponeurotic tendon. Usually the least moveable part of the muscle
This glycosaminoglycan is extremely long and unbranched and is widely distributed in most connective tissues, cartilage, synovial fluids, and vitreous humor.
Hyaluronic acid
Oxidative formation of ATP is considered _____ metabolism
aerobic
A sheet of dense connective tissue that completely surrounds and invests the muscle belly
Epimysium
Hypsodontic Teeth
Grow throughout life. Require floating. Horses teeth and the cheek teeth of ruminants
Muscle development require
neural innervation
Pennate muscles generate large amounts of _____ but allow for little _____. In contrast parallel muscle can _____ further and more rapidly but generate less _______
force, shortening, shorten, force
Sclerotomes give rise to
connective tissue and bone
Synovial tendon sheaths
Located in regions where friction is enhanced by greater movement tendons will form this sheath. Sheaths are filled with synovial fluid to reduce friction during movement.
Diathrotic
freely movable
Osteocytes
differentiated osteoblasts buried in bone matrix.
Long bones
appendicular skeleton
Brachydont teeth
Do not grow continously. Root not covered by enamel
What type of receptors are found on the crests of junctional folds and what is their purpose.
acetylcholine receptors. Upon activation open and increase membrane permeability to sodium and potassium
Two types of bone growth
endochondral ossification and appositional/intramembranous bone formation
Type I collagen
loose and dense proper connective tissue; found in collagen fibers, fibrocartilage bone and dentin. Originates from fibroblasts, osteoblasts, odontoblasts
What causes the amorphous substance to have a gel like nature
the presence of glycosaminoglycans and proteoglycans
What are chondrocytes
Mature cartilage cells embedded in matrix.reside in lacuna
Agonist muscles
muscles that produce similarly directed movements at a joint
A delicate connective tissue that surrounds each muscle fiber primarily composed of reticular fibers that harness the muscle fibers through connections with the external lamina.
Endomysium
Calcium uptake during neuromuscular transmission
with the arrival of an action potential the axon terminal, calcium ions enter the axon terminal via voltage gated calcium ion channels
Muscles that have an insertion point closer to the joint can generate a _______________ for the joint
greater range of motion
What is a skeletal muscle motor unit
alpha-motoneuron and the muscle fibers innervated by that neuron.
Responses to a single applied stimulus composed of a phase of developing tension followed by a phase of relaxation and diminishing tension.
Twitch contraction
Each sarcomere is encircled by longitudinal intermediate filaments of ______ that extend between Z lines of the same sarcomere. Z lines of adjacent myofibrils are held in register by intermediate filaments of _______
vimentin, desmin
Focal innervation
one synapse per muscle fiber. It is the most common form of innervation in mammalian species
Zone of calcified cartilage
matrix is more darkly stained due to calcium deposition. After growth is finished the tidemark will be a visible border between the zone of articular cartilage and the zone of calcification
The activity of the Ca++-ATPase pump is regulated by what?
Intracellular calcium concentrations
What is howship’s lacuna
The resorption concavity found on osteoclasts
Somite myotomes turn into
skeletal muscle
Myotomes give rise to
skeletal muscle
Zone of resting chondrocytes
chondrocytes are scattered, they do not divide, and may serve to weld the growth plate to the epiphysis
What is he active state of a muscle
Time course and magnitude of the contractile/chemical events associated with the interaction of myofilaments. Starts to develop quickly after the release of Ca++ from the SR. Mechanical events begin a little later due to titin and other structural proteins having to be stretched a finite amount before force production is transferred to the tendons of the muscle.
Methods to stimulate Bone fracture healing
- Implantation of cancellous bone autograft (most common)
- Precutaneous injection of bone marrow cells
- Implantation of bone graft substitute
- Bone morphogenetic protein
- Electrical or ultrasound stimulation
- Shock wave treatment
Troponin-Tropomyosin complex during relaxation
sarcoplasmic calcium ion concentration is low. The tropomyosin levels are elevated out of grooves and through the action of the Tn-1 subunit, block the myosin binding sites on actin
Multiaxial joints
three degrees or more of freedom such as ball and socket joints
Motor nerve conduction velocity
provides info on the integrity of nerve fibers in peripheral nerves. DOne under anesthesia. Demyelinating disorders cause slowed conduction
Uniaxial joints
one degree of freedom hinge joints such as elbow and knee
release of acetylcholine into the synaptic cleft occurs through __________
calcium ion dependent exocystosis
Within axon terminals are numerous _____ containing the neurotransmitter acetylcholine.
synaptic vesicles
Principal glycosaminoglycans of CT
hyaluronic acid, chondroitin-4-sulfate, chondoitin-6-sulfate, dematen sulfate, karetan sulfate and heparin sulfate.
What makes up glycosaminoglycans (GAGs)
Chondroitin
Flat bones
skull, scapula, pelvis
Length of a sarcomere following contraction
decreased
Fibrous layer of synovial joint
dense white fibrous connective tissue that contains elastic fibers attaches to the perichondral ring. Area of transition between articular cartilage and the periosteum of the metaphysis.
Zone of hypertrophied chondrocytes
Narrow zone at metaphyseal end of the column, in which chondrocytes with lacunae are large and intercellular matrix is minimal; since the matrix is minimal, this is the weakest site in the growth plate and therefore a major site for fractures
What is the purpose of cartilage
provides support and serves as a model or template for the formation of bones
Biaxial joints
two degrees of freedom can move in two planes such as wrists
Vertebral development comes from the
notochord
Flexion
refers to the bending of a limb at a joint, thereby decreasing the angle around the joint
Structure of fibrocartilage
Irregular dense fibrous tissue, thinly dispersed , encapsulated chondrocytes. LArge bundles of type I collagen fibers. No perichondrium
Dense regular connective tissue
comprises the majority of the ordinary connective tissues of the musculoskeletal system (tendons, ligaments, and aponeuroses). Tolerates tensile or stretching forces
Somite sclerotomes turn into
axial skeleton
Isometric contraction
force generated at constant length
During bone modeling bone formation occurs at the
periosteal surface
Type IV collagen (Laminar Collagen)
Basal lamina of epithelia cells, external lamina of muscle fibers. Originates from epithelial cells and muscle fibers
joint capsule
a thin, fluid filled, fibrous sac which encloses a synovial joint
What do you find in canaliculi
Osteocytes cell processes
How are proteoglycan aggregates formed
through the attachment of numerous proteoglycan molecules to hyaluronic acid via linking proteins
What allows the sarcoplasm to pump calcium ions from the sacroplasm to the lumen of the SR
CA++ ATPase pump
What are 3 ways muscles can produce ATP
- Breakdown of phosphocreatine
- Degredation of glucose or glycogen or glycolysis
- Oxidative formation of ATP
Activity of PFK is stimulated by ___ and ___ and inhibited by ____, _____, and _____
- ADP
- Pi
- ATP
- Decrease in pH
- High levels of phosphocreatine
What is the golgi tendon organ
a slender encapsulated sensory organ located in the tendon which lies in series with 15-20 muscle fibers.
A reflex can be defined as
an involuntary, qualitatively unvarying response generated by the CNS to a stimulus
______ are analogous to tendons but consist of flat sheets of dense connective tissue that typically attach flat muscles to bone.
Aponeuroses
What is the most abundant cells in mature bone
Osteocytes
Cancellous bone
inner spongy part
Miniature End-Plate Potentials
In the absence of nerve action potentials at the NMJ, there is a spontaneous process of single vesicle (quantum) release of ACh that forms a small local membrane potential change of about 0.5 to 1.0 mV, which is the MEPP. They are NOT sufficient to initiate muscle action potentials
Macromolecules with numerous sulfated glycosaminoglycans covalently bound as side chains to a core protein.
Proteoglycans
Troponin makes up __% of structural protein. Filaments are ___ and the general function is ____
2%, thin, regulation
Characteristics of mature bone
cortical and cancellous bone developed. Epiphyseal growth plate has fused at completion of bone growth. All perichondrium is now periostium
Medullary cavity development
Bone collar thickens and lengthens. Mature bone is produced from woven bone by remodeling which medullary cavity develops by osteoclasts resorption.
How is myostatin being used for therapy for muscular dystrophy
Myostatin is a muscle growth inhibitory factor. Blocking os myostatin with follistatin has been shown to facilitate muscle force production and promote muscle health in animals with muscular dystrophy
Eosin binds to
basic substance that are considered acidophilic i.e. proteins
A regular dense connective tissue that attaches bone to bone. Functions to stabilize and strengthen joints and limit the movement of bones in certain directions.
ligaments
synovial fold
infolding of synovial membrane into synovial space; not present in all synovial joints
Blood flow to cortical bone has a ______pattern
centripetal
Molecules of ACh diffuse across the synaptic cleft to the postsynaptic sarcolemmal membrane to bind with _______
ACh-receptors
Conversion of Bone lining cells to osteoblasts occurs via the function of the hormone
PTH
What makes up amorphous ground substance in bone
PG aggregates made up of chroitin sulfate, keratan sulfate, and hyaluronic acid as well as bone specific matrix proteins such as osteocalcin and osteopontin
Allometry
tool for assessing relative growth and involves the use of on structure as a means by which to gauge the growth of another
Dermatomes give rise to
dermis
Pale staining regions located in the middle of A-band
H-bands
What sensory receptors are important for the CNS to determine whether an initiated movement is appropriate
muscle spindles and Golgi tendon
synovial membrane
an epitheliod layer of fibroblasts that encases the synovial fluid
Troponin structure
globular protein bound to tropomyosin at40 nm intervals along the thin filament
What minerals are found in the bone matrix
primarily calcium and phosphorus arranged in hydroxyapatite crystals
Distributed innervation
involves 2-5 or more synapses per muscle fiber. This pattern is found in intrafusal fibers, some extraocular muscles and tonic fibers in avian species.
What is the sarcolemma
cell membrane of muscle fibers
Net production of aerobic metabolism of 1 pyruvate molecule
4 NADH, 1 GTP, 1 FADH
Each T-tubule is flanked by two terminal cisternae to form a ____
triad
What will an EMG show in a patient with muscular dystrophy
repetitive high frequency discharges
Glucose uptake in skeletal muscle during exercise is mediated by _________
insulin dependent glucose transporters (GLUT-4)
Fibrous protein composed of two polypeptide chains that sits within the grooves of thin filament, F-actin strands
Tropomyosin
Alpha actin makes up ___% of structural protein. Filaments are ___. The general function is to provide _____
10%, Z-line, structural
Muscles adapted for faster contractions have greater proportions of _____, ___ ___compared to muscles adapted for slower contraction
fast-twitch, type 2 fibers
The nuclei of muscle cells in mammals are located
peripherally
Somite dermatomes turn into
connective tissue
The reuptake of calcium ions largely occurs in the ______
sarcotubules
Clinical signs of patients with upper motoneuron disease
inappropriate movement, no atrophy, retrained segmental reflex
X-linked Muscular Dystrophy
Genetically linked deficiency of dystrophin well characterized in Goldens. Symptoms usually begin at 8-10 weeks
____ it the immediate source of energy for muscle contraction
ATP
The inner osteogenic (cambium) layer is composed of ______ cells and _____
osteoprogenitor, osteoblast
Syndesmosis joint
Mobility: Synarthrotic
Action potentials from the Golgi produce _______ in alpha motoneurons
inhibitory postsynaptic potentials (opposite of muscle spindles)
Hard callus
Later stage in the repair early immature bone is bridging the fracture gap. Woven bone is gradually converted to lamellar bone
What type of connective tissue do osteoblast and osteocytes make
Bone
Force of eccentric contractions
greater than concentric or isometric
Where is fibrocartilage found?
annulus fibrosis, menisci of stifle joint, symphysis pubis, and insertions of tendons and ligaments
Tidemark
the junction between the radial zone and calcified cartilage. Appears as “joint surface” in radiographs
In triads the 15 nm gap between the T-tuble membrane and the terminal cisternae is bridged by _____
junctional feet
Length of H band following contraction
decreased
Formation of secondary ossification centers
established in the epiphyses
Torque may change due to
the position of the limb due to the change in length of the arm
What genes are important for proper musculoskeletal development
Sonic Hedgehog (SHH)-sclerotome development and Wnt-promotes myotome
Longitudinal bundles of thick and thin myofilaments arranged in repeated sarcomeres along their length.
Myofibrils
Axial skeleton
Head, vertebrae, ribs, and sternum
Zones of cartilaginous growth and mineralization
- Zone of resting chondrocytes
- Zone of proliferative chondrocytes
- Zone of hypertrophied chondrocytes
- Zone of calcified cartilage
Three connective tissue components are associated with skeletal muscle
- epimysium
- perimysium
- endomysium
Which GAG is found in blood vessels and some cell surfaces
heparin sulfate
Sharpey’s Fibers
attach tendons, ligaments, and joint capsules to the bone. Made out of collagen
Appositional growth
deposition of new cartilage matrix by chondroblasts at the perichondrial surface
A reflex arc has 5 fundamental components. What are they?
- Receptor
- Sensory or afferent nerve
- Synapse within the CNS
- Motor or efferent nerve
- Target or Effector organ
What makes up extracellular matrix
Intercellular fibers and amorphous substances. The fibers provide tensile strength and elasticity while the ground substance provides compressive strength
What is responsible for contractility of muscle cells
interaction of myosin and actin in the presence of ATP
What are chondroblasts
Immature cartilage cells. Secrete extracellular matrix but are not yet imprisoned in a lacuna
Epimysium
fascia, the outer capsule of the muscle
Myasthenia Gravis
caused by Deficiency of ACh receptors on postsnyptic membrane. Signs of muscular weakness, EMG will show progressive decline in evoked potentials
Rate limiting enzyme of Krebs cycle
isocitrate dehydrogenase
Tropomysin makes up ___% of structural proteins. Filaments are ___ and the general function is ______
7%, thin, Regulation (limits availability of myosin)
What enzyme catalyzes the donation of a phosphate group to ADP for the formation of ATP in Phosphocreatine system
creatine kinase
Actin possesses a binding capacity for _____ and activates
myosin
Myoblasts are formed by ____ and undergo mitosis driven by fibroblast growth factors
myotome cell
_____ detect changes in muscle length
Muscle spindles
Zone of proliferative chondrocytes
isogenic columns of actively dividing chondrocytes; site of elongation of the long bone. The more mature chondrocytes are located at the metaphyseal end of the column
Light meromysin fraction
after proteolytic digestion the part that consists of mostly the tail portion of myosin
What is the most common form of cartilage
Hyaline
The sarcoplasmic reticulum acts as a _____ for calcium ions.
resorvoir
Evoked potential recordings
repetitive nerve stimulation provides info on the integrity of neuromuscular transmission
____ and ____ are regulatory proteins that regulate the interaction of actin and myosin in response to calcium ion concentrations in the sarcoplasm
Troponin, tropomyosin
Elastic Fibers
Allow organs to undergo expansion and recoil. Composed of elastin and fibrillin.
What is the net yield of each glyceraldehyde-3- phosphate molecule in Glycolysis
2 ATP molecules and one pyruvate molecule
What creates overlap and gap regions during the development on collagen.
staggering
The enzyme ______ is very important for the breakdown of glycogen into glucose for anaerobic metabolism. This enzyme is indirectly stimulated by increases in sarcoplasmic Ca++ associated with contraction
phosphorylase
Myoseptal innervation
involves pair of synapses situated near the origin and insertion of muscle fibers in some reptiles and lower vertebrates.
Fast-twitch, Fatigue resistant (FFR, Type IIA )
extremely resistant to fatigue and are able to sustain their tetanic tensions at 75% of maximum for 5 or more minutes
The basal lamina
a specialized component of the extracellular matrix. It is interfaced between connective tissue and the overlying epithelial cells it supports composed of type IV, type VII collagen, heparin sulfate proteoglycans and adhesive glycoproteins (fibronectin, laminin)
Phosphocreatine breakdown and glycolysis are considered _______metabolism
anaerobic
What do mechanical strains cause osteocytes to do.
Strains signal osteocytes through a biochemical pathway to orchestrate bone gain or bone loss as needed (functional syncytium involvement)
Clinical signs of lower motoneuron disease can be explained by the loss of alpha motoneuron or associated motor nerve. The signs are
Paralysis, atrophy, loss of segmental and intersegmental reflexes
Lateral plate somatic mesoderm turns into
appendicular skelton
Osteoclasts
Large multinucleated cells responsible for bone resorption
What type of growth does the osteogenic layer undergo?
Appositional
Length of A-band following contraction
unchaged
Isotonic contraction
recorded based on the amount of shortening that occurs when lifting weight. Displays force velocity relationship
Formation of compact bone
cartilage is entirely replace by bone except for the epiphyseal growth plate and articular cartilage
A second order of collagenous connective tissue composed of epimyseal septae that invade the depths of the muscle belly to ensheath varying numbers of muscle fibers to form muscle fascicles or bundles.
perimysium
The torque a muscle group can generate is
a function of both the force generated by the muscles and the moment arm of the muscle insertion. This means there can be two or more different torques on one joint
Crossed extension reflex results in
activation of extensor muscle and inhibition of flexor motor neurons
Flattened cells covering resting bone surfaces. Communicate with osteocytes via cell processes within canaliculi. Involved in regulation of the flow of calcium ions from bone to the extracellular fluid. Certain hormonal and mechanical stimuli induce them to convert into osteoblasts
Bone lining cells
Repeating Z-line to Z-line intervals of myofibrils. Represent basic contractile units of of striated muscle
Sarcomeres
The primary and secondary clefts are filled with external lamina that contains ________ an enzyme that hydrolyzes acetylcholine to acetate and choline
acetylcholinesterase
Threshold for an MAP is reached when membrane potential is reduced from ____ to ____.
-80 to -90 mv to about -50 to -55mV
Bone remodeling
Old bone is resorbed by osteoclasts and replaced by new bone by osteoblasts at the same bone surface
What gives the matrix compression and tensile strength
Aggregates of PGs= compression capacity and collagen fibers=tensile strength and durability
Epinephrine binds to ______ receptors on the liver and adipose tissue triggering the release of glucose from the liver and free fatty acids from adipose tissue
beta-adrenergic
Steps of bone remodeling
- Resorption: Osteoclasts break down mineralized matrix creating and erosion cavity
- Reversal: mononuclear cells prepare bone surface for new osteoblasts that will form bone
- Formation: Osteoblasts synthesize osteoid which is then mineralized
- Resting: prolonged resting period follows until a new remodeling cycle begins
Myofilament Ratios
6 thin myofilaments to 1 thick myofilament
A reflex that involves more than one segment of the CNS i.e. withdrawal reflex
intersegmental reflex
Periosteum
Outer fibrous layer composed of dense fibrous connective tissue
Length of M-line following contraction
unchanged
As tendons and ligaments approach attachment sites to bone or cartilage they form ________
sharpey’s fibers
Steps of bone resorption
- Decalcification of bone matrix-solubilization of calcium salts by acidification
- Digestion of the organic components of bone matrix
- Requires the release of lysosomal acid hydrolases (cathepsins)
Primary nutrients for energy are
carbs and fat
The axon terminal rests in the _________
primary-synaptic cleft
joint space
located between the articular heads; normally filled with synovial fluid, a modified blood filtrate which acts to lubricate, protect, and nourish the joint surfaces
Cylindrical regular dense connective tissue composed of arrays of type I collagen fibers in which muscle fibers end and by which muscles are attached to bones. Primary function is to transmit forces developed by muscles to the skeleton.
Tendons
____ are specialized sensory organs that lie in parallel with fibers of the muscle or extrafusal fibers
Muscle spindle
Soft callus
Organization of hematoma early primary new bone formation in subperiosteal regions of cartilage formation in other areas
Range of shortening for pennate muscles, greatest to least.
unipennate > bipennate> multipennate
Loose connective tissue
has a large number of cells and a loose, wispy arrangement of collagen fibers mixed in a relatively large volume of ground substance. usually found covering internal body surfaces
Cortical bone
hard outer part
Length-Tension relationships of sarcomeres
function of the sarcomere lengths of its myofibrils. Isometric contractions of single muscle fibers reveal that the tension generated is directly proportional to the number of cross-bridges exposed overlapped by thin filaments. No tension is developed when no overlap of thick and thin filaments
Reticular fibers
Composed of type III collagen and have a polysaccharide rich coating. Abundant in connective tissues
Smooth endoplasmic reticulum composed of tubular membranes that surround the myofibirls. Composed of sacrotubules and terminal cisternae.
Sarcoplasmic Reticulum
Myotendinous junctions
at the muscle’s origin and insertion where the mysial connective tissues merge and become confluent to form tendons or aponeruose.
Gamma motoneurons
believed to synapse with alpha motoneurons. Thought to help maintain sensitivity of muscle spindles when muscle undergoes shortening.
The arrangements of muscle fibers include:
Parallel, fan shaped, fusiform or pennate(parallel muscle fibers attached to a tendon at an angel.
Actin makes up ____% of structural protein. Filaments are ___ and the general function is for ____
20%, thin, contration (activates myosin ATP-ase)
Fast twitch muscles reach peak tension _____than slow twitch muscles
faster
Length of I band following contaction
decreased
____ is the principal structural protein of thin myofilaments
actin
A toxin that irreversible binds to presynaptic membrane and blocks release of ACh. Results in a functional denervation of all muscle fibers
Botulism
Consists of a biochemically complex hydrated gel in which the cells and intercellular fibers are embedded. Water, nutrients, and wastes can rapidly pass between the blood and parenchymal cells in the aqueous phase.
Amorphous ground substance
Electron lucent bands composed of parallel thin myofilaments. Principally composed of actin
I-bands
What are the principle types of intercellular fibers
Collagen Fibers, reticular fibers, and elastic fibers
Synarthrotic joints
No mobility, does not move
Symphysis joint
Mobility: Amphiarthrotic
Torque
Force x moment arm
Head mesenchyme (largely neural crest) turns into
skull and branchial arch bone + cartilage
Extension
refers to the straightening of a limb which increases the angle around the joint
Avascular/atrophic nonunion
Lacks callus
Synovial joint
Mobility: diathrotic
Endomysium
loose connective tissue that surrounds individual multinucleated muscle fibers. Brings in capillaries and the smallest division of nerves
S-1 and S-2 fraction form cross bridges allowing myosin of thick filaments to attach to ______ of thin filaments
actin
Thin dark lines that bisect I-bands. Composed of amorphous electron dense material containing alpha-actin and Z-line filaments.
Z-lines
What do you find in lacunae
Osteocyte nuclei
What type of connective tissue do fibroblasts and fibrocytes make
proper(ordinary) connective tissue
Intrafusal muscle fibers are specialized muscle fibers in muscle spindles that are connected to the muscle tendons at either end. What are two types?
Nuclear bag fibers and nuclear chain fibers
What type of connective tissue makes up fasciae, tendons, and ligaments, and the supportive specialized connective tissue of cartilage and bone?
Proper and ordinary (loose or dense) CT
Type III collagen
loose connective tissues; reticular fibers, blood vessels. Originates from fibroblast
The principle property of muscle cells is _______ but the property of _____ is also well developed
contractility, conductivity
What kind of strength is ground substance importance for
compressive strength
Tropomyosin-Troponin complex
regulatory proteins that regulate the interaction of actin and myosin in response to calcium ion concentrations in the sarcoplasm. Binds troponin to tropomyosin.
Positive allometry
means k >1. Organ weight increases at a faster rate than body weight. In other words organ weight is an ever increasing percentage of body weight. This is a form of elastic scaling.
Perimysium
inward extensions of epimysium that package groups of muscle cells into fascicles and bring nerves, blood vessels, and lymphatics into the muscle
Both the flexion withdrawal reflex and crossed extension reflex are mediated through ________ pathways
polysnaptic
Mechanisms of growth
- cell proliferation
- protoplasmic synthesis (new organic matter is created from nutrient supply via biosynthesis)
- water uptake
- intercellular matrix deposition (CT, cartilage, and bone)
structure of myosin
asymmetrical protein with a head and tail region. Composed of two polypeptides arranged in an alpha helix that form the tail and two globular heads composed of 4 small polypeptides that form the head region
What are small diameter muscle afferents responsible for
exercise pressor reflex- a component of the cardiovascular response to exercise. Important for muscle fatigue
Upon reaching the muscle fiber to be innervated the axon looses its myelin sheath to form an _______
axon terminal
How do primary ossification centers form
blood vessels invade calcified cartilage. Osteoblasts produce bone trabeculae in diaphysis
The connective tissue surrounding the different sub-compartments of muscle. In continuity with each other
Fascia
Articular cartilage
A type of hyaline cartilage located within joint spaces. Not covered in perichondrium, growth is interstitial and nutrients are received by diffusion from synovial fluid
Structure of the intervertebral disc
Center of the disc is the nucleous pulposus surrounded by the annulus fibrosis on the periphery of the disc
Can cartilage regenerate?
Very limited capacity for regeneration
Heavy meromysin fraction
after proteolytic digestion the fraction that holds the two globular heads and a short potion of the alpha helical chain. Can then be further divided to form an S-1 fraction (two globular heads), and an S-2 fraction (alpha-helix)
Flexion withdrawal affect acts to
move the body part away from painful stimulus as quickly as possible.
Limb development begins in week _____ and ____limb forms first.
3-4, forelimb
Slow twitch (S type I) Motor Units
Contraction time and tetanic frequency is relatively low. There motor units are resistant to fatigue and are able to maintain their tetanic frequency for long periods of time
What type of forces is fibrocartilage resistant to?
Resists compression and shear forces. Has durability and high tensile strength
Isometric contraction
Muscles are exerting force but no shortening occurs. Displays length tension relationship
A normal EMG of muscles at rest is ____
silent
