Muscles Flashcards
0
Q
Act of contraction with muscle
A
must be stimulated by a nerve ending,propagate an electrical current or action potential along its sarcolemma, and have a rise in intracellular calcium levels or the final trigger for contraction
- linking the electrical signal to the contraction is excitation-contraction coupling
- skeletal muscles are stimulated by motor neurons of the somatic nervous system
- axons of these neurons travel in nerves to the muscle cells
- axons of motor neurons branch profusely as they enter muscles
- each axonal branch forms a neuromuscular junction with a single muscle fiber
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Q
A band
A
the dark-staining zone of a sarcomere, whose center is traversed by the H band
2
Q
Cell
A
- each fiber is a long cylindrical cell with multiple nuclei just beneath the sarcolemma
- hundreds of centimeters long
- each cell is a syncytium produced by fusion of embryonic cell
- sarcoplasm has numerous glycosides and a unique oxygen binding protein called myoglobin
- fibers contain usual organelles,myofibrils,sarcoplasmic reticulum,and t tubules
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Q
Actin
A
the thin actin are found at ends of sacromeres nexts to z disc
-thin filaments do not overlap thick filaments in the lighter h zone
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Q
Action of muscles
A
- excitability or irritability:ability to receive and respond to stimuli or responsiveness
- contractility:the ability to shorten forcibly
- extensibility:the ability to be stretched or extended
- elasticity:ability to recoil and resume
5
Q
Activation of cross bridges
A
cross bridge forms-myosin cross bridge attatches to actin filament, working power stroke myosin head pivots and pulls actin filament toward m line
- cross bridge detaches ATP attaches to myosin hard and the cross bridge detaches
- cocking of the myosin head energy from hydrolysis Matt cocks the myosin head into the high energy
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Q
Adductor Magnus
A
the long, heavy triangular muscle of the medial aspect of the thigh. The adductor magnus acts to adduct the thigh. The proximal portion acts to rotate the thigh medially and flex it on the hip; the distal portion acts to extend the thigh and rotate it laterally.
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Q
Aerobic metabolism in muscles
A
when muscle contraction activity reaches 70 percent of maximum they start bulging muscles compress bv,oxygen delivery is impaired,pyruvic acid is converted to lactic acid
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Q
Agonist
A
- A contracting muscle that is resisted or counteracted by an antagonistic muscle.
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Q
Antagonist
A
a muscle that acts in opposition to the action of another muscle (e.g., flexor vs. extensor).
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Q
Biceps brachii
A
A muscle whose long head has origin from the supraglenoidal tuberosity of the scapula and whose short head has origin from the coracoid process, with insertion into the tuberosity of the radius, with nerve supply from the musculocutaneous nerve, and whose action flexes and supinates the forearm.
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Q
Biceps femoris
A
A muscle whose long head has origin from the tuberosity of the ischium and whose short head has origin from the lower half of the lateral lip of the linea aspera, with insertion into the head of the fibula, with nerve supply from the tibial nerve for the long head and from the peroneal nerve for the short head, and whose action flexes the knee and rotates the leg laterally.
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Q
Brachialis
A
a muscle of the upper arm, covering the distal half of the humerus and the anterior part of the elbow joint. It functions to flex the forearm.
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Q
Buccinator
A
Muscle of cheek used for blowing and sucking
14
Q
Calcium and role in contractions
A
-in order to contract it must be stimulated by a nerve ending,propagate an electrical current or action potential along its sarcolemma, and have a rise in intracellular calcium levels or the final trigger for contraction
15
Q
Cardiac muscles differences
A
- striated like skeletal muscle but involuntary
- contracts at a steady rate set by hearts pace maker
- neural controls allow heart rate to respond to changes in bodily needs
- cant be replaced
- all the fibers have to contract or none will
- can’t pump out more blood than what is received
16
Q
Characteristics of skeletal
A
:skeletal muscle tissue:packaged in skeletal muscles that attach to and cover bony skeleton
- has obvious stripes called striations
- is controlled voluntary
- contracts rapidly but tires easily
- is responsible for overall body motility
- is extremely adaptable and can exert forces ranging from a fraction of an ounce to over 70 pounds
17
Q
Muscle movement
A
- excitability or irritability:ability to receive and respond to stimuli or responsiveness
- contractility:the ability to shorten forcibly
- extensibility:the ability to be stretched or extended
- elasticity:ability to recoil and resume
18
Q
Characteristics of muscle tissue
A
:three types of muscle tissue,skeletal,cardiac,and smooth
- these tissues differ in structure,location,functions,and means of activation
- similarities:
19
Q
Circular muscles
A
Occur in both smooth and skeletal,for smooth they form sphincters in stomach
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Q
Contractile units of skeletal muscles
A
-sacromeres:smallest contractile unit of a muscle,10000 in each of myofibrils,highly active units of actin and myosin
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Q
Contractility
A
contractility:the ability to shorten forcibly
22
Q
Control of strong muscle
A
Hi
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Q
Contractions
A
- muscle contraction depends on two kinds of myofilaments which are actin and myosin
- muscle terms:sacrolemma(muscle plasma membrane)
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Convergent muscles
Tending toward a common point.
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Diaphragm
1. the musculomembranous partition separating the abdominal and thoracic cavities and serving as a major muscle aiding inhalation.
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Divergent muscles
Moving in different directions; radiating.
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Endomysium
fine sheath of connective tissue composed of reticular fibers surrounding each muscle fiber,muscle growth
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Epimysium
an over coat of dense regular connective tissue that surrounds the entire muscle,makes it a whole muscle
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Excitability
or irritability:ability to receive and respond to stimuli or responsiveness
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Extensibility
extensibility:the ability to be stretched or extended
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Extensor capri radialis
Brevis-the bursa between the tendon of the extensor carpi radialis brevis and the base of the third metacarpal.
Longus-radial side of forearm that abducts hand
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External abdominal oblique
A muscle with origin from the fifth to twelfth ribs, with insertion into the anterior lateral lip of the iliac crest, the inguinal ligament, and the anterior layer of the sheath of the rectus muscle of the abdomen, with nerve supply from the ventral branches of the lower thoracic nerves, and whose action diminishes the capacity of the abdomen and draws the chest down.
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External intercostals
Muscle on ribs for breathing
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Factor that controls levers
Origin?
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Fascia
a sheet or band of fibrous tissue such as lies deep to the skin or invests muscles and various body organs.fascial
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Fascicles
1. a small bundle or cluster, especially of nerve, tendon, or muscle fibers.
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Fatigue period
-intense exercise produces rapid muscle fatigue with rapid recovery,sodium potassium pump can't restore iconic balances quick enough,low intensity has gradual fatigue,sr damaged and calcium regulation is disrupted
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Fatigued muscles
muscle is in a state of physiological inability to contract
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Fibrin
an insoluble protein that is essential to clotting of blood, formed from fibrinogen by action of thrombin.
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Fixator
A device that provides rigid immobilization of a fractured bone by means of rods attached to pins that are placed in or through the bone.
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Fulcrum
1. The point or support on which a lever pivots.
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Functional unit of skeletal muscles
sacromeres:Myofibril:myofilaments
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Gluteus Maximus
Biggest,strongest
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Gracilis
The gracilis (Latin for "slender") is the most superficial muscle on the medial side of the thigh. It is thin and flattened, broad above, narrow and tapering below.
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I band
thin:or actin extend across the I band and partway into the A band,arrangement of myofibrils within a fiber is such that a perfectly aligned repeating series of dark A bands and light I bands is evident
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Iliocastalis
Muscle in mid back,week
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Infraspinatus
Under supraspinatus part of rotator cuff
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Insertion
Where the muscle can move or the boat
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Intermediate filament network
- myofilaments are two types or thick and thin
- thick:or myosin extend the entire length of an A band
- thin:or actin extend across the I band and partway into the A band
- Z disc:coin shaped sheet of proteins that anchors the thin filaments and connects myofibrils to one another
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Internal abdominal oblique
The internal oblique muscle is the intermediate muscle of the abdomen, lying just underneath the external oblique and just above the transverse abdominal muscle.
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Internal intercostals
are eleven in number on either side. They commence anteriorly at the sternum, in the interspaces between the cartilages of the true ribs, and at the anterior extremities of the cartilages of the false ribs, and extend backward as far as the angles of the ribs, whence they are continued to the vertebral column by thin aponeuroses, the posterior intercostal membranes.
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Isometric contractions
:isometric contraction-tension increases to muscles capacity but the muscle neither shortens nor lengthens
-occurs if the load is greater than the tension the muscle is able to develop
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Isotonic contraction
:isotonic contractions-muscles change in length decreasing angle of joint and moves load
- concentric:muscle shortens and does work
- eccentric:muscle contracts as it lengthens
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Lactic acid
- anaerobic glycolysis:when muscle contraction activity reaches 70 percent of maximum they start bulging muscles compress bv,oxygen delivery is impaired,pyruvic acid is converted to lactic acid
- lactic acid diffuses into blood stream,picked up and used by liver kidneys and heart then is converted back into pyruvic acid by the liver
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Latent period
- three phases to muscle twitch
- latent period
- period of contraction
- period of relaxation
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Latissmus dorsi
Back muscle used to aid in rotating arm
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Levator
Elevates bone
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Levers
Long bones are levers used to move things
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Masseter
Muscle in cheek for mastication
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Maximal stimulus
a stimulus strong enough to evoke a maximal response.
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Mechanical disadvantage
Weakness in advantage in body
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Method of classifying muscles
Size,shape,type
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Microtubules
microtubules intracellular subunits that offer an intracellular route for essential organelle movement
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Mitochondria
Energy source for muscle contraction by production of ATP
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Multiply motor unit summation
:a motor unit is a motor neuron and all the muscle fibers it supplies
- the number of muscle fibers per motor unit can vary from four to several hundred
- fine motor movements small motor unit
- muscles that control fine motor movements like fingers are small motor units
- large weight bearing muscles like thighs have large motor movements
- motor units are spread throughout muscle, if you trigger one it won't contract much,if you trigger all it will contract a lot
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Muscle cell membrane
:sacrolemma(muscle plasma membrane)
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Muscle tone
- muscle tone:it's constant,slightly contracted state of all muscles which doesn't produce active movements
- keeps muscles firm healthy and ready to respond to stimulus
- spinal reflexes account for muscle tone by activating one motor unit then another, responding to activation of stretch receptors in muscles and tendons
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Muscles contain
Myofilaments,myofibrils,sarcolemma,actin,myosin,
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Myofibril network
- sacromeres:smallest contractile unit of a muscle,10000 in each of myofibrils,highly active units of actin and myosin
- the region of a myofibrils between two successive Z discs(anchor for actin looks like frisbee)
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Myofibrils
- sacromeres:smallest contractile unit of a muscle,10000 in each of myofibrils,highly active units of actin and myosin
- the region of a myofibrils between two successive Z discs(anchor for actin looks like frisbee)
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Myoglobin
-sarcoplasm has numerous glycosides and a unique oxygen binding protein called myoglobin
:effects of aerobic exercise-increase is muscle capillaries,number of mitochondria,myoglobin synthesis
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Myosin
- thick myosin fibers are found mainly in the center of the sacromeres and they are always linked the m line,the thin actin are found at ends of sacromeres nexts to z disc
- thick:or myosin extend the entire length of an A band
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Myosin cross bridges
each myosin molecule has a rod like tail and two globular heads,
- tails:two interwoven heavy polypeptide chains
- heads:two smaller light polypeptide chains called cross bridges
- takes 300 myosin molecules to make one myofilaments
- thin filaments are composed of actin,each actin molecule is made up of sub units called g actins,300 in each actin,subunits contain active sites to which myosin heads attach during contraction
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Naming muscles
Hellifi know
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Nasalis
Bone of the bridge of nose
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Occipitalfrontalis
Muscles of occipital bone for raising eyebrows
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Orbicularis oculi
Muscle around the eye to shut lid
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Orbicularis kris
Muscle around mouth for chewing
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Origin
Where muscle is anchored or attached
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Parallel muscles
Any muscle having the long fibers arranged parallel to each other.
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Pectorals major
Pec muscle for arm rotation
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Pec minor
Under pec major
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Perimysium
:fibrous connective tissue that surrounds groups of muscle fibers called fascicles,puts muscles into groups
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Peristalsis
Movement through wave like contraction
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Platysma
Muscle in face
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Power of muscle determined by
:stimulation strength-threshold stimulus,the stimulus strength at which the first observable muscle contraction occurs
-beyond threshold muscle contractions more vigorously as stimulus strength is increased
-force of contraction is precisely controlled by multiple motor units summation
-recruitment brings more and more muscle fibers into play
Staircase effect
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Prime mover
muscle that produces a specific motion or maintains a specific posture.
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Procerus
Glabella
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Protagonist
Main muscle
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Quadriceps femoris
The large extensor muscle of the thigh, combining the rectus femoris and vastus muscles.
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Rectus abdominus
Biggest oblique
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Rectus femoris
A division of the quadriceps femoris inserting in the patella and ultimately into the tubercle of the tibia.
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Refractory period
A brief period of time following the stimulation of a nerve during which the nerve will not respond to a second stimulus.
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Regeneration of muscle tissue
When muscle cells are lost they can be replenished but takes awhile actually 3rd in all of the types of tissues there are that can be regenerated
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Relaxation period
- shortening occurs when the tension generated by the cross bridge exceeds opposing shortening
- con action ends when bridges become inactive, tension generated declines, and relaxation is induced
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Role of calcium in muscles
-in order to contract it must be stimulated by a nerve ending,propagate an electrical current or action potential along its sarcolemma, and have a rise in intracellular calcium levels or the final trigger for contraction
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Sarcolemma
Muscle plasma membrane
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Sacromere
- sacromeres:smallest contractile unit of a muscle,10000 in each of myofibrils,highly active units of actin and myosin
- the region of a myofibrils between two successive Z discs(anchor for actin looks like frisbee)
99
Sarcoplasmic reticulum
:sarcoplasmic reticulum:elaborate,smooth endoplasmic reticulum that runs longitudinally and surrounds each myofibril
- paired with terminal cisternae from perpendicular cross channels,functions in the regulation of intracellular calcium levels
- elongated tubules called t tubules penetrate into cells interior at each A band-I band junction
- t tubules associate with the paired terminal cisternae to form triads
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Sliding filament model
:sliding filament model of contraction-h band and I band have to get smaller,zone of overlap has to get bigger,z lines have to get closer,width of a band remains constant
- thin filaments slide past thicker ones so that actin and myosin filaments overlap to a greater degree
- attach,pivot,detach,and return
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Stimulus to start muscle contraction
Brain tells motor unit to contract and triggers nerve
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Strength of contractions
-increased contraction in response to multiple stimuli of same strength,increase Because increasing availibility of calcium in sarcoplasm, muscle enzyme systems become more efficient because heat is increase as muscle contractions
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Synergists
1. (Life Sciences & Allied Applications / Physiology) a drug, muscle, etc., that increases the action of another
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T tubules
:t tubules-continuos with sarcolemma
-conduct impulses to deepest part of muscle
-impulses signal for release of calcium from adjacent terminal
:triad relationship-t tubules and SR provide tight linked signals for muscle contraction,a double zipper of integral membrane proteins protrudes into inter membrane space
-t tubule proteins act as voltage sensors
-SR foot proteins are receptors that regulate calcium release from SR cisternae
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Tetanus
A state of continuous muscular contraction, especially when induced artificially by rapidly repeated stimuli.
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Treppe
Staircase effect one muscle fiber triggers next fibers until all are contracted
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Variations of contractions
I
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Wave summation
I
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Z discs
Anchors actin
