chapter 10 muscles tissues Flashcards
list the functions of the muscles tissues
Producing movement
Maintaining posture and body position
Supporting soft tissues
Guarding body entrances and exits
Maintaining body temperature
Storing nutrients
Collagen fibers of epimysium, perimysium, and endomysium come together
At ends of muscles to form?
tendon and aponeurosis
Surrounds muscle fiber bundles (fascicles)
Contains
Collagen fibers
Elastic fibers
Blood vessels
Nerves
which layer is this one ?
Perimysium
Layer of collagen fibers that surrounds the muscle
Connected to deep fascia
Separates muscle from surrounding tissue which layer is this?
Epimysium
Surrounds individual muscle cells (muscle fibers)
Contains
Capillary networks
Myosatellite cells (stem cells) that repair damage
Nerve fibers
what layer is this ?
Endomysium
Lengthwise subdivisions within a muscle fiber
Responsible for muscle contraction
Made of bundles of protein filaments (myofilaments)
Two types of myofilaments
Thin filaments
Composed primarily of actin
Thick filaments
Composed primarily of myosin
what part is this of the muscles skeleton fiber ?
Myofibril
Smallest functional units of a muscle fiber
Interactions between filaments produce contraction
Arrangement of filaments accounts for striated pattern of myofibrils
what part is this ?
Sarcomeres
Contain F-actin, nebulin, tropomyosin, and troponin proteins
which filament does this belong
thin filament
Dark region
Where thick and thin filaments overlap
what part of the a band is this?
zone of overlap
Holds F-actin strand together
which filament is this one?
Nebulin
Covers active sites on G-actin
Prevents actin–myosin interaction
what filament is this
Tropomyosin
A globular protein
Binds tropomyosin, G-actin, and Ca2+
which filament?
Troponin
def the motorneuron control
a stimulus arrives at the axon terminal
Excitation in contraction what does it release and where does is go into?
release the ach into the synaptic cleft, later into the sacrolemma
release of calcium ions function, where does it travel, where does it relase ca2+
travel down to the sarcolemma and to the t tubules, triggers the release of calcium to the cisternae to the sacroplasmic reticulum
what goes on during the contraction phase, when ca2+ arrvies
ca2+ binds to troponin, creating a cross bridge formation
sarcomere shortening what going on
thick and thin filament are interacting, both ends of the muscles are shortening
what are the steps of the contraction phase in arrival of ca2+
- Contraction cycle begins
- Active-site exposure
3. Cross-bridge formation (myosin binds to actin) - Myosin head pivoting (power stroke)
- Cross-bridge detachment
- Myosin reactivation
A single neural stimulation produces a single contraction, Lasts 7–100 msec
what is the term for this?
Twitch
A stair-step increase in tension
Caused by repeated stimulations immediately after relaxation phase
Stimulus frequency <50/second
Produces a series of contractions with increasing tension
Typically seen in cardiac muscle and not skeletal muscles
which term is this one?
Treppe
Increasing tension due to summation of twitches
Caused by repeated stimulations before the end of relaxation phase
Stimulus frequency >50/second
what is the definition of this ?
wave summation
Muscle produces near-maximum tension
Caused by rapid cycles of contraction and relaxation
which tetanus is this ?
incomplete tetanus
Higher stimulation frequency eliminates relaxation phase
Muscle is in continuous contraction
All potential cross-bridges form
which tetanus is this ?
complete tetanus
Skeletal muscle changes length
Resulting in motion
name the contraction of this ?
Isotonic
Muscle tension > load (resistance)
Muscle shortens
is concentric or eccentric
concentric
Muscle tension < load
Muscle elongates
is concentric or eccentric
eccentric
Skeletal muscle develops tension that never exceeds the load
Muscle does not change length
name the contraction of this one ?
Isometric
is a motor neuron and all of the muscle fibers it controls
May contain a few muscle fibers or thousands
All fibers in a motor unit contract at the same time
what is the term is this
Motor Unit
Increase in the number of active motor units
Produces smooth, steady increase in tension
Maximum tension is achieved when all motor units reach complete tetanus
what is the definition of this ?
recruitment
is the only energy source used directly for muscle contraction
what is the energy source
ATP
ATP transfers energy to creatine.
what is the end product of this
CP
Important energy source for peak muscular activity
Breaks down glucose from glycogen stored in skeletal muscles
Produces two ATP per molecule of glucose
which process is this
Anaerobic
what is the use of CK
Catalyzes the conversion of ADP to ATP using the energy stored in CP
Primary energy source of resting muscles
Breaks down fatty acids
is this Anaerobic or Aerobic
Aerobic
what is the function of skeletal muscles of the metabolism?
rest metabolize fatty acids and store glycogen and CP
During moderate activity, muscles generate ATP through aerobic
breakdown of glucose, primarily
At peak activity, pyruvate produced via glycolysis is converted to lactate
the layers of muscles from superficial to deep
- epimysium 2. perimysium, 3. Fascicles, 4. Endomysium, 5. Muscles Fiber, 6. Myofibirl
what happens in the excitable membrane where is found, the events,
Are found in skeletal muscle fibers and neurons
Depolarization and repolarization events produce action potentials (electrical impulses)
Skeletal muscle fibers contract due to stimulation by motor neurons
Two terminal cisternae plus a T tubule forms a
Traid
what does the sacromplasic reticulum surround, what do they form and what do they attach to
A tubular network surrounding each myofibril
Similar to smooth endoplasmic reticulum
Forms chambers (terminal cisternae) that attach to T tubules
what are the steps of the sliding filament theory
During a contraction,
1.H bands and I bands narrow
2.Zones of overlap widen
- Z lines move closer together
- Width of A band remains constant
Thus, thin filaments must slide toward center of sarcomere
what does rigort mortis fixed and when does is does happens
Fixed muscular contraction after death
Results when
ATP runs out and ion pumps cease to function
Calcium ions build up in cytosol
excitation and coupling where does the action potential travels, what does is release, and the events
Action potential travels down T tubules to triads
Ca2+ is released from terminal cisternae of SR
Ca2+ binds to troponin and changes its shape
Troponin–tropomyosin complex changes position
Exposes active sites on thin filaments
Contraction cycle is initiated
list of the characteristics of fast fiber muscles
Majority of skeletal muscle fibers
Contract very quickly
Large diameter
Large glycogen reserves
Few mitochondria
Produce strong contractions, but fatigue quickly
list of the characteristics of slow fibers
Slow to contract and slow to fatigue
Small diameter
Numerous mitochondria
High oxygen supply from extensive capillary network
Contain myoglobin (red pigment that binds oxygen)
list of the characteristics of intermediate fibers
Are mid-sized
Little myoglobin
Slower to fatigue than fast fibers
(e.g., 50-meter dash, weight lifting)
Uses fast fibers and stimulates hypertrophy
Improved by frequent, brief, intensive workouts
what is the term for this
anaerobic
(prolonged activities)
Supported by mitochondria
Does not stimulate muscle hypertrophy
Training involves sustained, low levels of activity
what is the term for this?
aerobic
