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What are the 3 types of muscle tissues?
What muscle tissue has the longest fibers?
What muscle tissue:
*attaches to skeleton by tendons
*Large, elongated, striated fibers
*Parallel,cylindrical fibers w/ peripheral nuclei
*40% of the body's mass
*over all body mobility
What are the pros and cons of skeletal muscle?
- contract rapidly
- exert tremendous power
- remarkably adaptable
- tires easily
- must rest after short periods of activity
What muscle tissue:
*is located only in the heart/ bulk of heart walls
*muscle cells are striated w/intercalated disc
*contracts at a fairly steady rate; but neural controls allow the heart to speed up for brief periods
What muscle tissue:
*located in the walls of hollow organs
*forces fluids and other substances through internal body channels
*contractions are slow and sustained
*dilates and constricts pupils/forms arrector pili muscle
What are the differences in the 3 muscle tissues?
- elongated fibers, striated, involuntary
- striated, intercalated disc, involuntary
- elongated cells, NO striations, involuntary
What are the special characteristics of muscle tissue?
What special characteristic allows the muscle to receive and respond to stimulus?
What special characteristic allows the muscle to shorten forcibly when adequately stimulated; this is unique to muscles
What special characteristic gives muscle the ability to stretch ? (shorten when contracting, can stretch when relaxed)
What special characteristic gives the muscle fiber the ability to recoil and resume its resting length after stretching?
- Produce movement
- Maintain Posture
- Stabilized Joints
- Generate Heat
What muscle tissue is most responsible for generating heat?
Define Contraction (twitch):
- working muscles generate tension
- drawing together;shortening or shrinkage
Gross Anatomy of Skeletal Muscles:
*Skeletal Muscle Tissue: skeletal muscle fibers predominate, blood vessels, nerve fibers & CT
*one nerve,one artery and one or more veins serve each muscle
- *supplied with a nerve ending that controls activity
- *has rich blood supply
- *fibers also give off large amounts of metabolic waste that must be removed through veins if contraction is to remain efficient
- **CAN NOT CONTRACT WITHOUT NERVE STIMULATION
What are the 3 CT sheaths that protect the skeletal muscle?
What protective CT layer encircles the entire skeletal muscle?
Epimysium (outside the muscle)=overcoat
grouped muscle fibers within skeletal muscles
what protective CT layer surrounds a fascicle of 10-100 muscle fibers?
Perimysium (around the muscle;fascicle)
What protective CT layer surrounds individual muscle fibers and is areolar CT?
Endomysium (within the muscle)
Broad sheaths of fibrous CT;supports and protects muscle tissue
What type of fascia separates skin and muscle,contains adipose that insulates to prevent heat loss and protects from physical trauma and contains nerves, blood and lymph vessels that supply muscles.
What type of fascia fills spaces between muscles? DRCT
- plasma membrane of muscle cells
- contains perpendicular T tubules
- muscle cell cytoplasm
- contains glycosomes and myoglobin
- Also contains Actin and Myosin
Sheet -like CT attachments of muscle to muscle
rope-like CT attachments of muscle to bone
non-movable attachment of muscle
movable attachment of muscle
What are muscles derived from?
- primary germ layer that forms the skeleton and muscles of the body
Immature mesoderm cells in which all muscle fibers develop is know as what?
- Diameter ranges from 10-100 um
- (10x larger than avg. cell)
- Length can range up to 30cm (12in/1ft)
granules of stored glycogen that provide glucose during muscle cell activity
a red pigment that stores oxygen, similar to hemoglobin.
What are the intracellular tubules that regulate contraction?
- Sarcoplasmic reticulum
- T-Tubules (transverse)
Sarcoplasmic Reticulum (SR):
- Smooth Endoplasmic Reticulum (ER)
- Fluid filled membranous sacs encircle each myofibril
- communicate at H zone
- stores and release ionic calcium C+ during contractions
What element provides the final go signal for contraction?
What is involved in producing the energy used during contraction?
Mitochondria & glycogen
- w/in the sarcolemma
- encircles each sarcomere
- conducts impulses to the deepest regions of the muscle fibers and every sarcomere
- impulses signal release of calcium
- ensures every myofibril and muscle fiber contracts at the same time
What proteins are involved with contraction?
Actin and Myosin
- Long, cylinderical bundles of proteins that run parallel to the length of the cell
- Contain sacromeres (composed of actin and myosin)
- 80% cellular volume
What myofilament is thin and contains binding-sites for the club-like heads of myosin?
What myofiliament is a thick motor filament that contains club-like heads that attach to binding sites of actin?
What are the 3 myofilaments?
Regulatory proteins which block the binding site of actin?
- Tropnin & Tropomyosin Complex (TTC)
- proteins w/in the thin filament
- Smallest functional contractile units of a muscle located on a myofibril
- Distance or region between 2 Z discs
- A band flanked by 1/2 I band @ each end
- align end to end
- Contains myofilaments
Within the sacromere the myofilaments overlap creating alternating dark and light bands know as what?
- A band (dark portions)
- contains both actin and myosin
- H zone (myosin only)-lighter region in A bands midsection
- M line (thick filaments linked by accessory proteins)-middle of sacromere
- I bands (light portions)
- Contains actin only
- Z discs- darker midline interuption of I band
Interaction between the thin actin fibers and the thick myosin fibers create what?
The area of sarcolemma where a motor neuron contacts a muscle
fiber and releases neurotransmitter.
Motor end plate
What space separates the axon terminal and muscle fiber, ACh is released into this place before attaching to ACh receptors
The neurotransmitter for skeletal muscle is what?
What enzyme located in the synaptic cleft breaks down ACh to its building blocks (acetic acid and choline)
What does a Motor Unit consist of?
1 motor neuron and all the muscles it innervates (fascicle of skeletal muscles)
Force of muscle contractions
4 MAJOR FACTORS
- Number of Muscle Fibers Stimulated
- Size of Muscle Fibers
- Frequency of Stimulation
- Degree of Muscle Stretch
Path ways for regenerating ATP
- 1)Direct phosphorylation
- -Coupled reaction of creatine phosphate and ADP
- 2)Anaerobic Pathway
- -Glycolysis and lactic acid formatio
- 3)Aerobic Pathway
- Aerobic cellular respiration
Point at which muscle metabolism converts to anaerobic glycolysis
length of time a muscle can continue to contract using aerobic pathways
energy rich molecule found in muscle allows for more energy for contraction
builds size by resistance, does not require oxygen, produces 2 ATP, duration of energy is 30-60 seconds.
builds endurance,requires oxygen, energy duration is hours, produces 32 ATP
what are the 3 types of muscle fibers?
- slow oxidative (red) aerobic
- Fast glycolutic (white) anaerobic
- fast oxidative (pink) hybrid
a slight contracted state in relaxed muscles due to reflex signals, helps stabilize joints and maintain posture but does not produce movement
Variations in the degree of muscle contraction by changing either
the strength or frequency of the stimulus:
Graded Muscle Response
response of a muscle to a single brief stimulis
temporary loss of excitability occurs in muscles and nerves
involuntary muscle contraction
Treatment of injured muscles: RICE