Muscle Flashcards
Outer most layer; skin and neuronal tissues
Ectoderm
Middle germ layer; muscle, fat, bone tissues
Mesoderm
Inner layer; respiratory and digestive tracts
Endoderm
What does myo- mean?
Muscle
Increase in number
Proliferation
Fuse and express muscle-specific gene
Differentiation
Myotube or myofiber
Maturation
MRF’s
Proliferation, Differentiation, Maturation
What does MRF stand for?
Myogenic Regulatory Factors
What do MRF’s help do?
Commit cells to myoblasts; family of transcription factors that ‘turn on’ transcription of other genes in the nucleus
Whats more preferred?
Proliferation
The cell cycle phases:
G1, S, G2, M
G1 Phase
3-12 hours; Environmental cues signal continuance
S Phase
DNA Synthesis
G2 Phase
Remodeling to accommodate mitosis
M Phase
Mitosis; Cell division
G0 Phase
Alternative G1 phase; Cells remain capable of proliferation without dividing; dormant; satellite cells
Satellite cells proliferate to repair muscle if damaged
G0 Phase
Myotube
Multi-nucleated; Nuclei are centrally located; Cannot contract; Mature into muscle fiber; Synthesize myofibrillar proteins and assembles them into myofibrils; Nuclei are unable to divide; Cannot create new myoblast
Go from mono-nucleated to multi-nucleated
Muscular precursor; muscle cell
First muscle fibers to develop; Act as scaffolding; “Hollow tubes”; Act as frame, everything builds around it
Primary myotube
Form gap junctions; Splinter away post contraction and post innervation;90% of muscle fibers
Secondary myotube
Primary myotube nuclei
Central for extended time
Secondary myotube nuclei
Central briefly
How does muscle grow?
Muscle hypertrophy
How do fish grow?
Hyperplasia
Hypertrophy
Increase muscle fiber size
Hyperplasia
Increase muscle fiber number
Add DNA to cells and repair injured fibers
Satellite cells
What factors affect muscle fiber number?
Animal to animal variation within species; Muscle to muscle variation; Nutrition; Breed and Genetics; Age; Sex; Genetic conditions
What do most fibers do?
Taper off and do not go length of muscle
Force depends on what?
Number of microfibers
Longer length of a fiber results in what?
Force lasts longer
Muscle tissue is used for what?
Locomotion Digestion Breathing Vision Circulation High quality food protein
30-40% of total body mass
Muscle tissue
What are the three types of muscle tissue?
Skeletal, Cardiac, Smooth
What muscle is non striated?
Smooth
What muscle is striated?
Skeletal and Cardiac
Sheet like; involuntary; regulate fluid movement
Smooth
Striated and involuntary
cardiac
Water, proteins, lipids, carbohydrates; Origin, Insertion, Tendon, Fascia
Skeletal
Thin sheet of connective tissue attachment below skin
fascia
Connective tissue attachment of origin or insertion into bone
tendon
Forms muscle fibers into bundles; Intramuscular fat
Perimysium
Connective tissue; Separates individual muscles; Provides avenues for nerves and blood vessels; Silver Skin
Epimysium
Connective tissue surrounds individual muscle fibers; Adjacent to muscle cell membrane and attached via basement membrane
Endomysium
Muscle fiber
Muscle cell, myocyte, myofiber; Fully mature myotube that contracts:Can extend length of muscle; Multi-nucleated
Sarcolemma
Cell membrane of muscle cells; Provides invaginations for communication channels
How many nuclei for every millimeter?
33
Where are the nuclei located?
On the outside edges of muscle cell
Myofibril
contracting apparatus
Help contract and cause striation
Myosin and Actin
