Lecture 10: Muscular Tissue Part 1 Flashcards
What are the 3 types of muscular tissue?
skeletal muscle tissue, cardiac muscle tissue, and smooth muscle tissue
Skeletal muscle tissue function
contracts to move bones
cardiac muscle tissue function
contracts to move blood through the heart
smooth muscle tissue function
contracts to regulate passage of substances through the body
What is the scientific study of muscular tissues called?
myology
What are the 4 special properties of muscular tissue?
it is electrically excitable, contractile, extensible, and elastic
Electrically excitable explained?
- produce electrical signals called muscle action potentials.
Contractile explained?
- muscle action potentials stimulate contractions
-contractions generate tension on bones which cause movement
extensible explained?
tissue can be stretched without tearing: smooth muscle around the stomach
elastic explained?
resting length is restored after stretching
What are the cells of skeletal muscle tissues called?
myocytes or muscle fibres
cells contain bunched protein filaments called?
myofibrils
what forms a muscle?
muscle fibres + connective tissue + nerve and blood supply
muscles are surrounded by connective tissue layers called?
fascia
what are the functions of fascia?
1) groups muscles with similar functions and provides passage for vessels
what are the 3 layers of the fascia?
1) epimysium: most superficial: wraps muscles
2) perimysium: middle layer: wraps fascicles(bundles of muscle fibres)
3) endomysium: deepest layer: wrap individual muscle fibres
what is aponeurosis?
special type of tendons: form broad sheets
ex: epicranial aponeurosis
what is voluntary muscle contraction regulated by?
somatic motor neurons
what are the immature muscle cells called?
myoblasts
myoblasts fuse and form what
large multinucleate cells
what is the plasma membrane of myocytes called?
- sarcolemma
- electrical signals run along this
- invaginates inwards to form t tubules
what is the cytoplasm of myocytes called?
-sarcoplasm
- densely packed with myofibrils
- rich in glycogen
sarcoplasm also contains myoglobin, what is it?
myoglobin is only found in muscle cells.
- binds oxygen at fe containing centre called heme
myofibrils are?
long threads of contractile protein filaments.(myofilaments) overlapping filaments gives muscle a striated appearance
what does the sarcoplasmic reticulum do?
store and release calcium
- folds around myofibrils
membrane folds are called?
cisternae and terminal cisternae release calcium to each t tubule.
- 2 terminal cisternae meet a t tubule = triad
muscular hypertrophy
increase in sarcoplasmic volume.
what is hypertrophy a response to
- increased mechanical stress
- hormones
- disease
myofibrils are made up of myofilaments, what are myofilaments made of?
sarcomeres joined end to end
each sarcomere consists of?
overlapping thin and thick filaments
thick filaments?
extend from the midline (m line) and are made of myosin
thin filaments?
extend from the ends (z discs) and are made of actin
the regions where the thick and thin filaments overlap and everything between is called?
a band
the regions between the zones of overlap around the m line is called?
h zone
the regions between zones of overlap around z discs is called?
I band
