Muscle Structure and Organization Flashcards
What are the different types of muscle?
Skeletal, cardiac, and smooth
Muscle is a ____________ tissue.
Heterogeneous
What is the composition (and %) of skeletal muscle?
- Water (75%)
- Protein (≈18%)
- Fat (3%)
- Carbohydrate (1%)
- Ash (1%)
As fat increases, the _______ will decrease in the composition of skeletal muscle.
Water
Give me the term:
? = connective tissue surrounding the muscle bundle (dense irregular)
Perimysium
Give me the term:
? = connective tissue connecting muscle to bone
Tendon
Give me the term:
? = connective tissue surrounding the entire muscle
Epimysium
Give me the term:
? = connective tissue surrounding a fiber
Endomysium
What does the muscle fiber contain?
Myocyte, muscle cell, and myofiber.
In the muscle cell, the sarcolemma is considered the…
muscle plasma membrane
In the muscle cell, the sarcoplasm is considered the…
cytoplasm
In the muscle cell, the mitochondria is considered the…
organelle of the muscle cell (powerhouse)
In the muscle cell, the myofilaments contain…
- thick filaments (myosin)
- thin filaments (actin) (also known as the motor protein)
In the muscle cell, the sarcoplasmic reticulum is considered the…
calcium reservoir - restores calcium to control muscle contraction.
What is the smallest contractile unit of muscle?
Sarcomere
Actin and myosin are _______ proteins.
Contractile
What is in a myosin filament?
- Myosin heavy chains (MHc).
^There are two MHcs per myosin molecule.
What is in an actin filament?
G-actin (Globular actin) and F-actin (filamentous actin)
In the thin filament, what kind of regulatory proteins are there?
- Tropomyosin
- Troponin complex:
- TnT
- TnC
- TnI
_______ is a barrier between actin and myosin protein filaments and prevents __________________.
Tropomyosin, prevents irregular contracting
What are the three subunits of the troponin complex?
1) TnT
2) TnC
3) TnI
What does TnT bind to?
Binds to tropomyosin and anchors
What does TnC bind?
Binds intracellular calcium
What does TnI bind?
Binds actin and inhibits (prevents) actin-myosin interaction
_______ promotes muscle contraction, whereas _________ blocks muscle contraction.
Troponin, tropomyosin
In the sarcomere, the ____ band is the dark region and is _________.
A-band, anisotropic
In the sarcomere, the ____ band is the light region and is _________.
I-band, isotropic
What does titin help with?
Helps keep the structural organization within a myofibril aligned and rests tension
When a muscle is fully contracted, there is a ______ gap between the Z lines and a ___________ in the H zone.
Shorter, reduction
What helps keep the Z-lines aligned?
Desmin and intermediate filaments
What links the myofibrils and cytoskeleton to the extracellular matrix through the sarcolemma?
Costameres
Costameres are ________-associated _________ complex
dystrophin, glycoprotein
What is Duchenne muscular dystrophy?
- It is the complete loss of dystrophin
- There is a loss of mechanical stability of the sarcolemma.
