Ch. 10 - Muscle cells Flashcards
This muscle tissue is voluntary and striated
Skeletal muscle
This muscle tissue is involuntary and striated
Cardiac muscle
This muscle tissue is involuntary and non-striated
Smooth muscle
A muscle cell can be AKA (x2)
Muscle fiber, myofiber
This is the plasma membrane of a muscle fiber
Sarcolemma
Where in a muscle fiber is Ca2+ stored?
Sarcoplasmic Reticulum
Glycogen provides this for the muscle cell
Energy
Myoglobin provides this for the muscle cell
Oxygen
That sarcoplasm contains
Glycogen and Myoglobin
These are the “organelles” of the muscle cell
Myofilaments
A segment of myofibril from one Z-disc to the other Z-disc
Sarcomere
What is the functional subunit of a muscle fiber?
Sarcomere
Fibrous protein strands that carry out the muscle contraction
Myofilaments
3 kinds of myofilaments
Thick
Thin
Elastic
Thick myofilaments are made of this ? called ?
motor protein called myosin
Thin myofilaments are made of intertwined strands of
Actin filaments
A subunit strung into the actin filaments are the
Globular (G) actin
Besides actin and globular filaments, a thin filament also has these proteins
Tropomyosin and troponin
The contractile proteins are
Actin and myosin
The regulatory proteins are
Tropomyosin and troponin
This additional accessory protein links actin filaments to transmembrane proteins in the sarcolemma
Dystrophin
What creates the striated appearance of a muscle fiber?
The alternating arrangements of myofilaments
Does myosin or actin stain darker?
Myosin
“Striated muscle has (darker/lighter) A-bands that alternate with (darker/lighter) I-bands under a microscope”
Darker A-bands
Lighter I-bands
Each A-band consists of (thick/thin) myofilaments
Thick
In the middle of each A-band is a lighter region called the (there’s 2)
H-band and the M-line
This section of the A-band stains lighter due to a lack of thin myofilaments
H-band
This section of the A-band anchors thick myofilaments together
M-line
This part of the muscle fiber is described as a light stripe of thin filaments only
I-Band
This is the midline of an I-band
Z-disc
Muscle fibers are (vascular/avascular)
Vascular
Skeletal muscle is innervated by which kind of neurons
Motor neurons
Where a neuron innervates a skeletal muscle
Neuromuscular junction
Acetylcholine is a
Neurotransmitter
This is the enzyme that breaks down Ach
Acetylcholinesterase
There are 2 types of motor units
Small and large motor units
There are 2 classes of muscle fibers
Slow-twitch and Fast-twitch
Which kind of muscle fiber is adapted to aerobic respiration?
Slow-twitch fiber
Do slow-twitch fibers fatigue easily?
No
Which kind of muscle fiber is adapted to anaerobic respiration?
Fast-twitch fiber
Skeletal fibers are (capable/incapable) of mitosis
Incapable of mitosis
What happens in a myofiber allowing the muscle to enlarge?
Myofibrils grow thicker
A muscle grows by (hyperplasia/hypertrophy)
Hypertrophy
Unused muscles shrink. Another name for this?
Muscle cells “atrophy”
These connect myocardial cells and appear as dark lines
Intercalated discs
Are there Z-discs in smooth muscle?
No
Instead of Z-discs, smooth muscle has these protein plaques
Dense bodies
“diseases of the muscle”
Myopathies
Sex-linked skeletal muscle degeneration
Muscular dystrophy
Autoimmune disease with damaged Ach receptors
Myasthenia gravis (MG)
