Ch 11- Musculoskeletal Flashcards
“Bones are more than simply a support structure, however; they also provide
protection to internal organs, serve as a storage reserve of calcium and other minerals, and are the site of hematopoiesis.”
“Rapid muscle contraction also leads to shivering, which is important in
thermoregulation. ”
“Muscle can be divided into the three different subtypes:
skeletal muscle, smooth muscle, and cardiac muscle.”
“Skeletal muscle is responsible for voluntary movement and is therefore innervated by the _________ nervous system”
Somatic
“Due to the arrangement of actin and myosin into repeating units called ________, it appears striped or striated when viewed microscopically.”
Sarcomeres
“Skeletal muscle is multinucleated”
_______ Have high myoglobin content and primarily derive their energy aerobically”
“Red fibers, also known as slow-twitch fibers
“also contain many mitochondria to carry out oxidative phosphorylation”
Muscles that contract slowly, but that can sustain activity (such as the muscles that support posture), contain a predominance of red fibers”
An oxygen carrier that uses iron in a heme group to bind oxygen, imparting a red color”
Myoglobin
_______ contain much less myoglobin. Because there is less myoglobin, and therefore less iron, the color is lighter.”
White fibers, also known as fast-twitch fibers
Muscles that contract slowly, but that can sustain activity (such as the muscles that support posture), contain a predominance of
Red fibers
“Muscles that contract rapidly, but fatigue quickly, contain mostly
White fibers
“have a single nucleus located in the center of the cell
Smooth muscle
“Just like skeletal muscle, smooth muscle cells contain _________, but the fibers are not as well-organized, so striations cannot be seen”
Actin and myosin
“ Compared to skeletal muscle, smooth muscle is capable of more sustained contractions; a constant state of low-level contraction, as may be seen in the blood vessels, is called
Tonus
“Smooth muscle can actually contract without nervous system input in what is known as
myogenic Activity
“both smooth and cardiac muscle exhibit _______. These muscle cells will respond to nervous input, but do not require external signals to undergo contraction.”
myogenic Activity
“Cardiac muscle cells are connected by intercalated discs, which contain many
Gap junctions
“These gap junctions are connections between the cytoplasm of adjacent cells, allowing for the flow of ions directly between cells. This allows for coordinated muscle cell depolarization and efficient contraction of cardiac muscle”
“One of the ways epinephrine does increases HR and contractility is by increasing intracellular ______ levels within cardiac myocytes.”
Calcium
“The _______ is the basic contractile unit of skeletal muscle”
Sarcomere
Troponin and tropyosin are associated with which filament
Actin
“To remember which filament is associated with troponin and tropomyosin, remember that actin has a T in it.”
________ define the boundaries of each sarcomere. ”
Z- Lines
“Z—Z is the end of the alphabet, and the end of the sarcomere
M—in the middle of the myosin filaments
I—I is a thin letter (thin filaments only)
H—H is a thick letter (thick filaments only)
A—all of the thick filament, whether or not it is overlapping”
runs down the center of the sarcomere, through the middle of the myosin filaments”
M-Line
“Z—Z is the end of the alphabet, and the end of the sarcomere
M—in the middle of the myosin filaments
I—I is a thin letter (thin filaments only)
H—H is a thick letter (thick filaments only)
A—all of the thick filament, whether or not it is overlapping”
“The ________ is the region containing exclusively thin filaments, whereas the ______ contains only thick filaments.”
I Band, H-Zone
“Z—Z is the end of the alphabet, and the end of the sarcomere
M—in the middle of the myosin filaments
I—I is a thin letter (thin filaments only)
H—H is a thick letter (thick filaments only)
A—all of the thick filament, whether or not it is overlapping”
The _______ contains the thick filaments in their entirety, including any overlap with thin filaments
A- Band
“Z—Z is the end of the alphabet, and the end of the sarcomere
M—in the middle of the myosin filaments
I—I is a thin letter (thin filaments only)
H—H is a thick letter (thick filaments only)
A—all of the thick filament, whether or not it is overlapping”
“Sarcomeres are attached end-to-end to form ______ and are surrounded by a covering known as the _________, a modified endoplasmic reticulum that contains a high concentration of Ca2+ ions”
myofibrils, Sarcoplasmic Reticulum
“The ________ is a modified cytoplasm located just outside the sarcoplasmic reticulum”
Sarcoplam
“The cell membrane of a myocyte is known as the
sarcolemma
“The sarcolemma is capable of propagating an action potential and can distribute the action potential to all sarcomeres in a muscle using a system of transverse tubules”
“The sarcolemma is capable of propagating an action potential and can distribute the action potential to all sarcomeres in a muscle using a system of
transverse tubules (T-Tubules)
Oriented perpendicular to myofibrils
“Each ______, or muscle cell, contains many myofibrils arranged in parallel and can also be called a ________”
Myocyte, Muscle Fiber
“A myofibril is an arrangement of many _______ in series. ”
Sarcomeres
“A muscle fiber (or myocyte, or muscle cell) contains many myofibrils within it, arranged in parallel. A muscle is made up of parallel muscle fibers”
Muscle contraction depends on
ATP and Calcium
3 Major steps of muscle contraction
Initiation, Contraction, Relaxation
“Addition of multiple simple twitches before the muscle has an opportunity to fully relax is called
frequency summation
“Simple twitches that occur so frequently as to not let the muscle relax at all can lead to ______, a more prolonged and stronger contraction.”
frequency summation
“Muscle cells have additional energy reserves to reduce _____ (the difference between the amount of oxygen needed and the amount present) and forestall fatigue.”
The 2 energy reserves are ____ and _____
Oxygen debt, Creatine Phosphate and Myoglobin
“Creatine phosphate can transfer a phosphate group to ADP, forming ATP.
Myoglobin is a heme-containing protein that is a muscular oxygen reserve.”
“Internal skeletons (like those in humans) are called ______; external skeletons (like those in arthropods) are called ______.”
Endoskeletons, Exoskeleton
“The human skeletal system can be divided into ___ And _____ skeletons
axial and appendicular skeletons.”
“The ______ skeleton consists of structures in the midline such as the skull, vertebral column, ribcage, and hyoid bone.”
Axial
“The ______skeleton consists of the bones of the limbs, the pectoral girdle, and the pelvis.”
appendicular
“Spongy or cancellous bone has a lattice-like structure consisting of bony spicules known as _______. The cavities are filled with ______.”
trabecular, bone marrow
“Bone matrix has both _______ components, like collagen, glycoproteins, and other peptides, and ______ components, like hydroxyapatite.”
Organic, Inorganic
______ also increases resorption of bone, leading to increased turnover and, subsequently, the production of stronger bone.”
Vitamin D
“Cartilage is a firm, elastic material secreted by chondrocytes. Its matrix is called
Chondrin
“In fetal life, bone forms from cartilage through _______ Some bones, especially those of the skull, form directly from undifferentiated tissue (mesenchyme) in _______
endochondral ossification, intramembranous ossification
______ are fused together to form sutures or similar fibrous joints.”
“Immovable joints
2 types of joints
Movable, immovable
“Movable joints are usually strengthened by ligaments and contain a ______
Synovial Capsul
_________, secreted by the synovium, aids in motion by lubricating the join”
Synovial Fluid
“Each bone in the joint is coated with ________ to aid in movement and provide cushioning.”
articular cartilage
“Muscles that serve opposite functions come in _________; when one muscle contracts, the other lengthens.”
antagonistic pairs
In muscle contraction what happens when atp is hydrolyzed
Myosin head recocks
In muscle contraction what happens when ADP and Pi dissociate
Sarcomere contracts power stroke occurs
In muscle contraction what happens when a new ATP bins to myosin
Causes detachment of myosin from actin
