| Question | Answer |
| Latin word for “little mouse” | Muscle |
| 1. Skeletal Muscle Tissue
2. Cardiac Muscle Tissue, &
3. Smooth Muscle Tissue |
| squeezes fluids and other substances through hollow organs | Smooth muscle |
| 4 main functions of Muscle Tissue | 1) Maintenance of posture & producing body movement—enables the body to remain sitting or standing
2) Stabilizating body positions
3) Storing & moving substances within the body
4) Heat generation |
| 4 main features of Muscle Tissue | Contractility-long cells shorten and generate pulling force
Excitability-electrical nerve impulse stimulate contraction
Extensibility-stretched back to its original length by contraction of an opposing muscle
Elasticit-recoil after being stretched |
| Packaged into skeletal muscles
Makes up 40% of body weight
Cells are striated | |
| occupies the walls of hollow organs, squeezes fluids and other substances through hollow organs, cells lack striations | |
| Cells of smooth and skeletal muscle are known as: | fibers |
| Plasma membrane of muscle cells is called the | sarcolemma |
| Cystoplasm of muscle cells is called the | sarcoplasm |
| Each muscle is an organ | Each muscle is an organ |
| dense regular connective tissue surrounding entire muscle | Epimysium |
| surrounds each fascicle (group of muscle fibers) | Perimysium |
| a fine sheath of connective tissue wrapping each muscle cell | Endomysium |
| Connective tissue sheaths are continuous with tendons | Connective tissue sheaths are continuous with tendons |
| provide elasticity and carry blood vessels and nerves | Sheaths |
| Each skeletal muscle is supplied by branches of | One nerve
One artery
One or more veins |
| Smallest nerve branches serve | |
| Bone markings present where tendons meet bones: | Tubercles, trochanters, and crests |
| Length and diameter of skeletal muscle fiber ((very large)): | Diameter:10–100µm
Length: several centimeters |
| Skeletal Muscle Tissue cells are multinucleate and the nuclei are peripherally located | Skeletal Muscle Tissue cells are multinucleate and the nuclei are peripherally located |
| Striations result from | myofibrils |
| Are long rods within cytoplasm
Make up 80% of the cytoplasm
Are a specialized contractile organelle found in muscle tissue
Are a long row of repeating segments called sarcomeres (functional unit of Skeletal MT) | Myofibrils |
| Overlap inner ends of the thin filaments
Contain ATPase enzymes | Thick (myosin) filaments |
| Full length of the thick filament (includes inner end of thin filaments) | A bands |
| center part of A band where no thin filaments occur | H zone |
| A bands and I bands refract polarized light differently:
A bands —anisotropic
I bands —isotropic | A bands and I bands refract polarized light differently:
A bands —anisotropic
I bands —isotropic |
| in center of H zone
Contains tiny rods that hold thick filaments together | M line |
| region with only thin filaments
Lies within two adjacent sarcomeres | I band |
| A specialized smooth ER that contains calcium ions that are released when muscle is stimulated to contract | |
| What do calcium ions trigger when by diffusing through the cytoplasm? | Sliding filament mechanism |
| deep invaginations of sarcolemma | T tubules |
| Triad |
| muscle shortens to do work | Concentric contraction |
| muscle generates force as it lengthens | Eccentric contraction (resists gravity)
(e.g. "Down" portion of a pushup) |
| Striation pattern when fully relaxed | thin filaments partially overlap thin filaments |
| Striation pattern when contracted | Z discs move closer together
Sarcomere shortens
I bands shorten, H zone disappears
A band remains the same length |
| Muscle is stretched by a movement opposite that which contracts it | Muscle extension |
| The greatest force is produced when a fiber: | starts out slightly stretched |
| Myosin heads can pull along the entire length of the thin filaments | Myosin heads can pull along the entire length of the thin filaments |
| a spring-like molecule in sarcomeres
Resists overstretching
Holds thick filaments in place
Unfolds when muscle is stretched | Titin |
| point where nerve ending and muscle fiber meet | Neuromuscular junction |
| Ends of axons
Store neurotransmitters | Axon terminals |
| space between axon terminal and sarcolemma | Synaptic cleft |
| 2 characteristic categories of skeletal muscle fibers | 1) How they manufacture energy (ATP)
2) How quickly they contract |
| produce ATP aerobically | Oxidative fibers |
| produce ATP anaerobically | Glycolytic fibers |
| 3 classes of skeletal muscle fibers | |
| Red color due to abundant myoglobin
Obtain energy from aerobic metabolic reactions
Contain a large number of mitochondria
Richly supplied with capillaries
Contract slowly and resistant to fatigue
Fibers are small in diameter | Slow oxidative fibers |
| Have an intermediate diameter
Contract quickly like fast glycolytic fibers
Are oxygen-dependent
Have high myoglobin content and rich supply of capillaries
Somewhat fatigue-resistant
More powerful than slow oxidative fibers | Fast oxidative fibers |
| Muscle tissues have few disorders (with the exception of the heart)
Skeletal muscle is remarkably resistant to infection
Smooth muscle problems stem from external irritants | Muscle tissues have few disorders (with the exception of the heart)
Skeletal muscle is remarkably resistant to infection
Smooth muscle problems stem from external irritants |
| A group of inherited muscle destroying disease
Affected muscles enlarge with fat and connective tissue
Muscles degenerate | |
| 2 types of muscular dystrophy | |
| Skeletal muscles contract by which week of development? | Week 7 |
| Pumps blood three weeks after fertilization | Cardiac muscle |
| Surround skeletal muscle fibers
Resemble undifferentiated myoblasts
Fuse into existing muscle fibers to help them grow | Satellite cells |
| Decrease in muscular strength is 50% by age | 80 |
| muscle wasting | Sarcopenia |
