The primary functions performed by skeletal muscles are to…
- Produce skeletal movement
- Guard entrances and exits
- Maintain body temperature
Muscle tissue consists of cells that are highly specialized for the…
- Excitability
- Contraction
- Maintain body temperature
Skeletal muscles move the body by…
Pulling on the bones of the skeleton
Skeletal muscles are often called voluntary muscles because…
They contract only when stimulated by motor neurons of the central nervous system
The three layers of connective tissue supporting each muscle are the…
Epimysium, perimysium, and endomysium
Nerves and blood vessels that supply the muscle fibers are contained within the connective tissues of the…
Endomysium and perimysium
The smallest functional unit of the muscle fiber is…
The sarcomere
The thin filaments consist of…
Pair of protein strands wound together to form chains of actin molecules
The thick filaments consist of…
Helical array of myosin molecules
The sliding filament theory explains that the physical change that takes place during contraction is the…
Thin filaments are sliding toward the center of the sarcomere alongside the thick filaments
Troponin and tropomyosin are two proteins that can prevent the contractile process by…
Covering the active site and blocking the actin-myosin interaction
The first step in excitation-contraction coupling is the…
Stimulation of the sarcolemma
Muscle relaxation begins with…
Breakdown of ACh by AChE
All of the muscle fibers controlled by a single motor neuron constitute a…
Motor unit
The tension in a muscle fiber will vary depending on the…
- Structure of individual sarcomeres
- Initial length of muscle fibers
- Number of cross bridge interactions within a muscle fiber
There is less precise control over leg muscles compared to the muscles of the eye because…
Many muscle fibers are controlled by a single motor neuron
Skeletal muscle fibers contract most forcefully when stimulated over a…
Narrow range of resting lengths
The amount of tension produced by a skeletal muscle is controlled by…
The total number of muscle fibers stimulated
Peak tension production occurs when all motor units in the muscle contract in a state of…
Complete tetanus
In a concentric isotonic contraction…
The cross bridges must produce enough tension to overcome the resistance
In an isometric contraction…
Tension rises but the length of the muscle remains constant
A high blood concentration of the enzyme creatine kinase usually indicates…
Serious muscle damage
Mitochondrial activities are relatively efficient, but their rate of ATP generation is limited by the…
Availability of oxygen
What has been correlated with muscle fatigue?
A decline of pH within the muscle, altering enzyme activities
During the recovery period, the body’s oxygen demand is…
Elevated above normal resting levels
The three major types of skeletal muscle fibers in the human body are…
Slow, intermediate, fast
Extensive blood vessels, mitochondria, and myoglobin are found in the greatest concentration in…
Slow fibers
The length of time a muscle can continue to contract while supported by mitochondrial activities is referred to as…
Aerobic endurance
Altering the characteristics of muscle fibers and improving the performance of the cardiovascular system results in improving…
Aerobic endurance
The property of cardiac muscle that allows it to contract without neural stimulation is…
Automaticity
Structurally, smooth muscle cells differ from skeletal muscle cells because smooth muscle cells…
Lack myofibrils and sarcomeres
Smooth muscle tissue differs from other muscle tissue in…
- Excitation-contraction coupling
- Length-tension relationships
- Control of contraction
Neural, hormonal, or chemicals factors can stimulate smooth muscle contraction, producing…
A decrease in muscle tone
Muscle contraction occurs as a result of…
Interactions between the thick and thin filaments of ten sarcomeres
The area of the A band in the sarcomere consists of…
M line, H band, and zone of overlap
The process of cross bridging, which occurs at an active site, involves a series of sequential cyclic reactions that include…
Attach, pivot, detach, and return
Excitation-contraction coupling forms the link between…
Electrical activity in the sarcolemma and the initiation of a contraction
When Ca2+ binds to troponin, it produces a change by…
Exposing the active site on the thin filaments
The phase of a single twitch in sequential order are…
Latent period, contraction phase, relaxation phase
After contraction, a muscle fiber returns to its original length through…
Elastic forces and the movement of opposing muscles
A muscle producing almost peak tension during rapid cycles of contraction and relaxation is said to be in…
Incomplete tetanus
The process of reaching complete tetanus is obtained by…
Increasing the rate of stimulation until the relaxation phase is completely eliminated
The total force exerted by a muscle as a whole depends on…
- The rate of stimulation
- How many motor units are activated
- The number of calcium ions released
The principal energy reserves found in skeletal muscle cells are…
ATP, creatine phosphate, and glycogen
The two mechanisms used to generate ATP from glucose are…
Carbohydrates, fats, and proteins
In anaerobic glycolysis, glucose is broken down to pyruvic acid, which is converted to…
Lactic acid
The maintenance of normal body temperature is dependent upon…
The production of heat by muscles
Growth hormone from the pituitary gland and the male sex hormone, testosterone, stimulate…
Synthesis of contractile proteins and the enlargement of skeletal muscles
The hormone responsible for stimulating muscle metabolism and increasing the force of contraction during a sudden crisis is…
Epinephrine
The type of skeletal muscle fibers that have low fatigue resistance are…
Fast fibers
An example of an activity that requires anaerobic endurance is…
A 50 yard dash
Athletes training to develop anaerobic endurance perform…
Frequent, brief, intensive workouts
The major support that the muscular system gets from the cardiovascular system is…
Nutrient and oxygen delivery and carbon dioxide removal
