Muscle Tissue

Harriet is a body builder, and regularly lifts weights to maintain muscle size. Which of the following statements correctly describes processes related to hypertrophy in skeletal muscles? Check all that apply. Decrease in tone and size of muscle Correct Decrease in mitochondria within muscle fibers Increase in number of myofibrils per muscle fiber Increased ability to produce ATP Increase in adipose tissue within muscle

Increase in number of myofibrils per muscle fiber Increased ability to produce ATP

Rachel is helping her sister install a heavy light fixture. While her sister connects the wires, Rachel must hold the light fixture in place. The wiring is taking longer than expected and Rachel's arms are beginning to tire even though she isn't moving. What type of muscle contraction is occurring in her arms? Concentric Eccentric Isometric Isotonic None of these answers is correct.

Isometric

Which term is associated with the proteins that connect myosin? M Line H zone Z line I band

M Line

Which of the following does troponin not have an attachment site for? Myosin Tropomyosin Actin Calcium

Myosin

Which of the following is/are a characteristic of skeletal muscle? Check all that apply. Overlapping thin and thick filaments Striations Overlapping myosin and actin proteins Excitability Involuntary

Overlapping thin and thick filaments Striations Overlapping myosin and actin proteins Excitability

Based on the size, shape, and ratio of muscle fibers to motor neurons (motor units), rank the following muscles in order of strongest to weakest, starting with #1 being the strongest. Quadriceps femoris Orbicularis oculi Lateral rectus Brachialis Gastrocnemius

Quadriceps femoris-1 Orbicularis oculi-4 Lateral rectus-5 Brachialis-3 Gastrocnemius-2

Which of the following is true concerning isotonic eccentric contraction? The muscle shortens but tension remains constant. The muscle lengthens but tension remains constant. The muscle tenses and shortens. The muscle tenses but length remains unchanged. The muscle lengthens and tension declines.

The muscle lengthens but tension remains constant.

Which of the following is true concerning isotonic concentric contraction? The muscle shortens but tension remains constant. The muscle lengthens but tension remains constant. The muscle tenses and shortens. The muscle tenses but length remains unchanged. The muscle lengthens and tension declines.

The muscle shortens but tension remains constant.

Which of the following marks the boundaries of a sarcomere? I bands H bands Z discs M lines A bands

Z discs

Which term is associated with myosin and the thick filament? I band Z line M Line H zone

Z line

Shortening a muscle while it maintains constant tension is called __________. complete tetanus incomplete tetanus an isokinetic contraction an isometric contraction an isotonic contraction

an isotonic contraction

Loss of muscle mass from lack of activity is called __________. myopathy dystrophy apathy atrophy tetanus

atrophy

A muscle twitch produces external tension and moves an object by shortening the muscles during the _____ phase. contraction latent twitch relaxation reload

contraction

Resistance exercise will most likely cause muscle to __________. myopathy dystrophy apathy atrophy hypertrophy

hypertrophy

The thick filaments of the sarcomere are made up mostly of the protein __________. actin myosin myofibrils troponin

myosin

A skeletal muscle generates the greatest tension when it is __________. greatly stretched before being stimulated partially stretched before being stimulated fully relaxed before being stimulated well-rested and low in creatine phosphate high in lactate concentration

partially stretched before being stimulated

Which statement is not true? The more frequent the stimulation of the muscle fibers, the stronger the force of the muscle. The smaller the muscles fibers, the stronger the force of the muscle. The more muscle fibers that are stimulated, the stronger the force of the muscle. If there are 50+% of the muscle fibers contracted to start with, the stronger the force of the muscle.

The smaller the muscles fibers, the stronger the force of the muscle.

Which of the following is predominately made up of myosin? G actin F actin The thin filament The thick filament The elastic filament

The thick filament

True or False Smooth and cardiac muscles are under involuntary control.

True

Put the steps of the sliding filament theory of contraction in order from first to last. -ADP + P is released causing the myosin heads to flip inward dragging the thin filament with it. -ATPase enzyme breaks ATP down into ADP + P again so myosin is ready for the next contraction. -Calcium binds to troponin which moves tropomyosin off the binding sites. -The introduction of ATP attached to myosin causes the myosin heads to release from the binding sites on actin and the heads to flip out to their original position. -Myosin and actin attach at the binding sites. -A stimulated nerve creates an electrical current and increased calcium into the muscle cell.

-A stimulated nerve creates an electrical current and increased calcium into the muscle cell. -Calcium binds to troponin which moves tropomyosin off the binding sites. -Myosin and actin attach at the binding sites. -ADP + P is released causing the myosin heads to flip inward dragging the thin filament with it. -The introduction of ATP attached to myosin causes the myosin heads to release from the binding sites on actin and the heads to flip out to their original position. -ATPase enzyme breaks ATP down into ADP + P again so myosin is ready for the next contraction.

How many somatic motor neurons stimulate one muscle fiber? 0 1 2 3 4

1

How many steps are involved during a muscle contraction? 1 2 3 4

4

Which of the following contains overlapping thick and thin filaments? A band H band I band M line Z discs

A band

Where in the human body would this tissue be found? Biceps brachii Wall of the heart Dermis of the skin Wall of a blood vessel Patellar tendon

Biceps brachii

Which type of muscle tissue is found in the walls of hollow organs? Smooth muscle Cardiac muscle Skeletal muscle Organ muscle Elastic muscle

Smooth muscle

___ is the smallest functional unit of skeletal muscle. Sarcomere Striations Filaments

Sarcomere

Muscle located attached by tendons to bones. Skeletal Smooth Cardiac

Skeletal

Muscle located in hollow visceral organs, blood vessels and rector pili muscles of hair follicles. Cardiac Smooth Skeletal

Smooth

Muscle that is unbranched and unstriated. Skeletal Cardiac Smooth

Smooth

Which muscle(s) can contract without the need for nervous stimulation? Skeletal muscle only Smooth muscle only Cardiac muscle only Smooth and cardiac muscle Skeletal, smooth, and cardiac muscle

Smooth and cardiac muscle

Astronauts in zero gravity are able to move food through their digestive tracts because __________. smooth muscle produces waves of contractions that propel material through the digestive tract skeletal muscle puts pressure on the digestive tract cardiac muscle maintains a high pressure that moves material through the digestive tract striated muscle creates a pressure gradient that forces material from one end of the digestive tract to the other skeletal muscle sphincters contract and allow materials to move through the digestive tract

smooth muscle produces waves of contractions that propel material through the digestive tract

Skeletal muscle is described as __________. striated and voluntary striated and involuntary nonstriated and voluntary nonstriated and involuntary fibrous and containing ground substance

striated and voluntary

In skeletal muscle, the term that describes the alternating light and dark bands is ___________. strabismus striations tetanus myofibrils myoblasts

striations

The minimum stimulus needed to cause muscle contraction is called the __________. threshold latent period twitch motor unit innervation

threshold

The protein that acts as a calcium receptor in skeletal muscle is __________. F actin tropomyosin troponin titin dystrophin

troponin

Skeletal muscle is called ___________, because it is usually subject to conscious control. excitable contractile striated voluntary isometric

voluntary