muscle tissue

What energizes the myosin head?

ATP hydrolysis reaction

Why do you think that a healthy 30-year-old can lift a 25-pound weight much more comfortably than a healthy 80-year-old?

All of the choices are correct.

Which statement explains the sarcomere appearance change during a muscle contraction?

The h zone shortens as actin filaments slide towards the m-line.

A runner nearing the end of a marathon race would produce most ATP by:

aerobic respiration.

The opening of ligand gates on the sarcolemma is directly caused by

all choices are correct

In which of the following do skeletal muscle and cardiac muscle differ?

all of the choices are correct

Muscle fibers produce ATP using:

all of the choices are correct.

After prolonged strenuous exercise has stopped, heavy breathing will often continue for several minutes in order to provide the oxygen needed to

all of these choices are correct

Which correctly lists the sequence of structures that action potentials must move through to excite skeletal muscle contraction?

axon of neuron, sarcolemma, T tubules

Smooth muscle tone is maintained by the prolonged presence of [_____] in the muscle cell's cytosol?

calcium ions

Contraction of myofibrils within a muscle fiber begins when

calcium is released from the sarcoplasmic reticulum

Skeletal and smooth muscle differ in all of the following EXCEPT:

contraction mechanism.

The zone of overlap increases during the

contraction period

The relaxation phase of a muscle contraction is often prolonged in a fatigued muscle, raising the likelihood of fused summation of action potentials causing painful disturbances to a skeletal muscle. What disturbance is being described?

cramp

World class shot-putters will have a higher percentage of ______in their arm muscles.

fast glycolytic fibers

Strength training would result in

hypertrophy of fast oxidative-glycolytic fibers

Motor unit recruitment occurs when there is a(n) _________ in the number of active motor units within a skeletal muscle.

increase

Which function do all three muscles perform?

moving and storing material throughout the body

Which disorder occurs when little to no proteins are produced to support the sarcolemma?

muscular dystrophy

Which of the following molecules found in skeletal muscle cells binds oxygen that can later be used during aerobic metabolism to help generate ATP?

myoglobin

Muscle damage can be indicated by...

myoglobin found in blood.

Which functions as a motor protein in all three types of muscle tissue?

myosin

Visceral and multiunit smooth muscle differ in:

number of gap junctions present

In a neuromuscular junction, the effect of acetylcholine (ACh) binding to receptors on the motor end plate lasts only briefly due to

rapid destruction of ACh in the synaptic cleft by acetylcholinesterase.

Which type of muscle tissue is capable of undergoing the stress-relaxation response when stretched?

single-unit smooth muscle fibers

Why will an individual who lifts weights build larger muscles?

skeletal muscles increase number of myofibrils but not number of cells

As Marie rounded the corner, she saw that people were already boarding her bus. Worried that she would miss her ride to campus, she sprinted to the bus stop. In what order were skeletal muscles recruited during her sprint?

slow oxidative, fast-oxidative glycolytic, fast glycolytic

Which characteristics describe both skeletal and cardiac muscle?

striations

The contractile organelle of skeletal muscle fibers is

the myofibril

What is the result of acetylcholine attaching to the ligand gates of the motor end plate?

the sarcolemma increases permeability to sodium

________ released from the sarcoplasmic reticulum bind to troponin to trigger exposure of binding sites on actin and begin the contraction cycle. ______ supplies energy to detach the myosin head from actin.

Calcium ions; ATP

When an athlete performs a pull up (raising their chin to a bar while their body hangs), the process of pulling the body up so the chin can touch the bar is

Concentric

When an athlete performs a pull up (raising their chin to a bar while their body hangs), the process of lowering the body down is

Eccentric

Which of the regions of a sarcomere contain titin?

From M line to Z disc

When athletes are preparing to perform a pull up, they hang from the bar. At this point, they are performing what type of contractions?

Isometric

Mitochondrial activity in skeletal muscle cells are usually efficient, but can have limited ATP production if

Mitochondrial activity in skeletal muscle cells are usually efficient, but can have limited ATP production if