Chapter 9 Muscles and Muscle Tissues

An entire skeletal muscle is surrounded by __________.

An entire skeletal muscle is surrounded by __________.

epimysium

A motor neuron along with all the muscle fibers it supplies is called a(n) __________.

motor unit

This does NOT occur during skeletal muscle contraction?

Calcium binds to myosin heads.

What is the ion released from the terminal cisternae that combines with troponin and removes the blocking action of tropomyosin, resulting in the formation of cross bridges?

Ca²⁺

Each skeletal muscle fiber is controlled by a neuron at a single __________.

neuromuscular junction

This best describes the composition of the structure known as a triad in a skeletal muscle fiber?

terminal cisterna, transverse tubule, and terminal cisterna

In the sliding filament model of muscle contraction, the myofilaments slide over each other, resulting in the overlapping of actin and __________.

myosin

What is Myoglobin?

an oxygen-storage molecule

The functional unit of contraction in a skeletal muscle fiber is the __________.

myofilament

sarcomere

The space between the axon terminus of the neuron and the sarcolemma of the muscle fiber is the __________.

synaptic cleft

Continued mild or partial contraction of a muscle that keeps it healthy and ready to respond is known as muscle __________.

tone

The type of muscle contraction in which the muscle fibers produce increased tension although the muscle neither shortens nor lengthens is called __________.

isometric

This statements about smooth muscle is true

Fibers are small and spindle-shaped.

The following statements is INCORRECT

Skeletal muscles are responsible for the pumping action of the heart.

This substances increases in quantity during repetitive muscle contraction during oxygen deficit

lactic acid

The sequence of electrical changes that occurs along the sarcolemma when a muscle fiber is stimulated is known as the __________.

action potential

This allows recoil of the muscle fiber when contraction ends?

elastic filaments

This binds calcium ions in a smooth muscle, causing contraction

calmodulin

All of the following terms refer to the ability to receive and respond to a stimulus EXCEPT

contractility

During the phase of excitation-contraction coupling of skeletal muscle, what occurs immediately after the action potential spreads down the T tubule?

The sarcoplasmic reticulum releases calcium.

This muscles is voluntary

the muscle that extends the arm at the elbow

Which of the following is NOT a characteristic of skeletal muscle contraction?

It can contract for long periods of time without tiring.

This type of skeletal muscle contains abundant quantities of glycogen

fast glycolytic fibers

Myofilament cross bridges form when which two structures bond?

myosin heads and globular actin

Which of the following is thought to be an autoimmune disease of acetylcholine receptors?

myasthenia gravis

The refractory period in which the muscle will NOT contract if stimulated occurs during __________ of the muscle cell.

repolarization

What is the cause of rigor mortis?

calcium influx into the sarcoplasm after death

Where does 95% of the energy needed for contraction come from during moderate exercise?

aerobic respiration

The alternating contraction and relaxation of opposing layers of smooth muscle is referred to as __________.

peristalsis

Which of the following characteristics is unique to smooth muscle?

the absence of striations