A&P Exam 4

Arrange the following steps for contraction in the correct sequence. 1. The muscle impulse reaches the sarcoplasmic reticulum and calcium is released. 2. Thin filaments are pulled over the thick filaments. 3. Calcium floods the sarcoplasm and binds to troponin molecules leaving active sites. 4. The impulse arrives at the synapse and travels through the transverse tubules. 5. The muscle fiber shortens and contracts. 6. Tropomyosin molecules move to exposed active sites, linking actin and myosin

4,1,3,6,2,5

You hear a sharp noise to your left causing you to shift your eyes in that direction. Which muscles were responsible for your glance?

Left eye- lateral rectus; right eye- medial rectus

The characteristic of muscle that allows it to be passively stretched is

extensibility

What is the action of the gluteus maximus muscle?

extension of thigh

Which of the following is found in the posterior group of forearm muscles?

extensor digitorum

Which muscle extends the big toe?

extensor hallucis longus

A bundle of muscle fibers is known as a

fascicle

What is one of the actions of the gastrocnemius muscle?

flexion of leg

Which of the following is inserted on the calcaneus by the Achilles tendon?

gastrocnemius

Which muscle is used for sticking out the tongue?

genioglossus

Which thigh muscle adducts the thigh and flexes the knee?

gracilis

In the gluteus maximus, each motor unit controls a _____________ amount of muscle fibers than a motor unit in the eye muscles.

greater

The biceps femoris is part of the

hamstring muscles

The rotator cuff muscles

hold the head of the humerus in the glenoid fossa of the scapula

The rotator cuff muscles

hold the head of the humerus in the glenoid fossa of the scapula.

There are four muscles of mastication. Select the exception. 1. hyoglossus 2. masseter 3. temporalis 4. lateral pterygoid 5. medial pterygoid

hyoglossus

Which protein makes up the thick filaments?

myosin

The sites where a chemical substance is transmitted from the presynaptic terminal of an axon to the postsynaptic membrane of a muscle fiber are called

neuromuscular junctions

When a person blinks, she is using her

orbicularis oculi

The word "biceps" in the name of a muscle refers to the fact that

the muscle has two tendons of origin

Concentric contractions occur when

the muscle produces increasing tension as it shortens.

Increased strength of a trained muscle is due to

the nervous system's ability to recruit a large number of motor units simultaneously

Arrange the following list of biochemical events in the correct sequence. 1. An action potential is conducted deep into the muscle fiber by the T-tubule. 2. Calcium ions bind to troponin. 3. The membranes of the sarcoplasmic reticulum become more permeable to calcium ions. 4. Calcium ions diffuse into the sarcoplasm around the myofibril. 5. The troponin-tropomyosin complex moves exposing active sites.

1,3,4,2,5

Which of the following is true? 1. The greater the overlap of actin and myosin, the stronger the contraction. 2. Overstretching a muscle will increase its tension. 3. Optimal actin and myosin overlap will produce maximal contraction. 4. The greatest amount of tension is achieved when actin and myosin do not overlap. 5. Tension is great when actin and myosin overlap as much as they can.

Optimal actin and myosin overlap will produce maximal contraction.

The sequence of crossbridge formation and myofilament movement will be repeated as long as calcium ions are present. True or False.

True

All the muscle fibers under the control of a single motor axon are referred to as

a motor unit

Which is the correct listing of the hierarchy of a skeletal muscle's components, beginning with the smallest? a. myofibrils b. muscle fiber c. fascicle d. skeletal muscle

a,b,c,d

Hold your arm out so that it is completely extended. The triceps brachii is causing the extension, so it is acting as what?

agonist

The bond between the actin and myosin head is broken when

an ATP molecule binds to the myosin head.

A muscle whose action opposes that of the prime mover is known as an

antagonist

The facial muscle that compresses the cheek against the teeth when we chew is the

buccinator

T-tubules

conduct action potentials deep into the muscle fiber

A drug that interferes with the active transport in Ca2+ from the sarcoplasm back into the sarcoplasmic reticulum would result in

contraction with no relaxation

Triangular muscles, like the pectoralis major are also called ---- muscles.

convergent

Alex is participating in a 50-meter dash. Predict the most immediate chemical process his muscles will rely on during this race.

creatine phosphate breakdown

Abducting your arm above shoulder level is accomplished mostly by the

deltoid

When contracted, this muscle causes expansion of the thoracic cavity and increases pressure in the abdominopelvic cavity. Its insertion is on a central tendon.

diaphragm

Which connective tissue wrapping separates individual muscle fibers?

endomysium

Internal muscles that change the shape of the tongue are called ---- muscles.

intrinsic

Your school wins the homecoming football game against its biggest rival. You watch as the smallest cheerleader tries to lift up the heaviest linebacker in her excitement. As she strains against his 300-pound load and does not move him, what type of muscle contraction are her muscles experiencing?

isometric

Which of the following extrinsic eye muscles moves the eye laterally

lateral rectus

The infraspinatus

laterally rotates the arm

Which muscle is the most powerful muscle of mastication and functions to elevate and protract the mandible?

masseter

The neurons that stimulate muscle contraction are called ---- neurons.

motor

The specialized region of the sarcolemma that has folds and indentations to increase the membrane surface area covered by the synaptic knob is the

motor end plate

The type of muscles in which the fascicles are at an oblique angle to the tendon and the muscle fibers resemble a large feather is called

pennate

The sarcolemma is the

plasma membrane of a muscle fiber

When the myosin head flexes into a bend, pulling the actin filament along with it, this is called the

power stroke

If you were studying the functions of skeletal muscle, you would be studying all of the following except 1. production of blood cells 2. holding the head erect 3. protecting internal organs 4. helping maintain a constant body temperature

production of blood cells

Which muscle forms the traditional "six-pack" of a well-toned abdominal wall?

rectus abdominis

Which muscle extends the leg?

rectus femoris

The contractile unit of a myofibril is called the

sarcomere

For relaxation to occur,

sarcoplasm calcium levels fall, calcium is removed from troponin, and tropomyosin blocks binding sites on actin.

The membranous network that wraps around myofibrils and holds relatively high concentrations of calcium is known as the:

sarcoplasmic reticulum

Which of the following muscles is the longest muscle in the body and is nicknamed the "tailor's muscle" because it flexes and laterally rotates the thigh while also flexing and medially rotating the leg (helping us to sit cross-legged, as tailors used to do)?

sartorius

The muscles that protract the scapula include

serratus anterior and pectoralis minor

_________ smooth muscle cells are stimulated to contract in unison (syncytium).

single-unit

The latchbridge mechanism of myosin heads is a property of ________ muscle.

smooth

The muscle that has its superior attachment on the mastoid process and has a bilateral action of flexing the neck is the

sternocleidomastoid

Endomysium is a delicate network of loose connective tissue that

surrounds each muscle fiber

The narrow space that separates the motor neuron and the skeletal muscle fiber in a neuromuscular junction is called the

synaptic cleft

Of the following muscles of the leg, which one is on the anterior side of the leg?

tibialis anterior

The primary muscle that dorsiflexes the foot is the

tibialis anterior

Which of the following muscles is used when dorsi flex and walk on your heels?

tibialis anterior

The component of a muscle fiber that quickly transports a muscle impulse from the sarcolemma throughout the entire muscle fiber is called the

transverse tubule (T-tubule)

The deepest of the abdominal muscles are the ---- muscles.

transversus abdominis

The calcium ions involved in skeletal muscle contraction bind to a ----- subunit.

troponin

During contraction of a muscle, calcium ions bind to the

troponin molecule