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The muscular system of humans contributes approximately what percentage to the adult body weight?


A muscle that controls the diameter of an opening is a ________ muscle


The most common lever systems in the body are those that have the applied force between the fulcrum and the load. These are called ________ levers.


A skeletal muscle fiber can contract until it has shortened by about


Muscles with fibers that run at an angle to the long axis of the body are called


Deep muscles are called


The "kissing muscle" that purses the lips is the

orbicularis oris

The ________ covers the anterior surface of the neck


Which eye muscle sends its tendon of origin through a pulley or trochlea before inserting on the globe?

superior oblique

The sternocleidomastoid inserts on the

mastoid process

In assessing a stroke patient, you ask her to stick out (protract) her tongue. You note that it deviates to one side. You suspect that damage to the neural control of the ________ muscle has occurred


The entire length of longissimus muscle extends from the mastoid process of the temporal bone to the __________.


The external intercostals elevate the rib cage during __________.


The origin of the external obliques includes ribs __________.

five through twelve

_____ have their origin on the transverse and costal processes of cervical vertebrae.

the scalenes

collagen sheath at the base of the clitoris or penis is the origin of the?


The following muscles: ischiocavernosus, coccyges, deep transverse perineal, and bulbospongiosus are found within the?

pelvic floor

Skeletal muscles in which the fascicles form a common angle with the tendon are ________ muscles.


Muscles with fibers that run parallel to the long axis of the body are called


A muscle that assists the muscle that is primarily responsible for a given action is a


Muscles with fibers that run perpendicular to the long axis of the body are called


Which of the following describes the action of the corrugator supercilii?

wrinkles the brow

The temporalis muscle passes through the

zygomatic arch

The muscle that elevates the tongue is the


The insertions of the semispinatus capitus are on the __________.

occipital bone

The actions of the internal intercostals are most important during __________.

forced expiration

The actions of the __________ include compression of the abdomen to assist in forced expiration

internal obliques

The origins of the rectus abdominus muscle are on the __________.

pubic bone

During abdominal surgery, the surgeon makes a cut lateral to the linea alba. The muscle that would be cut is the

rectus abdominis

The two heads of the biceps brachii combine to insert on the __________.

radial tuberosity

All fibers of the triceps brachii are innervated by the __________.

radial nerve

Muscles of the rotator cuff include all of the following, except the


The trapezius muscle may be separated into all of the following groups, except __________.


The latissimus dorsi inserts on the __________ of the humerus

intertubercular groove

One of the actions of the latissimus dorsi muscle is to __________.

adduct the arm

To keep the humeral head centered within the glenoidal cavity the rotator cuff muscles must be located __________.

in the same plane

The location of the rotator cuff muscles in relation to the glenohumoral joint minimizes the upward pressure against the __________ of the scapula.


Which muscle is not part of the rotator cuff?

trees major muscle

Downward dislocation of the humerus from the glenohumeral joint when carrying weight is prevented by the __________.

supraspinatus muscle

The angle of which muscle prevents the humeral head from sliding upward out of the joint as the arm is raised?


The rotator cuff is a term used to describe the group of muscles and tendons that stabilize and reinforce the __________.

glenohumeral joint

All the tendons of the rotator cuff muscles combine at which location?

humeral head

Damage to the pectoralis major would interfere with a person's ability to

adduct the humerus

To allow movement of the tendons within the carpal tunnel zone, each tendon is encased in a __________.


Carpal tunnel syndrome is characterized by inflammation of the __________.

flexor retinaculum and/or tendon sheaths

Of all the flexor muscles of the forearm, the __________ is the shortest.

pronator teres

The muscle that extends the arm while doing push-ups is the


The insertion of the extensor digitorum branches into __________.

four tendons

At the completion of supinator action, the palm is turned __________.


Of the intrinsic muscles of the hand, which one originates on the hamate bone?

flexor digiti minimi brevis muscle

All fibers of the trapezius muscle are innervated by the __________.

spinal accessory nerve

The prime mover of hip extension is the __________.

gluteus maximus

The tensor fascia latae is involved in hip __________.


Which of the following muscles pulls on the iliotibial tract?

gluteus maximus

The band of collagen fibers that laterally braces the knee is the

iliotibial tract

Both heads of the biceps femurs muscle flex the leg at the __________.


The long head of the biceps femoris muscle originates on the __________.

ischial tuberosity

The biceps femoris is located in the __________.

posterior thigh

All fibers of the semimembranosus muscle converge to insert on the __________.

posterior tibia

The semimembranosus __________ the thigh at the hip and __________ the leg at the knee.

extends; flexes

The semitendinosus muscle lies ______________ to the semimembranosus muscle.


The semitendinosus muscle is innervated by the tibial portion of the __________ nerve.


Which of the following is a flexor of the knee?

biceps femoris, semitendinosus, and semimembranosus

The main action of the fibularis longus is to __________.

evert the foot

The soleus muscle shares an insertion with the __________ muscle.


The soleus muscle __________ the foot at the ankle and is innervated by the __________.

flexes; tibial nerve

Which muscle is found in the superficial posterior compartment of the calf region?

gastrocnemius muscle

If the anterior compartment of the lower limb was suffering from "compartment syndrome," which of these muscles would be at risk of injury?

tibialis anterior, extensor hallucis longus, and extensor digitorum longus

The ________ nervous system controls the skeletal muscles.


The axon is connected to the cell body at the

axon hillock

Most CNS neurons lack centrioles. This observation explains why CNS neurons

cannot regenerate

Sensory neurons of the PNS are


The myelin sheath that covers many CNS axons is formed by


Small, wandering cells that engulf cell debris and pathogens in the CNS are called


________ account for roughly half of the volume of the nervous system.


Many medications introduced into the bloodstream cannot directly affect the neurons of the CNS because the astrocytes isolate the CNS by forming

a blood-brain barrier

After a stroke, what type of glial cell accumulates within the affected brain region?


The neurilemma of axons in the peripheral nervous system is formed by

schwann cells

Ion channels that are always open are called ________ channels.


Puffer fish poison blocks voltage-gated sodium channels like a cork. What effect would this neurotoxin have on the function of neurons?

The axon would be unable to generate action potentials.

If the sodium-potassium pumps in the plasma membrane fail to function, all of the following occur, except the intracellular concentration of potassium

ions will increase.

In the peripheral nervous system, Schwann cells participate in the repair of damaged nerves by forming a cellular cord that

directs axonal regrowth

In a typical undisturbed cell, the extracellular fluid (ECF) contains high concentrations of sodium ions and chloride ions, whereas the cytosol contains high concentrations of______ and negatively ______.

potassium ions; charged proteins

Chemically gated channels include receptors that bind

ACh at the neuromuscular junction

What prevents the Na+ and K+ gradients from dissipating?

Na+ K+ ATPase

The resting membrane potential depends on two factors that influence the magnitude and direction of Na+ and K+ diffusion across the plasma membrane. Identify these two factors

The presence of concentration gradients and leak channels

The plasma membrane is much more permeable to K+ than to Na+. Why?

There are many more K+ leak channels than Na+ leak channels in the plasma membrane.

On average, the resting membrane potential is -70 mV. What does the sign and magnitude of this value tell you?

The inside surface of the plasma membrane is much more negatively charged than the outside surface.

Sodium and potassium ions can diffuse across the plasma membranes of all cells because of the presence of what type of channel?

leak channels

Ions are unequally distributed across the plasma membrane of all cells. This ion distribution creates an electrical potential difference across the membrane. What is the name given to this potential difference?

resting membrane potential

Ions can move across the plasma membrane in which of the following ways?

through voltage-gated channels as in the action potential, through passive or leak channels by ATP-dependent ion pumps like the sodium-potassium exchange pump, through chemically-gated channels as in neuromuscular transmission
all of the above

Which type of membrane channels are found at label "3"?

voltage-gated Na+ channels, voltage-gated K+ channels

The dorsal root ganglia mainly contain

cell bodies of sensory neurons

Spinal nerves are

both sensory and motor

After age ________ the vertebral column continues to elongate, but the spinal cord itself does not.


In an adult, the conus medullaris is found at about


What is the function of denticulate ligaments?

They prevent lateral movement of the spinal cord

Samples of CSF for diagnostic purposes are normally obtained by placing the tip of a needle in the

subarachnoid space

Cerebrospinal fluid flows within the

subarachnoid space

The tough, fibrous, outermost covering of the spinal cord is the

dura mater

Which spinal cord structure contains somatic motor nuclei?

anterior gray horn

The white matter of the spinal cord contains

bundles of axons with common origins, destinations, and functions.

Nerve tracts or fasciculi make up the

anterior white columns

A viral disease that destroys the cells of the anterior gray horn will

lead to muscle weakness or paralysis

Spinal nerves from the sacral region of the cord innervate the ________ muscles.


Each peripheral nerve provides ________ innervation to peripheral structures.

motor AND sensory

The dorsal root of a spinal nerve contains

axons of sensory neurons

The ________ of each spinal nerve innervates the skin and muscles of the back.

dorsal ramus

If the dorsal root of a spinal nerve is severed,

sensory input would be blocked

The complex, interwoven network formed by contributions from the ventral rami of neighboring spinal nerves is termed a


The ________ nerve, which arises in the cervical plexus, innervates the diaphragm.


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