CH 7-10 Test Bank

How many pairs of spinal nerves are there in each vertebral level?

8 cervical, 12 thoracic, 5 lumbar, 5 sacral, 1 coccygeal

The ___ division of the nervous system brings sensory information to the central nervous

afferent

The part of the peripheral nervous system that brings information to the CNS is the

afferent division

Increased sodium ion concentration in the body can be caused by which adrenal hormone?

aldosterone

The all-or-nothing principle states that

all stimuli great enough to bring the membrane to threshold will produce identical action potentials

Steroid hormones

bind to intracellular receptors

Which of the following events causes the depolarization of the post-synaptic membrane at a cholinergic synapse?

binding of ACh to sodium channels

Neurons that have one axon and one dendrite with the cell body between them are called

bipolar

The release of PTH is controlled by

blood calcium ion levels

The enzyme acetylcholinesterase causes ACh to

break down

An important second messenger in hormonla action is

cAMP

Increased levels of the hormone ____ will lead to decreased levels of calcium ions in the blood

calcitonin

PTH stimulates the kidneys to form

calcitriol

Which of the following hormones is secreted by the kidneys in response to the presence of PTH?

calcitriol

The parathyroid (chief) cells of the parathyroid glands monitor the concentration of which of the following circulating ions?

calcium

Low ____ concentrations are dangerous because ____ permeabilities increase and muscle cells and neurons become extremely excitable

calcium; sodium

Muscle cells

can only contract

Generally, the actions of hormones

can produce complex changes in physical structure and physiological changes

Which of the following is characteristic of cardiac muscle?

cardiac muscle cells are striated

The gray matter of the spinal cord is dominated by

cell bodies of neurons and glial cells

All hormones are

chemical messengers

Which cells produce PTH?

chief cells

Branches that sometimes occur along the length of an axon are called

collaterals

During which phase is the stimulus frequency so high that the relaxation phase is eliminated?

complete tetanus

Peptide hormones are

composed of chains of amino acids

Which of the following terms defines a force that tends to push an object away from the source of the applied force?

compression

Multiple areas of the brain can regulate breathing at the same time by stimulating the diaphragm for contraction. This activity is best explained by

convergent neuronal pools

Cells of the adrenal cortex produce

corticosteroids

One adrenal hormone that affects glucose metabolism is

cortisol

The branching structures that, together with the cell body, are sensitive to chemical, mechanical, or electrical stimulation are called

dendrites

Opening of voltage-gated sodium channels in the membrane of a neuron results in

depolarization

Which of the following structures convey motor commands into the spinal cord?

descending tracts

This condition develops when the posterior pituitary no longer releases adequate amounts of ADH

diabetes insipidus

Which neuronal pool ocurs when information spreads from one neuron to several neurons?

divergence

Which of the meninges of the brain consists of two fibrous layers?

dura mater

List the three meninges in order, from the outermost to the innermost

dura mater, arachnoid, and pia mater

In adults, the spinal cord usually extends to which level

first or second lumbar vertebra

Which of the following targets the gonads?

follicle-stimulating hormone

Changes in the membrane potential that cannot spread far from the site of stimulation are called

graded potentials

Regarding muscle fiber elongation:

gravity may help lengthen a muscle fiber after elongation

Axons that cross from one side of the spinal cord to the other are found in the

gray commissures

Which of the following phenomena is a hormonal effect of PTH?

increased calcium concentration in body fluids

Which of the following events is a result of calcitonin secretion?

inhibition of osteoclasts

Unlike other hormones, T3 and T hormones require _____ for production

iodine

Glycolysis

is an anaerobic process

In general, the nervous system

is fast acting

Saltatory conduction

is faster than conduction on an unmyelinated axon

The nervous system

is ideal for crisis management

The hormone oxytocin

is involved in the milk "letdown" reflex

Which of the following statements correctly defines tension?

it is a force to an object that tneds to pull the object toward the source of the force

The target organs fro the PTH and calcitionin are

kidneys, bone, and digestive system

cyclic AMP often causes activation of

kinase enzymes

Which of the following occurs when glycolysis produces pyruvate faster than it can be used by the mitochondria?

lactic acid is produced

Calcium ions are released from the sarcoplasmic reticulum during the ____ phase of contraction

latent

In which of the following phases of a twitch is no tension produced by the muscle fiber?

latent period

Regarding lactic acid regulation, which cells in the body consume extra oxygen and produce ATP for the conversion of excess lactate absorbed from the blood back to glucose?

liver cells

During continuous conduction

local currents depolarize adjacent areas of membrane so that action potentials continue along the membrane

Which adrenal region produces epinephrine and norepinephrine?

medulla

The hormone responsible for daily changes in physiological processes that follow a day-night pattern is

melatonin

Which hormone is a very affective antioxidant, one that may protect CNS neurons from free radicals such as NO or H2O2?

melatonin

Which of the following hormones is an amino acid derivative?

melatonin

Aldosterone is the principal

mineralcorticoid

The outer zone of the adrenal cortex produces

mineralcorticoids

Which of the following adrenal hormones accelerate the urinary loss of potassium ions?

mineralcorticoids

The bloodstream normally contains how much thyroid hormone?

more than a week's supply

The specialzied sarcolemma that contains ACh receptors is the ___

motor end plate

Which of the following parts of a neuromuscular junction is a specialized portion of the sarcolemma that contains receptors for ACh?

motor end plate

Neurotransmitters that cause skeletal muscle contraction are normally stored in:

motor neuron axon terminals

Neurons that have two or more dendrites and a single axon extending away from the cell body are called

multipolar

The additional oxygen required during the recovery period to restore the normal pre-exertion levels is called the

oxygen debt

The effect of prolactin closely interacts with the hormone

oxytocin

The posterior pituitary gland stores

oxytocin

Which of the following hormones stimulates smooth muscle contrations in the uterine wall during labor and delivery?

oxytocin

The hormone that causes the activation of osteoclasts is

parathyroid hormone PTH

Which of the following hormones bind to membrane receptors and activate G-proteins?

peptide hormones

Muscle fasicles are separated by

perimysium

All of the nervous tissue outside of the CNS comprises the

peripheral nervous system

Which property of the sarcolemma is affected by the neurotransmitter ACh?

permeability

Which of the following substances inactivates cyclic AMP?

phosphodiesterase

The ____ is the layer of the meninges that is in direct contact with the surface of the brain

pia mater

Melatonin is the hormone produced by the

pineal gland

Excessive urine production, which is a characteristic symptom of all forms of diabetes, is known as

polyuria

Which of the following is an accurate characterisitc of slow fibers?

resting slow muscle fibers contain oxygen reserves, bound to myoglobin

An action potential jumps from node to node in

saltatory propagation

The skeletal muscles store calcium ions in the terminal cisternae of the

sarcoplasmic reticulum

Which of the following statements describes how muscles help maintain homeostasis?

skeletal muscle contractions help maintain body temperature

The active sites on actin molecules are usually covered up by other molecules. What is the critical material required to uncover the active sites on the actin molecules that will then bind to myosin heads?

calcium

Which of the following is a function of the efferent division of the nervous system?

sending signals to muscles

In response to action potentials arriving from the transverse tubules, the sarcoplasmic reticulum releases

calcium ions

Which of the following structures is a specialized form of smooth endoplasmic reticulum that forms a tubular network around each myofibril?

sarcoplasmic reticulum

The hormone that inhibits osteoblasts is

PTH

A resting muscle generates most of its ATP by

aerobic respiration

The resting potential of a neuron is

-70 mV

Muscular System Functions

1. move the skeleton 2. maintain posture and body position 3. support soft tissues 4. guard entrances and exits 5. maintain body temperature

Each myofibril consists of approximately ____ sarcomeres

10,000

Place these steps of muscle contraction in the correct order: 1. action potential is generated along the sarcolemma 2. nerve impulse arrives at synapse 3. calcium is released into muscle cell cytoplasm 4. ACh is produced 5. actin and myosin molecules continuously cross-link, with actin molecules being pulled inward

2, 4, 1, 3, 5

Identify the correct sequence of steps in the generation of an action potential 1. activation of sodium channels and rapid depolarization 2. inactivation of sodium channels and activation of potassium channels 3. depolarization to threshold 4. closing of potassium channels

3, 1, 2, 4

The entire spinal cord is divided into ___ segments

31

Which of the following is the correct order of events that occur at a cholinergic synapse? 1. extracellular calcium enters the axon terminal, triggering the exocytosis of ACh 2. ACh is removed by acetylcholinesterase 3. ACh binds to receptors and depolarizes the postsynaptic membrane 4. axon terminal depolarizes

4, 1, 3, 2

Communication between hormones and cells sometimes uses both first and second messengers. The link between first messenger and second messenger is usually

A G-protein enzyme

The region of a sarcomere containing myosin, going from one end of the mysoin molecules to the other end of the myosin molecules, is the

A band

The thick filaments of sarcomeres are contained in which band?

A band

The pituitary hormone that controls the release of glucocorticoids is

ACTH

Which of the following neurotransmitters usually depolarizes postsynaptic neurons?

ACh

Which of the following is one of the steps that ends a contraction?

ACh is broken down by acetylcholinesterase

Upon the nerve impulse arriving at the axon terminal

ACh is released

Which of the following substances is a hormone stored and released by the posterior lobe of the pituitary gland?

ADH

The stiffness that occurs at death, when actin and myosin molecules stay linked to each other in a contracted state, is due to a lack of

ATP

Which of the following statements describes the cause for the cessation of an action potential?

Acetylcholinesterase breaks down ACh

Two hormones are referred to as gonadotropins:

FSH and LH

The brain and spinal cord comprise the

CNS

The central canal of the spinal cord is filled with

CSF

Which of the following structures is composed of a layer of collagen fibers that separates a muscle from surrounding tissues and organs?

Epimysium

The pituitary hormone that stimulates the breakdown of stored fats and the release of fatty acids into the blood is

GH

Which statement regarding GH is true?

GH stimulates the breakdown of stored fats and the release of fatty acids into the blood

The area of the sarcomere that is the light region between two successive A-bands is the

I band

Which cells are responsible for distribution of sensory information and the coordination of motor activity within the CNS?

Interneurons

The pituitary hormone that promotes testosterone release in males and ovulation in females is

LH

Which of the following hormones is a pituitary hormone that induces ovulation?

LH

Which of the following structures is composed of proteins that connect the central portions of each thick filament to its neighbors?

M line

Which of the following hormones is secreted by the human pituitary during fetal development in very young children and in pregnant women, but is not usually found in adults?

MSH (melanocyte stimulating)

Which statement regarding "heat loss" is true?

Muscle contractions play an important role in the maintenance of normal body temperature

The neurilemma of axons in the PNS is the outer layer of

Schwann cells

Which of the following cells cover every axon outside the CNS?

Scwann cells

Choose the correct statement regarding motor units

a motor neuron may control only two or three muscle fibers of the eye muscles

When a protein or peptide hormone binds to receptors on the surface of a cell,

a second messenger appears in the cytoplasm

Myofibrils are made primarily of

actin and myosin

The striated appearance of skeletal muscle results from

actin and myosin arrangement

The hormone leptin is secreted by

adipose tissues

Melatonin and epinephrine are examples of which of the following hormone groups?

amino acid derivatives

A broad sheet formed by the collagen fibers of the connective tissues of skeletal muscle is called

an aponeurosis

Target cells of hypothalmic releasing and inhibiting hormones are located in the

anterior pituitary

Which of the following is released by the posterior pituitary?

antidiuretic hromone (ADH)

Interneurons

are found only in the CNS

Smooth muscle cells

are spindle-shaped

Steroid hormones

are structurally similar to cholesterol

You have been diagnosed with the demylinating disease called MS. The areas of damage seem to be centered within the spinal cord. The demyelinated areas are most probably within the

ascending and/or descending tracts

The glial cells responsible for maintaining blood-brain barrier are the

astrocytes

The largest and most numerous of the glial cells in the CNS are the

astrocytes

Where does an action potential in a neuron begin?

at the axon hillock

A few spiders produce a venom that is calcium-channel blocker. Where would this venom have on nerve impulse transmission?

at the axon terminal

Which of the following phrases best describes the cyclical actions of a myosin cross-bridge during a muscle contraction?

attach, pivot, detach, and reactivate

The ___ nervous system provides involuntary regulation of smooth muscle, cardiac muscle, and glandular activity.

autonomic

Which nervous system division is also called the "visceral motor system"?

autonomic nervous system

Which of the following structures controls individual muscle fibers?

axon (nerve fiber)

The _____ contains vesicles filled with ACh

axon terminal

The somatic nervous system is part of the

efferent division of the PNS

Which of the following structures surrounds each skeletal muscle fiber and ties adjacent muscle fibers together?

endomysium

Which neuroglial cells produce CSF in some regions of the brain

ependymal cells

A layer of collagen fibers that surround an entire muscle is called:

epimysium

One hormone that is released from the adrenal medulla is

epinephrine

Diabetes insipidus can be caused by

failure of the kidneys to respond to ADH

When calcium ion concentrations ____ normal, the ___ cells of the parathyroid glands secrete PTH

fall below; chief

Fast fibers

have high glycogen reserves

Skeletal muscle fibers differ from "typical cells" in that these muscle fibers

have many nuclei

The chemical messengers of the endocrine system are called

hormones

The projections of gray matter extending through the white matter toward the outer surface of the spinal cord are called

horns

In the simplest case, endocrine activity may be controlled by changes in the extracellular fluid composition called ____ stimuli

humoral

A stimulus that opens gated potassium ion channels, moving the membrane voltage value below the resting potential value, results in which of the following?

hyperpolarization

The term used to describe muscular growth in response to usage is

hypertrophy

Hypothalamic signals reach the anterior pituitary thourhg the

hypophyseal portal system

Hormones from the ____, which travel in the hypophyseal portal vessels, alter the activity of the anterior pituitary

hypothalamus

The highest level of endocrine control is provided by the

hypothalamus

Where are the hormones secreted by the posterior pituitary made?

hypothalamus

Which of the following structures acts as an endocrine organ by synthesizing ADH and oxytocin?

hypothalamus

Regulatory hormones produced by the ____ control the activities of the ___ pituitary

hypothalamus; anterior

Which statement is true regarding action potential propagation?

in saltatory conduction, the myelin is composed of fat, which insulates the axon membrane against sodium ion flow across the membrane

Enlargements of the spinal cord occur

in the cervical and lumbar regions

The thyroid gland stores thyroid hormones ____

in the colloid of the follicles

If the dorsal root of a spinal nerve is severed

incoming sensory information would be disrupted

Exhaustion of energy reserves or decline in pH due to production and dissociation of lacticc acid causes

muscle fatigue

Which statement regarding the relaxation phase of a muscle twitch is true?

muscle tension falls to resting levels

Which of the following helps maintain body position by tensing and firming a muscle even when the entire muscle is not contracting?

muscle tone

Which of the following occurs as a result of motor units in a particular muscle being always active, even though their contractions do not produce enough movement to cause contraction?

muscle tone

Hormone concentration levels are most commonly controlled by

negative feedback

The endocrine system is regulated primarily by

negative feedback control mechanisms

The hypothalamus transports hormones to the posterior pituitary by way of

neural axons, directly

Clusters of RER and free ribosomes are known as

nissl bodies

Adrenergic synapses release the neurotransmitter

norepinephrine

The myelin sheaths that surround the axon of some of the neurons in the CNS are formed by

oligodendrocytes

Marissa had her entire thyroid gland removed because of a malignant tumor. She takes synthetic thyroid hormone to replace the thyroxine that her thyroid gland would have produced. but she is worried about her blood calcium. Does she need to be worried about this problem?

possibly, it depends on whether the parathyroid glands were taken with the thyroid by accident

Sensory nuclei are found in which of the following parts of the spinal cord?

posterior gray horn

Which hormone of the anterior pituitary gland works with other hormones to stimulate mammary gland development?

prolactin (PRL)

A target cell's sensitivity to a given hormone results from the presence or absence of a specific

receptor

Which of the following is true about red muscles?

red muscles are slower than white muscles

Hypothalmic hormones that stimulate the synthesis and secretion of one or more hormones in the anterior lobe are called

releasing hormones

The endocrine system

relies on the release of chemicals that bind to target cells

The membrane potential of an unstimulated cell is known as its

resting membrane potential

Which statement regarding skeletal muscle is true?

skeletal muscles contain blood vessels

A person whose genetic makeup makes him or her a better marathon runner than a sprinter probably has more _____ in his or her leg muscles

slow fibers

The effects of hormones may be ____ to appear, and they often persist for ____

slow; days

Nonstriated, involuntary muscle is

smooth

The suddent rush of which ion into the sarcoplasm produces an action potential in the sarcolemma?

sodium

Which of the following systems provides control over skeletal muscle contractions?

somatic nervous system

Which of the following hormones enter a cell by diffusion

steroid hormones

In the regulation of GH production, somatomedins ____ GH-IH and ____ GH-RH

stimulate; inhibit

Aldosterone, the principal mineralcorticoid, ____ the conservation of sodium ions and the _____ of potassium ions

stimulates; elimination

Which of the following contains a delicate network of collagen and elastic fibers through which CSF circulates?

subarachnoid space

Creatine phosphate serves to

supply energy to synthesize ATP

Acetylcholinesterase is found within the

synaptic cleft

Which of the following synapse structures contains neurotransmitters?

synaptic vesicles

Peripheral structures sensitive to presence of hormones are called

target cells

Which statement is true about the adrenal glands?

the adrenal cortex is most important in the control of sodium, potassium, and glucose blood levels

Head injuries that damage cerebral blood vessels are serious conditions because

the blood could compress and distort the relatively soft tissues of the brain

The heart has to be able to regulate its contractions. Heart muscle, unlike skeletal muscle, cannot go into a tetanus. This is because

the heart muscle has to be able to consistently contract and pump blood in a controlled fashion

The amount of tension produced by an individual muscle fiber depends solely upon which of the following factors?

the number of pivoting cross-bridges

Which statment is true about the pituitary?

the pituitary hormones all work by activating G proteins and triggering cAMP within cells

Regarding a skeletal muscle fiber, wherever a T-tubule encircles a myofibril, the tuble is tightly bound to:

the sarcoplasmic reticulum

Which statement regarding isometric contractions is true?

the tension produced never exceeds the load

Which statement is true regarding steroid hormones?

they can alter the rate of mRNA transcription

How do skeletal muscle contractions cause movement of the bones?

they pull on tendons

Myosin molecules are found in which of the following structures?

thick filaments

Which endocrine gland stores its hormones in follicle cavities?

thyroid

Hormones from which of the following glands are responsible for the calorigenic effect?

thyroid gland

Triiodothyronine is hormone secreted by the

thyroid gland

Bundles of CNS axons that share a common origin, destination, and function are called

tracts

During a skeletal muscle contraction, calcium binds to which molecule?

troponin

Tropomyosin strands are held in position by which of the following?

troponin molecules

A single stimulus-contraction-relaxation sequence in a muscle fiber is known as a

twitch

Thyroid hormones are derived from the amino acid

tyrosine

In which type of cells are the dendrites and axon continous, with the cell body lying off to one side?

unipolar neurons

Smooth muscle

uses primarily aerobic metabolism

Another name for antidiuretic hormone is

vasopressin

Which of the following spinal cord structures contain the axons of CNS motor neurons that control muscle and glands?

ventral roots

Which spinal cord structure contains the axons of the CNS motor neurons that control muscles and glands?

ventral roots

Action potentials are generated by the opening and closing of which of the following channels?

voltage-gated sodium and potassium channels

Disorders associated with thyroid hormone excess have symptoms related to

weight loss

Most neurons lack centrioles. This observation explains

why such neurons cannot divide through mitosis

A bundle of muscle fibers is a

fascicle

A muscle ____ contains a sarcolemma, sarcoplasm, myofilaments, and myofibrils.

fiber

During moderate activity, which of the following is true regarding muscle metabolism?

glucose and fatty acids are catabolized

A muscle producing almost peak tension during rapid cycles of contraction and relaxation is said to be in

incomplete tetanus

Which of the following occurs when tension production rises to a peak and very brief periods of relaxation occur?

incomplete tetanus

"Anaerobic endurance"

is exemplified by contractions of fast muscle fibers

Small phagocytic glial cells, which are derived from white blood cells are called

microglia

During activities requiring anaerobic endurance

most of the muscle's energy is produced in mitochondria

Why do individual muscle twitches have to be added together, as in summation or tetanus?

multiple twitches add up to an increase in muscle fiber tension, which increases the strength of the muscle

Most neurons in the brain are

multipolar

A traid is a

pair of terminal cisternae of the SR with a T tubule between them

A sheath of connective tissue surrounding a bundle of striated muscle fibers is called

perimysium

The area between Z lines is the ___

sarcomere

The repeating functional unit of a myofibril is the

sarcomere

The terminal cisternae are structural features of the

sarcoplasmic reticula

As a skeletal muscle contraction is initiated, ACh binding alters the motor end plate membrane's permeability to

sodium ions

What is the function of the transverse tubules?

to transmit electrical impulses to the cell's interior