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