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419 Cards in this Set

  • Front
  • Back
Four physiological properties of muscle tissue:
- contractility
- extensibility
- elasticity
- excitability (or irritability/responsiveness)
ability of a muscle to shorten or contract

(irritability or responsiveness)
capacity to receive and respond to stimulus
ability to be stretched
ability to return to original shape after being stretched or contracted
extensibility + contractility =
Three functions of muscle tissue
- movement
- posture
- thermogenesis (heat production)
Movement function of muscle tissue in smooth muscle
e.g., rhythmic contractions move food along the gut
Movement function of muscle tissue in cardiac muscle
contractions that pump blood to the entire body
Movement function of muscle tissue in skeletal muscle
contractions to move parts of the body
How do muscles help maintain posture?
muscle contractions help hold body in place (e.g. in sitting or standing position)
How do muscles assist in thermogenesis?
muscle contractions generate a large portion of body heat
Muscles can also determine:
size of an organ (e.g., uterus before or during pregnancy, stomach when full or empty)
myofiber =
muscle cell
Myofibers (muscle cells) are surrounded by
A fascicle is
a bundle of muscle cells (myofibers)
Fasciculi are surrounded by
An entire muscle is surrounded by
- Epimysium
- Perimysium
- Endomysium
- surrounds entire muscle
- surrounds a fascicle
- surrounds a muscle cell/muscle fiber/myofiber
Skeletal muscle is also called
- voluntary muscle (conscious control) or
- striated muscle (alternating stripes)
The endomysium surrounds
one muscle cell (myofiber)
Most skeletal muscles are attached
to the skeleton (duh!)
Describe the nucleus of a skeletal muscle cell
skeletal muscles are multinucleated, thus have several to many nuclei per cell
What is sarcolemma?
the membrane of the muscle cell (under the endomysium)
What is sarcoplasm?
the cytoplasm of a muscle cell
(surrounds the bundles of myofibrils within a muscle cell (myofiber)

contains calcium-storing sarcoplasmic reticulum, the specialised endoplasmic reticulum of a muscle cell
What are T-tubules?
(a.k.a. transverse tubules)

tubes from the sarcolemma to the sarcoplasm

carry the signal (stimulus) for contraction deep into the sarcoplasm
What are myofibrils?
tubules or cylinders within the muscle cell that shorten/contract
Composition of a myofibril?
- enclosed by sarcoplasmic reticulum for calcium storage
- contain myofilaments (actin and myosin)
Describe the makeup of the thin filaments comprising the myofibrils of a skeletal muscle.
composed of three proteins:
- actin
- troponin
- tropomyosin
What is actin?
the majority protein in the thin filament of the myofibril
What myofilaments comprise a myofibril?
actin and myosin
What is the function of troponin?
binds calcium and holds the troponin-tropomyosin complex in position
What is the function of tropomyosin?
prevents the myosin and actin from interacting
What proteins make up the thin filaments of a myofibril?
- actin
- tropomyosin
- troponin
What is cardiac muscle?
the heart muscle or
Describe cardiac muscle
- striated
- involuntary
By what means is cardiac muscle controlled?
by the actions of hormones and neurotransmitters
Another name for smooth muscle
visceral muscle
Why is smooth muscle also called visceral muscle?
because it lines the walls of hollow organs and other internal structures (e.g., arteries, veins, uterus, stomach, intestines)
Where else is smooth muscle found?
in the skin (arrector pili muscles that give you goosebumps)
Describe smooth muscle
- non-striated
- involuntary
By what means is smooth muscle controlled?
by hormones and neurotransmitters
Each individual myofiber (muscle cell) consists of:
- sarcolemma (plasma membrane)
- sarcoplasm (cytoplasm containing many mitochondria)
- myofibrils (comprised of myofilaments)
Why does skeletal muscle appear striated?
because of the overlapping arrangement of
- thick myofilaments (composed of myosin) and
- thin myofilaments (composed mainly of actin, but also troponin and tropomyosin)
What protein makes up the thick myofilament in a myofibril?
Thick filaments contain
- a head
- a hinge
- a tail
What is a cross bridge?
occurs when the myosin heads interact with the thin filaments during muscle contraction
Why is the hinge in the thick filament important?
allows the head to pivot, enabling muscle contraction
What theory governs muscle contraction?
the Sliding Filament Theory
What is fascia?
a network of connective tissue that surrounds skeletal muscle
Where is superficial fascia found?
- scalp
- palm
- sole
Where is deep fascia found?
- between muscles
- around blood vessels
Myofibers are innervated by
motor neurons
What is a motor unit?
an alpha motor neuron and the muscle fibers it innervates
What is a synaptic cleft?
an area where neurons dump neurotransmitters
Between what structures can synaptic connections occur?
neuron-gland (neuroglandular)
neuron-muscle (neuromuscular junction)
neuron-neuron (neuroneuronal)
A synapse is a neural connection containing
a presynaptic ending that contains neurotransmitters, mitochondria and other cell organelles

a postsynaptic ending that contains receptor sites for neurotransmitters

a synaptic cleft or space between the presynaptic and postsynaptic endings
What law governs muscle contraction?
All or None Principle
What protein makes up the thick myofilament of a myofibril?
The striations/bands appearing across the longitudinal axis of a myofiber consist of what two bands?
- A bands (anisotropic bands) made of overlapping myosin and actin strands (dark bands)
- I bands (isotropic bands) made of actin (light bands)
Within the A band is a lighter zone called the
H zone

(only myosin, no actin)
Within the I band is a dark line called the
Z line or Z disc
What is a sarcomere?
the functional unit of the myofilament that extends from Z line to Z line

the actual functioning unit/fundamental unit of the myofiber
Sarcomeres link together to form
What causes muscle contractions?
the thick and thin filaments forming crossbridges and pulling together
How wide is the A band?
the width of the myosin (thick) filament
Another name for A band
dark band
The distance from Z line to Z line is called a
A band
I band
H zone
- actin and myosin
- actin only, no myosin
- myosin only, no actin
Describe the nuclei of skeletal muscle

located peripherally
Width of myosin filament
A band
Between A bands
I band
Boundary between 2 sarcomeres
Z line (disc)
What is the M line?
the middle of the sarcomere (and of the A band and H zone)

composed of protein
How many T-tubules encircle each sarcomere?
What is the function of the T-tubules?
carry action potential (polarity change) from neuromuscular junction to sarcoplasmic reticulum to increase its permeability and induce release of Ca++
Striations in skeletal and cardiac muscle can be generally said to be due to
alignment of the A and I bands; specifically due to the Z lines where thin filaments interconnect
Is glycolysis aerobic or anaerobic?
Does acetylcholine (ACh) keep the heart rate high or low?

What substance has the opposite effect?

What structure allows impulses to travel from the SA node to the left atrium and left and right ventricles?
intercalated discs
What is the Sliding Filament Theory?
the explanation for the changes that occur during muscle contraction

cross bridges between myosin and actin filaments help the filaments slide past each other, producing contraction
Cardiac muscle is also called
What is a motor unit?
a functional structure composed of a neuron and the muscle fibers that it innervates
What is a neuromuscular junction?
the junction between a motor nerve ending and a muscle fiber
What is a synaptic cleft?
a tiny gap between the nerve endings (axon terminals) and the sarcolemma of the myofiber
What is the All or None Principle?
the ability of a muscle fiber to contract fully or not at all
What is the threshold stimulus?
the minimal nervous stimulation needed to cause a muscle fiber to contract
What governs the strength of a muscle contraction?
- how many myofibers/motor units are stimulated (number)
- size of motor units stimulated (size)
- frequency of stimulation of muscle fibers (frequency)
What is summation?
contraction of varying numbers of muscle fibers at once, varying by number or size of motor units stimulated or frequency of stimulation

more myofibers involved or more frequent stimulation of them produces stronger muscle contraction
What is the recovery period after a contraction called?
refractory period
What are the sources of energy for muscle contraction?
- direct energy source is ATP

- indirect energy sources are:
----creatinine phosphate
All energy sources for muscle contraction depend on the breakdown of
ATP into ADP and Pi
Five types of muscular contraction
- twitch
- isotonic
- isometric
- treppe
- tetanus
What is a twitch?
a momentary contraction of a muscle in response to a single stimulation (electrical current)
What is an isotonic contraction?
a type of contraction in which the muscle contracts by becoming thicker and shorter (e.g., running)
What is an isometric contraction?
a type of contraction in which a muscle develops tension, but remains the same length
What is treppe?
a type of contraction in which a rested muscle receives repeated stimulation over a prolonged period

the first few contractions increase in strength so that the myogram resembles an upward staircase
What is tetanus?
a continuous contraction of muscle; can be
- complete or
- incomplete
What is complete tetanus?
the muscle is in a steady state of contraction with no relaxation at all between stimuli, such as in lockjaw
What is incomplete tetanus?
when incomplete relaxations are evident between contraction
If treppe-like stimulation continues _______ occurs.
What is oxygen debt?
a state resulting from strenuous activity in which lactic acid is generated faster than oxygen can be brought to the muscle fiber
Muscle fatigue is a result of
strenuous activity during which the contraction becomes weak because not enough ATP is available.
What are slow-twitch muscles?
those containing a large amount of myoglobin

also called red muscle

(e.g., back muscles, latissimus dorsi)
What are fast-twitch muscles?
contain small amount of myoglobin

have many energy-producing mitochondria and many sarcoplasmic reticula supplying calcium

also called white muscle

(e.g., eye and hand muscles)
Describe cardiac muscle
- found only in the heart
- striated
- involuntary (controlled by hormones and neurotransmitters)
- branched
- cells are uninucleated
- organized myofibrils
- T-tubules at the Z line (vice at zone of overlap as in skeletal muscle)
- intercalated discs that strengthen the junction between cells and facilitate passing of impulses from one cell to another
Function of cardiac muscle depends on
- nervous impulse
- self-rhythmic contractions
Location of T-tubules in skeletal muscle
at the zone of overlap between A and I bands
Characteristics of sarcoplasmic reticulum of cardiac muscle
- lacks internal cisternae
- tubules are in contact with T-tubules and the cell membrane
Cardiac muscle thrives on ______ metabolism

consists of many mitochondria and myoglobin proteins
In which type of muscle can intercalated discs be found?
only cardiac muscle
What do the intercalated discs do?
- contain gap junctions and desmosomes

- location where electrical connection occurs between cardiac cells
What are pacemaker cells?
specialized cardiac muscle cells that time the contraction of cardiac muscle tissue

therefore, cardiac muscle tissue contracts without neural stimulation
Can cardiac muscle tissue have tetanic contractions?
In which type of muscle does contraction last longer, skeletal or cardiac?
Characteristics of smooth muscle
- uninucleated, nucleus at center
- tapered at each end
- cells are called fibers
- no pattern
- not striated
- no sarcomeres
- involuntary (controlled by hormones and neurotransmitters)
- no T-tubules
- myofibrils not arranged in organized manner
- contain myosin and actin (and tropomysin) with the actins attached to dense bodies (anchors)
- troponin is absent
- cells attached to each other at their dense bodies
Two types of smooth muscle contractions
- tonic contractions - cause muscle to remain in partial state of contraction or tonus (e.g., in the stomach, intestine, sphincters)

- rhythmic contractions - pattern of repeated contractions produced by the presence of self-exciting muscle fibers from which spontaneous impulses occur (e.g., peristalsis)
What type of contraction is peristalsis?
rhythmic contraction of smooth muscle
At how many points do skeletal muscles attach?
What is the origin of a skeletal muscle?
the end of the muscle that is anchored (the less movable end)
What is the insertion of a skeletal muscle?
the more movable end
What is the general pattern of contraction for skeletal muscle?
the insertion moves toward the origin during contraction
What is the belly of a skeletal muscle?
the bulk of the muscle located between the origin and insertion
General functions of skeletal muscle
- move skeletal system/body
- maintain body position (posture)
- contribute to overall shape of body
- cover and protect some deeper tissues/organs
- open and close some body sphincters
- enable speech
- contribute to beginning of swallowing reflex
- physically move eyes
Another name for smooth muscle
visceral muscle
General functions of smooth muscle
- move material along various systems (e.g., digestive, urinary, respiratory, circulatory, reproductive)
- contribute to swallowing reflex
- focus the eye
- respond to autonomic nervous system (e.g., arrector pili muscles, eye responses)
- open and close some body sphincters
- enable certain organs to function
Function of cardiac muscle
to cause the heart to pump blood into the circulatory system
All muscle contraction (and its metabolism) produce
heat for the body
What is a motor unit?
a motor neuron and all the muscle fibers (myofibers/muscle cells) it stimulates/innervates
How does a muscle contraction start?
the CNS sends stimulus through the motor (efferent) nerves to distal axon endings adjacent to the muscle cell's sarcolemma
What occurs after the motor stimulus reaches the distal axon?
the stimulus causes the distal motor neuron to secrete a neurotransmitter (acetylcholine for skeletal muscle)
What neurotransmitter is secreted in response to a skeletal muscle motor stimulus?
What does the presence of acetylcholine on the sarcolemma trigger?
an action potential
What does an action potential do?
opens up channels in the sarcolemma and sodium ions enter the muscle cell in large amounts

causes muscle depolarization
What does the presence of sodium in the muscle cell cause?
it causes the action potential to travel down the T-tubules and trigger the sarcoplasmic reticulum to release calcium
An action potential traveling down the T-tubules causes
the sarcoplasmic reticulum to release calcium
What happens to the calcium released by the sarcoplasmic reticulum in response to an action potential from the T-tubules?
it binds to troponin
Calcium initiates
movement between actin and myosin

it initiates muscle contraction
Calcium binds to troponin, causing
tropomyosin to pull away from the active site, exposing positions on the actin filament for attachment of the myosin heads
Once tropomyosin pulls away from the active site, exposing positions on the actin filament
the myosin heads bind to the actin's active sites, creating cross bridges
What is created when a myosin head binds to an active site on the actin filament?
a cross bridge
Once the cross bridge is created, what happens next?
energy (from ATP) is released
What substance is needed to break the cross bridge between the myosin head and actin active site?
What moves toward each other causing muscle contraction?
Z lines
Strength of muscle contraction increases proportionally with
the number of cross bridges pulling on the thin filaments (actin's) active sites
When a muscle contracts, how many of the cross bridges are attached at a particular time?
only a fraction
What is the sarcoplasmic reticulum?
a type of endoplasmic reticulum (contains calcium)
Outline steps for stimulation of calcium release for muscle contraction
- neural stimulation
- neurotransmitter released into synaptic cleft (e.g. ACh)
- action potential created; depolarization of cell
- action potential travels across sarcolemma and down T-tubules
- stimulates sarcoplasmic reticulum to release calcium
- calcium binds to troponin and causes tropomyosin to reveal binding sites on thin fiber (actin)
- myosin head attaches to binding site
- contraction occurs
Describe function of T-tubules
- extensions from cell membrane (sarcolemma) that contain extracellular fluid
- run perpendicular to myofibrils
- assist action potential in penetrating deep into myofiber (muscle cell)
- adjacent to the sarcoplasmic reticulum
Where are the T-tubules located?
- there are 2 T-tubules on skeletal muscle cell

- they are at the A-band/I-band junction
How do muscles relax?
- an enzyme (acetylcholinesterase) breaks down acetylcholine (the neurotransmitter)

- calcium is released from troponin, which then returns to its former position and tropomyosin covers the active sites on the thin filament (actin)

- contraction ceases and the muscle cell is now repolarized

- the sarcoplasmic reticulum reabsorbs the calcium in the sarcoplasm
What is necessary for muscle contraction to continue?
- neural stimulation (with resulting action potentials) must continue

- calcium concentration from sarcoplasmic reticulum must remain high in the sarcoplasm
What does botulism do?
- blocks release of acetylcholine

(therefore a contraction cannot be generated)
What does tetanus do?
- blocks acetylcholinesterase

(therefore a contraction cannot be broken)
Strength of skeletal muscle contraction increases proportionally with
the number of cross bridges pulling on the thin filament (actin) active sites
A muscle cell is also called
muscle fiber

What is a twitch?
one contraction produced by one stimulus with a period of muscle relaxation to follow

a brief, involuntary muscle fiber contraction
What is summation?
- adding two or more twitches together to increase overall muscle contraction

- frequent repetition of stimuli used to cause a response
What is tetanus?
when stimulation to muscle arrives with such frequency that there is no relaxation between twitches

this produces a smooth and sustained contraction
What is tetanus complete (fused)?
no break in the contraction

no periods of relaxation

(approximately 100 contractions per second would do it)
What is tetanus incomplete (unfused)?
when small relaxations are seen between contractions

(seen even at 50 contractions per second)
The amount of muscle contraction and the strength and duration of the contraction are related to
- the amount/strength of stimulation
- the frequency of stimulation
- the number of muscle fibers involved in the contraction
- the actual anatomy of the muscle fibers involved (fast, slow)
- length of contraction
- type of contraction (isotonic, isometric, etc.)
What is tone?
- muscle firmness (or tension) when the muscle is relaxed (and not due to pathological or neurological problems)

- due to some level of motor unit stimulation within the muscle at all times

- helps keep body posture and balance
Range of muscle tone
hypertonic (good) to

hypotonic (poor)
What is treppe?
a.k.a. staircase

- when a muscle is stimulated to contract after relaxation, each successive contraction causes muscle tension to build and contraction becomes stronger (to a point--this is the principle applied when athletes "warm up")
What is an isometric contraction?
muscle tension increases, but no movement occurs
What is an isotonic contraction?
an actual muscle contraction

however, during the contraction the tension remains almost the same (e.g., weight lifting)
What is hypertrophy?
increase in muscle size (mass)
What is atrophy?
decrease in muscle size (mass)
What body structure monitors the body's CO2 level?
medulla oblongata
Describe rigor mortis
- a phenomena that occurs after death
- all cross bridges are attached
- there is no ATP to break the attachments
- enzyme released by lysosome destruction (after death) ends rigor mortis through breakdown of the muscle structure
What is the neuromuscular junction?
the union of the neuron's axon and the sarcolemma
What is the motor end plate?
specific part of the sarcolemma that is in contact with the terminal part of the neuron's axon
What is glycogen?
stored glucose
Describe resting muscle metabolism
- mostly aerobic (requiring oxygen)
- involves metabolism of fatty acids for ATP (via Kreb cycle of mitochondria)
Describe contracting muscle metabolism
- both aerobic and anaerobic (via glycolysis)
What is glycolysis?
breakdown of glycogen to glucose, then to pyruvic acid to produce ATP
Differentiate between aerobic and anaerobic glycolysis in creation of energy for muscle contraction
glycogen---->glucose----->2 pyruvic acid molecules

aerobic - to Kreb's cycle (and fatty acid metabolism, which mainly occurs in the cytoplasm)
anaerobic - to lactic acid and 2 ATP molecules
What happens following anaerobic muscle contraction?
conditions which produced the lactic acid are reversed and the muscle rests (recovery period)

lactic acid is converted by the liver into glucose (gluconeogenesis) or into ATP via pyruvic acid entering the Kreb's cycle)
What is creatinine phosphate?
an energy compound which contributes a phosphate (energy) for ADP; ADP then is restored to ATP
Which are the oxygen delivery proteins?
hemoglobin - part of RBC

myoglobin - present in muscle tissue
Characteristics of slow-twitch skeletal muscle fibers

(SO fiber - slow oxidative fiber)
- resistant to fatigue
- extensive blood supply--many capillaries
- many mitochondria (therefore function aerobically)
- lots of myoglobin thus muscle appears reddish
- smaller than fast-twitch fibers
- posture muscles
- short fibers

- small/short, red (myoglobin/capillaries), aerobic (more mitochondria/fatigue-resistant)
Characteristics of fast-twitch skeletal muscle fibers
- fatigue faster
- less extensive blood supply
- fewer mitochondria (therefore function anaerobically)
- fewer myoglobin proteins, thus muscle appears whiter
- larger than slow-twitch muscles
- active muscles
- densely packed myofibrils produce powerful contractions

- larger/powerful, white (less blood/myoglobin), anaerobic (less mitochondria/fatigue easier)
Are most skeletal muscles slow-twitch or fast-twitch?
most skeletal muscles have both fiber types in their composition
What are the three major actions of skeletal muscles?
- prime mover (agonist)
- synergist
- antagonist
What is a prime mover?
a skeletal muscle that contracts to give the person the action he/she desires

a.k.a. agonist
What is a synergist?
assists a prime mover (agonist) in producing the desired movement

prevents unwanted movement and helps prime mover/agonist work efficiently
What is an antagonist?
functions with an opposite contraction from the prime mover's (agonist's) desired contraction

when the prime mover is contracting, the antagonist muscle relaxes or offers little resistance

helps produce a smooth movement by slowly relaxing as the prime mover/agonist contracts
Can a muscle be a prime mover and an antagonist?
Yes, a muscle may be a prime mover for one movement and an antagonist for another

actually, in different conditions, the same muscle can act as prime mover, antagonist, synergist, or fixator
What are somatic afferent nerves?
carry sensory stimuli from skeletal muscle to CNS
What are somatic efferent nerves?
carry motor stimuli from CNS to skeletal muscle
What are visceral afferent nerves?
carry sensory stimuli from smooth or cardiac muscles to CNS
What are visceral efferent nerves?
carry motor stimuli from CNS to smooth or cardiac muscles
What is the latent period of muscle contraction?
a period of relaxation before contraction polarization
What is the contraction period of muscle contraction?
the period of of contraction/activation depolarization
What is the relaxation period of muscle contraction?
the period that follows activation repolarization
What is the refractory (recovery) period of muscle contraction?
a period of time during which the muscle will not respond to further stimulus

skeletal - short
smooth - medium
cardiac - prolonged
What is a tendon?
attaches muscle to bone
What is a ligament?
attaches bone to bone
What is aponeurosis?
a broad sheet that functions like a tendon, attaching muscle to bone
What is fibrillation?
rapid, irregular, and unsynchronized contraction of muscle fibers
What is convulsion?
muscles contract and relax rapidly and repeatedly, resulting in an uncontrolled shaking
What is a spasm?
sudden, involuntary contraction of a muscle
What is muscular dystrophy?
a group of muscle diseases that weaken the musculoskeletal system and hamper locomotion

characterized by progressive skeletal muscle weakness, defects in muscle proteins, and the death of muscle cells and tissue
What is muscular sclerosis?

multiple sclerosis?
I would imagine "muscular sclerosis" is some type of hardening of muscles

multiple sclerosis is an inflammatory disease in which the fatty myelin sheaths around the axons of the brain and spinal cord are damaged, leading to demyelination and scarring as well as a broad spectrum of signs and symptoms
What is myasthenia gravis?
an autoimmune neuromuscular disease leading to fluctuating muscle weakness and fatiguability

it is an autoimmune disorder, in which weakness is caused by circulating antibodies that block acetylcholine receptors at the postsynaptic neuromuscular junction, inhibiting the excitatory effects of the neurotransmitter acetylcholine on muscarinic receptors throughout neuromuscular junctions
What is myalgia?
muscle pain
What are adductors?
muscles that move bones toward the body
What are abductors?
muscles that move bones away from the body, generally in a lateral direction
What are flexors?
muscles that decrease the angle (at a joint) between bones
What are extensors?
muscles that increase the angle (at a joint) between bones
What are levators?
muscles that raise a part of the body
What are depressors?
muscles that lower a part of the body
What are the muscles in the quadriceps femoris group?
- rectus femoris
- vastus lateralis
- vastus medialis
- vastus intermedius
What are the muscles in the hamstring group?
- biceps femoris
- semitendinosus
- semimembranosus
What is the importance of fascicle arrangement within muscles?
the fascicles are organized in various patterns in different muscles

the pattern determines range of movement and power of the muscle
What are the four main patterns of muscle arrangement?
- strap
- fusiform
- pennate
- circular
Describe a strap muscle
fascicles are parallel to long axis

muscle has wide ROM, but is not powerful (e.g., rectus abdominis)
Describe a fusiform muscle
fascicles are spindle-shaped with a thick belly

(e.g., biceps brachii)
Describe a pennate muscle
fascicles are short in relation to muscle length and the tendon extends the entire length of the muscle
Describe a unipennate muscle
fascicles are on one side of the tendon

(e.g., extensor digitorum longus)
Describe a bipennate muscle
fascicles are on both sides of the tendon

(e.g., rectus femoris)
Describe a multipennate muscle
many oblique fascicles arranged along several tendons

(e.g., deltoid)
Describe a circular muscle
fascicles arranged in circular pattern around an opening or structure

(e.g., orbicularis oris/oculi)
What are pronators?
muscles that turn the forearm so the palm faces posteriorly
What are supinators?
muscles that turn the forearm so the palm faces anteriorly (anatomical position)
What are rotators?
muscles that move the bone around a longitudinal axis
What are sphincters?
muscles that reduce the size of an opening
What are tensors?
muscles that make body parts more tense
What is a fixator?
a muscle that provides a stable base for the action of the prime mover (agonist)
Most skeletal muscles accomplish action through a _______ ________.
lever system
How does the lever system work for skeletal muscles?
the bone acts as the lever arm (pivot)

the joint acts as a fulcrum (fixed point)
What are some bases for naming muscles?
- size (gluteus minimus/maximus)
- shape (deltoid, trapezius)
- location (supra/infraspinatus)
- action (extensor, levator)
What is the basic functional cell of the nervous system?
the neuron
What are the functions of neurons?
- respond to stimuli (excitability)
- conduct impulses (conductivity)
What does the PNS permit?
it allows the brain and spinal cord to communicate with the rest of the body
Autonomic =
Somatic afferent cells
carry information from eyes, ears, skin, skeletal muscle, joints, tongue, and nose etc. to CNS via the spinal and cranial nerves

at the conscious level, this sensory input is perceived as touch, pain, heat, cold, sound, sight, taste, and smell
Somatic efferent cells
carry information from the CNS to skeletal muscles and excite them to contract

this system regulates voluntary contraction of skeletal muscle
Visceral afferent
info from heart, lungs, digestive system, urinary organs, etc. to CNS
Visceral efferent
sympathetic/parasympathetic CNS to smooth and cardiac muscle, glands, and skin
What is the CNS?
the control center for the entire system

it receives, interprets, and integrates all stimuli and relays all nerve impulses to muscles and glands for appropriate action
What is the function of the brain?
it is the primary center for regulating and coordinating body activities

(the computer)
What is the function of the spinal cord?
the center of reflex action containing the conducting paths to and from the brain

(the tail of the brain)
What is the function of the PNS?
to convey impulses to and from the brain (cranial nerves) or spinal cord (spinal nerves)
What comprises the CNS?
brain and spinal cord
What comprises the PNS?
- Somatic Nervous System
- Autonomic Nervous System
-----Sympathetic Nervous System
-----Parasympathetic Nervous System

- afferent (sensory) division
- efferent (motor) division
What is the function of the afferent (sensory) nerves?
conduct information toward the CNS through the dorsal horn
What is the function of the efferent (motor) division?
conduct information away from the CNS and toward the periphery via the ventral horns
What is the structure and function of the Somatic Nervous System?
consists of efferent (motor) neurons that conduct impulses from the CNS to skeletal muscles

is under conscious control
What is the structure and function of the Autonomic Nervous System?
consists of efferent (motor) neurons that conduct impulses from the CNS to smooth muscle, cardiac muscle, and glands of the viscera and skin

also afferent (sensory) neurons that convey sensory information from the viscera (heart, respiratory organs, reproductive organs, digestive organs, and urinary organs) to CNS where they are consciously perceived as pain, smell, taste, urinary fullness, etc.

usually not under conscious control
What are the two divisions of the Autonomic Nervous System?
- Sympathetic Nervous System

- Parasympathetic Nervous System
What is the function of the Sympathetic Nervous System?
- fight or flight

- maintenance of homeostasis

- relaxes intestinal wall muscles; increases sweating, heart rate, and blood flow to skeletal muscle
What is the function of the Parasympathetic Nervous System?
- rest and digest

- sex, salivation, lacrimation, digestion, urination, defecation

- contracts intestinal wall muscles; decreases sweating, heart rate, and blood flow to skeletal muscle
What are the two categories of cells comprising the nervous system?
- neuroglial cells

- neurons
What is the function of neuroglial cells?
to support and protect the nervous system
What are the four types of neuroglia?
- astrocytes
- oligodendrocytes
- ependymal cells
- microglia
Description of astrocytes
- most numerous neuroglia
- star-shaped
- play a major role in transfer of materials to and from circulation (the blood-brain barrier)
- attaches neurons to their blood vessels
Description of oligodendrocytes
functions in myelination of the CNS

(= Schwann cells in PNS)

oligo - few, having little
Description of ependymal cells
cellular layer of epithelial cells that line the ventricles of the CNS, modified to produce cerebrospinal fluid; therefore are also cells of choroid plexus
Function and location of choroid plexus
- production of cerebrospinal fluid

- located in ventricles of brain
Description of microglia
small, phagocytic cells derived from connective tissue

play a role in the destruction of dead tissue and defense against microorganisms
Description of a neuron
- structural and functional unit of nervous system

- conducts action potentials
What is the cell body of a neuron?
- central portion
- contains nucleus, nucleolus and other organelles
What are Nissl bodies?
condensations of rough endoplasmic reticulum (RER) which form dark-staining bodies

clumps of highly basophilic cytoplasmic material found in the perikaryon (cytoplasm) but not in the axon hillock or axon

contain RNA and protein and function in protein synthesis
What are the components of a neuron?
- cell body
- axon
- dendrite
What are neurofibrils?
slender, rod-like structures composed of microtubules and fibrils

they play a role in cell support and release of neurotransmitters
What structures comprise the cell body of the neuron?
- Nissl bodies
- neurofibrils
- neurotubules
- nucleus
- nucleolus
Function of neurotubules
involved in intracellular transport
What are dendrites?
highly branched, short cell processes which conduct action potentials toward the cell body

they contain Nissl bodies
What are axons?
- a single, long cell process which conducts action potentials away from the cell body
- arise from axon hillock (cone-shaped portion of cell body)
- extends as a cylindrical process and terminates on other neurons or effector organs by a variable number of branches which end in small swellings called terminal buttons
- may be coated with myelin sheath to enhance conduction speed
- myelin sheath formed by Schwann cells (PNS) or oligodendrocytes (CNS)
- do not contain Nissl bodies
What is the myelin sheath?
a white, fatty covering of the axons produced by Schwann cells in the PNS or oligodendrocytes in the CNS

- insulates and protects the axons
What are Schwann cells?
cells that produce myelin in the PNS

a.k.a. neurolemma
Contrast Schwann cells and oligodendrocytes
Schwann cells produce myelin in the PNS

oligodendrocytes produce myelin in the CNS
Running is aerobic and involves
the Krebs cycle (via mitochondria)
Neurotransmitters are comprised of:
amino acids (proteins)
Neurotransmitters are released
into synaptic cleft in response to nerve impulses
When a cell is about to "work"
- Na+ moves in (depolarization)
- cell becomes positive inside and acquires action potential
excitatory post-synaptic potential

makes it easier for a nerve to fire an action potential

decrease polarization - positively charged ions flow into postsynaptic cell (or negatively charged ions flow out)

are graded (additive effect) in that one EPSP may not be sufficient to surpass the threshold for firing AP, but the sum of three together may be sufficient
inhibitory post-synaptic potential

makes it more difficult for a nerve to fire an action potential

increases polarization - negatively charged ions flow into postsynaptic cell (or positively charged ions flow out)

are graded (additive effect) in that one IPSP may not be sufficient to suppress firing of an AP, but the sum of three together may be sufficient
Neurotransmitters leave synapse by
- uptake
- enzymatic destruction
- diffusing into intracellular space
Function of dopamine
- makes you happy, pleasured
- skeletal muscle contraction
- increase muscle tone
- addictive
Function of seratonin
- increase appetite, then
- produce crash, making you sleepy
- calms you down
Function of norepinephrine
- increase heartrate
- open airways
What are the Nodes of Ranvier?
unmyelinated segments of an axon (between Schwann cells) where nerve impulses are produced
What is the neurolemma?
the outermost membrane, the cell membrane of a neuron's Schwann cell

it covers the myelin sheath
What is a synapse?
junction between two neurons

where end fibers of the axon of one cell body meet the end fibers of the dendrite of another
How are neurons classified?
by function and/or by structure

the functional (physiological) classification is according to the direction in which the impulse is traveling

the structural (anatomical) classification is according to the number of processes extending from the cell body
Direction of impulse travel for motor (efferent) neurons
from the CNS to the affected site
Direction of impulse travel for sensory (afferent) neurons
from the affected site to the CNS
What are interneurons?
found in CNS

connect sensory neurons to motor neurons
Functional neural classifications
- motor (efferent) neurons
- sensory (afferent) neurons
- interneurons (associate neurons)
Structural neural classifications
- multipolar neurons
- bipolar neurons
- unipolar neurons
How are neurons classified structurally?
by the number of processes extending from the cell body
Multipolar neurons
- most common type of neuron
- several dendrites and one axon extending from the cell body
(e.g., motor neurons, neurons of brain and spinal cord)
What is the most common neuronal structure?
Bipolor neurons
- have two processes
- one dendrite and one axon extending from the cell body
- relay information concerning special senses (exteroreception, interoreception, proprioception)
Unipolar neurons
- dendrite and axon are a single, continuous process and this process comes off the cell body
(e.g., one branch extends to the brain or spinal cord, and the other branch extends to the peripheral sensory receptor)
- sensory neurons are usually unipolar
What type of neuron is usually unipolar?
sensory neuron
What are receptors?
processes of specialized sensory neurons
What are the classifications of receptors?
- exteroceptors (outside)
- interoceptors (inside)
- proprioceptors
What are exteroceptors?
- located near the surface
- provide data about external environment
(e.g., touch, temperature, hearing, vision, smell, etc.)
What are interoceptors?
- provide information about the internal environment
- located in digestive, respiratory, cardiovascular, urinary, and reproductive systems
- sense deep pressure and pain
What are proprioceptors?
- provide information about the position and movement of skeletal muscles and joints

- where body is in space, even with eyes closed
Upon what does a nerve impulse depend?
on polarization and depolarization of the neuronal membrane (as seen in muscle contraction)
By what are membrane potentials indicated?
by the difference between the amount of ion concentration outside (and inside) the plasma membrane
Characteristics of a polarized neuron (resting state)
- K+ ions are highly concentrated inside the cell
- Na+ ions are highly concentrated outside the cell
Characteristics of a depolarized neuron (stimulated state)
- allows for transport of Na+ across the cell membrane and into the cell
- allows for transport of K+ across the cell membrane and outside the cell
What is the name for the mechanism that depolarizes neuron cells?
the sodium-potassium pump
What is repolarization?
when the ions return to the resting state (polarization)
What is the principal way by which neurons communicate?
via action potential
What is an action potential?
the principal means by which neurons communicate

it is initiated after depolarization has taken place
What is a refractory period?
the time a nerve needs to recover from the initial stimulus; during this time, it will not respond to a second stimulus
What is the "All or None Response" with respect to neurons?
a neuron will fire at full power or not at all

if a stimulus is strong enough to initiate an action potential, the impulse will travel along a neuron until its transmission is complete
What is saltatory conduction?
movement of a nerve impulse by jumping over myelinated Schwann cells from node of Ranvier to node of Ranvier

this is faster than smooth propagation

increases conduction velocity without having to increase diameter of axon
What is white matter?
group of myelinated nerve fibers and associated neuroglia
What is gray matter?
contains cell bodies and unmyelinated nerve fibers
What is a nerve?
a group of neurons located outside the CNS
What are tracts?
a group of nerve cells (neurons) located inside the CNS
What are ascending tracts?
a group of nerve cells (neurons) that conducts sensory impulses up the spinal cord to the brain
What are descending tracts?
conduct motor impulses down the spinal cord
What is a ganglion?
a collection of neuron cell bodies located in the PNS

a bundle of cell bodies and dendrites

may connect with other ganglia to produce a complex system of ganglia called a plexus

two major groups of ganglia:
- dorsal root ganglia
- autonomic ganglia
What is a nucleus?
a collection of neuron cell bodies located in the CNS
What are horns?
areas of gray matter located in the spinal cord
What are the two types of horns located in the spinal cord?
- dorsal (posterior) gray horns
- ventral (anterior) gray horns
What is the function of the dorsal (posterior) horns?
transmit sensory data to CNS
What is the function of the ventral (anterior) horns?
transmit motor data to PNS
What two bodily systems function to maintain homeostasis?
- endocrine system
- nervous system
How does the nervous system help maintain homeostasis?
by making proper responses to stimuli
How are stimuli received by the nervous system processed?
rapidly, though a combination of electrical impulses and chemical substances (neurotransmitters) for communication between
- nerves-nerves
- nerves-muscles
- nerves-glands
What are stimuli?
changes in the body's inner or outer environments
What are impulses?
nerve impulses or action potentials are electrochemical processes propagated along the nerve fibers
What are neurotransmitters?
chemicals synthesized within the nerve axon terminals, and released in the synaptic cleft by the transmissive segment of the presynaptic neuron in response to a nerve impulse

they are capable of changing the resting membrane potential in the plasma membrane of the receptive segment of the postsynaptic cell

(e.g., ACh, GABA, dopamine, norepinephrine, seratonin)
The CNS consists of:
- brain (protected by skull)
- spinal cord (protected by vertebral column)
The CNS is the body's...
central control system which receives, interprets, and integrates all stimuli, and relays nerve impulses to muscles and glands, where the appropriate action takes place
The PNS is composed of
nerve cells and their fibers emerging from and going to the brain (cranial nerves) and the spinal cord (spinal nerves)
The PNS allows the brain and spinal cord to
communicate with the rest of the body
The PNS is comprised of what two types of nerve cells?
- afferent/sensory nerve cells to carry impulses from the sensory receptor to the CNS

- efferent/motor nerve cells to carry impulses from the CNS to the effectors (muscles and glands)
What are the two functional divisions of the PNS?
(actually, of the efferent/motor division of the PNS)
- somatic nervous system
- visceral (autonomic) nervous system
What are the two properties of a neuron?
- excitability - ability to respond to a stimuli
- conductivity - ability to transmit a signal
Function of neurofilaments
provide skeletal framework for the axon
How does Alzheimer disease affect neurons?
many cell bodies in the cerebral cortex of the brain contain tangles of neurotubules and neurofilaments
Bipolar neurons
the neuron has only two processes
(e.g., neurons of the retina of the eye, or olfactory nerve)
Excitability of a neuron involves a change in
membrane permeability in response to appropriate stimuli, such that the ionic gradient is reversed and the plasma membrane becomes depolarized
A wave of depolarization that spreads along the plasma membrane of a neuron is called a(n)
action potential
What is a post-synaptic potential?
an electrical potential occurring when neurotransmitters interact with receptor sites on the postsynaptic membrane of neurons, muscle cells, or gland cells

they may be excitatory (EPSP) or inhibitory (IPSP)
What is a synapse?
a functional contact between
neuron-muscle or
Can severed peripheral nerves regenerate?
it may be possible if the cell body is undamaged and the myelin sheath is intact

(1 mm/day or about 1"/mo)
The characteristic of muscle tissue that allows it to shorten is called…
a. Contractility
b. Responsiveness
c. Excitability
d. Extensibility
a. contractility
The characteristic of muscle tissue that allows it to expand is called…
a. Extensibility
b. Contractility
c. Elasticity
d. Irritability
a. extensibility
All these properties pertain to muscle tissue except…
a. Elasticity
b. Contractility
c. Excitability
d. Coagulation
d. coagulation
One of these statements is untrue as far as skeletal muscle is concerned:
a. Skeletal muscle fibers are striated because of alternating patterns of thick myofilaments (myosin) and thin myofilament (actin).
b. Skeletal muscle cells are multinuleated
c. Skeletal muscle cells (myofibers) have several mitochondria
d. Skeletal muscle cells have sarcoplasmic reticulum to store sodium and to release potassium simultaneously
d. Skeletal cells have sarcoplasmic reticulum to store sodium and to release potassium simultaneously

(sarcoplasmic reticulum holds calcium)
The connective tissue that wraps the muscle cell (muscle fiber) is called…
a. Endomysium
b. Perimysium
c. Epimysium
d. Endoneurium
a. Endomysium
The connective tissue that covers the entire muscle is called…
a. Perimysium
b. Endomysium
c. Sarcolemma
d. Epimysium
d. Epimysium
The connective tissue that lies below the hypodermis is…
a. Periosteum
b. Perimysium
c. Epimysium
d. Superficial fascia
d. Superficial fascia
The connective, tissue that surrounds a bundle of myofibers or fascicles is…
a. Deep fascia
b. Superficial fascia
c. Perimysium
d. Chondroitin sulfate
c. Perimysium
A group of myofibers or muscle fibers is called…
a. Epineurium
b. Sarcolemma surrounding sarcoplasm
c. Osteosarcoma
d. Fascicles
d. Fascicles
All these types of muscles are involuntary except…
a. Smooth muscle
b. Cardiac muscle
c. Visceral muscle
d. Skeletal muscle
d. Skeletal muscle
All these organs contain smooth muscle except…
a. Uterus
b. Arteries
c. Stomach
d. Biceps brachii
d. biceps brachii
The pigment that stores oxygen in the muscle is called…
a. Myoglobin
b. Hemoglobin
c. Fast twitch muscle
d. Transverse tubules
a. Myoglobin
The thick myofilaments are composed of…
a. Actin
b. Myosin
c. Tropomyosin
d. Troponin
b. Myosin
The thin filaments will mostly consist of…
a. Myosin and actin
b. Actin, tropomyosin and troponin
c. Ribosome and lysosome
d. Fat vacuole and sarcolemma
b. Actin, tropomyosin, and troponin
The cell membrane of the myofiber is called…
a. Sarcoplasm
b. Smooth endoplasmic reticulum
c. Rough endoplasmic reticulum
d. Sarcolemma
d. Sarcolemma
The basic unit of the skeletal muscle cells is…
a. Sarcolemma
b. H zone
c. Sarcomere
d. A band
c. Sarcomere
This type of muscle has intercalated discs
a. Skeletal muscle
b. Visceral muscle
c. Cardiac muscle
d. Arrector pili
c. Cardiac muscle
Among all these types of muscle, the only nonstriated muscle is…
a. Myocardium or cardiac muscle
b. Smooth muscle or visceral
c. Skeletal muscles or voluntary muscles
d. None of the above
b. Smooth muscle or visceral
The A band is composed of…
a. Myosin and Actin
b. Myosin only
c. Actin only
d. Tropomyosin and troponin
a. Myosin and actin
The theory which governs muscle contraction is…
a. Frank-Starling theory
b. Henry-Ficks mechanism
c. River Analogy theory
d. Sliding-filament mechanism
d. Sliding filament mechanism
If you get involved in a body building competition, your muscles will undergo hypertrophy because of…
a. Hyperplasia of your muscle fibers
b. Increase in the number of myofibrils
c. Increase in the number of mitochondria
d. B & C
d. B & C
During weight lifting, the myofibers acquire most of their ATP through…
a. Aerobic cellular respiration
b. Anaerobic cellular respiration
c. Krebs cycle
d. Electron transport chain
b. Anaerobic cellular respiration
The source of energy for muscle fiber includes all these chemicals except…
a. Glycogen
b. Glucose
c. Creatine-phosphate
d. Cocaine & cellulose
d. Cocaine & cellulose
The chemical that inhibits the continuous stimulation of the myofiber…
a. Tropomyosin
b. Adrenalin
c. Acetylcholinesterase
d. Acetylcholine
c. Acetylcholinesterase
A motor unit consists of a motor neuron and…
a. All the myofibers that it innervates and stimulates
b. Epineuron and perineurium
c. Tropomyson and actin
d. Only I band
a. all the myofibers that it innervates and stimulates
All these statements are correct as far as muscle fatigue is concerned, except
a. Lack of glycogen
b. Drop in the level of oxygen
c. Decrease in the level of lactic acid
d. Lack of creatin phosphate
c. decrease in the level of lactic acid

(lactic acid increases during muscle fatigue)
The attachment of the head of myosin to actin will result in the formation of…
a. Crossbridges
b. Inertia of myosin
c. Covering of the binding sites by tropomyosin
d. None of the above
a. crossbridges
28. A single muscle contraction is called…
a. Isotonic
b. Bilateral
c. Treppe
d. Twitch
d. Twitch
29. The strength of muscle contraction depends upon…
a. Frequency of stimulation
b. Number of motor units involved
c. Strength of the stimulus
d. All the above
d. All of the above
Production of a staircase-like contraction due to immediate muscle stimulation after muscle relaxation called…
a. Isotonic
b. Isometric
c. Tetanus
d. Treppe
d. treppe
If you try to pick up a heavy object and you are unable to lift it at all, the contraction will be…
a. Isotonic
b. Tetanus complete (fused)
c. Tetanus incomplete
d. Isometric
d. isometric
32. Some sphincters contain smooth muscle.
a. True
b. False
a. True
All the sphincters are made up of smooth muscles
a. True
b. False
b. False

three examples: external urethral sphincter, external anal sphincter, orbicularis oris are made of voluntary skeletal muscle
The pulse reflects the contraction of smooth muscle on the walls of blood vessels
a. True
b. False
a. True
35. The ability of a muscle to contract fully after the stimulation reaches the threshold is called…
a. Law of all or none
b. Law of return to growth
c. Boyles law
d. Newton’s law
a. Law of all or none
The refractory period coincides with…
a. The recovery time
b. The active time
c. Dead space
d. None of the above
a. The recovery time
The walls of all these internal organs (stomach, jejunum, ileum, transverse colon, rectum, common bile duct, urinary bladder, fallopian tubes, uterus, vagina, vas deferens, arteries, and veins) will contain…
a. Striated muscles
b. Myocardium
c. Smooth muscle
d. Periosteum
c. Smooth muscle
Between the axon end bulb and the sarcolemma there is a groove (gap) were the neurotransmitters are released.
a. Interventricular sulcus
b. Synaptic cleft
c. Longitudinal fissure
d. Neuron-neuronal junction
b. Synaptic cleft
The connection between a neuron and a myofiber is called…
a. Junction
b. Synaptic cleft
c. Neurovascular network
d. Nervous plexus
a. Junction
Fast twitch muscle (fast glycolytic fibers (FG) on white fibers…
a. Have large amount of myofibrils and generate most rapid and powerful contraction
b. Has few mitochondria and few myoglobin
c. Contain glycogen and produce their ATP mainly through anaerobic glycolysis
d. All the above
d. all of the above
What type of skeletal muscle fibers are used for strength training exercise…
a. Fast glycolytic fibers on white fibers
b. Slow oxidative fibers or red fibers
c. Phosphonic fibers or methylated fibers
d. None of the above
a. Fast glycolytic fibers on white fibers
Why are red fibers called slow oxidative?
a. Because they produce their ATP mainly by aerobic respiration
b. Because they produce their ATP mainly by anaerobic glycolysis in their cytosol
c. Because they are large in diameter and contain few myofibrils
d. They do not have mitochondria
a. Because they produce their ATP mainly by aerobic respiration
A synapse can be a connection between…
a. Neuron and myofiber
b. Neuron and gland
c. Neuron and neuron
d. All the above
d. All of the above
Thermogenesis occurs during muscle contraction.
a. True
b. False
a. True
A single muscle cell is called…(note: 2 answers are correct)
a. Myofiber
b. Muscle fiber
c. Neurilemma
d. Sarcoplasm
a. Myofiber and
b. Muscle fiber
Muscle attaches to the bone by…
a. Ligament
b. Tendon
c. Bursae
d. Cartilage
b. Tendon
When a muscle has a short fascicle in relation to the tendon which extends the entire length of the muscle…
a. Strap
b. Pennate
c. Circular
d. Fusiform
b. Pennate
The primary mover muscles are also called…
a. Antagonist
b. Synergist
c. Agonist
d. None of the above
c. agonist
(also prime mover)
The principle muscle involved in the muscle action is…
a. Primary mover
b. Antagonist
c. Fixation
d. Fulcrum
a. primary mover
(also agonist)
Antagonist muscle…
functions with opposite contraction to prime mover/agonist
Synergist muscle…
assists prime mover/agonist in the desired movement
The muscle which increases the angle of a joint…
a. Flexor
b. Abductor
c. Rotator
d. Extensor
d. Extensor
The muscle involved in the movement further away from the midline…
a. Adductor
b. Supinator
c. Abductor
d. Pronator
c. Abductor
Muscle which increases the movement upward
a. Depressor
b. Levator
c. Compressor
d. Multiaxial only
b. Levator
When a muscle is stimulated 100 times per second, the contraction will be categorized as…
a. Tetanus incomplete (unfused)
b. Tetanus complete (unfused)
c. Tetanus incomplete (fused)
d. Tetanus complete (fused)
d. Tetanus complete (fused)
In order for the neurolemma to undergo depolarization
a. Extracellular sodium has to move into the intracellular compartment by using sodium channel.
b. sodium channel will avoid the influx of sodium into the cell
c. potassium channels will allow potassium, to move into the cells
d. no sodium or potassium channel will be involved only calcium ion channels will be in action.
a. Extracellular sodium has to move into the intracellular compartment by using sodium channel.
a. Allow the liver to convert fat into glucose
b. Are dumped into synaptic cleft and affect depolarization of the sarcolemma or the myofiber.
c . Release steroid in the synaptic cleft to stimulate the growth of the cell
d. They are never involved in neuromuscular junction.
b. Are dumped into synaptic cleft and affect depolarization of the sarcolemma or the myofiber.
Which statement is correct:
a. As long as the neurotransmitter is bound to the receptors of the postsynaptic neuron, muscle or glands; their functions will be affected.
b. The removal of the neurotransmitter on receptor of the postsynaptic neuron will result in the depolarization of the post synaptic neuron
c. No neurotransmitter can be destroyed by enzyme
d. The re-uptake of the neurotransmitter into the neuron that release it will continue to excite the post synaptic neuron.
a. As long as the neurotransmitter is bound to the receptors of the postsynaptic neuron, muscle or glands; their functions will be affected
Fluoxetine, commonly called Prozac provides relief to those suffering from depression by:
a. Increasing the release of the serotonin and acetylcholine in the synaptic cleft
b. Blocking the re-uptake of serotonin, thus prolonging the activities at the neuron-neuronal junction in the brain
c. Decrease the release of dopamine while enhancing the effect of endorphins, epinephrine, and the acetylcholine in the brain cells.
d. increasing the release of acetylcholine and norepinephrine on the myofiber.
b. Blocking the re-uptake of serotonin, thus prolonging the activities at the neuron-neuronal junction in the brain
The neurotransmitter that excites myofiber once released by the presynaptic neuron in the synaptic cleft:
a. Gaba
b. Endorphin
c. Adrenalin
d. Acetylcholine
d. Acetylcholine
Once this neurotransmitter is released by the parasymphatetic neurons the heart rate will decrease:
a. Dopamine
b. Serotonin
c. Acetylcholine
d. Norepinephrine
c. Acetylcholine
The active neurotransmitter during emotional response, addiction, and pleasurable experience is
a. Dopamine
b. Serotonin
a. dopamine
The neurotransmitter which regulates muscle tone and muscle contraction, and addiction is:
a. Dopamine
b. Serotonin
c. Acetylcholine
a. dopamine
Cocaine causes euphoria by blocking the reuptake of:
a. Serotonin and Gaba
b. Dopamine
c.Norepinephrine and epinephrine
d. None of the above
a. seratonin and GABA
Your cousin has asthma attack, his physician prescribes him Isoproterenol (ISUPREL) to dilate his airways because it.
a. Binds to and activates the receptors of Norepinephrine
b. It destroys the receptors for dopamine
c. It forms antibodies – antigen complex and increases the release of complements
d. It reduces the release of serotonin and GABA
a. Binds to and activates the receptors of norepinephrine
The visceral nervous system regulates all these structures except:
a. the lungs
b. the cardiovascular system system
c. the stomach and small intestine
d. femur and flexor hallucis longus muscle
d. femur and flexor hallucis longus muscle
The somatic nervous system afferent:
a. affect sweat glands
b. striated Muscles
c. blood flow
d. none of the above
b. striated muscles
These are all functions of the myofiber except:
a. elasticity
b. conductivity
c. excitability
d. responsiveness
b. conductivity
Action potential is related to
a. depolarization
b. irritability
c. excitability
d. responsiveness
a. depolarization
In neurobiology PEPSI, EPSP, IPSP are all the same
a. true
b. false
b. false