BSC Test 3
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Communication by neurons is based on changes in the......
Permeability to ions.
What two types of membrane potentials are major functional significance?
Graded Potentials and action potentials.
Within the PNS?
major divisions are the somatic nervous system and the autonomic nervous system (parasympathetic & sympathetic)
Receive information, normally neurotransmitters, the undergo graded potentials.
Undergo Action potentials to deliver information
Myelinated neurons conduct action potentials______.
PNS = Afferent Neurons?
their actibity "affect" what will happen next (into the CNS)
PNS = Efferent Neurons??
"effecting" change movement, secretion, ect., projecting out of the CNS
CNS = Interneurons??
function as integrators & signal changers
99% of all neurons
A single neruron postsynaptic to one cell can bepresynaptic to another cell.
The size of a graded potential is proportionate to the_________.
intensity of the stimulus.
*Graded potential decay as they move over distance.
Graded potentials can be;
Excitatory (action potential is more likely)
Inhibitory (action potential is less likely)
Depolarization for action potential is???
Opening Na- (sodium) channels for __________.
Opening K+ (potassium) channels for____
The rapid openning of voltage-gated Na+ channels explains the __________ phase at the begining of the action potential.
The slower openning of voltage-gated K+ channels explains the ___________ and sfter hyperpolarization phases that complete the action potential.
The propagation of the action potential from the dendritic to the axon-terminal end is typically_______ because the absolute refractory period follows alongin the "wake" of the moving action potential.
PNS = Somatic Division...
-Innervates skeletal muscle
-only muscle excitation
PNS= Autonomic Division
-Innervates smooth & cardic muscle, glands & GI neurons
- can be either excitatory or inhibitory
CNS-> preganglionoc fiber-> ganglion->postganglionoc fiber
Most structure is _______ smooth muscle.
The _____ is the point of communication between twoo nerons that operate sequentially.
The _________ ________ is the space between to nerve cells.
______________ __________: Action potentials jump from pne node to the next as they propagate along a myelinated axon.
Myelinated fiber only depolorize at active ____ __ ____site of action potential.
node of Ranvier
Non-myelinated fibers depolorize ________.
Characteristics Graded Potentail
- -amplitude varies
- -can be summed
- - no threshold
- -no refractory period
- -can be depolarization or hyperpolarization
- -initiated by environmental stimulus, neurontransmitter, or spontaneously
- -ligand gated channels
Characteristics of Action Potential
- - All-or-none, amplitude is independent
- - cannot be summed
- -has a threshold
- -has a refractory period
- -only depolarization
- -initiated by action potential
- -voltage-gated channels
Path of action potential from presynaptic cell to postsynaptic cell. 5 steps
- 1. action potential reaches termial
- 2. Voltage-gated Ca channels open
- 3. Ca enters axon termial
- 4. Neurotransmitter release & diffusion (synaptic cleft)
- 5. Neurotransmitter binds to postsynaptic receptors
Two overlapping graded depolarization demonstrates ______ ______.
Distinct actions of stimulating neurons A & B demonstrate_____ ______.
All action potential are the ____. The more action potential the more____.
The greater density of nerve endings in a receptive field has _______.
more sensitivate = greater number of action potential
"sharpens contrast" in the pattern of action potential received by the CNS
allows the CNS to more accurately locate the cource of stimulation
Different sensory units ____________ of adaptation to stimuli.
- vary in their speed
- (rapidly and slowly adapting)
Sensory association in the Auditory Cortex?
Sensory association in the Parietal Lobe?
Sensory association in the Occipotal Lobe?
Sensory association in the Temporal Lobe?
pain, bodily sensation
All ascending pathwa, EXCEPT for those involved in______ synapse in the ________ on their way to the cortex.
Meissner's Corpuscle (recepte cell)
Merkle's Corpuscle (recepte cell)
Free Nerve endings (recepte cell)
Pacinian Corpuscle (recepte cell)
vibration and deep pressure
Ruffini Corpuscle (recepte cell)
Somatosensory Cortex give the sensation of?
Somatosensory areas in the cortex of the brain are ______ organized in relation to the source of information, with larger areas dedicated to parts of the body that process __________.
anatomically, fine dicrimination
ex hands receptor fields are more dense
Visual transductio occurs on the ____ and is based in the images focused there by the _____ & _____.
retina, corna, lens
Normal sight the image is focused ______ on the retina.
Nearsighted the image is focused ________ the retina.
Farsighted the image is focused _____ the retina.
normal = onto
nearsighted = infront
farsighted = behind
Lost of rods =
Lost of cones =
rods- night blindness
cones- color blindness
Light penetration past the _____ prior to transduction by the rods and cones.
Visual fields "NOT" crossed over
L visual is on the right side of the eye then processed by right side of the brain
The pinna & external auditory canal focus sound waves on the _______, which rocks the _____, ______ & _____ causing ripples in the cochlear fluid and auditory transduction.
malleus, incus, & stapes
Ripples of the cochlear fluid are transmitted to movement of the?
Two major function of the ear?
hearing & balance
___________ system detects change in the motion and position of the head by the use of 3 fluid filled tubes near each ear.
45* angels, lined w/ hairs, which depolarizes and causes a action potential
_______ provides diagnostic information about the location of abnormal activity of the brain.
located on top of the brain steam
reset of the brain develops aroun the limbic system
Fuctions- emotion, learning, appetite, sex, endrocrine
Comprehension of speech is located in which part of the brain?
Production of speech is produced in which area of the brain?
Motor communication command of the brain.....
- highest level = intent plan )cerebral cortex)
- middle level = bounces around to for a list of commands
- local level = brain to muscle, consitly check for correct actions
Brainsteam is the main control for?
involuntary GI & heart rate
Cerebellum is the main control for?
Sensorimotor certex is the main control for?
What provides information about muscle position and stretch?
muscle spindles & golgi tendon (saftey step)
The pain-withdrawal reflex is?
Bilateral spinal cord level
Efferent motor commands are ________.
The brainsteam influences __________ motoe activity.
ipsilateral "same side"
The sarcomere is composed of:
thick filaments, anchored in place by titin fibers
thin filaments, anchored in place by Z-lines
Factors that determining muscuel tension?
- tesion by each fiber
- action potential, length, diameter, fatigue
- number of fibers (whole muscle)
- # of fiber per unit, # of active motor units
The thick filament called myosin is actually a___________
polymer of myosin molecules
The _____ ______ between excitation and development of tension in a skeletal muscle, time which Ca from sarcoplasmic reticulum is released to move tropomyosin
Ca is stored in the?
Slow-oxidative skeletal muscle........
repetitive stimulation w/out becoming fatigues
ex. body posture
Fast-oxidative skeletal muscle......
Type II A
quickly and to repetitive stimulation w/out becoming fatigues
Fast-glycolytic skeletal muscle is used or??
Type II B
quick burst of strong activation
A single ____ consists of a motor neuron and all of the muscle fibers it contols.
* you want a mixture of both single & two motor units
Partial dissipation of elastic tension between subsequent stimuli is ?
No time for dissipation of elastic tension between rapidly recurring stimuliis?
The exoxytosis of acetylcholine from the axon termial occurs when the ________ merge into the membrane covering the termial
______________lots of actin-myosin overlap and plenty of room to slide.
________ actinfilaments lack room to slide, so little tension can be developed.
_________ actin and myosin do notoverlap much, so little tension can be developed.
creatine phosphate -----> creatine & phosphate =
Ca binding to troponin removes blocking action of______
Passage of an action potential along the transverse tubule opens nearby voltage gated channels _____________
Functions of ATP in skeletal muscle contraction.....
hydrolysis of ATP by myosin
binding of new ATP allowing the bridges to repeat
Ca-ATPase, active transport of Ca ions into reticulum
Charateristics of the three TYPES of skeletal muscle fibers....
- I II A IIB
- source ATP Oxidative phosphorylation "" Glycolytic
- Mitochondria Many Many Few
- Rate if fatigue slow intermediate fast
- Contraction slow fast fast
- Dianeter small intermediate large
Contraction occurs when Ca ions bind to ________, this pulls ___________ awayfrom the cross-bridge binding site.
myosin binds to action, and slides it, pulling the z-line closer, and reduceing the width of the I-band
thin over thick
The reflex that prevents a muscle from exerting too much tension is the?
The part of the peripheral nervous system that brings information to the central nervous system is?
The cell membrane of skeletal muscle is called the
At the normal resting potential of a typical neuron, its ion exchange pump transports
3 intracellular sodium ions for 2 extracellular potassium ions.
During saltatory conduction,
action potentials occur at successive nodes along the length of the stimulated axon.
When calcium ion binds to troponin,
tropomyosin moves out of the groove between the actin molecules
Thin filaments at either end of the sarcomere are attached to the
produce powerful contractions.
The most important factor in decreasing the intracellular concentration of calcium ion aftercontraction is
active transport of calcium into the sarcoplasmic reticulum.
________ are the most numerous type of neuron.
Voluntary control of skeletal muscles is provided by the ________ nervous system.
When a second EPSP arrives at a single synapse before the effects of the first have disappeared,what occurs?
The functional unit of a skeletal muscle fiber is the
EPSPs (excitatory postsynaptic potentials) occur when
sodium channels are opened.
At rest, active sites on the actin are blocked by
The area of the sarcomere that contains only thin filaments is the
The type of contraction in which the muscle fibers produce increased tension but do not shorten iscalled
The myelin sheaths that surround the axons of some of the neurons in the CNS are formed by
Opening of sodium channels in the membrane of a neuron results in
The series of membranous channels that surround each myofibril is the
Each thin filament consists of
a pair of protein strands wound together.
Action potentials are conducted into a skeletal muscle fiber by
The type of contraction represented by a single stimulus/contraction/relaxation sequence is a(n)
The increase in muscle tension that is produced by increasing the number of active motor units iscalled
In an isotonic contraction
tension rises and the skeletal muscle length changes.
may involve either depolarization or hyperpolarization.
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