A&P unit 2
The functions of astrocytes are to ______.
-Assist neuronal development -Regulate the composition of interstitial fluid -Help form the blood-brain barrier
Which of the following are characteristics of neurons?
-Conductivity -Amitotic -Excitability -Secretion -Extreme longevity
A resting membrane potential is essential in the normal function of which of the following type of cells?
-Nerve -Muscle
Place the events in the correct sequence. Not all items will be used.
1. Action potential reaches the synaptic knob 2. Voltage gated calcium channels open 3. Calcium enters the synaptic knob 4. Synaptic vesicles merge with synaptic knob plasma membrane 5. Neurotransmitter is released by exocytosis 6. Neurotransmitter crosses the synaptic cleft 7. Neurotransmitter attaches to receptors on a muscle, neuron, or gland cell.
The arrival of a nerve impulse at the synaptic knob of a motor neuron causes synaptic vesicles to release _____ into the synaptic cleft.
ACh Acetylcholine Neurotransmitter
The motor end plate has large numbers of ______ receptors.
ACh Acetylcholine
Which of the following are used for fast axonal transport?
ATP Microtubules Motor proteins
Each myosin head in a thick filament can bind to the protein in a thin filament called ______
Actin
Thin filaments are composed of
Actin Tropomyosin Troponin proteins
A flow of electrical current called a(n) ______ ______is generated within the initial segment of a neuron.
Action potential
The division of the nervous system that is subdivided into the sympathetic and parasympathetic divisions is the _____ nervous system.
Autonomic Involuntary ANS Visceral
The ______ is the functional division of the nervous system that controls the involuntary movement of smooth muscle.
Autonomic motor nervous system
The synapse is located ______ the presynaptic neuron and postsynaptic neuron.
Between
Unipolar neurons start out as ______ neurons during development.
Bipolar
The brain and spinal cord are part of the ______.
CNS
Which of the following are among the general characteristics of graded potentials?
Can either be depolarizing or hyperpolarizing. The degree of change in membrane potential is dependent on the stimulus magnitude. The decreased intensity with distance traveled along the membrane.
A muscle fiber is what level of organization in the body?
Cellular
The ependymal cells help produce ______.
Cerebrospinal fluid
H zone
Contains thick filaments only
What are the four types of neuronal pathways?
Converging Diverging Reverberating Parallel-after-discharge
Sarcoplasm
Cytoplasm of a muscle cell
Actin
Double stranded contractile protein Binding site for myosin to shorten a sarcomere
Numerous ______ must be generated and arrive at the initial segment at nearly the same moment if a threshold is to be reached.
EPSP's
Numerous ______ must be generated and arrive at the initial segment at nearly the same moment if a threshold is to be reached.
ESPSs
Gap junctions are found in ______.
Electrical synapses
Stages of cross-bridge cycling in order
1- Calcium binds troponin; myosin-binding site uncovered 2- Cross-bridge formation 3- Power stroke 4- Release of myosin head by ATP 5- Reset of myosin head
Voltage is a measure of relative _____ energy.
Potential or Electrical
Chromatophilic substance and Nissl bodies are both types of ____.
Ribosomes
If a skeletal muscle is injured, surrounding ______ cells may be stimulated or differentiate and assist in its repair and regeneration
Satellite (or) stem
If the sarcoplasm of a muscle cell is flooded with calcium ions, to which protein will they bind?
Troponin
The flow of sodium ions through sodium channels is best described as ______.
From outside the cell to inside
Sarcomere
Functional contractile unit of skeletal muscle
A cluster of neuron cell bodies found along a peripheral nerve is known as a(n)
Ganglia
Match the neurotransmitter to its class.
Glutamate ---> amino acid Norepinephrine -----> Monoamine
Match the neurotransmitter with its correct class.
Glycine ----> amino acid Dopamine ---> monoamine Neuropeptide --> enkephalin
A potential that is a temporary change in membrane potential which lasts only as long as the stimulus that causes it and can vary in size is called a _____ potential.
Graded
Choose which of the following can be the mechanism by which neurotoxins may do harm.
Interfere with the transmission of action potentials Induce detrimental structural change to a neuron Alter events that occur at a synapse
Because muscle cells require a huge amount of ATP in order to contract, they have a large number of which organelle?
Mitochondria
The autonomic division of the nervous system is part of the ______ nervous system.
Motor
In a motor unit, a single _____ neuron typically controls numerous muscle fibers ina muscle.
Motor Somatic
The inside of the cell is relatively more ______ than the outside of the cell.
Negative
When electrodes are placed just inside and just outside of the cell membrane, there is a relatively more ______ charge on the ______ of the cell.
Negative; inside
The thin outer layer of the neurolemmocyte is called the ______.
Neurilemma
Neurofilaments aggregate to form bundles called ______.
Neurofibrils
Clusters of neuron cell bodies called ganglia are found in the ______ nervous system.
Peripheral
Guillain-Barré syndrome is a disorder of the ______ nervous system.
Peripheral
In a unipolar neuron, the portion of the axon stretching from the dendrites to the cell body is known as the _______ ________.
Peripheral process
A ______ transmits an impulse through its axon toward the synapse.
Presynaptic
Membrane molecules that use the energy of ATP to move ions against a concentration gradient are called
Proteins Pumps
A ______ is a type of circuit that causes a cyclic response.
Reverberating circuit
Some antidepressant drugs are SSRIs. SSRI stands for ______ _______ _______ _______.
Selective Serotonin Reuptake Inhibitors
The somatic division of the nervous system that receives information from the eyes, ears, and skin is the somatic _____ division.
Sensory Afferent
A change in membrane potential insufficient to cause an action potential is known as a _______ ________.
Subthreshold Value
The process by which postsynaptic potentials are added together at the initial segment is known as
Summation
The motor end plate has folds and indentations to increase the membrane surface area adjacent to the ______.
Synaptic knob
As a result of ACh stimulation, calcium ions are released from the _____ of the sarcoplasmic reticulum
Terminal cisternae
What must happen in order for a chemical signal to change the membrane potential of a neuron?
There must be a change in ion flow across the membrane. (And) There must be a change in the number of open ion channels.
Vesicles involved in retrograde transport are moving ______ the cell body.
Toward
True or false: Facilitation and inhibition may be caused by changes in either the presynaptic neuron or the postsynaptic neuron.
True
What are the two structural examples of sensory neurons?
Unipolar Bipolar
Both Na+ and K+ are pumped by the Na+/K+ pumps ______ their concentration gradients in maintaining the resting membrane potential.
Up
______ are unique channels in that they have three states; resting, activation, and inactivation.
Voltage gated channels
______ are not commonly found in the receptive segment of a neuron.
Voltage-gated ion channels
M line
appears as a dark protein disc in the center of the H zone
Streps in neuromuscular junction
1- Nerve signal arrives at the synaptic knob 2- Calcium enters and binds synaptic vesicle 3- ACh is released via exocytosis into the synaptic cleft 4- ACh binds receptors on the motor end plate
Which two are divisions of the sensory nervous system?
1- Somatic division 2- Visceral division
Most channels have ________ gates(s), but a sodium channel has _______ Gates(s).
1. one 2. two
Thick filaments are composed of
200-500 myosin protein molecules
Membrane pumps require ______ energy.
A lot
Each myosin head in a thick filament can bind to the protein in a thin filament called _____
Actin
Sensory ______ neurons carry information ______ the central nervous system.
Afferent; toward
Current is measured in
Amps
Local _______ like lidocaine work by inhibiting impulse propagation along nerves.
Anesthetics
A substance synthesized at the cell body must undergo ______ transport to reach the synaptic knobs.
Anterograde
Substances can be moved in fast axonal transport (in) ______.
Anterograde and retrograde directions
The endoneurium is made of ______.
Areolar connective tissue
The connective tissue layers in muscle provide protection, distribution sites for blood vessels and nerves, and a means of ______ to the skeleton.
Attachment
Sympathetic and parasympathetic are divisions of the ______ nervous system.
Autonomic (peripheral)
A fascicle is a bundle of ______.
Axons
Troponin
Bound to tropomyosin; can bind calcium ions
Ependymal cells produce and circulate cerebrospinal fluid. The ______ helps circulate the CSF.
Cilia
Thin filament
Composed of actin, troponin, and tropomyosin. Bind to thick filaments and cause contaction
Thick filament
Composed of myosin Bind to thin filaments and cause contraction
The somatic sensory division detects stimuli that are ______ perceived.
Consciously
______ is the type of neuronal circuit that is made when multiple impulses come together at a single postsynaptic neuron.
Converging
What is the movement of charged particles called?
Current
Myofibrils
Cylindrical organelles specialized for contraction Contain myofilaments that are responsible for muscle contraction
A band
Dark band containing both actin and myosin
The epineurium is made of ______ connective tissue.
Dense irregular
Another way for the neurotransmitter to be removed from the synaptic cleft is by ______ where there is uptake by surrounding glial cells.
Diffusion
A message traveling from one presynaptic neuron to multiple postsynaptic neurons is an example of a ______ circuit.
Diverging
Tropomyosin
Double-stranded regulatory protein covers the active sites on actin, preventing myosin from binding to actin when muscle fiber is at rest
Motor neurons are classified as ______ neurons.
Efferent
The gradient that is dependent on the combination of the electrical gradient and the chemical concentration gradient is the __________ gradient.
Electrochemical
The resting membrane potential is a(n) ______ gradient at the plasma membrane.
Electrochemical
in a muscle there are concentric layer of connective tissue. From deep to superficial these connective tissue layers are the ______, the ______, and the _______
Endomysium Epimysium Perimysium
The lining ventricles of the brain is a location of ______.
Ependymal cells
An increase in the response of a postsynaptic neuron to a neurotransmitter is known as ______.
Facilitation
True or false: Ion channels use the energy of ATP to maintain concentration gradients across neuron membranes.
False
True or false: Many voltage-gated channels are found in the receptive segment of a neuron.
False
A skeletal muscle cell is also called a muscle _____
Fiber
Th peripheral nervous system is made of nerves and ____.
Ganglia Ganglion
The chromatophilic substance helps create the ______ color in parts of the brain and spinal cord.
Grey
At maximal contraction of a muscle fiber, the thin filaments are pulled into the ______ zone which disappears.
H
In a sarcomere, the ______ zone (or band) is the light, central region of the A band.
H zone
What part of a myosin molecule does ATP bind to?
Head
Many local anesthetics prevent the transmission of pain by ______.
Inhibiting voltage-gated sodium channels
If you were moving across a neuron's membrane from the receptive segment toward the transmissive segment, in the ______ is where would you first encounter large numbers of voltage-gated Na+ and K+ channels.
Initial segment
Which of the following segments of a neuron contains large numbers of voltage-gated potassium channels and voltage-gated sodium channels?
Initial segment Conductive segment
Neuronal pools are made of ______.
Interneurons
The cytosol close the the plasma membrane contains relatively more ______ ion than does the interstitial fluid that is close to the plasma membrane.
K+
IPSPs
K+ and Cl- ions current with this, local currents of ions associated with the graded potentials.
The net movement of K+ and Na+ in maintaining the resting membrane potential is partially dependent upon the number of ______ channels.
Leak
In neurons, most chemically gated ion channels open in response to the binding of a(n)
Ligand
I band
Light band containing thin filaments only
Cells that wander through the CNS and replicate in response to infection are called
Microglia
The resting membrane potential is measured in ______.
Millivolts
Upon release from the synaptic knob, acetylcholine attaches to receptors on the ______.
Motor end plate
______ is caused by the destruction of oligodendrocytes.
Multiple sclerosis
Interneurons are _____ neurons.
Multipolar
The sarcoplasm of a skeletal muscle fiber contains hundreds to thousands of long, cylindrical structures called __________
Myofibrils
Muscle cells store oxygen bound to a ____ molecule.
Myoglobin
Which of the following ions have leak channels on the plasma membrane?
Na+ K+
ESPSs
Na+ ions currents with this, local currents of ions associated with the graded potentials
The relative distributions of K+, which is more concentrated inside the cell, and Na+, which is more concentrated outside the cell, are the result of the activity of the ______.
Na+/K+ pump
Which of the following membrane transporters are present throughout the membrane of a neuron?
Na+/K+ pumps Potassium leak channels Sodium leak channels
The ability to alter the response of neurons to neurotransmitters is known as ______.
Neuromodulation
Synaptic knob, motor end plate, and synaptic cleft are parts of a ______.
Neuromuscular junction
Neuronal pools are also called ______.
Neuronal pathways and Neuronal circuits
A toxin that interferes with the activity of neurons is called a
Neurotoxin
Choose the cells that are part of the central nervous system.
Oligodendrocyte Microglia Ependymal cells Astrocyte
Na+ and K+ are moved in ______ directions to maintain the resting membrane potential.
Opposite
A fascicle is surrounded by a layer of dense irregular connective tissue called ______.
Perineurium
Sarcolemma
Plasma membrane of a muscle fiber
An inhibitory neurotransmitter may cause the opening of a ______ channel.
Potassium and Chloride
The period following an action potential in which an action potential can be initiated with a larger stimulus is known as the _____ ______ period.
Relative Refractory
The plasma membrane also functions in establishing and maintaining electrochemical gradient at the plasma membrane called _______ ________ potential.
Resting membrane
Some antidepressant drugs work by blocking the _______ of serotonin.
Reuptake
The removal of neurotransmitters from the synaptic cleft by transport into the synaptic knob is known as ______.
Reuptake
The repetitious nature of a ______ circuit ensures that we continue breathing while we are asleep.
Reverberating
After stimulation of ACh receptors, a muscle impulse spreads quickly along the ______ and into the muscle fiber along T-tubules.
Sarcolemma
The motor end plate is a specialized region of the ______.
Sarcolemma
Within a myofibril, each ______ shortens as the muscle fiber contracts.
Sarcomere
During the development of skeletal muscle cells, some myoblasts do not fuse and instead become ______ cells.
Satellite
_____ are voltage-gated ion channels that have two gates.
Sodium channels
If several EPSPs occur at different synapses, they undergo ______ at the initial segment.
Spatial summation
The expanded tip of an axon is called a ______.
Synaptic knob
A neuromuscular junction contains a(n) ______
Synaptic knob Motor end plate Synaptic cleft
Neurotransmitters are stored in ______.
Synaptic vesicles
If several EPSPs occur at a synapse over a short period of time, they undergo ______ at the initial segment.
Temporal summation
A thick cordlike structure that attaches a muscle to a bone is called a(n) ______.
Tendon
The H band (or H zone) is more lightly shaded because only ____ filaments are present
Thick (or) myosin
The all-or-none law refers to the fact that action potentials will only occur if the initial segment reaches
Threshold or -mV
True or false: Skeletal muscle is usually attached to the skeleton, but it is also found at the openings between the digestive tract and the external environment and the urinary tract and the opening to the external environment.
True
Tropomyosin
Two intertwined strands' cover myosin-binding sites Covers the active sites on actin when muscle cell is at rest
Actin
Two intertwines strands; each bead has a myosin-binding site.
Myosin protein consist of_____
Two strands; each has a globular head and an elongated tale.
Most afferent neurons are classified functionally as ______.
Unipolar
Pseudounipolar is another name for a ______ neuron Multiple choice question. multipolar
Unipolar
The ______ functional division of the nervous system transmits information from the viscera to the central nervous system.
Visceral sensory division
Ganglia are ______.
clusters of neuron cell bodies in PNS
When a nerve impulse reaches the end of an axon of a neuromuscular junction, calcium flows ______ the synaptic knob.
into
H zone
lighter region in middle of dark A band
Z disk
made of dark proteins that create a zig-zag line
The components of the somatic sensory division are ______.
-Receptors for hearing -Receptors for taste -Receptors in joints and muscles
Neurons have a resting membrane potential of ______ mV.
-70 mV