Exam 2 Flashcards
The _______ in neurons has a high abundance of voltage-gated sodium channels and determines whether an action potential will be fired.
axon hillock
______________send action potentials AWAY from the central nervous system.
efferent neurons
The resting membrane potential of neurons:
is negative.
is closer to the equilibrium potential of potassium than sodium.
is maintained by the sodium potassium pump.
can be changed in excitable cells like neurons
ALL OF THE ABOVE
If a cell has a resting membrane potential of -70mV and the membrane potential changes to -55mV this is an example of:
depolarization
If a neuron becomes permeable to sodium:
the neuron would depolarize.
Graded potentials:
can sum temporally or spatially
The rising or depolarization phase of an action potential is due to:
opening of voltage gated sodium channels.
The falling or repolarization phase of an action potential is due to:
closing of voltage gated sodium channels.
opening of voltage gated potassium channels.
The absolute refractory period of an action potential:
spans all of the depolarization phase and most of the repolarization phase.
is the period in which a second action cannot be fired.
is the period in which the voltage gated sodium channels are either open or inactivated.
causes the unidirectional flow of action potentials.
ALL OF THE ABOVE
During the relative refractory period it is harder to fire another action potential because _________.
voltage gated potassium channels are open and the membrane is hyperpolarized.
Unmyelinated axons:
have action potentials spread down the axon by contiguous conduction.
Myelin:
allows for faster salutatory conduction of action potentials.
Electrical synapses:
are formed when two neurons are connected by gap junctions.
Order the following events that occur at the synapse from first to last. 1 - calcium triggers exocytosis of neurotransmitter from the presynaptic neuron 2 - neurotransmitter diffuses across the synapse and binds to a receptor on the postsynaptic cell 3 - an action potential reaches the axon terminal of the presynaptic cell 4 - neurotransmitter is removed from the synapse to terminate the response 5 - voltage gated calcium channels open on the axon terminal of the presynaptic cell 6 - the postsynaptic cell responds
3,5,1,2,6,4
How are neurotransmitters removed from synapses?
all of the above.
At an excitatory synapse neurotransmitter released from the presynaptic neuron may cause the:
opening of ligand gated non-specific cation channels on the postsynaptic cell
What type of glial cells aid in the formation and modification of synapses?
astrocytes
Which of the following is the correct order of the meninges, from neural tissue to bone?
Pia mater : arachnoid mater : dura mater
Which of the following statements is correct about the solute composition of cerebrospinal fluid (CSF) compared to plasma?
CSF is lower in protein than plasma.
The blood brain barrier:
is due to the capillary endothelial cells in the pia mater forming tight junctions with each other.
The reticular formation in the ___________receives and integrates incoming sensory information.
brainstem
The _______ SUBCONCIOUSLY coordinates muscle movement.
cerebellum
Which part of the brain controls thirst and urine output, food intake, and body temperature, among other things?
hypothalamus
The ________ in the diencephelon filters and refines sensory information, allowing us to direct our attention to specific external stimuli.
thalamus
The ______ are pockets of grey matter in the interior of the cerebrum that help to select and maintain purposeful movement while suppressing useless or unwanted patterns of movement.
basal nuclei
Which of the following characteristics is a specialization of the rleft side of the cerebrum in most individuals?
logic
The ________ in the cerebral cortex deals with speaking ability and is found in the _______ lobe.
Brocas area : frontal
During an electroencephalogram (EEG) high frequency low amplitude ______ waves dominate when the patient is awake, relaxed with their eyes open.
beta
Which of the following is found in the GRAY MATTER of the spinal cord?
efferent neuron cell bodies
In the knee jerk reflex the quadriceps and hamstring are the________.
effector organs
Most visceral organs are innervated by both the sympathetic and parasympathetic nervous systems an exception to this rule is:
most arterioles and veins are innervated only by the sympathetic nervous system.
Which of the following is NOT characteristic of sympathetic pathways in the peripheral nervous system?
postganglionic fibers release acetylcholine
The adrenal medulla is considered part of the sympathetic nervous system because when stimulated it secretes:
epinephrine
Parasympathetic stimulation ____ heart rate and ____ the motility of the digestive tract.
decreases : increases
Muscarine is a compound found in toxic mushrooms. After consumption of mushrooms containing muscarine a patient may start to excessively salivate and have a decreased heart rate. Based on these symptoms muscarine is an acetylcholine ________ at muscarinic cholinergic receptors.
agonist
The neuromuscular junction is a synapse between a ________ neuron and __________.
motor : skeletal muscle
The release of acetylcholine at the neuromuscular junction is always ______ due to the fact that the motor end plate has nicotinic cholinergic receptors and when acetylcholine binds to those receptors _________ channels open.
excitatory : nonspecific cation
Which of the following types of receptors would the body use to detect solute levels in the blood?
osmoreceptors
The hair follicle mechanoreceptors in our skin are phasic and therefore ________ to stimuli and _____ sending action potentials to the central nervous system.
rapidly adapt : stop
An afferent neuron codes for the intensity of a stimulus by:
changing the frequency of the action potentials it sends.
Which of the following statements about sensory coding is FALSE?
The ability to locate the stimulus is inhibited by lateral inhibition.
__________ detect skin temperatures between 20-35°C while ___________ detect skin temperatures between 30-43°C, _______ detect potentially damaging temperatures
Cold thermoceptors : warm thermoceptors : nociceptors
Polymodal nociceptors are ______ receptors and _______ to sustained stimuli.
tonic : do not adapt
Fast pain occurs _______ is transmitted on _______ neurons and is _____ localized.
first : myelinated : easily
Pain signals from visceral receptors are ‘referred’ to the body surface because:
nociceptors from visceral organs synapse on the same second-order neurons as nociceptors from the skin surface.
When your pupil constricts it is because the _______ nervous system causes the ______ muscles in your iris to constrict.
parasympathetic : circular
If your lens is too weak and unable to do accommodation you will be hyperopic or farsighted and need _______ eyewear.
convex
Which of the following statements is true about rods?
Rods are more numerous in the periphery of the retina.
When we leave a dark theater and it is bright and sunny out, the retinal and opsin molecules within the ________ must first ________ before we can see clearly without squinting.
rods : bleach
rods : dissociate
