Anatomy & Physiology Exam 3

Two types of cells: 1. __ 2. __

Two types of cells: 1. Neurons 2. Supporting cells

Drag the labels to identify the events in the generation of an action potential in order and correctly name the refractory periods.

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During depolarization, which gradient(s) move(s) Na+ into the cell? A. Both the electrical and chemical gradients B. Only the electrical gradient C. Na+ does not move into the cell. D. Na+ moves out of the cell.only the chemical gradient

A. Both the electrical and chemical gradients - A positive ion is driven into the cell because the inside of the cell is negative compared to the outside of the cell, and Na+ is driven into the cell because the concentration of Na+ is greater outside the cell.

Following a head injury, Kevin can think of the word he wants to say but cannot make his mouth form the correct sounds to produce the word. He is most likely suffering from damage to A. Broca's area B. The basal nuclei. C. Wernicke's area. D. Brodmann's area. E. The general interpretive area.

A. Broca's area

Which anatomical division of the nervous system consists of the brain and spinal cord? A. Central nervous system B. Peripheral nervous system C. Efferent division D. Autonomic nervous system

A. Central nervous system

________ monitor the digestive, respiratory, cardiovascular, urinary, and reproductive systems. A. Internoceptors B. Unipolar neurons C. Spinal nerves D. Proprioceptors E. Exteroceptors

A. Internoceptors

Jean needs to have a tooth in her mandible filled. Her dentist injects a local anesthetic to block pain afferents in one of her cranial nerves. What cranial nerve does the dentist numb? A. Trigeminal B. Facial C. Trochlear D. Hypoglossal E. Glossopharyngeal

A. Trigeminal

Which of the following cranial nerves is classified as mixed nerve? A. Vagus nerve (X) B. Optic nerve (II) C. Olfactory nerve (I) D. Oculomotor (III)

A. Vagus nerve (X)

Which of the following cranial nerves relays information regarding hearing, motion and balance? A. Vestibulocochlear nerve (VIII) B. Facial nerve (VII) C. Trochlear nerve (IV) D. Hypoglossal nerve (XII)

A. Vestibulocochlear nerve (VIII)

What opens first in response to a threshold stimulus? A. Voltage-gated Na+ channels B. Ligand-gated Cl- channels C. Voltage-gated K+ channels D. Ligand-gated cation channels

A. Voltage-gated Na+ channels - The activation gates of voltage-gated Na+ channels open, and Na+ diffuses into the cytoplasm.

Axonal (axoplasmic) transport: - Movement of materials between __ and __. - Materials move along __ within axon. - Powered by __,__, and __.

Axonal (axoplasmic) transport: - Movement of materials between cell body and axon terminals. - Materials move along __ within axon. - Powered by mitochondria, kinesin, and dynein.

In which area of the graph do you see a sudden rush of sodium ions into the neuron? A. 1 B. 2 C. 3 D. 4

B. 2

Rabies is a viral disease contracted from the bite of an infected animal. Rabies bypasses many immune system defenses by traveling in peripheral neurons to reach the CNS. Which method of transport is NOT used by the rabies virus to reach the CNS? A. Osmosis B. Anterograde flow C. Retrograde flow D. Axoplasmic transport

B. Anterograde flow

The CSF leaves the CNS and enters the circulation at the __________. A. Arachnoid trabeculae B. Arachnoid granulations C. Pia mater D. Denticular ligaments

B. Arachnoid granulations

Where are action potentials regenerated as they propagate along an unmyelinated axon? A. At the internodes B. At every segment of the axon C. At myelin D. At the nodes

B. At every segment of the axon - In unmyelinated axons, the action potential is regenerated continuously along every segment of the axon (continuous propagation). In humans, only small diameter axons (for example, type C fibers) are unmyelinated. These neurons carry low-priority information, such as smell (olfaction) and temperature sensations.

The simplest level of information processing takes place at the __________. A. Dendrites B. Axon hillock C. Soma D. Axon terminals

B. Axon hillock

In the adult brain, which is the largest region? A. Cerebellum B. Cerebrum C. Midbrain D. Diencephalon

B. Cerebrum

Leak channels allow the movement of potassium and sodium ions by what type of membrane transport? A. Active transport B. Channel-mediated diffusion C. Facilitated diffusion D. Simple diffusion

B. Channel-mediated diffusion - Ions move through leak channels because of chemical and electrical gradients.

EPSPs are ___________. A. Postsynaptic B. EPSPs have all of these characteristics. C. Graded D. Excitatory

B. EPSPs have all of these characteristics.

Which of the following cranial nerves innervates the tongue musculature? A. Trigeminal nerve (V) B. Hypoglossal nerve (XII) C. Accessory nerve (XI) D. Abducens nerve (VI)

B. Hypoglossal nerve (XII)

Where do most action potentials originate? A. Axon terminal B. Initial segment C. Cell body D. Nodes of Ranvier

B. Initial segment - The first part of the axon is known as the initial segment. The initial segment is adjacent to the tapered end of the cell body, known as the axon hillock.

If a nerve cell receives many IPSPs at the same time, __________. A. The membrane potential will depolarize B. It will show temporal summation C. The nerve cell will be strongly excited D. The nerve cell will approach threshold

B. It will show temporal summation

The membranes of neurons at rest are very permeable to _____ but only slightly permeable to _____. A. Na+; Cl- B. K+; Na+ C. K+; Cl- D. Na+; K+

B. K+; Na+ - More K+ moves out of the cell than Na+ moves into the cell, helping to establish a negative resting membrane potential.

Sodium and potassium ions can diffuse across the plasma membranes of all cells because of the presence of what type of channel? A. Ligand-gated channels B. Leak channels C. Voltage-gated channels D. Sodium-potassium ATPases

B. Leak channels - Leak channels for Na+ and K+ are ubiquitous, and they allow for the diffusion of these ions across plasma membranes.

Graded potentials A. Produce an effect that increases with distance from the point of stimulation. B. May be either a depolarization or a hyperpolarization. C. Cause repolarization. D. Produce an effect that spreads actively across the membrane surface. E. Are often all-or-none.

B. May be either a depolarization or a hyperpolarization.

What is the role of neurotransmitter at a chemical synapse? A. Neurotransmitter causes vesicles to fuse with the presynaptic membrane. B. Neurotransmitter binds to receptors on the postsynaptic cell membrane. C. Neurotransmitter causes calcium to enter the presynaptic cell. D. Neurotransmitter causes an action potential in the presynaptic cel

B. Neurotransmitter binds to receptors on the postsynaptic cell membrane. - Neurotransmitter leaves the presynaptic neuron by exocytosis and binds to receptors on the postsynaptic cell membrane, opening ion channels. The movement of ions through these channels causes a graded potential in the postsynaptic cell.

How do action potential propagation speeds in myelinated and unmyelinated axons compare? A. Propagation speeds are similar in both axon types. B. Propagation is faster in myelinated axons. C. Propagation is faster in unmyelinated axons. D. Propagation in myelinated axons is faster over short distances, but slower over long distances.

B. Propagation is faster in myelinated axons. - The internode segments of myelinated axons allow local currents to travel quickly between nodes where the action potential is regenerated. This leaping of action potentials from node to node is several times faster than the continuous propagation found in unmyelinated axons. Myelinated axons also tend to have larger diameters, which enhances propagation speed.

Hyperpolarization results from __________. A. Slow closing of voltage-gated Na+ channels B. Slow closing of voltage-gated K+ channels C. Fast closing of voltage-gated K+ channels

B. Slow closing of voltage-gated K+ channels - The slow closing of the voltage-gated K+ channels means that more K+ is leaving the cell, making it more negative inside.

The sodium-potassium exchange pump transports potassium and sodium ions in which direction(s)? A. Sodium and potassium ions are both transported out of the cell. B. Sodium ions are transported out of the cell. Potassium ions are transported into the cell. C. Sodium and potassium ions are both transported into the cell. D. Sodium ions are transported into the cell. Potassium ions are transported out of the cell.

B. Sodium ions are transported out of the cell. Potassium ions are transported into the cell. - The energy of ATP is used to actively transport potassium and sodium ions against their electrochemical gradients. Potassium and sodium ions diffuse in the opposite direction through channels.

What is the function associated with the indicated neural activity? A. A stimulus that temporarily causes a localized change in the resting potential B. The production of graded potentials in the plasma membrane of the postsynaptic cell C. The electrical impulse that propagates along the surface of the axon D. The moment to moment variation of the transmembrane potential in all living cells

B. The production of graded potentials in the plasma membrane of the postsynaptic cell - Synaptic activity results in the production of graded potentials in the plasma membrane of the postsynaptic cell.

If a signal from a sending neuron makes the receiving neuron more negative inside, A. The sending neuron becomes more negative inside. B. The receiving neuron is less likely to generate an action potential. C. The sending neuron becomes more positive inside. D. The receiving neuron immediately generates an action potential. E. The receiving neuron is more likely to generate an action potential.

B. The receiving neuron is less likely to generate an action potential. - If the receiving neuron is more negative inside, it is less likely to generate an action potential.

What is indicated by the arrow? A. The area of the skull into which the fingerlike extensions, arachnoid villi, extend for reabsorption of CSF B. The space surrounding the brain, spinal cord, and cauda equina through which CSF flows C. A network of specialized ependymal cells that are involved in the production of CSF D. Absorption of cerebrospinal fluid into the venous circulation

B. The space surrounding the brain, spinal cord, and cauda equina through which CSF flows - The subarachnoid space surrounds the brain, spinal cord, and cauda equina and is the space through which CSF flows

Which functional class of neurons carries electrical signals that control the contractions of smooth muscle and cardiac muscle? A. Somatic motor neurons B. Visceral motor neurons C. Somatic sensory neurons D. Visceral sensory neurons

B. Visceral motor neurons

Which area of the graph shows when potassium channels open? A. 1 B. 2 C. 3 D. 4

C. 3

The plasma membrane of an axon is called the A. Neurilemma. B. Myelin sheath. C. Axolemma. D. Sarcolemma. E. Axon terminal.

C. Axolemma.

Which of the following best describes the role of calcium in synaptic activity? A. Calcium diffuses across the synaptic cleft and binds to chemically gated channels on the postsynaptic cell. B. Calcium breaks down acetylcholine. C. Calcium influx into the synaptic terminal causes vesicle fusion with the plasma membrane and the release of neurotransmitter. D. Calcium influx into the axon causes an action potential to propagate into the synaptic terminal.

C. Calcium influx into the synaptic terminal causes vesicle fusion with the plasma membrane and the release of neurotransmitter. - When an action potential reaches the synaptic terminal, voltage-gated calcium channels open and calcium enters the cell. Calcium causes vesicles to fuse with the plasma membrane and release neurotransmitter into the synaptic cleft.

The huge, highly branched neurons known as Purkinje cells are found in the __________. A. Cerebellar nuclei B. Cerebral cortex C. Cerebellar cortex D. Arbor vitae

C. Cerebellar cortex

Branches that may occur along an axon are called A. Hillocks. B. Telodendria. C. Collaterals. D. Synapses. E. Synaptic terminals.

C. Collaterals.

Which structure connects the left and right cerebral hemispheres? A. Optic chiasm B. Fornix C. Corpus callosum D. Mamillary body

C. Corpus callosum

The portion of a neuron that primarily receives communication is the _______. A. Axon B. Cell body C. Dendrite D. Axon terminal

C. Dendrite

Opening of sodium channels in the axon membrane causes A. Inhibition. B. Hyperpolarization. C. Depolarization. D. Repolarization. E. Increased negative charge inside the membrane.

C. Depolarization.

Which of the following is NOT a characteristic of neurons? A. Lack centrioles B. Highly metabolic with large number of mitochondria C. Divide when lost to injury or disease D. Possess an excitable membrane for the production of action potentials

C. Divide when lost to injury or disease

When neurotransmitter molecules bind to receptors in the plasma membrane of the receiving neuron, A. The receiving neuron becomes more positive inside. B. The receiving neuron becomes more negative inside. C. Ion channels in the plasma membrane of the receiving neuron open. D. Vesicles in the synaptic terminal fuse to the plasma membrane of the sending neuron. E. Ion channels in the plasma membrane of the sending neuron open.

C. Ion channels in the plasma membrane of the receiving neuron open.

Ions are unequally distributed across the plasma membrane of all cells. This ion distribution creates an electrical potential difference across the membrane. What is the name given to this potential difference? A. Positive membrane potential B. Threshold potential C. Resting membrane potential (RPM) D. Action potential

C. Resting membrane potential (RPM)

The CSF circulates within the __________. A. Epidural space B. Denticular space C. Subarachnoid space D. Subdural space

C. Subarachnoid space

What is the function of the myelin sheath? A. The myelin sheath decreases the speed of action potential conduction from the initial segment to the axon terminals. B. The myelin sheath decreases the resistance of the axonal membrane to the flow of charge. C. The myelin sheath increases the speed of action potential conduction from the initial segment to the axon terminals. D. The myelin sheath increases the insulation along the entire length of the axon.

C. The myelin sheath increases the speed of action potential conduction from the initial segment to the axon terminals. - The myelin sheath increases the velocity of conduction by two mechanisms. First, myelin insulates the axon, reducing the loss of depolarizing current across the plasma membrane. Second, the myelin insulation allows the voltage across the membrane to change much faster. Because of these two mechanisms, regeneration only needs to happen at the widely spaced nodes of Ranvier, so the action potential appears to jump.

Chemical synapses: - Most common type of synapse between neurons. - Only type of synapse between neurons and other cells. - Cells are separated by __. - __ cell sends the message. - __ cells receives the message.

Chemical synapses: - Most common type of synapse between neurons. - Only type of synapse between neurons and other cells. - Cells are separated by synaptic cleft. - Presynaptic cell sends the message. - Postsynaptic cells receives the message.

Cholinergic synapses: - Release __ at: - All neuromuscular junctions involving skeletal muscle fibers - Many synapses in __ - All neuron-to-neuron synapses in __ - All neuromuscular and neuroglandular junctions in __ division of __.

Cholinergic synapses: - Release acetylcholine (ACh) at: - All neuromuscular junctions involving skeletal muscle fibers - Many synapses in CNS - All neuron-to-neuron synapses in PNS - All neuromuscular and neuroglandular junctions in parasympathetic division of ANS.

Cytoskeleton of perikaryon: - Neurofilaments and __ - Similar to intermediate filaments and microtubules - Neurofibrils - Bundles of neurofilaments that provide support for __ and __.

Cytoskeleton of perikaryon: - Neurofilaments and neurotubules - Similar to intermediate filaments and microtubules - Neurofibrils - Bundles of neurofilaments that provide support for dendrities and axon.

The sodium-potassium exchange pump stabilizes resting potential at about __________. A. -10 mV B. -90 mV C. +66 mV D. -70 mV

D. -70 mV

Which of the following is an example of a presynaptic cell? A. A muscle cell B. A secretory cell C. A Schwann cell D. A neuron

D. A neuron - For the most part, signals flow in one direction across a synapse, from the presynaptic cell to the postsynaptic cell. The presynaptic cell is always a neuron. In contrast, postsynaptic cells are more variable in type. They can be neurons, muscle cells, secretory cells, or other types of cells.

Which of these is found in the pons? A. Tracts to the cerebellum B. Nuclei for four cranial nerves C. Respiratory control nuclei D. All of these are found in the pons.

D. All of these are found in the pons.

The neurotransmitter glutamate opens channels that are permeable to sodium ions. What effect does glutamate produce on a postsynaptic neuron? A. Neither IPSPs nor EPSPs B. Both IPSPs and EPSPs C. IPSPs D. EPSPs

D. EPSPs

The region of cerebrum anterior to the central sulcus is the __________ lobe. A. Parietal B. Occipital C. Temporal D. Frontal

D. Frontal

What separates the presynaptic and postsynaptic cells at a chemical synapse? A. Chemically gated ion channels B. Calcium channels C. Vesicles filled with neurotransmitter D. Synaptic cleft

D. Synaptic cleft - The synaptic cleft is a space separates the pre- and postsynaptic cells. Neurotransmitter is released from the presynaptic cell, diffuses across this space, and binds to receptors on the postsynaptic cell. This process relays a signal between the cells.

What event triggers the generation of an action potential? A. The membrane potential must return to its resting value of -70 mV from the hyperpolarized value of -80 mV. B. The membrane potential must hyperpolarize from the resting voltage of -70 mV to the more negative value of -80 mV. C. The membrane potential must depolarize from the resting voltage of -70 mV to its peak value of +30 mV. D. The membrane potential must depolarize from the resting voltage of -70 mV to a threshold value of -55 mV.

D. The membrane potential must depolarize from the resting voltage of -70 mV to a threshold value of -55 mV. - This is the minimum value required to open enough voltage-gated Na+ channels so that depolarization is irreversible.

Compared to type A axons, type C axons are __________. A. Slower propagating B. Smaller diameter C. Unmyelinated D. Type C axons have all of these characteristics.

D. Type C axons have all of these characteristics.

Dendrites: - Short and highly branched process extending from cell body - Dendritic spines - Fine processes on dendrites - Receive information from other neurons - __-__ percent of neuron surface area

Dendrites: - Short and highly branched process extending from cell body - Dendritic spines - Fine processes on dendrites - Receive information from other neurons - 80-90 percent of neuron surface area

A molecule that carries information across a synaptic cleft is a A. Synapse B. Synaptic cleft C. Sending neuron D. Receiving neuron E. Neurotransmitter

E. Neurotransmitter - Neurotransmitter molecules carry information across a synaptic cleft.

Efferent division of PNS: - Somatic nervous system (SNS) - Controls __ contractions - Both voluntary and involuntary (reflexes) - Autonomic nervous system (ANS) - Controls __ actions, contractions of smooth and cardiac muscle, and __ secretions - Sympathetic division has a stimulating effect - Parasympathetic division has a relaxing effect - Enteric nervous system (ENS) - 100 million neurons in walls of __ tract - As many or more in the spinal cord - Use the same neurotransmitters as the brain - Initiates and coordinates __ reflexes locally - Without instructions from __ - Can be influenced by __

Efferent division of PNS: - Somatic nervous system (SNS) - Controls skeletal muscle contractions - Both voluntary and involuntary (reflexes) - Autonomic nervous system (ANS) - Controls subconscious actions, contractions of smooth and cardiac muscle, and glandular secretions - Sympathetic division has a stimulating effect - Parasympathetic division has a relaxing effect - Enteric nervous system (ENS) - 100 million neurons in walls of digestive tract - As many or more in the spinal cord - Use the same neurotransmitters as the brain - Initiates and coordinates visceral reflexes locally - Without instructions from CNS - Can be influenced by ANS

Functional divisions of the PNS: - Receptors - Detect changes or respond to stimuli - May be __ or __ cells - May be single cells or __ organs (e.g., eyes, ears) - Effectors - Target organs that respond to __ commands.

Functional divisions of the PNS: - Receptors - Detect changes or respond to stimuli - May be neurons or specialized cells - May be single cells or complex sensory organs (e.g., eyes, ears) - Effectors - Target organs that respond to motor commands.

How an action potential happens: Action potential: 1. __ channels open one by one down the axon - Depolarization - Reaches __mV - Pass threshold 2. __ channels open - Repolarization - Takes the membrane potential back down to below RMP (__mV) - hyper polarization

How an action potential happens: Action potential: 1. Na+ channels open one by one down the axon - Depolarization - Reaches 40mV - Pass threshold 2. K+ channels open - Repolarization - Takes the membrane potential back down to below RMP (-70mV) - hyper polarization

Information processing: - Response of postsynaptic cell (integration of stimuli) - At the simplest level (individual neurons) - Many __ receive neurotransmitter messages simultaneously - Some excitatory, some inhibitory - Net effect on axon __ determines if action potential is produced - __ potentials - Graded potentials developed in a postsynaptic cell - In response to neurotransmitters

Information processing: - Response of postsynaptic cell (integration of stimuli) - At the simplest level (individual neurons) - Many dendrites receive neurotransmitter messages simultaneously - Some excitatory, some inhibitory - Net effect on axon hillock determines if action potential is produced - Postsynaptic potentials - Graded potentials developed in a postsynaptic cell - In response to neurotransmitters

Major classes of transmitters include: Biogenic amines: - __ - Released by __ - Excitatory and depolarizing effect - Widely distributed in brain and portions of ANS - __ - A CNS neurotransmitter - May be excitatory or inhibitory - Involved in Parkinson's disorder and cocaine use - __ - CNS neurotransmitter - Affects attention and emotional states - __ - Inhibitory effect - Functions in CNS are not well understood

Major classes of transmitters include: Biogenic amines: - Norepinephrine (NE) - Released by adrenergic synapses - Excitatory and depolarizing effect - Widely distributed in brain and portions of ANS - Dopamine - A CNS neurotransmitter - May be excitatory or inhibitory - Involved in Parkinson's disorder and cocaine use - Serotonin - CNS neurotransmitter - Affects attention and emotional states - Gamma-aminobutytric acid (GABA) - Inhibitory effect - Functions in CNS are not well understood

Major classes of transmitters include: Dissolved gases: - Are important neurotransmitters - __ - __

Major classes of transmitters include: Dissolved gases: - Are important neurotransmitters - Nitric oxide (NO) - Carbon monoxide (CO)

Major classes of transmitters include: Opioids: - Bind to the same receptors as opium and morphine - Classes of opioids in __ - __ - __ - __

Major classes of transmitters include: Opioids: - Bind to the same receptors as opium and morphine - Classes of opioids in CNS - Enkephalins - Endorphins - Dynorphins

Neurotransmitters: - Chemical messengers contained within __ vesicles in __ of presynaptic cell. - Released into __. - Affect receptors of postsynaptic membrane. - Broken down by __. - Reabsorbed and reassembled by __.

Neurotransmitters: - Chemical messengers contained within synaptic vesicles in axon terminal of presynaptic cell. - Released into synaptic cleft. - Affect receptors of postsynaptic membrane. - Broken down by enzymes. - Reabsorbed and reassembled by axon terminal.

Nissl bodies: - Dense areas of __ and __ in __ - Make nervous tissue appear __ (__ matter)

Nissl bodies: - Dense areas of RER and ribosomes in perikaryon - Make nervous tissue appear gray (gray matter)

Propagation in unmyelinated axon: - Threshold graded current at __ zone causes action potential - Action potential in one site causes action potential at next location - Cannot go backwards

Propagation in unmyelinated axon: - Threshold graded current at trigger zone causes action potential - Action potential in one site causes action potential at next location - Cannot go backwards

Protection of the CNS: - Meninges: supporting and protecting the __ - Dura mater - __ mater - Pia mater

Protection of the CNS: - Meninges: supporting and protecting the CNS - Dura mater - Arachnoid mater - Pia mater

Two divisions of the nervous system: 1. CNS - Central nervous system - Includes the __ and the __ 2. PNS - Peripheral nervous system - __ nerves of the body

Two divisions of the nervous system: 1. CNS - Central nervous system - Includes the brain and the spinal cord 2. PNS - Peripheral nervous system - Outer nerves of the body

Neural responses to injuries: - Wallerian degeneration - Axon distal to injury degenerates - Schwann cells - Form path for new growth - Wrap around new axon - Nerve regeneration in __ - Limited by __, which: - Produce scar tissue - Release chemicals that block regrowth

- Wallerian degeneration - Axon distal to injury degenerates - Schwann cells - Form path for new growth - Wrap around new axon - Nerve regeneration in CNS - Limited by astrocytes, which: - Produce scar tissue - Release chemicals that block regrowth

What is the magnitude (amplitude) of an action potential? A. 100 mV B. 30 mV C. 70 mV

A. 100 mV - The membrane goes from -70 mV to +30 mV. Thus, during the action potential, the inside of the cell becomes more positive than the outside of the cell.

What is indicated by the arrow? A. A network of specialized ependymal cells that are involved in the production of CSF B. The space surrounding the brain, spinal cord, and cauda equina through which CSF flows C. Absorption of cerebrospinal fluid into the venous circulation D. The area of the skull into which the fingerlike extensions, arachnoid villi, extend for reabsorption of CSF

A. A network of specialized ependymal cells that are involved in the production of CSF - The choroid plexus is a network of specialized ependymal cells involved in the production of CSF.

The mechanism by which the neurotransmitter is returned to a presynaptic neuron's axon terminal is specific for each neurotransmitter. Which of the following neurotransmitters is broken down by an enzyme before being returned? A. Acetylcholine B. Glutamate

A. Acetylcholine - Acetylcholine is broken down by acetylcholinesterase before being returned to the presynaptic neuron's axon terminal.

After a large meal, Michelle's stomach feels very full. The sensory neurons responsible for sending this sense of fullness are __________. A. Interoceptors B. Exteroceptors C. Somatic sensory neurons D. Proprioceptors

A. Interoceptors

Interneurons are responsible for __________. A. Analyzing sensory inputs and coordinating motor outputs B. Collecting information from the external or internal environment C. Delivering information to the CNS D. Carrying instructions from the CNS to peripheral effectors

A. Analyzing sensory inputs and coordinating motor outputs

Telodendria __________. A. Are fine extensions at the end of axons B. Directly communicate with another cell C. Are the same as the plasma membrane of the axon D. Are major branches along an axon

A. Are fine extensions at the end of axons

Cortical regions that interpret sensory information or coordinate motor responses are called ________ areas. A. Association B. Processing C. Commissural D. Somesthetic E. Sensory

A. Association

Efferent pathways consist of axons that carry impulses __________. A. Away from the CNS B. To the CNS C. From the PNS to the CNS D. To the spinal cord and into the brain

A. Away from the CNS

What is the function of the brain structure indicated by the arrow? A. Conscious thought B. Relays sensory information to the thalamus C. Processes visual data D. Coordination of complex motor patterns

A. Conscious thought - The cerebrum processes conscious thoughts, memory, intellect, and the conscious and subconscious regulation of skeletal muscle.

What type of conduction takes place in unmyelinated axons? A. Continuous conduction B. Synaptic transmission C. Electrical conduction D. Saltatory conduction

A. Continuous conduction - An action potential is conducted continuously along an unmyelinated axon from its initial segment to the axon terminals. The term continuous refers to the fact that the action potential is regenerated when voltage-gated Na+‎ channels open in every consecutive segment of the axon, not at nodes of Ranvier.

Which of these cranial nerves does not carry motor impulses to the eyes? A. Cranial nerve II B. Cranial nerve III C. Cranial nerve VI D. Cranial nerve IV

A. Cranial nerve II

Binding of the neurotransmitter to its receptor causes the membrane to __________. A. Either depolarize or hyperpolarize B. Hyperpolarize C. Depolarize

A. Either depolarize or hyperpolarize - The neurotransmitter can cause the postsynaptic membrane to either depolarize or hyperpolarize, depending on which ion channels are opened.

Which division of the nervous system, comprised of about 100 million neurons, initiates and coordinates many complex visceral reflexes in the walls of the digestive tract? A. Enteric nervous system B. Parasympathetic nervous system C. Sympathetic nervous system D. Central nervous system

A. Enteric nervous system

What mechanism releases neurotransmitter from presynaptic neurons? A. Exocytosis B. Pinocytosis C. Phagocytosis D. Endocytosis

A. Exocytosis - Neurotransmitter molecules are released from vesicles that fuse with the plasma membrane through exocytosis ("exo-" means outside, and "cyto" means cell). Once released, neurotransmitter diffuses across the synaptic cleft.

Rachel decides to go swimming, but when she sticks her big toe into the water, she changes her mind because the water is too cold. The sensory neurons responsible for sending the message about the cold temperature of the water are __________. A. Exteroceptors B. Enviroceptors C. Interoceptors D. Proprioceptors

A. Exteroceptors

In contrast to the internodes of a myelinated axon, the nodes __________. A. Have lower membrane resistance to ion movement B. Only occur at the beginning and end of the axon C. Have higher membrane resistance to ion movement D. Are wrapped in myelin

A. Have lower membrane resistance to ion movement - In a myelinated axon, action potential regeneration occurs at the nodes where myelin is absent. Here, the ion channels associated with the action potential provide a low resistance pathway for ions to cross the axon membrane. In contrast, the myelin surrounding the internode regions makes it difficult for ions to cross the membrane. Therefore, membrane resistance at the internodes is higher than membrane resistance at the nodes. Conversely, membrane resistance at the nodes is lower than membrane resistance at the internodes.

Action potential propagation begins (is first generated at) what region of a neuron? A. Initial segment B. Myelin C. Node D. Dendrite

A. Initial segment - Graded potentials created in the dendrites and soma will, if sufficiently depolarizing, generate an action potential in the initial segment of the axon. The action potential will then propagate away from this region, down the axon.

Which of these is not a property of the limbic system? A. It regulates body temperature. B. It includes the hippocampus. C. It is central to our ability to experience emotions. D. It is important in learning and memory.

A. It regulates body temperature.

The most abundant class of neuron in the central nervous system is A. Multipolar. B. Pseudopolar. C. Unipolar. D. Bipolar. E. Anaxonic.

A. Multipolar.

Which of these neurotransmitters does not bind to a plasma membrane receptor? A. Nitric oxide B. Norepinephrine C. GABA D. Serotonin

A. Nitric oxide

What structure secretes the hormone melatonin? A. Pineal gland B. Choroid plexus C. Eeptum pellucidum D. Infundibulum

A. Pineal gland

In a synapse, neurotransmitters are stored in vesicles located in the __________. A. Presynaptic neuron B. Postsynaptic neuron C. Synaptic cleft

A. Presynaptic neuron - Yes, neurotransmitters are stored in the axon terminals of the presynaptic neuron.

The surface of the postcentral gyrus contains the ________ cortex. A. Primary sensory B. Primary motor C. Visual D. Auditory E. Olfactory

A. Primary sensory

What is the function of the brain structure indicated by the arrow? A. Relaying sensory information to the thalamus B. Coordination of complex motor patterns C. Processing visual data D. Conscious thought

A. Relaying sensory information to the thalamus - The pons relays sensory information to the cerebellum and thalamus.

The node-to-node "jumping" regeneration of an action potential along a myelinated axon is called __________. A. Saltatory propagation B. Local propagation C. Myelinated propagation D. Continuous propagation

A. Saltatory propagation

The largest component of the diencephalon is the __________. A. Thalamus B. Epithalamus C. Tegmentum D. Hypothalamus

A. Thalamus

What is the function associated with the indicated neural activity? A. The electrical impulse that propagates along the surface of the axon B. The moment-to-moment variation of the transmembrane potential in all living cells C. A stimulus that temporarily causes a localized change in the resting potential D. The production of graded potentials in the plasma membrane of the postsynaptic cell

A. The electrical impulse that propagates along the surface of the axon - An action potential is the electrical impulse that propagates along the surface of the axon.

The resting membrane potential depends on two factors that influence the magnitude and direction of Na+ and K+ diffusion across the plasma membrane. Identify these two factors. A. The presence of concentration gradients and leak channels B. The presence of concentration gradients and Na+-K+ pumps C. The presence of a resting membrane potential and leak channels D. The presence of concentration gradients and voltage-gated channels

A. The presence of concentration gradients and leak channels - The large number of K+ leak channels ensures that the membrane is highly permeable to K+. The concentration gradient for K+ means that K+ diffuses out of the cell, leaving the inside of the cell negatively charged. In contrast, the relatively few Na+ leak channels means that the membrane is almost impermeable to Na+. The concentration gradient for Na+ means that Na+ will diffuse into the cell through the few leak channels that are open for it.

In an unmyelinated axon, why doesn't the action potential suddenly "double back" and start propagating in the opposite direction? A. The previous axonal segment is refractory. B. The extracellular sodium concentration is too low around the previous axonal segment for an action potential to be (re)generated. C. Positive charges only move in one direction. D. New action potential generation near the soma repels previously generated action potentials.

A. The previous axonal segment is refractory. - A propagating action potential always leaves a trail of refractory membrane in its wake. The trailing membrane takes some time to recover from the action potential it just experienced, largely because the membrane's voltage-gated sodium channels are inactivated. By the time this membrane segment is ready to (re)generate another action potential, the first propagating action potential is long gone.

In a neuron, sodium and potassium concentrations are maintained by the sodium-potassium exchange pump such that __________. A. The sodium concentration is higher outside the cell than inside the cell and the potassium concentration is higher inside the cell than outside the cell. B. The sodium concentration is higher inside the cell than outside the cell and the potassium concentration is higher outside the cell than inside the cell. C. The concentration of sodium outside the cell is equal to the concentration of potassium inside the cell. D. Both sodium and potassium concentrations are higher outside the cell compared to inside.

A. The sodium concentration is higher outside the cell than inside the cell and the potassium concentration is higher inside the cell than outside the cell. - Because the sodium-potassium exchange pump moves sodium and potassium ions in opposite directions, the pump generates concentration gradients for these ions that are opposite in direction. The opposite direction of these concentration gradients explains why the equilibrium potentials for those ions are opposite in sign (that is, -90 mV for potassium and +66 mV for sodium).

Multiple sclerosis (MS) is a disease that stops action potential propagation by destroying the myelin around (normally) myelinated axons. Which of the following best describes how MS stops action potential propagation? A. Without myelin, the internode membrane resistance decreases, preventing local currents from reaching adjacent nodes. B. Without myelin, the internode membrane is depolarized more easily. C. Without myelin, the node membrane more easily becomes refractory. D. Without myelin, the internode membrane resistance increases, preventing local currents from reaching adjacent nodes.

A. Without myelin, the internode membrane resistance decreases, preventing local currents from reaching adjacent nodes. - Myelin increases the membrane resistance of the axon section it surrounds, allowing local currents to travel between nodes, even though they are 1-2 mm apart. Removing myelin decreases the membrane resistance of internode regions. This shortens the distance that local currents travel because more charge now exits at the internode regions before it reaches the next node.

Events that occur at a cholinergic synapse are listed here, but they are arranged in an incorrect order. Choose the correct order of these events below. (a) Calcium influx triggers exocytosis of ACh. (b) An action potential depolarizes the synaptic terminal. (c) ACh is removed by AChE. (d) ACh binds to receptors on the postsynaptic membrane. A. b→→ a→→ d→→ c B. c→→ d→→ b→→ a C. a→→ b→→ d→→ c D. b→→ a→→ c→→ d

A. b→→ a→→ d→→ c - This correct sequence starts with an action potential at the presynaptic cell, followed by the release of ACh, binding of ACh to postsynaptic receptors, and degradation of the ACh molecules. Neurotransmitters like ACh transfer information between a neuron and a postsynaptic cell. This process gets a "message" across a physical separation, much like sending a text to your friend who is across town.

Action potential frequency: - Number of potentials produced per unit of time to a stimulus. - __ stimulus: causes a graded potential that is great enough to initiate an action potential. - __ stimulus: does not cause a graded potential that is great enough to initiate an action potential. - __ stimulus: just strong enough to produce a maximum frequency of action potentials. - __ stimulus: all stimuli between __ and the __ stimulus strength. - __ stimulus: any stimulus stronger than a maximal stimulus - Cannot produce a greater frequency of action potentials than a maximal stimulus

Action potential frequency: - Number of potentials produced per unit of time to a stimulus. - Threshold stimulus: causes a graded potential that is great enough to initiate an action potential. - Subthreshold stimulus: does not cause a graded potential that is great enough to initiate an action potential. - Maximal stimulus: just strong enough to produce a maximum frequency of action potentials. - Submaximal stimulus: all stimuli between threshold and the maximal stimulus strength. - Supramaximal stimulus: any stimulus stronger than a maximal stimulus - Cannot produce a greater frequency of action potentials than a maximal stimulus

Anatomy of the brain: - CNS - Diencephalon - Located under cerebrum and __ - Thalamus - Relays and processes sensory information - Hypothalamus is involved with - Emotions - __ function - Hormone production - Pituitary gland - Part of __ - Major __ gland - Connected to hypothalamus via infundibulum (stalk) - Integrates nervous and __ systems - Brainstem - Relays information between spinal cord and cerebrum or cerebellum - Includes: - Midbrain - Pons - Medulla oblongata - Midbrain - Processes sight, sound, and associated reflexes - Maintains consciousness - Pons - Connects __ to brainstem - Contains: - Tracts (collections of CNS axons) - Relay centers - Nuclei for somatic and visceral motor control - Medulla oblongata - Connects __ to spinal cord - Inferior portion has a narrow __ canal - Relays sensory information - Regulates autonomic functions - Heart rate, blood pressure, and digestion

Anatomy of the brain: - CNS - Diencephalon - Located under cerebrum and cerebellum - Thalamus - Relays and processes sensory information - Hypothalamus is involved with - Emotions - Autonomic function - Hormone production - Pituitary gland - Part of Diencephalon - Major endocrine gland - Connected to hypothalamus via infundibulum (stalk) - Integrates nervous and endocrine systems - Brainstem - Relays information between spinal cord and cerebrum or cerebellum - Includes: - Midbrain - Pons - Medulla oblongata - Midbrain - Processes sight, sound, and associated reflexes - Maintains consciousness - Pons - Connects cerebellum to brainstem - Contains: - Tracts (collections of CNS axons) - Relay centers - Nuclei for somatic and visceral motor control - Medulla oblongata - Connects brain to spinal cord - Inferior portion has a narrow central canal - Relays sensory information - Regulates autonomic functions - Heart rate, blood pressure, and digestion

Anatomy of the brain: Ventricles of the brain: - In the __, neural tube encloses neurocoel - Neurocoel expands to form chambers (__) lined with ependymal cells - Each cerebal hemisphere contains one large __ ventricle. - Third ventricle in diencephalon - Communicates with each lateral ventricle - Via __ __ - Fourth ventricle - Extends into medulla oblongata - Joins central canal of spinal cord - Connects with third ventricle - Via narrow canal in midbrain (cerebral __)

Anatomy of the brain: Ventricles of the brain: - In the embryo, neural tube encloses neurocoel - Neurocoel expands to form chambers (ventricles) lined with ependymal cells - Each cerebal hemisphere contains one large lateral ventricle. - Third ventricle in diencephalon - Communicates with each lateral ventricle - Via interventricular foramen - Fourth ventricle - Extends into medulla oblongata - Joins central canal of spinal cord - Connects with third ventricle - Via narrow canal in midbrain (cerebral aqueduct)

Axoaxonic synapses: - Synapses between axons of two neurons - Presynaptic inhibition - __ the rate of neurotransmitter release at presynaptic membrane - Presynaptic facilitation - __ the rate of neurotransmitter release at presynaptic membrane

Axoaxonic synapses: - Synapses between axons of two neurons - Presynaptic inhibition - Decreases the rate of neurotransmitter release at presynaptic membrane - Presynaptic facilitation - Increases the rate of neurotransmitter release at presynaptic membrane

Axon: - Single, long cytoplasmic process - Propagates electrical signals (action potentials) - Axoplasm - Cytoplasm of axon - Contains __, __, __, and __ - Axolemma - Plasma membrane of the axon - Covers the __ - Initial segment - Base of axon - Axon hillock - Thick region that attaches initial segment to __ - Collaterals - Branches of the axon - Telodendria - Fine extensions of distal axon - Axon terminals (synaptic terminals) - Tips of __

Axon: - Single, long cytoplasmic process - Propagates electrical signals (action potentials) - Axoplasm - Cytoplasm of axon - Contains neurofibrils, neurotubules, enzymes, and organelles - Axolemma - Plasma membrane of the axon - Covers the axoplasm - Initial segment - Base of axon - Axon hillock - Thick region that attaches initial segment to cell body - Collaterals - Branches of the axon - Telodendria - Fine extensions of distal axon - Axon terminals (synaptic terminals) - Tips of telodendria

What is the primary role of the enzyme acetylcholinesterase (AChE) at a cholinergic synapse? A. AChE depolarizes the postsynaptic cell. B. AChE degrades acetylcholine in the synaptic cleft. C. AChE releases acetylcholine into the synaptic cleft. D. AChE binds to ACh receptors, causing them to open.

B. AChE degrades acetylcholine in the synaptic cleft. - AChE is an enzyme that breaks down, or degrades, ACh in the synaptic cleft. Degradation and removal of ACh allows the postsynaptic membrane to return to its resting potential after depolarization.

________ is a disorder affecting the ability to speak or read. A. Apraxia B. Aphasia C. Dysphagia D. Ataxia E. Bell's palsy

B. Aphasia

Which structural class of neurons consists of neurons with one axon and one dendrite? A. Unipolar neurons B. Bipolar neurons C. Multipolar neurons D. Anaxonic neurons

B. Bipolar neurons

Making rapid postural adjustments is a major function of the __________. A. Medulla oblongata B. Cerebellum C. Cerebrum D. Diencephalons

B. Cerebellum

Binding of a neurotransmitter to its receptors opens __________ channels on the __________ membrane. A. Voltage-gated; postsynaptic B. Chemically gated; postsynaptic C. Voltage-gated; presynaptic D. Chemically gated; presynaptic

B. Chemically gated; postsynaptic - The neurotransmitter is a chemical released from the presynaptic membrane, so it would open chemically gated channels on the postsynaptic membrane.

An action potential is self-regenerating because __________. A. repolarizing currents established by the efflux of K+‎ flow down the axon and trigger an action potential at the next segment B. Depolarizing currents established by the influx of Na+‎ flow down the axon and trigger an action potential at the next segment C. Repolarizing currents established by the efflux of Na+‎ flow down the axon and trigger an action potential at the next segment D. Depolarizing currents established by the influx of K+‎ flow down the axon and trigger an action potential at the next segment

B. Depolarizing currents established by the influx of Na+‎ flow down the axon and trigger an action potential at the next segment - The Na+‎ diffusing into the axon during the first phase of the action potential creates a depolarizing current that brings the next segment, or node, of the axon to threshold.

In which type of axon will velocity of action potential conduction be the fastest? A. Unmyelinated axons of the shortest length B. Myelinated axons with the largest diameter C. Unmyelinated axons with the largest diameter D. Myelinated axons with the smallest diameters

B. Myelinated axons with the largest diameter - The large diameter facilitates the flow of depolarizing current through the cytoplasm. The myelin sheath insulates the axons and prevents current from leaking across the plasma membrane.

What prevents the Na+ and K+ gradients from dissipating? A. Na+ and K+ leaks B. Na+-K+ ATPase C. Na+ cotransporter D. H+-K+ ATPase

B. Na+-K+ ATPase - Also known as the Na+-K+ pump, or simply the pump, this transporter moves three Na+ out of the cell and two K+ into the cell for every ATP it hydrolyzes. This pumping action prevents the Na+ and K+ gradients from running down as these ions passively move through leak channels.

Which type of ion channel is always open? A. Chemically gated B. Passive C. Voltage-gated D. Mechanically gated

B. Passive

What structure is covered by many blood vessels and adheres tightly to the surface of the brain? A. Cranial plexus B. Pia mater C. Dura mater D. Arachnoid mater E. Choroid plexus

B. Pia mater

Which functional division of the nervous system controls skeletal muscle contractions? A. Afferent division B. Somatic nervous system C. Peripheral nervous system D. Autonomic nervous system

B. Somatic nervous system

What contains a spider web-like network of cells and fibers through which cerebrospinal fluid flows? A. subdural space B. Subarachnoid space C. Falx cerebri D. Dural sinus E. Pia mater

B. Subarachnoid space

The region of cerebral cortex inferior to the lateral sulcus is the __________ lobe. A. Frontal B. Temporal C. Parietal D. Occipital

B. Temporal

Which part of the nervous system controls smooth muscle, cardiac muscle, glands, and adipose tissue subconsciously? A. The somatic nervous system B. The autonomic nervous system C. The central nervous system D. The afferent division of the peripheral nervous system

B. The autonomic nervous system

The repolarization phase of an action potential results from __________. A. The opening of voltage-gated Na+ channels B. The opening of voltage-gated K+ channels C. The closing of voltage-gated K+ channels D. The closing of voltage-gated Na+ channels

B. The opening of voltage-gated K+ channels - As the voltage-gated K+ channels open, K+ rushes out of the cell, causing the membrane potential to become more negative on the inside, thus repolarizing the cell.

The cranial and spinal nerves make up what part of the nervous system? A. The somatic nervous system only B. The peripheral nervous system C. The autonomic nervous system only D. The central nervous system

B. The peripheral nervous system

A node along a myelinated axon represents an area where __________. A. There is a gap in the cell membrane B. There is an absence of myelin C. There are interwoven layers of myelin and protein D. There is a layer of fat

B. There is an absence of myelin

What is the first change to occur in response to a threshold stimulus? A. Voltage-gated Na+ channels change shape, and their inactivation gates close. B. Voltage-gated Na+ channels change shape, and their activation gates open. C. Voltage-gated K+ channels change shape, and their activation gates open. D. Voltage-gated Ca2+ channels change shape, and their activation gates open.

B. Voltage-gated Na+ channels change shape, and their activation gates open. - The activation gates of voltage-gated Na+ channels open very rapidly in response to threshold stimuli. The activation gates of voltage-gated K+ channels are comparatively slow to open.

What is the value for the resting membrane potential for most neurons? A. +30 mV B. -90 mV C. -70 mV

C. -70 mV - The resting membrane potential for neurons depends on the distribution of both Na+ and K+ across the cell membrane. The potential is closer to the equilibrium potential of K+ because the cell is more permeable to K+.

Approximately how fast do action potentials propagate in unmyelinated axons in humans? A. 120 meters per second B. 0.1 meters per second C. 1 meter per second D. 12 meters per second

C. 1 meter per second - While 1 m per second (2 mph) seems slow, most axons are short, and these speeds are fast enough for low-priority information such as smell (olfaction), temperature, and general touch sensations. Unmyelinated type C fibers have propagation speeds in this range.

The electrochemical gradient for potassium ions when the transmembrane potential is at the resting potential (-70 mV) is caused by what? A. Chemical and electrical gradients both going into the cell B. A chemical gradient going into the cell and an electrical gradient going out of the cell C. A chemical gradient going out of the cell and an electrical gradient going into the cell D. Chemical and electrical gradients both going out of the cell

C. A chemical gradient going out of the cell and an electrical gradient going into the cell - The higher concentration of potassium inside the cell than outside the cell results in an outward chemical gradient. However, the electrical gradient is in the opposite direction (inward) because, at the resting potential, the inside of the cell is more negative, which is attractive to the positively charged potassium ions.

What type of channel in the postsynaptic membrane binds neurotransmitter? A. A leakage channel B. A voltage-gated channel C. A chemically gated channel D. A mechanically gated channel

C. A chemically gated channel - At chemical synapses, neurotransmitter molecules are released by the presynaptic neuron and bind to chemically gated channels in the postsynaptic cell membrane. The opening of these chemically gated channels causes a graded potential.

Which of the following describes multipolar neurons? A. A neuron with one dendrite and one axon; characteristic of neurons in special sense organs B. A neuron with numerous dendrites but no visible axon; characteristic of some small neurons in the brain C. A neuron with two or more dendrites; characteristic of all motor neurons D. A neuron with continuous dendrites and axon; characteristic of most sensory neurons

C. A neuron with two or more dendrites; characteristic of all motor neurons

The main functional difference between the autonomic nervous system and the somatic nervous system is that the activities of the ANS __________. A. Are primarily voluntarily controlled B. Carry impulses to the CNS C. Are primarily involuntary, or under "automatic" control D. Affect skeletal muscle activity

C. Are primarily involuntary, or under "automatic" control

Where in the neuron is an action potential initially generated? A. Anywhere on the axon B. Soma and dendrites C. Axon hillock

C. Axon hillock - This region (first part of the axon) receives local signals (graded potentials) from the soma and dendrites and has a high concentration of voltage-gated Na+ channels.

What is the function of the brain structure indicated by the arrow? A. Conscious thought B. Relays sensory information to the thalamus C. Coordination of complex motor patterns D. Processes visual data

C. Coordination of complex motor patterns - The cerebellum coordinates complex somatic motor patterns and adjusts output of somatic motor centers in the brain and spinal cord.

What changes occur to voltage-gated Na+ and K+ channels at the peak of depolarization? A. Inactivation gates of voltage-gated Na+‎ channels close, while inactivation gates of voltage-gated K+‎ channels open. B. Activation gates of voltage-gated Na+‎ channels close, while activation gates of voltage-gated K+‎ channels open. C. Inactivation gates of voltage-gated Na+‎ channels close, while activation gates of voltage-gated K+‎ channels open. D. Activation gates of voltage-gated Na+‎ channels close, while inactivation gates of voltage-gated K+‎ channels open.

C. Inactivation gates of voltage-gated Na+‎ channels close, while activation gates of voltage-gated K+‎ channels open. - Closing of voltage-gated channels is time dependent. Typically, the inactivation gates of voltage-gated Na+‎ channels close about a millisecond after the activation gates open. At the same time, the activation gates of voltage-gated K+‎ channels open.

Which of these is not a property of the epithalamus? A. It is the location of the choroid plexus. B. It is the location of the pineal gland. C. It is the roof of the fourth ventricle. D. It is the roof of the diencephalon.

C. It is the roof of the fourth ventricle.

The cerebrum is divided into two hemispheres by the __________. A. Sagittal sinus B. Central sulcus C. Longitudinal fissure D. Sagittal sulcus

C. Longitudinal fissure

The sodium-potassium ion exchange pump A. Must reestablish ion concentrations after each action potential. B. Transports potassium ions out of the cell during repolarization. C. Moves sodium and potassium opposite to the direction of their electrochemical gradients. D. Transports sodium ions into the cell during depolarization. E. Depends on a hydrogen gradient for energy.

C. Moves sodium and potassium opposite to the direction of their electrochemical gradients.

The Na+-K+ pump actively transports both sodium and potassium ions across the membrane to compensate for their constant leakage. In which direction is each ion pumped? A. Both Na+ and K+ are pumped out of the cell. B. Both Na+ and K+ are pumped into the cell. C. Na+ is pumped out of the cell and K+ is pumped into the cell. D. K+ is pumped out of the cell and Na+ is pumped into the cell.

C. Na+ is pumped out of the cell and K+ is pumped into the cell. - Na+ is pumped out of the cell against its electrochemical gradient and K+ is pumped into the cell against its concentration gradient.

________ account for roughly half of the volume of the nervous system. A. Synapses B. Dendrites C. Neuroglia D. Axons E. Efferent fibers

C. Neuroglia

What characterizes repolarization, the second phase of the action potential? A. Before the membrane has a chance to reach a positive voltage, it repolarizes to its negative resting value of approximately -70 mV. B. Once the membrane depolarizes to a threshold value of approximately -55 mV, it repolarizes to its resting value of -70 mV. C. Once the membrane depolarizes to a peak value of +30 mV, it repolarizes to its negative resting value of -70 mV. D. As the membrane repolarizes to a negative value, it goes beyond the resting state to a value of -80 mV.

C. Once the membrane depolarizes to a peak value of +30 mV, it repolarizes to its negative resting value of -70 mV. - The plasma membrane was depolarized to a positive value at the peak of the first phase of the action potential. Thus, it must repolarize back to a negative value.

The small space between the sending neuron and the receiving neuron is the A. Synaptic terminal. B. Calcium channel. C. Synaptic cleft. D. Neurotransmitter. E. Vesicle.

C. Synaptic cleft. - The synaptic cleft is the small space between the sending neuron and the receiving neuron.

The events that occur at a functioning cholinergic synapse cause _____________ . A. Strengthening of the synapse B. A flow of acetylcholine (ACh) into the synaptic cleft that is removed only by simple diffusion C. Synaptic delay D. Loss of transmission of the action potential

C. Synaptic delay - Due to the time involved in calcium influx and neurotransmitter release, the transmission of an action potential is delayed at the synaptic cleft.

The cerebrum develops from the embryonic __________. A. Diencephalon B. Mesencephalon C. Telencephalon D. Metencephalon

C. Telencephalon

On average, the resting membrane potential is -70 mV. What does the sign and magnitude of this value tell you? A. The inside surface of the plasma membrane is much more positively charged than the outside surface. B. The outside surface of the plasma membrane is much more negatively charged than the inside surface. C. The inside surface of the plasma membrane is much more negatively charged than the outside surface. D. There is no electrical potential difference between the inside and the outside surfaces of the plasma membrane.

C. The inside surface of the plasma membrane is much more negatively charged than the outside surface. - The inside surface of the plasma membrane accumulates more negative charge because of the presence of Na+ and K+ gradients and the selective permeability of the membrane to Na+ and K+.

What is the electrochemical gradient of an ion? A. The electrochemical gradient is the direction an ion would diffuse (either outward or inward) when the neuron is at rest, regardless of the transmembrane potential. B. The transmembrane potential at which the electrical and chemical gradients are equal in magnitude, but opposite in direction C. The sum of the electrical and chemical gradients for that ion D. The difference between the concentrations of an ion inside and outside the cell

C. The sum of the electrical and chemical gradients for that ion - Together, these two gradients determine the net movement of a particular ion across the plasma membrane.

Sensory neurons are responsible for carrying impulses __________. A. From the CNS to the PNS B. To the PNS C. To the CNS D. Away from the CNS

C. To the CNS

Which of these axons will conduct an action potential most quickly? A. Type B fiber B. Type C fiber C. Type A fiber D. All fibers have the same propagation speed.

C. Type A fiber

An action potential releases neurotransmitter from a neuron by opening which of the following channels? A. Voltage-gated K+ channels B. Chemically gated Ca2+ channels C. Voltage-gated Ca2+ channels D. Voltage-gated Na+ channels

C. Voltage-gated Ca2+ channels - Yes, opening of these channels causes calcium to move into the axon terminal. Calcium inside the neuron causes the vesicles to merge with the membrane and release the neurotransmitter via exocytosis into the synaptic cleft.

Classes of neurotransmitters: - __ neurotransmitters - Cause depolarization of postsynaptic membranes - Promote action potentials - __ neurotransmitters - Cause hyperpolarization of postsynaptic membranes - Suppress action potentials

Classes of neurotransmitters: - Excitatory neurotransmitters - Cause depolarization of postsynaptic membranes - Promote action potentials - Inhibitory neurotransmitters - Cause hyperpolarization of postsynaptic membranes - Suppress action potentials

What is indicated by the arrow? A. A network of specialized ependymal cells that are involved in the production of CSF B. The area of the skull into which the fingerlike extensions, arachnoid villi, extend for reabsorption of CSF C. The space surrounding the brain, spinal cord, and cauda equina through which CSF flows D. Absorption of cerebrospinal fluid into the venous circulation

D. Absorption of cerebrospinal fluid into the venous circulation - Cerebrospinal fluid is absorbed into the venous circulation at the arachnoid granulations.

The cerebellum __________. A. Coordinates learned movements B. Has peduncles connecting to the cerebrum C. Adjusts posture D. All of these are true for the cerebellum.

D. All of these are true for the cerebellum.

During propagation of the action potential, __________. A. After threshold is reached, sodium channels open rapidly B. The axon hillock depolarizes the initial segment C. Local currents depolarize a spot adjacent to the active zone D. All of these events occur during propagation of the action potential.

D. All of these events occur during propagation of the action potential.

The effect of a nerve impulse on a postsynaptic neuron depends on the __________. A. Characteristics of the receptor on the postsynaptic neuron B. Kind of neurotransmitter released by the presynaptic neuron C. Quantity of neurotransmitter released D. All of these factors affect what happens at the postsynaptic neuron.

D. All of these factors affect what happens at the postsynaptic neuron.

Which of these statements about the medulla oblongata is true? A. It connects the brain and spinal cord. B. It is part of the brain stem. C. It contains centers for respiration. D. All of these statements are true of the medulla oblongata.

D. All of these statements are true of the medulla oblongata.

Where are action potentials regenerated as they propagate along a myelinated axon? A. At myelin B. At the internodes C. At every segment of the axon D. At the nodes

D. At the nodes - In myelinated axons, voltage-gated sodium channels are largely restricted to the nodes between myelinated internodes. Therefore, action potentials only regenerate at the nodes. The high membrane resistance of the internodes ensures that local currents generated at one node will quickly bring the next node to threshold, even though it is 1-2 mm away.

What part of the neuron is a long cytoplasmic process capable of propagating an action potential? A. Dendrite B. Perikaryon C. Soma D. Axon

D. Axon

EPSPs and IPSPs summate at the __________. A. Electrical synapse B. Synaptic knob C. Postsynaptic receptors D. Axon hillock

D. Axon hillock

The part of the neuron that performs the metabolic work of the cell to keep the neuron alive and functioning properly is the __________. A. Axon terminal B. Axoplasm C. Dendrite D. Cell body or soma

D. Cell body or soma

Which part of the nervous system performs the higher-order thinking required to complete a practice exam? A. Peripheral nervous system B. Afferent division C. Autonomic nervous system D. Central nervous system

D. Central nervous system

Sensory (ascending) pathways distribute information __________. A. From motor pathways to interneurons in the CNS B. From processing centers in the brain to peripheral receptors C. From the central nervous system to the peripheral nervous system D. From peripheral receptors to processing centers in the brain

D. From peripheral receptors to processing centers in the brain

If EPSPs summate to a sustained value above threshold, then the initial segment will __________. A. Generate larger than normal action potentials B. Generate both large and frequent action potentials C. Inactivate D. Generate a string of action potentials

D. Generate a string of action potentials

Which of these is not a property of cerebrospinal fluid (CSF)? A. It protects the brain and spinal cord. B. It circulates in the subarachnoid space. C. It supports the brain. D. It is produced at the arachnoid granulations.

D. It is produced at the arachnoid granulations.

The concentrations of which two ions are highest outside the cell. A. Na+ and A- (negatively charged proteins) B. K+ and A- (negatively charged proteins) C. K+ and Cl- D. Na+ and Cl-

D. Na+ and Cl- - Both Na+ and Cl- are in higher concentrations outside the cell.

Which of these neurotransmitters is released at CNS adrenergic synapses? A. GABA B. Adrenaline C. Serotonin D. Norepinephrine

D. Norepinephrine

Droopy eyelids and double vision can result from injury to the ________ nerve. A. Optic B. Facial C. Trochlear D. Oculomotor E. Olfactory

D. Oculomotor

The myelin sheath that covers many CNS axons is formed by A. Ependymal cells. B. Satellite cells. C. Microglia. D. Oligodendrocytes. E. Astrocytes.

D. Oligodendrocytes.

What part of the neuron consists of the cytoplasm that surrounds the nucleus? A. Collateral B. Neurofibril C. Nissl body D. Perikaryon

D. Perikaryon

The primary somatosensory cortex is found on the __________. A. Precentral gyrus B. Cingulate gyrus C. Frontal lobe D. Postcentral gyrus

D. Postcentral gyrus

The movement of what ion is responsible for the local currents that depolarize other regions of the axon to threshold? A. Voltage-gated sodium (Na+) channels B. Potassium (K+) C. Calcium (Ca2+) D. Sodium (Na+)

D. Sodium (Na+) - Sodium ions enter the cell during the beginning of an action potential. Not only does this (further) depolarize the membrane where those channels are located, but it also sets up local currents that depolarize nearby membrane segments. In the case of myelinated axons, these local currents depolarize the next node, 1-2 mm away.

Why does regeneration of the action potential occur in one direction, rather than in two directions? A. The activation gates of voltage-gated K+‎ channels open in the node, or segment, that has just depolarized. B. The activation gates of voltage-gated Na+‎ channels close in the node, or segment, that has just depolarized. C. The inactivation gates of voltage-gated K+‎ channels close in the node, or segment, that has just fired an action potential. D. The inactivation gates of voltage-gated Na+‎ channels close in the node, or segment, that has just fired an action potential.

D. The inactivation gates of voltage-gated Na+‎ channels close in the node, or segment, that has just fired an action potential. - At the peak of the depolarization phase of the action potential, the inactivation gates close. Thus, the voltage-gated Na+‎ channels become absolutely refractory to another depolarizing stimulus.

What characterizes depolarization, the first phase of the action potential? A. The membrane potential reaches a threshold value and returns to the resting state. B. The membrane potential changes to a much more negative value. C. The membrane potential changes to a less negative (but not a positive) value. D. The membrane potential changes from a negative value to a positive value.

D. The membrane potential changes from a negative value to a positive value. - The plasma membrane, which was polarized to a negative value at the RMP, depolarizes to a positive value.

The plasma membrane is much more permeable to K+ than to Na+. Why? A. There are many more voltage-gated K+ channels than voltage-gated Na+ channels. B. Ligand-gated cation channels favor a greater influx of Na+ than K+. C. The Na+-K+ pumps transport more K+ into cells than Na+ out of cells. D. There are many more K+ leak channels than Na+ leak channels in the plasma membrane.

D. There are many more K+ leak channels than Na+ leak channels in the plasma membrane. - More leak channels translates into more leakiness. Thus the permeability to K+ is greater than the permeability to Na+, and so K+ contributes the most to determining the resting membrane potential.

The patient has the following symptoms: change in vocal tone, problems swallowing, inability to control urination, erratic heart rate, and gastric problems. You would identify the problem as being related to the A. Hypoglossal nerve. B. Accessory nerve. C. Abducens nerve. D. Vagus nerve. E. Trigeminal nerve.

D. Vagus nerve.

The depolarization phase of an action potential results from the opening of which channels? A. Voltage-gated K+ channels B. Chemically gated K+ channels C. Chemically gated Na+ channels D. Voltage-gated Na+ channels

D. Voltage-gated Na+ channels - When the voltage-gated Na+ channels open, Na+ rushes into the cell causing depolarization.

When calcium ions enter the synaptic terminal, A. Neurotransmitter molecules are quickly removed from the synaptic cleft. B. They cause an action potential in the sending neuron. C. The inside of the receiving neuron becomes more positive. D. The inside of the receiving neuron becomes more negative. E. They cause vesicles containing neurotransmitter molecules to fuse to the plasma membrane of the sending neuron.

E. They cause vesicles containing neurotransmitter molecules to fuse to the plasma membrane of the sending neuron.

Electrical synapses: - Presynaptic and postsynaptic membranes are locked together at __. - Ions pass between cells through __. - Local current affects both cells. - Action potentials are __ quickly. - Found in some areas of brain, the eye, and ciliary ganglia.

Electrical synapses: - Presynaptic and postsynaptic membranes are locked together at gap junctions. - Ions pass between cells through pores. - Local current affects both cells. - Action potentials are propogated quickly. - Found in some areas of brain, the eye, and ciliary ganglia.

Events at a cholinergic synapse: - Action potential arrives at __ and depolarizes membrane. - Extracellular calcium ions enter axon terminal and trigger __ of __. - ACh binds to receptors on postsynaptic membrane and depolarize it. - ACh is removed from __ by __. - __ breaks ACh into __ and __.

Events at a cholinergic synapse: - Action potential arrives at axon terminal and depolarizes membrane. - Extracellular calcium ions enter axon terminal and trigger exocytosis of ACh. - ACh binds to receptors on postsynaptic membrane and depolarize it. - ACh is removed from synaptic cleft by acetylcholinesterase (AChE). - AChE breaks ACh into acetate and choline.

Function of chemical synapses: - Axon terminal releases neurotransmitters that bind to postsynaptic __. - Produces localized change in permeability and __. - Action potential may or may not be generated in postsynaptic cell, depending on - Amount of __ released - Sensitivity of __ cell

Function of chemical synapses: - Axon terminal releases neurotransmitters that bind to postsynaptic plasma membrane. - Produces localized change in permeability and graded potentials. - Action potential may or may not be generated in postsynaptic cell, depending on - Amount of neurotransmitter released - Sensitivity of postsynaptic cell

Functional classifications of neurons: Sensory neurons: - Afferent neurons - Unipolar - Cells bodies grouped in sensory __. - Processes (afferent fibers) extend from __ to __. - Somatic sensory neurons - Monitor __ environment - Visceral sensory nuerons - Monitor __ environment - Types of sensory receptors 1. Interoceptors - Monitor internal systems (e.g., digestive, urinary) - Internal senses (stretch, deep pressure, pain) 2. Exteroceptors - Monitor external environment (e.g., temperature) - Complex senses (e.g., sight, smell, hearing) 3. Proprioceptors - Monitor position and movement of skeletal muscles and joints Motor neurons: - Efferent neurons - Carry instructions from __ to __. - Via efferent fibers (axons) - Somatic motor neurons of SNS - Innervate skeletal muscles - Visceral motor neurons of ANS - Innervate all other __ effectors. - Smooth and cardiac muscle, glands, adipose tissue - Motor nuerons - Signals from __ to __ effectors cross autonomic __ that divide axons into: - __ fibers - __ fibers Interneurons: - Most are in __ and __ - Some in autonomic ganglia - Located between sensory and motor neurons - Responsible for: - Distribution of sensory information - Coordination of motor activity - Involved in higher functions - Memory, planning, learning

Functional classifications of neurons: Sensory neurons: - Afferent neurons - Unipolar - Cells bodies grouped in sensory ganglia. - Processes (afferent fibers) extend from sensory receptors to CNS. - Somatic sensory neurons - Monitor external environment - Visceral sensory nuerons - Monitor internal environment - Types of sensory receptors 1. Interoceptors - Monitor internal systems (e.g., digestive, urinary) - Internal senses (stretch, deep pressure, pain) 2. Exteroceptors - Monitor external environment (e.g., temperature) - Complex senses (e.g., sight, smell, hearing) 3. Proprioceptors - Monitor position and movement of skeletal muscles and joints Motor neurons: - Efferent neurons - Carry instructions from CNS to peripheral effectors. - Via efferent fibers (axons) - Somatic motor neurons of SNS - Innervate skeletal muscles - Visceral motor neurons of ANS - Innervate all other peripheral effectors. - Smooth and cardiac muscle, glands, adipose tissue - Motor nuerons - Signals from CNS to visceral effectors cross autonomic ganglia that divide axons into: - Preganglionic fibers - Postganglionic fibers Interneurons: - Most are in brain and spinal cord - Some in autonomic ganglia - Located between sensory and motor neurons - Responsible for: - Distribution of sensory information - Coordination of motor activity - Involved in higher functions - Memory, planning, learning

How an action potential happens: Getting ready for the action potential: - Ligand gated ion channels - Example: __ - Voltage gated ion channels - Example: __

How an action potential happens: Getting ready for the action potential: - Ligand gated ion channels - Example: Ach to receptor - open channel - Voltage gated ion channels - Example: low Ca++ in area causes opening of Na+ channels

How an action potential happens: Refractory period: - Sensitivity of area to further stimulation decreases for a time - Parts: - Absolute - Complete insensitivity to another stimulus - From beginning of action potential until near end of __ - Relative - A stronger-than-threshold stimulus can initiate another __.

How an action potential happens: Refractory period: - Sensitivity of area to further stimulation decreases for a time - Parts: - Absolute - Complete insensitivity to another stimulus - From beginning of action potential until near end of repolarization - Relative - A stronger-than-threshold stimulus can initiate another action potential .

How an action potential happens: Resting membrane potential: - Its all about ions - __mV - __ and proteins inside - __ outside - Maintained by : - __ leak channels - Negatively charged proteins inside the cell - Na+/K+ pump (__ Na+ in/ __ K+ out)

How an action potential happens: Resting membrane potential: - Its all about ions - -70mV - K+ and proteins inside - Na+ outside - Maintained by : - K+ leak channels - Negatively charged proteins inside the cell - Na+/K+ pump (3Na+ in/ 2K+ out)

How fast will the AP go? - In myelinated axons - Faster - Jump from __ to __ - Speed is affected by __ of myelin sheath - Diameter of axons - Large-diameter conduct more rapidly - More __ channels

How fast will the AP go? - In myelinated axons - Faster - Jump from node to node - Speed is affected by thickness of myelin sheath - Diameter of axons - Large-diameter conduct more rapidly - More voltage-gated Na+ channels

Neuroglia (Types of neuroglia in the CNS): - Astrocytes - Shaped like __ - Abundant - Make exchanges of nutrients between __ and __ - Blood brain barrier - Microglia - Small oval cells with long, skinny processes - Monitor __ - Surround a cell that is injured or has been infected - Ependymal cells - Form a barrier in the lining of __ cavities - Choroid plexus: forms __ - Neuroglia in the __ - Satellite cells - Surround neuron cell bodies in the __ - Cell membrane wraps around neuron (phospholipids) - Schwann cells - Surround neuron cell bodies in __ - Provide __ - Oligodendrocytes - Fewer processes than astroglia - Wrap along thick neuron fibers - Insulation - Make up __ - Internodes - __ segments of axon - Nodes (nodes of Ranvier) lie between __: where __ may branch - White matter: region of __ with many myelinated axons - Gray matter of __: contains __, neuron cell bodies, and dendrites

Neuroglia (Types of neuroglia in the CNS): - Astrocytes - Shaped like stars - Abundant - Make exchanges of nutrients between blood supply and neurons - Blood brain barrier - Microglia - Small oval cells with long, skinny processes - Monitor neuronal health - Surround a cell that is injured or has been infected - Ependymal cells - Form a barrier in the lining of brain cavities - Choroid plexus: forms CSF - Neuroglia in the PNS - Satellite cells - Surround neuron cell bodies in the PNS - Cell membrane wraps around neuron (phospholipids) - Schwann cells - Surround neuron cell bodies in sensory ganglia - Provide nutrients - Oligodendrocytes - Fewer processes than astroglia - Wrap along thick neuron fibers - Insulation - Make up myelin sheaths - Internodes - myelinated segments of axon - Nodes (nodes of Ranvier) lie between internodes: where axons may branch - White matter: region of CNS with many myelinated axons - Gray matter of CNS: contains unmyelinated axons, neuron cell bodies, and dendrites

Neurotransmitters and Neuromodulators: - Neurotransmitters and neuromodulators may have - A direct effect on membrane potential - By opening or closing chemically gated ion channels - Example: __, glutamate, aspartate - An indirect effect through __ proteins - Example: E, NE, dopamine, serotonin, histamine, GABA - An indirect effect via __ enzymes - Example: lipid-soluble gases (NO, CO) - Second messengers - Indirect effects by second messengers - __ protein links - First messenger (neurotransmitter) - And second messengers (ions or molecules in cell) - __ proteins include an enzyme that is activated when an extracellular compound binds - Example: __ - Produces the second messenger __ - Intracellular enzymes - Indirect effects by intracellular enzymes - Lipid-soluble gases (NO, CO) - Diffuse through lipid membranes - Bind to enzymes inside of __ cells

Neurotransmitters and Neuromodulators: - Neurotransmitters and neuromodulators may have - A direct effect on membrane potential - By opening or closing chemically gated ion channels - Example: ACh, glutamate, aspartate - An indirect effect through G proteins - Example: E, NE, dopamine, serotonin, histamine, GABA - An indirect effect via intracellular enzymes - Example: lipid-soluble gases (NO, CO) - Second messengers - Indirect effects by second messengers - G protein links - First messenger (neurotransmitter) - And second messengers (ions or molecules in cell) - G proteins include an enzyme that is activated when an extracellular compound binds - Example: adenylate cyclase - Produces the second messenger cyclic-AMP (cAMP) - Intracellular enzymes - Indirect effects by intracellular enzymes - Lipid-soluble gases (NO, CO) - Diffuse through lipid membranes - Bind to enzymes inside of brain cells

Structural classification of neurons: - Anaxonic neurons - Small - All cell processes look similar - Found in __ and __ organs. - Bipolar neurons - Small and rare - One __ and one __. - Found in __ organs. - Unipolar neurons (pseudounipolar neurons) - Axon and dendrites are fused - Cell body to one side - Most sensory nuerons of __. - Multipolar neurons - Have one long __ and two or more __. - Common in the __ - All motor neurons that control __ muscles.

Structural classification of neurons: - Anaxonic neurons - Small - All cell processes look similar - Found in brain and special sense organs. - Bipolar neurons - Small and rare - One dendrite and one axon. - Found in special sense organs (sight, smell, hearing). - Unipolar neurons (pseudounipolar neurons) - Axon and dendrites are fused - Cell body to one side - Most sensory nuerons of PNS. - Multipolar neurons - Have one long axon and two or more dendrites. - Common in the CNS - All motor neurons that control skeletal muscles.

Summation: - __ - Rapid, repeated stimuli at a single synapse - __ - Simultaneous stimuli arrive at multiple synapses - A neuron becomes __ - As EPSPs accumulate - And raise membrane potential closer to threshold - Until a small stimulus can trigger action potential - Summation of EPSPs and IPSPs - Neuromodulators and hormones - Can change membrane sensitivity to neurotransmitters - Shifting balance between EPSPs and IPSPs

Summation: - Temporal summation - Rapid, repeated stimuli at a single synapse - Spatial summation - Simultaneous stimuli arrive at multiple synapses - A neuron becomes facilitated - As EPSPs accumulate - And raise membrane potential closer to threshold - Until a small stimulus can trigger action potential - Summation of EPSPs and IPSPs - Neuromodulators and hormones - Can change membrane sensitivity to neurotransmitters - Shifting balance between EPSPs and IPSPs

Synapses: - Specialized site where a neuron communicates with another cell - __ neuron - Sends the message - __ neuron - Receives message

Synapses: - Specialized site where a neuron communicates with another cell - Presynaptic neuron - Sends the message - Postsynaptic neuron - Receives message

Synaptic delay: - A synaptic delay of 0.2-0.5 msec occurs between - Arrival of action potential at axon terminal - And affect on postsynaptic membrane - Mostly due to time required for __ and __ release. - Fewer synapses lead to __ responses. - Some reflexes involve only one synapse.

Synaptic delay: - A synaptic delay of 0.2-0.5 msec occurs between - Arrival of action potential at axon terminal - And affect on postsynaptic membrane - Mostly due to time required for calcium ion influx and neurotransmitter release. - Fewer synapses lead to faster responses. - Some reflexes involve only one synapse.

Types of chemical synapses: - Neuromuscular junction - Synapse between __ and __ cell - Neuroglandular junction - Synapse between __ and __ cell

Types of chemical synapses: - Neuromuscular junction - Synapse between neuron and skeletal muscle cell - Neuroglandular junction - Synapse between neuron and gland cell

Types of nerves found in the PNS: - Afferent vs efferent - Afferent - begins with an A - Goes from __ to __. - Efferent - beings with an E (after an A) - Goes from __ to __ - Something happens to the body the Afferent nerve allows the electricity to travel to the __. - From the __, an Efferent nerve tells the __ to move.

Types of nerves found in the PNS: - Afferent vs efferent - Afferent - begins with an A - Goes from body to brain. - Efferent - beings with an E (after an A) - Goes from brain to body - Something happens to the body the Afferent nerve allows the electricity to travel to the brain. - From the brain, an Efferent nerve tells the body to move.

Types of postsynaptic potentials: - __ - Graded depolarization of postsynaptic membrane - __ - Graded hyperpolarization of postsynaptic membrane - Information processing: - A neuron that receives many __ - Is __ from producing an action potential - Because the stimulation needed to reach threshold is increased - To trigger an action potential - One ESPS is not enough - ESPSs (and IPSPs) combine through __ - __ - __

Types of postsynaptic potentials: - Excitatory postsynaptic potential (EPSP) - Graded depolarization of postsynaptic membrane - Inhibitory postsynaptic potential (IPSP) - Graded hyperpolarization of postsynaptic membrane - Information processing: - A neuron that receives many IPSPs - Is inhibited from producing an action potential - Because the stimulation needed to reach threshold is increased - To trigger an action potential - One ESPS is not enough - ESPSs (and IPSPs) combine through summation - Temporal summation - Spatial summation

Types of snyapses: - Electrical synapses - Direct physical contact between cells - Chemical synapses - Signal transmitted across a gap by __.

Types of snyapses: - Electrical synapses - Direct physical contact between cells - Chemical synapses - Signal transmitted across a gap by neurotransmitters.