The Brain (Exam 3), A & P Exam 3

Neurons may be classified according to several characteristics. Which of the following is correct?

Group C fibers are not capable of saltatory conduction.

A neuron that has as its primary function the job of connecting other neurons is called a(n) ________.

association neuron

Neuroglia that control the chemical environment around neurons by buffering potassium and recapturing neurotransmitters are ________.

astrocytes

The sympathetic and parasympathetic are subdivisions of the ________.

autonomic nervous system

________ potentials are short-lived, local changes in membrane potential that can be either depolarized or hyperpolarized.

Graded

Bipolar neurons are commonly ________.

found in the retina of the eye

Collections of nerve cell bodies outside the central nervous system are called ________.

ganglia

When a sensory neuron is excited by some form of energy, the resulting graded potential is called a(n) ________.

generator potential

Ependymal cells ________.

help to circulate the cerebrospinal fluid

Which of the following is not a function of the autonomic nervous system?

innervation of skeletal muscle

In what way does the interior surface of a cell membrane of a resting (nonconducting) neuron differ from the external environment? The interior is ________.

negatively charged and contains less sodium

The sheath of Schwann is also called the ________.

neurilemma

The substance released at axon terminals to propagate a nervous impulse is called a(n) ________.

neurotransmitter

Which of the following is a good example of a neuromodulator?

nitric oxide

A gap between Schwann cells in the peripheral system is called a(n) ________.

node of Ranvier

Schwann cells are functionally similar to ________.

oligodendrocytes

Direct-acting neurotransmitters ________.

open ion channels to provoke rapid responses

When information is delivered within the CNS simultaneously by different parts of the neural pathway, the process is called ________ processing.

parallel

The sodium-potassium pump ________.

pumps three sodium ions outside the cell and two potassium ions inside

That part of the nervous system that is voluntary and conducts impulses from the CNS to the skeletal muscles is the ________ nervous system.

somatic

The point at which an impulse from one nerve cell is communicated to another nerve cell is the ________.

synapse

Which of the following is not a structural feature of a neuron?

synaptic cleft

When one or more presynaptic neurons fire in rapid order it produces a much greater depolarization of the postsynaptic membrane than would result from a single EPSP; this event is called ________ summation.

temporal

Saltatory conduction is made possible by ________.

the myelin sheath

Nerve cell adhesion molecules (N-CAMs) ________.

are crucial for the development of neural connections

A second nerve impulse cannot be generated until ________. A) the membrane potential has been reestablished B) proteins have been resynthesized C) the Na ions have been pumped back into the cell D) all sodium gates are closed

A

All of the following are true of graded potentials except that they ________. A) increase amplitude as they move away from the stimulus point B) can form on receptor endings C) are short-lived D) can be called postsynaptic potentials

A

An excitatory neurotransmitter secreted by motor neurons innervating skeletal muscle is ________. A) acetylcholine B) norepinephrine C) cholinesterase D) gamma aminobutyric acid

A

An inhibitory postsynaptic potential (IPSP) is associated with ________. A) hyperpolarization B) a change in sodium ion permeability C) opening of voltage-regulated channels D) lowering the threshold for an action potential to occur.

A

The chemically gated channel, NMDA, allows ________ ions entry into the nerve cell. A) Ca2+ B) Cl- C) Na+ D) K+

A

The limbic association area of the multimodal association areas provides our ________. A) emotional impact B) working memory C) recall and personality D) learning abilities

A

The part of the neuron that normally receives stimuli is called ________. A) a dendrite B) an axon C) a neurolemma D) a Schwann cell

A

The primary auditory cortex is located in the ________. A) temporal lobe B) prefrontal lobe C) parietal lobe D) frontal lobe One of the four lobes in each cerebral hemisphere of the brain, primarily involved with hearing, but also plays an important role in memory and other mental processes. ~Located in the lower, central area of the brain. ~The primary auditory cortex is located in the temporal lobe. ~Association areas are involved in memory, facts, how to do things, and important personal experiences. ~Wernicke's area is located in the temporal lobe.

A

Period during which the neuron cannot respond to a second stimulus, no matter how strong.

Absolute refractory period

Also called a nerve impulse transmitted by axons.

Action potential

A language disorder apparent in speech, writing or reading produced by injury to brain areas specialised for these functions.

Aphasia

Intergrate information from different brain areas and are mainly involved in complex cognitive processes such as percieving, thinking, learning and remembering. ~Located in all four lobes of each hemisphere.

Association areas

________ are found in the CNS and bind axons and blood vessels to each other.

Astrocytes

Conducting region of the neuron.

Axon

) Neurotransmitters are released at the ________.

Axon terminal

An action potential ________. A) involves impulse propagation dependent on chemically gated ion channels B) is essential for impulse propagation C) involves the influx of negative ions to depolarize the membrane D) is initiated by potassium ion movemen

B

The role of acetylcholinesterase is to ________. A) amplify or enhance the effect of ACh B) destroy ACh a brief period after its release by the axonal endings C) stimulate the production of serotonin D) act as a transmitting agent

B

The term central nervous system refers to the ________. A) spinal cord and spinal nerves B) brain and spinal cord C) brain, spinal cord, and peripheral nerves D) autonomic nervous system

B

Which of the following will occur when an excitatory postsynaptic potential (EPSP) is being generated on the dendritic membrane? A) Sodium gates will open first, then close as potassium gates open. B) A single type of channel will open, permitting simultaneous flow of sodium and potassium. C) Specific sodium gates will open D) Specific potassium gates will open

B

Imagine a neuron that has several hundred axonal knobs impinging on it. The majority of these axonal knobs are shown to be "firing." However, the neuron in question does not transmit an impulse. Give a valid explanation of why this could occur.

Both excitatory and inhibitory potentials impinge on neurons. Inhibitory postsynaptic potentials (IPSPs) are "firing," but due to the neurotransmitter released and its action, the postsynaptic neuron is inhibited from "firing" (hyperpolarized).

A complex structure that is responsible for virtually everything we think, feel and do.

Brain

A language disorder resulting from damage to Broca's area and involving production of speech that consists of very short sentences comprising mostly verbs and nouns. ~Also called non-fluent aphasia.

Broca's aphasia

A specialised area of the brain located in the left frontal love that coordinates movements of muscles involved in speech production and supplies this information to the appropriate cortex areas.

Broca's area

If a motor neuron in the body were stimulated by an electrode placed about midpoint along the length of the axon ________. A) the impulse would move to the axon terminal only B) muscle contraction would occur C) the impulse would spread bidirectionally D) the impulse would move to the axon terminal only, and the muscle contraction would occur

C

Which group of fibers spreads impulses at up to 1 meter per second? A) group A fibers B) group B fibers C) group C fibers D) group D fibers

C

The coiled outer layer of the brain's cerebral hemispheres that is involved with information-processing activities such as perception, language, learning, memory, thinking and problem solving, as well as the planning and control of bodily movements.

Cerebral cortex

Two almost symmetrical brain structures that appear to be seperated by a deep groove running from the front to the back of the brain.

Cerebral hemispheres

A band of nerve tissue that connects the left and right cerebral hemispheres and serves as the main communication pathway between them.

Corpus callosum

Areas of the brain associated with different structures and functions.

Cortical lobes

Which of the following is correct relative to Ohm's law?

Current is directly proportional to the voltage

A neural circuit in which a single impulse is transmitted over and over is a ________. A) diverging circuit B) converging circuit C) repetitive circuit D) reverberating circuit

D

A neuronal circuit that concentrates or directs a large number of incoming impulses to a rather small number of neurons is called a(n) ________. A) diverging circuit B) parallel circuit C) oscillating circuit D) converging circuit

D

Immediately after an action potential has peaked, which cellular gates open? A) calcium B) sodium C) chloride D) potassium

D

The part of a neuron that conducts impulses away from its cell body is called a(n) ________. A) dendrite B) neurolemma C) Schwann cell D) axon

D

Receptive region of the neuron.

Dendrites

The interior of the cell becomes less negative due to an influx of sodium ions.

Depolarization

The largest of the four lobes in each cerebral hemisphere, situated in the front of the brain, involved in higher mental abilities. ~The primary motor cortex is located at the rear of each frontal lobe. ~Association areas perform complex mental functions. ~Coordinates many of the functions of other lobes. ~Broca's area is located in the left frontal lobe.

Frontal lobe

________ is a neurotransmitter of the CNS that is used by Purkinje cells of the CNS.

GABA (gamma aminobutyric acid)

The specialisation and dominance of certain functions of the left and right cerebral hemispheres. ~The left hemisphere specialises in verbal tasks such as speech production, comprehension, reading and writing. It also specialises in analysis, maths, sequential tasks, evaluation, and logical reasoning. ~The right hemisphere specialises in non-verbal tasks and spatial and visual thinking, such as solving jigsaw puzzles, map reading, and visualising a location. It specialises in creativity, fantasy, appreciation of art and music, as well as recognising emotions and reading body language.

Hemespheric specialisation

Why does a hyperpolarization phase generally follow a repolarization phase in an action potential?

Immediately after an action potential the potassium gates, being slow gates which do not respond to change in the electrical charge, allow additional K+ ions to flood into the cell. These K+ ions decrease the positive ion concentration momentarily below the normal -70mV and thus hyperpolarize the cell.

What function is served by the increased axon diameter at the nodes of Ranvier?

Increased diameter results in increased surface area on the membrane for sodium channels. This results in increased speed of impulse propagation.

Recieve and process information about voluntary bodily movements. ~Primary motor cortex located in the frontal lobe.

Motor areas

________ is a disease that gradually destroys the myelin sheaths of neurons in the CNS, particularly in young adults.

Multiple sclerosis (MS)

Which of these ions is actively transported through the cell membrane to establish a resting potential?

Na

Define neurotransmitter. Name two amino acid neurotransmitters, two catecholamines, and two peptides.

Neurotransmitters are chemical signals used as a means of communication. GABA and glycine are amino acid neurotransmitters; dopamine and norepinephrine are catecholamines; and endorphin and enkephalin are peptide transmitters.

The rough ER of the cell.

Nissl bodies

One of four lobes in each cerebral hemisphere of the brain, primary involved in vision. ~Located at the back of the brain. ~The primary visual cortex is found in the occipital lobe. ~Only some of the information crosses over from one side to the other. ~Association areas interact with the primary visual cortex to select, organise, and intergrate visual information. They also interact with association areas in the other cortical lobes to intergrate visual information with other information such as memory, language and sounds.

Occipital lobe

________ law is the relationship between voltage, current, and resistance.

Ohm's

One of four lobes in each cerebral hemisphere of the brain that recieves and processes sensory information from the body and other sensory areas in the brain. ~Found behind the frontal lobe. ~Also involved in spatial perception and memory. ~The primary somatosensory cortex is located in the parietal lobe. ~Association areas help us determine the position of our body in space.

Parietal lobe

An area in each temporal lobe that recieves and processes information from the ears.

Primary auditory cortex

A strip of neural tissue at the rear of the frontal lobe that is specifically involed in controlling voluntary bodily movements through its control of skeletal muscles. ~Different areas move specific body parts. ~The more complex a movement, the more cortical area is taken up. ~Lips and hands take up a lot of cortical space.

Primary motor cortex

A strip of neural tissue in the parietal lobe that ecieves and processes information from the skin and body, enabling us to percieve bodily sensations. ~Sensory information includes touch, pressure, temperature, muscle movement. ~The amount of cortex devoted to a particular body part corresponds to the sensitivity and amount of use of the body part. Just as with the primary motor cortex.

Primary somatosensory cortex

Neural tissue in the occipital lobe that recieves and processes visual information from the eyes.

Primary visual cortex

An exceptionally strong stimulus can trigger a response.

Relative refractory period

The specific period during which potassium ions diffuse out of the neuron due to a change in membrane permeability.

Repolarization

What are the basic divisions of the peripheral nervous system?

Sensory and motor divisions. Motor has two divisions: the somatic and autonomic. The autonomic has two divisions: the sympathetic and parasympathetic.

Recieve and process information from sensory receptors in the body. ~Primary visual cortex located in the occipital lobe. ~Primary auditory cortex located in the temporal lobe. ~Primary somatosensory cortex located in the parietal lobe.

Sensory areas

________ is an indolamine.

Serotonin

How can a single axon respond to several different kinds of events?

Some axon terminals contain more than one kind of neurotransmitter. Therefore, the axon can release one or more neurotransmitters simultaneously, creating singular or multiple events.

Which of the following is true about the movement of ions across excitable living membranes?

Some ions are prevented from moving down their concentration gradients by ATP-driven pumps.

An attentional disorder in which a person fails to notice either objects on their left or right side. ~Considered to be a disorder of attention, not memory. ~Most common in people who have damage to the rear of the right parietal lobe. Therefere most often seem oblivious to the left side.

Spatial neglect

Stimulation of a postsynaptic neuron by many terminals at the same time.

Spatial summation

Select the correct statement about serial processing.

Spinal reflexes are an example of serial processing.

Involved surgically cutting the corpus callosum so that the two hemispheres do not directly recieve information from each other. ~Used to treat epilepsy.

Split brain surgery

An insufficient stimulus

Subthreshold stimulus

Numerous nerve impulses arriving at a synapse at closely timed intervals exert a cumulative effect.

Temporal summation

A brain structure that filters information from the senses and transmits the information to the cerebral cortex.

Thalamus

Since all action potentials are alike, how does the brain separate situations that require immediate attention from ordinary "positional" reports?

The importance of a stimulus is derived from the number of stimuli received from the same source. The frequency of impulse transmission indicates the stimulus intensity and the brain responds appropriately.

Select the correct statement about synapses.

The synaptic cleft prevents an impulse from being transmitted directly from one neuron to another.

How can potentially poisonous gasses like NO and CO be used by the body?

These gasses are neurotransmitters that act indirectly. Similar to hormones, NO and CO promote longer-lasting effects by acting through intracellular second-messenger molecules.

ATP neurotransmitters have what basic effect on the body?

They provoke a sensation of pain.

Any stimulus below this intensity will result in no response in a neuron.

Threshold stimulus

Choose the statement that is most correct about membrane potential

Voltage would be measured by placing one electrode inside the membrane and another outside the membrane.

A speech impairment resulting from damage to Wernicke's area and involving difficulties with speech comprehension and producing fluent speech. ~Also called fluent aphasia.

Wernicke's aphasia

A specialised area usually in the left temporal lobe that is involved with comprehending the sounds of human speech.

Wernicke's area

The period after an initial stimulus when a neuron is not sensitive to another stimulus is the ________.

absolute refractory period

The synapse more common in embryonic nervous tissue than in adults is the ________.

electrical synapse

Ciliated CNS neuroglia that play an active role in moving the cerebrospinal fluid are called ________.

ependymal cells