Bio Ch11 Homework

Which of the following statements correctly characterizes an action potential?

Action potentials are initiated by depolarization of the membrane to threshold.

Why are many muscles at the effector end of the reflex arc found in antagonistic pairs?

Antagonistic muscles have opposite actions. This is often needed for a reflex.

During synaptic transmission, the influx of ________ causes vesicles in the axon bulb to fuse with the cell membrane, releasing ________

Ca2+, neurotransmitter

Which statement accurately describes the myelin sheath?

It speeds up the conduction of nervous impulses.

Which one of the following diseases is a progressive degenerative disorder caused by destruction of dopamine-releasing neurons in the brain that coordinate muscle movement?

Parkinson's disease

What does saltatory conduction mean?

Saltatory conduction means that the nerve impulse seems to jump from one node to the next—and is regenerated as it speeds along.

When speaking of myelinating glial cells, we can correctly say that ________.

Schwann cells are glial cells found outside the brain and spinal cord; oligodendrocytes are glial cells found in the brain and spinal cord

What causes an action potential to be conducted along a neuron's axon?

The change in charge difference across the membrane spreads from open sodium channels, causing sodium channels farther along the axon to open.

Which of these causes the release of neurotransmitter molecules?

an action potential reaching the end of the axon

Control of smooth muscle and internal organs is the role of the ________ division of the nervous system?

autonomic

The part of the nerve cell responsible for origination of the nerve impulse is the ________.

axon hillock, because this is the specific area of the nerve cell that generates the electrical impulse that travels along the axon

A nerve impulse moves away from a neuron's cell body along _____.

axons

A neuron's nucleus is located in its _____.

cell body

Part complete People who are intoxicated cannot coordinate their movements or walk a straight line because alcohol disrupts the normal function of which region of the brain?

cerebellum

The coordination necessary for a musician to play the piano depends on control exerted by the __________.

cerebellum

The left and right sides of the cerebrum are interconnected by which one of the following?

corpus callosum

A nerve impulse moves toward a neuron's cell body along _____.

dendrites

Name the three principal parts of the nerve cell.

dendrites, cell body, axons

Which one of the following types of neurotransmitter functions as an inhibitory agent, typically suppressing the sensation of pain?

endorphins

Which set of words can correctly be used to describe interneurons?

excitatory and inhibitory

True or false. An individual who has suffered a stroke, which has caused damage in his cerebrum, and is now having problems with his hearing, has probably suffered damage to his occipital lobe.

false

Which lobe of the cerebral cortex is responsible for speech and conscious thought?

frontal

From an evolutionary standpoint, which of the following structures is considered the oldest, most primitive division of the brain?

hindbrain

The sympathetic and parasympathetic divisions of the autonomic division of the peripheral nervous system work antagonistically to maintain ________.

homeostasis

Which one of the following parts of the brain effectively links the nervous system and the endocrine system?

hypothalamus

Short-term memory is associated with the ________, whereas long-term memory is associated with the ________.

limbic system, cerebral cortex

Which part of the brain is responsible for regulating the heart and respiratory rates and blood pressure?

medulla oblongata

Which one of the following cells transmits impulses away from the central nervous system to the muscles and other organs?

motor neurons

Axons insulated by a(n) _____ are able to conduct impulses faster that those not so insulated.

myelin sheath

White matter of the spinal cord contains __________, whereas gray matter contains __________.

myelinated nerves; unmyelinated cell bodies

Cells that provide direct protection and physical support to neurons are

neuroglial cells

Arrival of an action potential at an axon terminal ultimately results in the release of ________ into the synaptic cleft.

neurotransmitters

An impulse relayed along a myelinated axon "jumps" from _____ to _____.

node of ranvier; node of ranvier

Which one of the following divisions of the nervous system predominates during the relaxed state?

parasympathetic division

Parkinson's disease primarily affects __________.

physical ability

What type of cell makes up the myelin sheath of a motor neuron?

schwann cells

Which one of the following provides the central nervous system with information about the outside environment?

sensory division

Because the central nervous system is so important to the proper functioning of the body, the brain is protected by the ________ and the spinal cord is protected by the ________.

skull; vertebrae

Which of the following events is the first to occur during an action potential?

sodium channels open

Which one of the following establishes and maintains the resting potential?

sodium-potassium pump

Both voluntary and involuntary skeletal muscle movement are controlled through which one of the following divisions of the nervous system?

somatic division

Part complete If your heart rate and blood pressure increase in response to a crisis, you are experiencing the immediate effects of the __________ nervous system (NS).

sympathetic

Which of the following would cause an acceleration of heart rate, an increase in blood pressure, and a slowing of digestive processes?

sympathetic division of the autonomic nervous system

What part of a neuron relays signals from one neuron to another neuron or to an effector?

synaptic terminal

Neurons store neurotransmitter molecules in vesicles located within _____.

synaptic terminals

Which part of the brain functions as a relay station for information to the limbic system and the cerebral cortex?

thalamus

The brain and spinal cord make up the __________.

the central nervous system

A spinal reflex requires the participation of each of the following, EXCEPT __________.

the cerebral cortex

Long-term memory occurs __________.

when neurons are permanently changed

how synapses work

1: an action potential arrives as the synaptic terminal 2: calcium channels open, and calcium ions enter the synaptic terminal 3: vesicles containing neurotransmitters fuse with the plasma membrane of the sending neuron 4: neurotransmitter molecules diffuse across the synaptic cleft 5: neurotransmitter molecules bind to receptors in the plasma membrane of the receiving neuron, causing ion channels there to open

Sodium-potassium pumps

restore the distribution of ions inside and outside a neuron's membrane following an action potential.

What is the difference between a reflex and a reflex arc?

A reflex is an automatic response; a reflex arc is the neural circuitry.

Which of the following characteristics of the neuron cell membrane contributes to the maintenance of the resting membrane potential?

The sodium-potassium pump transports three sodium ions out of the cell for every two potassium ions it pumps into the cell.

Insufficient production of acetylcholine in the synapses of the brain, abnormal tangled neurons, and large deposits of beta-amyloid are problems associated with which one of the following diseases?

Alzheimer's disease

What do multiple sclerosis and ALS (amyotropic lateral sclerosis) have in common?

They both damage the myelin sheath, slowing action potential transmission.

Oligodendrocytes are similar to Schwann cells in that they

a type of neuroglial cell

Which part of the brain is associated with conscious thought, memory, and personality?

cerebral cortex

Which component of a reflex arc carries information to the central nervous system?

sensory neuron

You touch a hot stove and your hand quickly jerks away. What is the path of the nerve impulses that are responsible for this reflex?

sensory neuron to interneuron to motor neuron

Part complete Neurons of the PNS that transmit information to the CNS are __________.

sensory neurons

During an action potential

the inside of the neuron becomes positively charged relative to the outside.

Saltatory conduction is

the process of conduction leaping along myelinated neurons

Part complete Amyotrophic lateral sclerosis (ALS) is a demyelinating disease that results from nerve damage beginning in the

the spinal cord

The space between an axon of one neuron and the dendrite of another neuron is called a(n) _____.

the synaptic cleft

Current nervous system research includes exploring which of the following to treat spinal cord injuries?

the use of stem cells to replace damaged cells

When a neuron is at its resting potential

there are more potassium ions inside the neuron than outside.