BIO 360 - Exam 2 - Chapter 8 Summary Questions

Question 1

The ______ ______ is a complex network of neurons that form the rapid control system of the body.

Answer 1

nervous system

Question 2

______ ______ of the nervous system include consciousness, intelligence, and emotion.

Answer 2

Emergent properties

Question 3

The nervous system is divided into the ______ ______ ______, composed of the brain and spinal cord, and the ______ ______ ______.

Answer 3

central nervous system (CNS) / peripheral nervous system (PNS)

Question 4

The peripheral nervous system has ______ (______) neurons that bring information into the CNS, and ______ neurons that carry information away from the CNS back to various parts of the body.

Answer 4

sensory (afferent) / efferent

Question 5

The efferent neurons include ______ ______ neurons, which control skeletal muscles, and ______ neurons, which control smooth and cardiac muscles, glands, and some adipose tissue.

Answer 5

somatic motor / autonomic

Question 6

Autonomic neurons are subdivided into ______ and ______ branches.

Answer 6

sympathetic / parasympathetic

Question 7

Neurons have a ____ ____ with a nucleus and organelles to direct cellular activity, ______ to receive incoming signals, and an ______ to transmit electrical signals from the cell body to the ______ ______.

Answer 7

cell body / dendrites / axon / axon terminal

Question 8

______ are neurons that lie entirely within the CNS.

Answer 8

Interneurons

Question 9

Material is transported between the cell body and axon terminal by ______ ______.

Answer 9

axonal transport

Question 10

The region where an axon terminal meets its target cell is called a ______.
The target cell is called the ______ ______.
The neuron that releases the chemical signal is known as the ______ ______.
The region between these two cells is the ______ ______.

Answer 10

synapse / postsynaptic cell / presynaptic cell / synaptic cleft

Question 11

Developing neurons find their way to their targets by using ______ ______. The human CNS also contains electrical synapses that allow electrical current and chemical signals to pass between cells through gap junction channels. Communication at electrical synapses is bidirectional as well as faster than at chemical synapses. Electrical synapses allow multiple CNS neurons to coordinate and fire simultaneously.

Answer 11

chemical signals

Question 12

______ ______ provide physical support and communicate with neurons.
______ ______ and ______ ______ are glial cells associated with the peripheral nervous system.
______, ______, ______, and ______ cells are glial cells found in the CNS.
______ are modified immune cells that act as scavengers.

Answer 12

Glial cells / Schwann cells / satellite cells / Oligodendrocytes, astrocytes, microglia, and ependymal cells / Microglia

Question 13

Schwann cells and oligodendrocytes form insulating ______ ______ around neurons. The ______ ___ ______ are sections of uninsulated membrane occurring at intervals along the length of an axon.

Answer 13

myelin sheaths / nodes of Ranvier

Question 14

______ ______ ______ that can develop into new neurons and glia are found in the ependymal layer as well as in other parts of the nervous system.

Answer 14

Neural stem cells

Question 15

The ______ ______ describes the membrane potential of a cell that is permeable to only one ion.

Answer 15

Nernst equation

Question 16

Membrane potential is influenced by what two things?

Answer 16

(1) the concentration gradients of ions across the membrane (2) the permeability of the membrane to those ions.

Question 17

The Goldman-Hodgkin-Katz (GHK) equation predicts what two things?

Answer 17

(1) membrane potential based on ion concentration gradients
(2) membrane permeability for multiple ions.

Question 18

The permeability of a cell to ions changes when?

Answer 18

Ion channels in the membrane open and close. Movement of only a few ions significantly changes the membrane potential.

Question 19

Gated ion channels in neurons open or close in response to?

Channels also close through?

Answer 19

(1) chemical or mechanical signals
(2) in response to depolarization of the cell membrane.

inactivation.

Question 20

Current flow (I) obeys what law?

______ to current flow comes primarily from the cell membrane, which is a good insulator, and from the cytoplasm. ______ is the reciprocal of resistance: ______.

Answer 20

Ohm’s law: I = voltage / resistance

Resistance / Conductance (G) / G = 1/R

Question 21

______ ______ are depolarizations or hyperpolarizations whose strength is directly proportional to the strength of the triggering event.
______ ______ lose strength as they move through the cell.

Graded potentials in neurons are depolarizations or hyperpolarizations that occur in the dendrites and cell body or, less frequently, near the axon terminals.

Answer 21

Graded potentials

Question 22

The wave of depolarization that moves through a cell is known as?

Current in biological systems is the net movement of ______ electrical charge.

Answer 22

Local current flow / positive

Question 23

______ ______ are rapid electrical signals that travel undiminished in amplitude (strength) down the axon from the cell body to the axon terminals. Action potentials are very brief, large depolarizations that travel for long distances through a neuron without losing strength. Their function is rapid signaling over long distances, such as from your toe to your brain.

Answer 23

Action potentials

Question 24

Action potentials begin in the ______ ______ if a single graded potential or the sum of multiple graded potentials exceeds the ________ voltage.

Answer 24

trigger zone / threshold

Question 25

______ ______ ______ make a neuron more likely to fire an action potential.
______ ______ ______ make a neuron less likely to fire an action potential.

Answer 25

Depolarizing graded potentials / Hyperpolarizing

Question 26

Action potentials are uniform, ______ depolarizations that can travel undiminished over long distances.

Answer 26

all-or-none

Question 27

The rising phase of the action potential is due to increased ______ permeability. The falling phase of the action potential is due to increased ______ permeability.

Answer 27

Na+ / K+

Question 28

The voltage-gated ______ channels of the axon have a fast ______ ______ and a slower ______ ______ .

Answer 28

Na+ / activation gate / inactivation gate

Question 29

Very few ions cross the membrane during an action potential. The ____________ eventually restores ______ and ______ to their original compartments.

This exchange does not need to happen before the next action potential fires, however, because the ion concentration gradient was not significantly altered by one action potential.

Answer 29

Na+-K+-ATPase / Na+ / K+

Question 30

Once an action potential has begun, there is a brief period of time known as the ______ ______ ______ during which a second action potential ______ ______ ______, no matter how large the stimulus. Because of this, action potentials cannot be summed.

Answer 30

absolute refractory period / cannot be triggered

Question 31

During the ______ ______ ______ , a higher-than-normal graded potential is required to trigger an action potential.

Answer 31

relative refractory period

Question 32

The myelin sheath around an axon speeds up conduction by what two things?

______ ______ ______ conduct action potentials faster than ______ ______ ______ do.

Answer 32

(1) increasing membrane resistance
(2) decreasing current leakage

Larger-diameter axons / smaller-diameter axons

Question 33

The apparent jumping of action potentials from node to node is called?

Answer 33

saltatory conduction

Question 34

Changes in blood ______ concentration affect what two things?

Answer 34

K+ / resting membrane potential and the conduction of action potentials.

Question 35

In ______ ______, signal passes directly from the cytoplasm of one cell to another through gap junctions.
______ ______ use neurotransmitters to carry information from one cell to the next, with the neurotransmitters diffusing across the synaptic cleft to bind with receptors on target cells.

Answer 35

electrical synapses / Chemical synapses

Question 36

Neurotransmitters come in a variety of forms.
______ neurons secrete ______ .
______ neurons secrete ______.
______, ______, ______, ______, and ______ are other major neurotransmitters.

Answer 36

Cholinergic / acetylcholine

Adrenergic / norepinephrine.

Glutamate, GABA, serotonin, adenosine, and nitric oxide

Question 37

Neurotransmitter receptors are either one of which two receptors?

Answer 37

(1) Ligand-gated ion channels (ionotropic receptors)
or
(2) G protein-coupled receptors (metabotropic receptors).

Question 38

Neurotransmitters are synthesized in the _____ _____ or the ______ ______ . They are stored in ______ ______ and are released by ______ when _______________________________.

Answer 38

cell body / axon terminal / synaptic vesicles / exocytosis / an action potential reaches the axon terminal.

Question 39

Neurotransmitter action is rapidly terminated by what three things? RED

Answer 39

(1) Re-uptake into cells
(2) Enzymatic breakdown
(3) Diffusion away from the synapse

Question 40

Information about the strength and duration of a stimulus is conveyed by the amount of ______ ______.
Increased frequency of action potentials releases more ______.

Answer 40

neurotransmitter released / neurotransmitter

Question 41

What is divergence? Convergence?

Answer 41

When a presynaptic neuron synapses on a larger number of postsynaptic neurons, the pattern is known as divergence.

When several presynaptic neurons provide input to a smaller number of postsynaptic neurons, the pattern is known as convergence.

Question 42

Synaptic transmission can be modified in response to activity at the synapse, a process known as ______ ______.

Answer 42

synaptic plasticity

Question 43

G protein-coupled receptors either create ______ ______ ______ or modify ______ ______.
Ion channels create ______ ______ ______.

Answer 43

slow synaptic potentials / cell metabolism / fast synaptic potentials

Question 44

What is spatial summation? Temporal summation?

Answer 44

The summation of simultaneous graded potentials from different neurons is known as spatial summation.

The summation of graded potentials that closely follow each other sequentially is called temporal summation.

Question 45

______ ______ of an axon terminal allows selective modulation of collaterals and their targets.

______ ______ occurs when a modulatory neuron synapses on a postsynaptic cell body or dendrites.

Answer 45

Presynaptic modulation / Postsynapticmodulation

Question 46

Long-term ______ and long-term ______ are mechanisms by which neurons change the strength of their synaptic connections.

Answer 46

potentiation / depression