Biology Chapter 4: The Nervous System (4 Stars)

Question 1

Neurons are highly specialized cells responsible for the conduction of _________

Answer 1

impulses

Question 2

Neurons communicate using both electrical and ______ forms of communication.

Answer 2

chemical

Question 3

Electrical communication occurs via _____ and the generation of membrane potentials down the length of the axon.

Answer 3

ion exchange

Question 4

Chemical communication occurs via ______ release from the presynaptic cell

Answer 4

neurotransmitter
release from the presynaptic cell and the binding of these neurotransmitters to the postsynaptic cell.

Question 5

Dendrites are appendages that receive _____ from other cells.

Answer 5

signals

Question 6

The ________ is the location of the nucleus as well as organelles such as the endoplasmic reticulum and ribosomes.

Answer 6

cell body or soma

Question 7

The ______ is where the cell body transitions to the axon, and where action potentials are initiated.

Answer 7

axon hillock

Question 8

The axon is a long appendage down which a(n) __________travels.

Answer 8

action potential

Question 9

The nerve terminal or synaptic bouton is the ____ of the axon from which neurotransmitters are released.

Answer 9

end

Question 10

Nodes of Ranvier are exposed areas of ______ axons that permit saltatory conduction.

Answer 10

myelinated

Question 11

The synapse consists of the nerve terminal of the presynaptic neuron, the membrane of the postsynaptic cell, and the space between the two, called the _______

Answer 11

synaptic cleft.

Question 12

Many axons are coated in ______, an insulating substance that prevents signal loss.

Answer 12

myelin

Question 13

Myelin is created by ________ in the central nervous system and Schwann cells in the peripheral nervous system.

Answer 13

oligodendrocytes

Question 14

Myelin prevents dissipation of the neural impulse and crossing of neural impulses from ______ neurons.

Answer 14

adjacent

Question 15

Individual axons are bundled into ______ or tracts.

Answer 15

nerves

Question 16

A single nerve may carry multiple types of information, including sensory, motor, or both. Tracts contain # ____ type of information.

Answer 16

only one

Question 17

Cell bodies of neurons of the same type within a nerve ______ in ganglia in the peripheral nervous system.

Answer 17

cluster

Question 18

Neuroglia or _____ cells are other cells within the nervous system in addition to neurons.

Answer 18

glial

Question 19

Astrocytes nourish _______ and form the blood–brain barrier, which controls the transmission of solutes from the bloodstream into nervous tissue.

Answer 19

neurons

Question 20

________ line the ventricles of the brain and produce cerebrospinal fluid, which physically supports the brain and serves as a shock absorber.

Answer 20

Ependymal cells

Question 21

______ are phagocytic cells that ingest and break down waste products and pathogens in the central nervous system.

Answer 21

Microglia

Question 22

Oligodendrocytes (CNS) and Schwann cells (PNS) produce _____ around axons.

Answer 22

myelin

Question 23

All neurons exhibit a resting membrane potential of approximately ____ mV.

Answer 23

–70 mV.

Question 24

Resting potential is maintained using selective permeability of ions as well as the ________

Answer 24

Na+ /K+ ATPase.

Question 25

The Na+ /K+ ATPase pumps # ___ sodium ions out of the cell for every #\_\_\_ potassium ions pumped in.

Answer 25

3 sodium ions out 2 potassium ions pumped in.

Question 26

Incoming signals can be either _______ or inhibitory.

Answer 26

excitatory

Question 27

Excitatory signals cause _______ of the neuron.

Answer 27

depolarization

Question 28

Inhibitory signals cause __________ of the neuron.

Answer 28

hyperpolarization

Question 29

\_\_\_\_\_\_ summation refers to the addition of multiple signals near each other in time.

Answer 29

Temporal

Question 30

\_\_\_\_\_\_\_ summation refers to the addition of multiple signals near each other in space.

Answer 30

Spatial

Question 31

An action potential is used to propagate signals ______ the axon.

Answer 31

down

Question 32

When enough excitatory stimulation occurs, the cell is _______ to the threshold voltage and voltage-gated ______ channels open.

Answer 32

depolarized sodium

Question 33

\_\_\_\_\_ flows into the neuron due to its strong electrochemical gradient. This continues depolarizing the neuron.

Answer 33

Sodium

Question 34

At the peak of the action potential (approximately +35 mV), ________ channels are inactivated and ___________ channels open.

Answer 34

At the peak of the action potential (approximately +35 mV), sodium channels are inactivated and potassium channels open.

Question 35

Potassium flows out of the neuron due to its strong electrochemical gradient,\_\_\_\_\_\_\_ the cell. \_\_\_\_\_\_\_\_\_ channels stay open long enough to overshoot the action potential, resulting in a hyperpolarized neuron; then, the potassium channels close.

Answer 35

repolarizing the cell. Potassium

Question 36

While the axon is hyperpolarized, it is in its _______ period.

Answer 36

refractory period.

Question 37

The impulse propagates down the length of the axon because the influx of sodium in one segment of the axon brings the subsequent segment of the axon to \_\_\_\_\_\_\_.

Answer 37

threshold. The fact that the preceding segment of the axon is in its refractory period means that the action potential can only travel in one direction.

Question 38

At the nerve terminal, neurotransmitters are released into the \_\_\_\_\_\_\_

Answer 38

synapse.

Question 39

When the action potential arrives at the nerve terminal, voltage-gated calcium channels \_\_\_\_\_

Answer 39

open.

Question 40

The influx of ______ causes fusion of vesicles filled with neurotransmitter with the presynaptic membrane, resulting in exocytosis of neurotransmitter into the synaptic cleft.

Answer 40

calcium

Question 41

The neurotransmitters bind to receptors on the ________ cell, which may be ligand-gated ion channels or G protein-coupled receptors.

Answer 41

postsynaptic cells

Question 42

The neurotransmitter can be ________ back into the presynaptic cell by reuptake channels.

Answer 42

absorbed

Question 43

There are three types of neurons in the nervous system: motor (efferent) neurons, ________ and sensory (afferent) neurons.

Answer 43

interneurons SAME

Question 44

The nervous system is made up of the (2)

Answer 44

(CNS; brain and spinal cord) and peripheral nervous system (PNS; cranial and spinal nerves).

Question 45

In the CNS, white matter consists of myelinated axons, and grey matter consists of _______ bodies and dendrites. In the brain, _______ matter is deeper than grey matter. In the spinal cord, ______ matter is deeper than white matter.

Answer 45

unmyelinated cell bodies white matter grey matter

Question 46

The PNS is divided into the\_\_\_\_\_\_\_\_ (voluntary) and autonomic (automatic) nervous systems.

Answer 46

somatic (voluntary)

Question 47

The autonomic nervous system is further divided into the __________ (rest-and-digest) and ______ (fight-or-flight) branches.

Answer 47

parasympathetic sympathetic

Question 48

Reflex arcs use the ability of _______ in the spinal cord to relay information to the source of a stimulus while simultaneously routing it to the brain.

Answer 48

Reflex arcs use the ability of interneurons in the spinal cord to relay information to the source of a stimulus while simultaneously routing it to the brain.

Question 49

In a monosynaptic reflex arc, the _______ neuron fires directly onto the motor (efferent, postsynaptic) neuron.

Answer 49

sensory (afferent, presynaptic)

Question 50

In a polysynaptic reflex arc, the sensory neuron may fire onto a _____ neuron as well as interneurons that fire onto other motor neurons

Answer 50

motor

Question 51

During the absolute refractory period, the cell is _____ to fire another action potential.

Answer 51

unable

Question 52

During the relative refractory period, the cell requires a _____ than normal stimulus to fire an action potential.

Answer 52

larger