Chapter 4: The Nervous System

Question 1

Astrocytes form the __________ which controls the transmission of solutes from the bloodstream into nervous system

Answer 1

Blood Brain Barrier

Question 2

Ependymal cells lines the ventricles of the brain and produce __________ , which physically supports the brain and serves as a shock absorber.

Answer 2

Cerebrospinal fluid

Question 3

Microglia are __________ cells that ingest an break down waste products and pathogens in the central nervous system.

Answer 3

Phagocytic cells

Question 4

__________ (CNS) and ____________ (PNS) produce myelin around axons.

Answer 4

Oligodendrocytes and Schwann cells

Question 5

_________ are specialized cells capable transmitting electrical impulses and then translating those electrical impulses into chemical signals.

Answer 5

Neurons

Question 6

________ = neuron cell body

Answer 6

Soma

Question 7

The neutron has many appendages emanating directly from the soma called _________

Answer 7

Dendrites

Question 8

The information received from the dendrites is transmitted through the cell body before it reaches the __________, which integrates the incoming signals.

Answer 8

Axon hillock

Question 9

The axon hillock plays an important role in ___________, or the transmission of electrical impulses down the axon.

Answer 9

Action potential

Question 10

The ________ is a long appendage that terminates in close proximity to a target structure (a muscle, a gland, or another neutron).

Answer 10

Axon

Question 11

Most mammalian nerve fibres are insulated by _________, a fatty membrane, to prevent signal loss or crossing of signals.

Answer 11

Myelin

Question 12

Just like insulation prevents wires next to each other from accidentally discharging each other, the ____________ maintains the electrical signal within one neuron. It also increases the speed of conduction in the axon.

Answer 12

Myelin sheath

Question 13

There are small breaks in the myelin sheath with exposed areas of axon membrane called __________

Answer 13

Nodes of Ranvier

Question 14

At the end of the axon is the ___________ or ____________ (knob)

Answer 14

Nerve terminal or synapsing bouton

Question 15

______________ are the chemicals that transmit information between neuron.

Answer 15

Neurotransmitters

Question 16

Between neuron, there is a small space called _________ into which the terminal portion of the axon releases neurotransmitters, which bind to the dendrites of the adjacent neuron (postsynaptic neuron)

Answer 16

Synaptic cleft

Question 17

Together, the nerve terminal, synaptic cleft, an postsynaptic membrane are known as a ________

Answer 17

Synapse

Question 18

Multiple neurons may be bundled together to form a _________ in the peripheral nervous system.

Answer 18

Nerve

Question 19

Nerves in the PNS can be identified as __________, __________, or mixed.

Answer 19

Sensory, motor

Question 20

The cell bodies of the same nerve type (sensory, motor, or mixed) are clustered together into _________ in the PNS.

Answer 20

Ganglia

Question 21

In CNS, axons may be bundled together to form _________.

Answer 21

Tracts

Question 22

The cell bodies of neurons in the same tract of the CNS are grouped into _________.

Answer 22

Nuclei

Question 23

Astrocytes, ependymal cells, and microglia are types of ___________ or ____________

Answer 23

Glial cells or neuroglia

Question 24

Neurons use all-or-nothing messages called ___________ to relay electrical impulses down the axon to the synaptic bouton.

Answer 24

Action potentials

Question 25

A cell's ______________ is the net electric potential different that exists across the cell membrane, created by movement of charged molecules sodium and potassium across the membrane.

Answer 25

Resting membrane potential

Question 26

To facilitate the outward movement of potassium K+, the cell membrane has transmembrane _________________, which allows the slow leak of potassium out of the cell.

Answer 26

Potassium leak channels

Question 27

_____________ is when there is no net movement of the potassium ion, as the cell is in equilibrium with respect to potassium (inside and outside of cell).

Answer 27

Equilibrium potential of potassium (around -90 mV)

Question 28

The slow leak of sodium Na+ into the cell, which causes a build-up of electric potential is facilitated by _____________

Answer 28

Sodium leak channels

Question 29

___________ is when there is no net movement of sodium ions, as the cell is in equilibrium after sodium moves into the cell.

Answer 29

Equilibrium potential of sodium (around +60 mV)

Question 30

_____________ continually pumps sodium out of the cel and potassium into the cell to maintain their respective gradients, if a resting potential is to be maintained.

Answer 30

Na+/K+ ATPase Sodium/Potassium ATPase

Question 31

Excitatory input causes ___________ (raising the membrane potential, Vm, from its resting potential) and thus makes the neuron more likely to fire an action potential.

Answer 31

Depolarization

Question 32

Inhibitory input causes ____________ (lowering the membrane potential from its resting potential) and thus makes the neuron less likely to fire an action potential.

Answer 32

Hyperpolarization

Question 33

If the axon hillock receives enough excitatory input to be depolarized to the __________ value (usually in the range of -55 mV to -40 mV), an action potential will be triggered.

Answer 33

Threshold value

Question 34

The additive effect of multiple signals (excitatory + inhibitory) is known as ___________

Answer 34

summation

Question 35

There are 2 types of summation: ____________ and ___________.

Answer 35

Temporal and spatial

Question 36

In ___________, multiple signals are integrated during a relatively short period of time.

Answer 36

Temporal summation

Question 37

In ___________, the additive effects are based on the number and location of the incoming signals.

Answer 37

Spatial summation

Question 38

The voltage-gated sodium channel is __________ before the cell reaches threshold, and after inactivation has been reversed).

Answer 38

Closed

Question 39

The voltage-gated sodium channel is __________ from threshold to approximately +35 mV.

Answer 39

Opened

Question 40

The voltage-gated sodium channel is __________ from approximately +35 mV to the resting potential

Answer 40

Inactive

Question 41

As positively charged potassium cations are driven out of the cell, there will be a restoration of the negative membrane potential called ______________

Answer 41

Repolarization

Question 42

During the ___________ refractory period, no amount of stimulation can cause another action potential to occur.

Answer 42

Absolute refractory period

Question 43

During the ___________ refractory period, there must be greater than normal stimulation to cause an action potential because the membrane is starting from a potential that is more negative than its resting value.

Answer 43

Relative refractory period

Question 44

For a signal to be conveyed to another neuron, the action potential must travel down the axon and initiate neurotransmitter release. This movement is called ____________

Answer 44

Impulse propagation

Question 45

__________ is an extraordinarily good insulator, preventing the dissipation of the electric signal.

Answer 45

Myelin

Question 46

The myelin insulation is so effective that the membrane is only permeable to ion movement at the nodes of Ranvier. Thus, the signal "hops" from node to node - what is called _____________

Answer 46

Saltatory conduction

Question 47

The neuron preceding the synaptic cleft is called the _____________

Answer 47

Presynaptic neuron

Question 48

The neuron after the synaptic cleft is called the _____________

Answer 48

Postsynaptic neuron

Question 49

If a neuron signals to a gland or muscle, rather than another neuron, the postsynaptic cell is termed an ___________

Answer 49

Effector

Question 50

When the action potential reaches the nerve terminal, voltage-gated __________ channels open, allowing __________ to flow into the cell. This sudden increase in intracellular __________ triggers fusion of the membrane-bound vesicles with the cell membrane at the synapse, causing exocytosis of the neurotransmitters.

Answer 50

Calcium

Question 51

If the receptor is a ____________, the postsynaptic cell will either be depolarized or hyperpolarized.

Answer 51

Ligand--gated ion channel

Question 52

If the postsynaptic receptor is a _____________, it will cause either changes in the levels of cyclic AMP (cAMP) or an influx of calcium.

Answer 52

G protein-coupled receptor

Question 53

Neurotransmitters can be broken down by enzymatic reactions. For example, acetylcholine (ACh) neurotransmitters can be broken down by ______________ to be removed from the synaptic cleft.

Answer 53

Acetylcholinesterase

Question 54

Neurotransmitters can be brought back into the presynaptic neuron using ______________. Examples are serotonin (5-HT), dopamine (DA) and norepinephrine (NE).

Answer 54

Reuptake carriers

Question 55

_____________, a gaseous signalling molecule, can simply diffuse out of the synaptic cleft.

Answer 55

Nitric oxide (NO)

Question 56

_____________ neurons (also known as _____________ neurons) transmit sensory information from sensory receptors to the spinal cord and brain.

Answer 56

Sensory, afferent

Question 57

_____________ neurons (also known as _____________ neurons) transmit motor information from the brain and spinal cord to muscles and glands.

Answer 57

Motor, efferent

Question 58

_____________ are found between sensory and motor neurons, and are the most numerous of the three types. They are located predominantly in the brain and spinal cord ad are often linked to reflexive behaviour.

Answer 58

Interneurons

Question 59

The ______________ is composed of the brain and spinal cord.

Answer 59

Central nervous system (CNS)

Question 60

The ______________ consists of axons encased in myelin sheaths.

Answer 60

White matter

Question 61

The ______________ consists of unmyelinated cell bodies and dendrites.

Answer 61

Grey matter

Question 62

At the base of the brain is the ___________, which is largely responsible for basic life functions such as breathing.

Answer 62

Brainstem

Question 63

The spinal cord extends downward from the brainstem and can be divided into 4 regions: _________, __________, ___________, and __________.

Answer 63

Cervical, thoracic, lumbar and sacral

Question 64

The spinal cord is protected by the ____________, which transmits nerves at the space between adjacent vertebrae.

Answer 64

Vertebral column

Question 65

The sensory neurons bring information in from the periphery and enter the dorsal (back) side of the spinal cord. The cell bodies of these sensory neurons are found in the ______________.

Answer 65

Dorsal root ganglia

Question 66

The __________________ is made up of nerve tissue and fibers outside the brain and spinal cord, including all 31 pairs of spinal nerves and 10 of the 12 pairs of cranial nerves (the olfactory and optic nerves are technically outgrowths of the CNS)

Answer 66

Peripheral nervous systems (PNS)

Question 67

The ____________ consists of sensory and motor neurons distributed throughout the skin, joints, and muscles.

Answer 67

Somatic nervous system

Question 68

__________ neurons transmit information through afferent fibers.

Answer 68

Sensory neurons

Question 69

__________ neurons travel along efferent fibers.

Answer 69

Motor neurons

Question 70

The ______________ generally regulates heartbeat, respiration, digestion, and glandular secretions.

Answer 70

Autonomic nervous system (ANS)

Question 71

A motor neuron in the __________ nervous system goes directly from the spinal cord to the muscle without synapsing.

Answer 71

Somatic nervous system

Question 72

In the ___________ nervous system, 2 neurons work in series to transmit messages from the spinal cord.

Answer 72

Autonomic nervous system

Question 73

The first neuron in the autonomic nervous system that helps transmit messages from the spinal cord is known as the _______________ neuron.

Answer 73

Preganglionic neuron

Question 74

The second neuron in the autonomic nervous system that helps transmit messages from the spinal cord is known as the _______________ neuron.

Answer 74

Postganglionic neuron

Question 75

The main role of the ______________nervous system is to conserve energy.

Answer 75

Parasympathetic nervous system

Question 76

______________ is the neurotransmitter responsible or parasympathetic responses in the body and is released by both preganglionic and postganglionic neurons.

Answer 76

Acetylcholine

Question 77

The __________ nerve (cranial nerve X) is responsible for much of the parasympathetic innervation of the thoracic and abdominal cavity.

Answer 77

Vagus nerve

Question 78

The _____________ nervous system is activated by stress.

Answer 78

Sympathetic nervous system

Question 79

In the sympathetic nervous system, the preganglionic neurons release ______________ neurotransmitter.

Answer 79

acetylcholine

Question 80

In the sympathetic nervous system, the postganglionic neurons release ______________ neurotransmitter.

Answer 80

Norepinephrine

Question 81

Neural circuits called ___________ control reflexive behaviour.

Answer 81

Reflex arcs

Question 82

In a ___________ reflex arc, there is a single synapse between the sensory neuron that receives the stimulus and the motor neuron that responds to it. An example is the knee-jerk reflex, which may be elicited by swiftly stretching the patellar tendon with a reflex hammer.

Answer 82

Monosynaptic reflex arc

Question 83

In a ____________ reflex arc, there is at least one interneuron between the sensory and motor neurons. Interneurons in the spinal cord provide the connections from the incoming sensory information to the motor neurons.

Answer 83

Polysynaptic reflex arc