Chapter 12: Nervous system

A unipolar neuron has one extension. A bipolar neuron has ___ extensions

2

The central nervous system is made up of the ______and spinal_____

Brain, Spinal cord

Amino acids

Building blocks of proteins secreted as neurotransmitters

Satellite cells are found surrounding

Cell bodies

The neuron's control center is the

Cell body

Which structural division of the nervous system contains the brain?

Central nervous system

Neuropeptide

Chain of amino acids secreted as neurotransmitter

Type A

Conduction velocity up to 150 meters per second

Cells that are part of the Central nervous system

-Astrocyte -Oligodendrocyte -Microglia -Ependymal cells

Synapses are classified as

-Chemical synapses -Electrical synapses

Which terms are used for the structural classification of nerves?

-Cranial -Spinal

Which of the following are among the general characteristics of graded potentials?

-Degree of change in membrane potential is dependent of the stimulus magnitude -Can either be depolarizing or hyperpolarizing -Decrease intensity with distance traveled along membrane

The___receive impulses from the motor neurons

-Effectors

Synapses occur where axons contact:

-Gland cells -Muscle cells -Other neurons

Which of the following are functional classes of neurons?

-Interneurons -Motor neurons -Sensory neurons

The components of the somatic sensory division are:

-Joints and muscles -Hearing -Taste

Which of the following ions have leak channels on the plasma membrane?

-Na+ -K+

Which of the following pumps can you find in the plasma membrane?

-Na+/K+ -Ca2+

Which of the following would be likely to cause hyperpolarization of a neuron?

-Opening of a chemically gated chloride channel -Opening of a Voltage potassium channel

Intracellular

-Potassium -Organic anions

Which of the following are functions of astrocytes?

-Replaces damaged neurons -Helps form the blood-brain barrier -Regulates the composition of interstitial fluid

Extracellular

-Sodium -Chloride

Which two are divisions of the sensory nervous system?

-Somatic division -Visceral division

Which of the following segments of a neuron contain large numbers of voltage-gated potassium channels and voltage-gated sodium channels?

-The conductive segment -The initial segment

What must happen in order for a chemical signal to change the membrane potential of a neuron?

-There must be a change in the number of open ion channels -There must be a change in ion flow across the membrane

Which of the following are true of neurolemmocytes?

-They are also called Schwann cells -They create the myelin sheath in the PNS

Which of the following events help return the membrane potential to the resting state following hyperpolarization?

-Voltage gated potassium channels close -Na/K pumps restore gradients

The voltage gated sodium channels undergo changes in activity during the depolarization phase of an action potential. Place in order from first to last

1. A graded potential depolarizes the initial segment 2. Voltage gated sodium channels open 3. Sodium flows into i the neuron at the initial segment 4. Further depolarization of the initial segment occurs 5. Sodium channels enter the inactive state

Place the events of synaptic transmission from earliest to latest

1. Action potential reaches synaptic knob 2. Voltage gated calcium channels open 3. Calcium enters the synaptic knob 4. Calcium triggers exocytosis of vesicles 5. Neurotransmitter diffuses across synaptic cleft 6. Neurotransmitter binds to postsynaptic receptors

Events of an EPSP in order

1. Excitatory neurotransmitter binds to receptor Na+ channel 2.Na+ enters the postsynaptic cell 3.The inside of the cell becomes more positive 4.The local current of Na+ becomes weaker as it moves toward the axon hilliock

Chloride-based IPSP in order from earliest to latest

1. Inhibitory neurotransmitter binds to postsynaptic chemically gated chloride channels 2. Chloride moves from outside the cell to the inside 3. The inside of the postsynaptic cell becomes more negative 4. The local chloride current becomes weaker as it moves towards the axon hillock

A positive change in the membrane potential is called

Depolarization

_______occurs when the inside of the cell becomes more positive (less negative) than the resting membrane potential

Depolarization

Monoamine

Derived from certain amino acids

Tissue that responds to neural input by changing its activity is called an

Effector

A difference in the number of charged particles between two sides of membranes forms

Electrical Gradient

The electricochemical gradient is formed from a combination of the _____gradient and the _____gradient

Electrical, chemical

An individual axon is wrapped in a connective tissue covering called the

Endoneurium

Resting state

Entry of sodium is prevented; activation gate is closed

Inactivation state

Entry of sodium is prevented; activation gate is open

The choroid plexus is made from capillaries and

Ependymal cells

T/F: Ion channels use the energy of ATP to maintain concentration gradients across neuron membranes

False

T/F: Neurons far outnumber glial cells

False

The sequential opening of voltage gated sodium channels is followed by the sequential opening of voltage gated__channels

K+

Type B

Medium conduction velocity

_____cells are the least common glial cell of the central nervous system

Microglia

Which type of neurons is most common?

Multipolar

Oligodendrocytes create the ____sheath in the central nervous system

Myelin

Which cell type is considered "Nerve glue" ?

Neuroglial cells

What is the basic structural unit of the nervous system?

Neuron

Nervous tissue is composed of glial cells and _____

Neurons

____are specialized nervous system structures that detect stimuli

Receptors

A return of the membrane potential towards the resting membrane potential immediately following depolarization is called

Repolarization

____nerves always relay information to the CNS

Sensory

An action potential is also called a nerve

Signal

Type C

Slowest conduction velocity

Activation state

Sodium moves into the cell through the open channel

If several EPSPs occur at different synapses, they undergo____at the initial segment

Spatial summation

A change in membrane potential insufficient to cause an action potential is known as a

Subthreshold value

The process by which postsynaptic potentials are added together at the initial segment is known as

Summation

The all or none law refers to the fact that action potentials will occur if the initial segment reaches

Threshold

Dendrites transfer information______the cell body

Toward

T/F: Most voltage-gated ion channels are closed until the electrical potential across a membrane changes

True

Most sensory neurons are

Unipolar

Which of the nervous system detects nerve impulses from blood vessels and internal organs?

Visceral sensory division

____is the measure of difference in electrical charge

Voltage

Which of the following is essential for the generation of an action potential?

Voltage gated channel

The "I" in IPSP stands for _____, meaning that the potential makes the inside of the postsynaptic cell more_____-

Inhibitory, negative

What type of neuron is also called an association neuron?

Interneuron

The____division of the nervous system is subdivided into the sympathetic and parasympathetic divisions

Autonomic

The plasma membrane of an axon is called the

Axolemma

A substance synthesized at the cell body must undergo___transport to reach the synaptic knobs

Anterograde

A cluster of neuron cell bodies found along a peripheral nerve is known as a

Ganglia

A____ ____is a temporary change in membrane potential which lasts only as long as the stimulus that causes it and can vary in size

Graded Potential

The___the resistance, the___the current.

Higher, lower

The motor nervous system is responsible for

Output

A graded potential caused by the opening of chemically gated channels on a postsynaptic membrane is known as a

Postsynaptic potential

What type of neuron transmits an impulse through its axon toward the synapse?

Presynaptic neuron