Connect: Ch 12 HW (CENTRAL NERVOUS SYSTEM)

Classify the given items with the appropriate group.

Structural Classifcation: -Based upon the CNS component nerve arises from -Would include spinal nerves Functional Classification: -Based upon direction information is sent -Would include sensory nerves -Would include motor nervs -Would include mixed nerves

Which part of a neuron contains calcium pumps and channels?

Synaptic bulbs

Place the events in the correct sequence. Not all items will be used.

TOP TO BOTTOM: -Action potential reaches synaptic knob -Voltage-gated calcium channels open -Calcium enters the synaptic knob -Synaptic vesicles merge with synaptic knob plasma membrane -Neurotransmitter released by exocytosis -Neurotransmitter crosses synaptic cleft -Neurotransmitter attaches to receptors on a muscle, nueron, or gland cell

A recently depolarized area of a cell membrane cannot generate an action potential because of the

absolute refractory period

The _______ is a period of time when a membrane cannot respond to another stimulus (no matter how strong).

absolute refractory period

Pain receptors in the skin send signals to the CNS for processing. These pain receptors are an example of ____________ neurons.

afferent

Neurons that carry signals from the CNS to skeletal muscle for contraction would be classified as _____________ neurons.

efferent

On a graph of an action potential, the small depolarizations that lead to threshold are from

excitatory postsynaptic potentials (EPSPs)

Greater current flow is possible with larger resistance and a lower voltage.

false

In neurons, protein pumps allow substances to move passively down their concentration gradients

false

he endoneurium wraps around groups of fasicles to form a nerve.

false

In a nerve, groups of axons are wrapped into separate bundles called

fascicles

When chloride enters the neuron via chemically gated chloride channels, the membrane potential will become more negative than the resting membrane potential. This is called _____________.

hyperpolarization

If neurotransmitter from Neuron A causes Neuron B to hyperpolarize, this is an example of an

inhibitory postsynaptic potential

The vagus nerve contains afferent and efferent neurons, therefore it is an example of a(n) __________ nerve.

mixed

The most common type of neuron contains many dendrites and a single axon. Structurally, this is classified as a(n) ______________ neuron.

multipolar

The intermediate filaments of a neuron are also called ___________.

neurofilaments

Nerve growth factors that stimulate outgrowth of severed axons are secreted by

neurolemmocytes.

Myelin sheaths mainly consist of which part of the glial cells that form them?

plasma membranes

When sodium enters the neuron via chemically gated sodium channels, the membrane will depolarize. Therefore, the membrane potential will become more

positive.

Another term for the __________ system is the afferent nervous system.

sensory

The ___________ nervous system transmits information from receptors to the CNS, while the ___________ nervous system transmits information from the CNS to the rest of the body

sensory; motor

The specific location where two neurons meet is called a ____________.

synapse

A typical synapse in the CNS consists of a presynaptic neuron and a postsynaptic neuron, separated by a narrow space called the

synaptic cleft.

When threshold is reached, depolarization occurs with the same amplitude of potential change. This is known as

the All-or-None principle.

If all the sodium leakage channels were removed from the cell membrane of a neuron,

the membrane potential would be about -90 millivolts.

On a typical neuron, the axon is usually longer in length than the dendrites.

true

Postsynaptic neurons can generate both inhibitory and excitatory postsynaptic potentials simultaneously.

true

Sodium has a higher concentration outside the cell than within.

true

The leakage of potassium plays a more significant role in the resting membrane potential than the leakage of sodium.

true

Functional Classification

-Sensory neuron -Motor neuron -Interneuron neuron -Afferent neuron -Efferent neuron -Association neuron

More abundant in ISF

-Sodium -Chloride

Place the items in the correct order for an IPSP from beginning to end. Not all items will be used.

1. An inhibitory neurotransmitter binds to chemically gated K+ channels 2. K+ channels open 3. K+ flows out of the nueron 4. The inside of the nueron becomes more negative 5. The IPSP propagates towards the axon hillock

Place the following structures in the order that an electrical impulse would travel beginning with the postsynaptic membrane

1. Dendrites 2. Soma 3. Axon hillock 4. Internode 5. Node of Ranvier 6. Terminal arborization 7. Synaptic knobs

Place the following structures in the order that an electrical impulse would travel beginning with the postsynaptic membrane.

1. Dendrites 2. Soma 3. Axon hillock 4. Internode 5. Node of Ranvier 6. Terminal arborization 7. Synaptic knobs

Place the items for an EPSP in the correct order from beginning to end. Not all items will be used.

1. Excitatory neurotransmitter released from presynaptic neuron 2. Neurotransmitter binds to chemically gated sodium channels 3.Sodium channels open 4.Sodium flows into neuron 5.Inside of neuron becomes more positive 6. This EPSP propagates toward axon hillock

What is the correct order for the events of neurotransmitter release from the synaptic terminal? 1 - Extracellular Ca2+ enters terminal and binds to sensor protein in the cytoplasm 2 - Exocytosis of neurotransmitter into synaptic cleft 3 - Action potential reaches axon terminal 4 - Ca2+-protein complex stimulates fusion of the docked synaptic vesicle with the plasma membrane 5 - Voltage-gated Ca2+ channels open

3, 5, 1, 4, 2

Place the components of a peripheral nerve in sequence from outside to inside.

From outside to inside: Epineurium Nerve Perineurium Fasicles Endoneurium Neurolemmocytes Axolemma

What type of cells produce the myelin sheath in the central nervous system (CNS)?

Oligodendrocytes

Place the following labels in the proper position to designate the appropriate glial cells.

Oligodendrocytes: Form the myelin sheath in the CNS Ependymal Cells: Function in the production and circulation of CSF Microglia: Macrophages of the CNS Asotrocytes: Most abundant CNS glial cells & involved with neurogenesis, scar formation, and BBB maintenance Neurolemmocytes: Form the myelin sheath in the PNS Satelite Cells: PNS cells that surround and insulate the somas

Relative Refractory Period

-Occurs when voltage-gated sodium channels have return to resting state -Ensures that the action potential moves down the axon in only one direction -Neuron is hyperpolarized

More Abundant in Cytosol

-Phosphate -Negatively charged proteins -Potassium

Structural Classification

- Multipolar neuron - Bipolar neuron - Unipolar neuron

Inhibitory Neurotransmitter Actions

-Binds to a chemically gated potassium channel -Binds to chemically gated chloride channel -Potassium moves down its concentration gradient out of the nueron -Chloride moves down its concentration gradient into the nueron

Excitatory Neurotransmitter Actions

-Binds to chemically gated sodium channel -Sodium moves down the concentration gradient into the neuron -The inside of the neuron becomes more positive

Absolute Refractive Period

-Occurs about 1ms after an action potential -No amount of stimulus will initiate a second action potential -Voltage-gated sodium channels are opened then closed in the inactiviate state

Place each of the following labels in the proper position on the curve where each of the indicated items would occur.

A: Potential across the membrane becomes less negative B: At threahold, voltage-gated Na+ channels opens quickly, Threshold , -55mV C: Voltage-gated potassium channels open D: Hyperpolarization E: Resting membrane potential, -70mV

The fundamental physiological properties that enable nerve cells to communicate with other cells are

All of these choices are correct.

Scorpion agitoxin is a neurotoxin that blocks the activity of voltage-gated potassium channels. In the presence of agitoxin, which will occur during an action potential?

The neuron will remain depolarized and unable to repolarize.

A depolarizing graded potential can cause an action potential.

True

Graded potentials can result from mechanical stimulation or temperature changes.

True

Graded potentials can result from voltage across the plasma membrane.

True

Increased permeability of the membrane to sodium results in depolarization.

True

The effects produced by one graded potential can be added onto the effects of another graded potential.

True

The potential change can vary from small to large depending on the stimulus strength or summation.

True