Exam 3 - Chapter 11

________ containing neurotransmitters are found in the axon terminals of the pre- synaptic neuron, near the pre- synaptic membrane.

Vesicles

Prevents the neuron from firing multiple action potentials too quickly

refractory period

________ is a fatty substance that surrounds some axons and serves to insulate and speed up the signal transmission.

Myelin

________ are responsible for depolarization, while potassium channels are responsible for repolarization and hyperpolarization.

Sodium channels

Hyperpolarizing potential makes the post-synaptic neuron less likely to fire an action potential.

IPSP (inhibitory postsynaptic potential)

________ refers to the addition of EPSPs or IPSPs that come from different synapses on the same post- synaptic neuron.

Spatial summation

________ are myelinated to increase the speed and efficiency of signal transmission.

Axons

The ________ contains the nucleus and other organelles, while the dendrites receive signals from other neurons.

cell body

________ have multiple dendrites and a single axon

Multipolar neurons

________ are generated by ligand- gated channels in the dendrites and cell body, while action potentials are generated by voltage- gated channels in the axon.

Local potentials

A(n) ________ (excitatory postsynaptic potential) is a depolarizing potential that makes the post- synaptic neuron more likely to fire an action potential.

EPSP

________ is a type of signal transmission that occurs in myelinated axons.

Saltatory conduction

CNS

Brain and Spinal Cord

PNS

Cranial nerves and spinal nerves and their branches

What are the two types of neuroglial cells and where are they present?

* Present in the CNS and PNS
* CNS: astrocytes, oligodendrocytes, microglia, and ependymal cells
* PNS: Schwann cells and satellite cells

What is the function of astrocytes?

Structural support, regulate the chemical environment, and form the blood-brain barrier in the CNS.

What is the function of oligodendrocytes?

Produce myelin sheaths around axons in the CNS, which increases the speed of nerve impulses.

What is the function of microglia?

Immune cells of the CNS and protect against infection and injury.

What is the function of ependymal cells?

Line the ventricles of the brain and produce cerebrospinal fluid (CSF).

What is the function of Schwann cells?

Produce myelin sheaths around axons in the PNS, which increases the speed of nerve impulses.

What is the function of satellite cells?

Structural support and regulate the chemical environment in the PNS.

What are the three main components of a neuron?

Cell body, dendrites, and an axon.

What is the function of the dendrites?

Receive signals from other neurons

What is the function of the axon?

Transmitting signals to other neurons or effector cells.

Where are multipolar neurons located?

Brain and spinal cord

Where are bipolar and pseudounipolar neurons found?

In sensory structures such as the retina and sensory ganglia

What is the function of sensory neurons?

Transmit information from sensory receptors to the CNS.

What is the function of interneurons?

Integrate and process information within the CNS.

What are the types of ion channels present in the axon and dendrites/cell body?

Sodium and potassium channels are present in the axon, while ligand-gated channels are present in the dendrites and cell body.

Ion responsible for local potentials (small depolarizations in a small area)

Sodium ions

Type of signal transmission that occurs in myelinated axons, involving the rapid conduction of signals from one node of Ranvier to the next, which speeds up signal transmission

Saltatory conduction

Axons that exhibit saltatory conduction due to the presence of myelin sheath

Myelinated axons

Where are vesicles containing neurotransmitters found?

In the axon terminals of the pre-synaptic neuron, near the pre-synaptic membrane

What is the difference between an EPSP and an IPSP?

* EPSP is a **depolarizing** potential that makes the post-synaptic neuron **more** likely to fire an action potential, while an


* IPSP is a **hyperpolarizing** potential that makes the post-synaptic neuron **less** likely to fire an action potential.

What determines whether activation of a given neurotransmitter receptor will generate an EPSP or an IPSP?

Whether the receptor is excitatory or inhibitory

Why do we need temporal and spatial summation?

Individual EPSPs and IPSPs may not be strong enough to cause the post-synaptic neuron to fire an action potential on its own.

* Temporal summation: addition of multiple EPSPs or IPSPs that occur in rapid succession
* Spatial summation: addition of EPSPs or IPSPs that come from different synapses on the same post-synaptic neuron.

The neurotransmitter present at the neuromuscular junction

Acetylcholine

Name two excitatory neurotransmitters

Glutamate and dopamine

Name two inhibitory neurotransmitters

GABA and glycine

How do we terminate the action of neurotransmitters? (Name three things that can happen to the neurotransmitter.) 

* Reuptake of the neurotransmitter by the pre-synaptic neuron
* Enzymatic degradation of the neurotransmitter in the synaptic cleft
* Diffusion of the neurotransmitter away from the synaptic cleft.

**Describe how interneurons are organized into neuronal pools** (groups of interneurons responsible for a particular function or behavior).

Neuronal pools can receive input from sensory neurons, other interneurons, or both, and they can also send output to motor neurons, other interneurons, or both.

Type of neural circuit where a single neuron sends output to multiple neurons downstream.

Diverging circuits

Type of neural circuit where multiple neurons send input to a single neuron upstream.

Converging circuits

Neurons have one dendrite and one axon.

bipolar