Glial Cells in the Nervous System

Schwann cells

Oligodendrocytes

Microglia help protect nerve cells by removing harmful substances.

<p>Connect to blood vessels and help form the blood-brain barrier (A), Surround and support nerve cell connections (synapses) and nerve cell surfaces (B), Have receptors that respond to various neurotransmitters (C), Produce substances that nourish nerve cells and help control the levels of ions and neurotransmitters (D)</p> Signup and view all the answers

<p>Producing neurotransmitters (D)</p> Signup and view all the answers

<p>True (A)</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>True (A)</p> Signup and view all the answers

<p>Axon</p> Signup and view all the answers

<p>Synapse</p> Signup and view all the answers

<p>True (A)</p> Signup and view all the answers

<p>Sodium (Na+) and Potassium (K+) (D)</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>Na+/K+ ATPase</p> Signup and view all the answers

<p>Adenosine triphosphate</p> Signup and view all the answers

<p>-70 mV (A)</p> Signup and view all the answers

<p>True (A)</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>True (A)</p> Signup and view all the answers

<p>True (A)</p> Signup and view all the answers

<p>Depolarization (D)</p> Signup and view all the answers

<p>Repolarization (B)</p> Signup and view all the answers

<p>Hyperpolarization (B)</p> Signup and view all the answers

<p>True (A)</p> Signup and view all the answers

<p>True (A)</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>True (A)</p> Signup and view all the answers

<p>Nodes of Ranvier</p> Signup and view all the answers

<p>True (A)</p> Signup and view all the answers

<p>Insulate the neuron and increase the speed of signal conduction (B)</p> Signup and view all the answers

<p>True (A)</p> Signup and view all the answers

<p>True (A)</p> Signup and view all the answers

Specialized cells that support and protect neurons in the peripheral nervous system (PNS). They wrap around axons to form myelin sheaths, which insulate and speed up nerve impulse conduction.

Specialized cells that support and protect neurons in the central nervous system (CNS). Similar to Schwann cells, they create myelin sheaths around axons, enhancing nerve impulse conduction.

Immune cells of the CNS that protect neurons by removing debris, pathogens, and other harmful substances.

Star-shaped glial cells that perform various crucial functions in the CNS, including:

A protective barrier that restricts the passage of certain substances from the bloodstream into the brain. It is formed by astrocytes and capillaries.

The junction between two neurons where communication occurs. Astrocytes surround and support these connections.

Astrocytes produce substances that nourish neurons and help regulate the levels of ions and neurotransmitters.

Astrocytes have receptors that respond to various neurotransmitters, allowing them to sense and influence neuronal activity.

The process by which a neuron generates and transmits an electrical signal.

The movement of ions across the cell membrane, which is the basis of electrical signaling in neurons.

The electrical activity in neurons is very fast, measured in milliseconds (ms).

The change in voltage across the neuron's membrane during an electrical impulse.

Even though conduction of nerve impulses is rapid, it is much slower than the flow of electricity through a wire.

Sodium (Na+) and potassium (K+) are the main ions involved in the propagation of nerve impulses (action potentials).

The difference in electrical charge between the inside and outside of a neuron's membrane when it's not transmitting a signal.

The sodium-potassium pump (Na+/K+ ATPase) actively transports ions across the membrane, maintaining the resting membrane potential.

The Na+/K+ ATPase pumps 3 Na+ ions out of the cell and 2 K+ ions into the cell for every cycle, contributing to the negative charge inside the neuron.

The concentration of K+ ions is higher inside the neuron compared to outside, contributing to the resting membrane potential.

The concentration of Na+ ions is much higher outside the neuron compared to inside, contributing to the resting membrane potential.

The process by which a neuron generates an electrical signal (action potential) in response to a stimulus.

The opening of Na+ channels allows Na+ ions to rush into the neuron, causing depolarization.

The influx of positive charges (Na+) makes the inside of the neuron more positive, reversing the membrane potential towards zero.

The membrane potential becomes positive (around +30 mV) as Na+ accumulates inside the neuron.

The opening of K+ channels allows K+ ions to rush out of the neuron, causing repolarization.

The membrane potential becomes negative again as K+ ions leave the neuron.

The membrane potential temporarily becomes even more negative than the resting potential (about -100 mV) as K+ ions continue to leave.

The Na+/K+ ATPase pumps Na+ ions out and K+ ions in, restoring the resting membrane potential.

A short period following an action potential when the neuron is less sensitive to stimulation.

A period during which the neuron cannot generate another action potential, no matter how strong the stimulus.

A period during which the neuron can generate another action potential but only with a stronger than usual stimulus.

The process by which an action potential travels along the neuron's axon.

The speed of impulse conduction can be influenced by the size of the neuron, temperature, and the presence of myelin.

Myelinated axons conduct impulses much faster than non-myelinated axons.

A neuron will fire a maximal action potential if the stimulus reaches a certain threshold, or it will not fire at all if the stimulus is below that threshold.