A&P2 WK1 Lecture QUIZ

What are the three functions of the nervous system?

Sensory input, integration, and motor output.

What function sends signals from the spinal cord to skeletal muscle?

Motor output.

At a synapse, what is the effector?

The postsynaptic cell.

What is reuptake?

The pumping of a neurotransmitter back into the presynaptic cell.

What ion is found in higher concentration inside a resting cell?

K⁺ (potassium).

What ion is found in higher concentration outside a resting cell?

Na⁺ (sodium).

What type of channels does K⁺ use to move at rest?

Leakage channels.

Which direction does K⁺ move at rest?

Out of the cell.

What type of channels does Na⁺ use to move at rest?

Leakage channels.

Which direction does Na⁺ move at rest?

Into the cell.

The Na⁺/K⁺ pump moves ions in what direction relative to their concentration gradients?

Against their concentration gradients.

What does the Na⁺/K⁺ pump require?

ATP.

If chemically gated K⁺ channels open, what happens to K⁺?

It leaves the cell.

Opening K⁺ channels causes the inside of the cell to become what?

More negative.

Opening K⁺ channels produces what type of graded potential?

Hyperpolarization

Hyperpolarization moves the membrane potential where relative to threshold?

Further from threshold.

Hyperpolarization has what effect on the likelihood of an action potential?

It decreases the likelihood.

What is the resting membrane potential?

Approximately −70 mV.

What must happen before an action potential begins?

Local depolarization.

What membrane potential is threshold?

Approximately −55 mV.

What is the first stage of an action potential?

Depolarization.

During depolarization, does membrane potential increase or decrease?

Increase.

During depolarization, the membrane reaches about what voltage?

+30 mV.

Which channels open during depolarization?

Voltage-gated Na⁺ channels.

Which direction does Na⁺ move during depolarization?

Into the cell.

What is the second stage of an action potential?

Repolarization

During repolarization, does membrane potential increase or decrease?

Decrease.

Which channels open during repolarization?

Voltage-gated K⁺ channels.

Which direction does K⁺ move during repolarization?

Out of the cell.

What is the final stage of an action potential?

Hyperpolarization.

What does acetylcholinesterase (AChE) break down?

Acetylcholine (ACh).

What type of molecule is acetylcholinesterase?

An enzyme.

Where are neurotransmitters produced?

Cell body (soma).

Which cell myelinates axons in the PNS?

Schwann cells.

Which cell myelinates axons in the CNS?

Oligodendrocytes.

What channel opens when ACh acts on cardiac muscle?

K⁺ channels.

Is ACh excitatory or inhibitory at the neuromuscular junction?

Excitatory.

Which neurotransmitter is excitatory at cardiac muscle?

Norepinephrine (NE).

Indirect neurotransmitters can do what?

Open ion channels, activate enzymes, and activate genes.

What is an IPSP?

A local hyperpolarization.

What happens if an EPSP and IPSP of equal strength occur at the same place and time?

They cancel each other out, causing no net change in membrane potential.

What is a unipolar neuron?

A neuron with one extension directly off the cell body.

What is a bipolar neuron?

A neuron with two extensions directly off the cell body.

What is a multipolar neuron?

A neuron with many extensions off the cell body.

What structures make up the CNS?

The brain and spinal cord.

What structures make up the PNS?

All nervous tissue outside the brain and spinal cord.

What does the sensory (afferent) division do?

Carries information from receptors to the CNS.

What does the motor (efferent) division do?

Carries information from the CNS to muscles and glands.

What does the somatic nervous system control?

Voluntary skeletal muscle.

What does the autonomic nervous system control?

Involuntary smooth muscle, cardiac muscle, and glands.

Alcohol is an agonist for which neurotransmitter?

GABA.

What does an agonist do?

Binds to and activates a receptor.

Caffeine is what type of adenosine drug?

An antagonist.

Is adenosine excitatory or inhibitory?

Inhibitory.

What effect does adenosine have?

Makes you more sleepy.

How does caffeine work?

Blocks adenosine receptors, making you less sleepy.

Cocaine blocks the reuptake of which neurotransmitters?

Dopamine and norepinephrine.

Blocking reuptake causes neurotransmitters to stay where?

In the synaptic cleft longer.

What is the result of blocking reuptake?

More neurotransmitter binds to receptors on the postsynaptic cell.