Nervous System

What is the resting membrane potential of a neuron?

-70 mV

Dopamine

-Affects sleep, mood, attention, and learning -Made from Tyrosine -Inhibitory and excitatory depending on the location of the neurons

Serotonin

-Also known as the happy chemical -Affects brain, sleep, mood, attention, and learning -Works with Dopamine -Made from Tryptophon -Precursor for Melatonin as it helps regulate the body's sleep-wake cycles -Inhibitory

Glutamate

-An amino acid that can act as a neurotransmitter -Affects memory -Excitatory

GABA

-Binds to receptors in postsynaptic cells to increase membrane permeability to Cl- -Inhibitory

Endorphins

-Decrease pain perception -Produced during times of stress -Morphine and heroin mimic this -Inhibitory

Acetylcholine

-Invertebrates and vertebrates -Muscle stimulation, memory formation, and learning -Excitatory

Norepinephrine

-Made from Tyrosine -Contraction of skeletal muscles -Excitatory

What is the ratio if sodium ions to potassium ions that are moved through the sodium/potassium pump each cycle?

3 sodium out for every 2 potassium in

What will happen to the ions that entered the cell through the gated channel in the time that follow the closing of the channel?

Sodium ions will be pumped back out of the neuron by the sodium/potassium pump

Which way does the sodium/potassium pump move sodium and potassium ions when activated?

Sodium out of the cell and potassium into the cell

How does the flood of ions through the gated channel affect the membrane potential in the area further away from the protein channel?

Stays the same

When the gated channel is open and ions flow through, does the concentration of that ion species inside of the cell increase, decrease, or stay the same in the area further away from the protein channel?

Stays the same

Which side of the membrane has more potassium ions when the neuron is at rest?

The inside

What type of ions are moving through the ligand-gated protein channel when it is open?

Sodium ions

Which direction should sodium ions flow naturally if a channel is provided?

Sodium ions should flow into the cell until equilibrium is reached- the number of ions moving out would equal those moving in

Extreme athletes use sports drinks not only to hydrate but also to replenish the electrolytes (ions) in their body that are lost through sweat. Propose some reasons why this would be necessary to keep an athlete healthy and in top condition?

A lack of electrolytes would impede the proper function of nerves because the sodium and potassium ions would not be at the correct concentrations

What must occur for the "gate" to open and allow movement of ions across the membrane?

A ligand must bind to the protein which causes a protein channel to open

Describe the cellular structure of a neuron's membrane.

A phospholipid bilayer or cell membrane with several embedded proteins

What will happen to the membrane potential in the time that follows the closing of the channel?

As the ions diffuse and get pumped back out of the cell, the membrane potential will return to -70 mV in all areas of the membrane

The shapes of some proteins are dependent on the electrical potential in the surrounding area. What would happen to such a protein if it was near one of the gated protein channels as it opened?

As the potential changed across the membrane, the protein would change its shape

How long is the longes neuron in the human body, and where is it located?

Base of the spine to the foot (1 meter long)

Which structure on the neuron would receive a signal from either a sensory cell or from another neuron?

Dendrite

If the sodium/potassium pump were to stop functioning, what would eventually happen to the concentration gradients of sodium and potassium ions across the membrane?

Eventually, the concentration gradients of sodium and potassium would reach equilibrium across the membrane because of the passive transport that occurs in either direction across the membrane

When the gated channel is open and ions flow through, does the concentration of that ion species inside of the cell increase, decrease, or stay the same in the immediate vicinity of the protein channel?

Increase

How does the flood of ions through the gated channel affect the membrane potential in the immediate vicinity of the protein channel?

It makes it more positive (decreases)

Which direction should potassium ions flow naturally if a channel is provided?

Out of the cell until equilibrium is reached

Is the transport of ions across the membrane active or passive transport?

Passive because no energy is required for the ions to cross the membrane and the ions are moving with the gradient

Which side of the membrane has more sodium ions when the neuron is at rest?

The outside

Why can't sodium ions cross the membrane without the use of a protein channel?

The sodium ions are charged while the phospholipid tails in the membrane are nonpolar. The protein channel provides a pathway that is surrounded by polar groups allowing the ions to move

Why is ther an uneven distribution of charge across the membrane, resulting in a potential?

There are additional negatively charged ions inside the neuron and the membrane is more permeable to potassium ions

Are the ions moving against or with the original concentration gradient?

With the gradient