HBS TEST 2.1.3 - 2.1.4

Neuron

A specialized cell that transmits nerve impulses

Cell body

The central part of the neuron that contains the nucleus and is the main structural component of gray matter.

Axon

the long thread-like part of a nerve cell along which impulses are conducted from the cell body to other cells.

Axon Hillock

A specialized part of the cell body (or soma) of a neuron that connects to the axon.

Nodes of Ranvier

The gaps in the myelin sheath of a nerve, between adjacent Schwann cells.

Myelin Sheath

A wrapping of myelin around certain nerve axons, serving as an electrical insulator that speeds nerve impulses to muscles and other effectors.

Synapse

a junction between two nerve cells, consisting of a minute gap across which impulses pass by diffusion of a neuro transmitter

Synaptic Cleft

the space between neurons at a nerve synapse across which a
nerve impulse is transmitted by a neurotransmitter

presynaptic neuron

the neuron that is SENDING the signal

postsynaptic neuron

the neuron RECEIVING the signal

neurotransmitters

a substance that transmits nerve impulses across a synapse

vesicles

a small sac containing neurotransmitters enclosed by a lipid bilayer

Action Potential (word form)

The change in electrical potential associated with the passage of an impulse along the membrane of a muscle cell or nerve cell

axon terminals

The end of a neuron. The part of the neuron that sends the signal

dendrites

The part of the neuron that receives the signal from another neuron.

Cell membrane

A semi-permeable membrane made of phospholipids that surrounds the cytoplasm of cells; found in all cell types

Nucleus (cells)

The organelle found in all eukaryotic cells that contains all of the chromosomal DNA of the cell.

Schwann Cell

Cell that produces the myelin sheath

Passive transport

• high to low

• moves with the gradient

• does not require atp

Simple diffusion

• passive transport

• molecules moving directly across a cell membrane without the assistance of any proteins

Facilitated Diffusion

• passive transport

• requires specific transport proteins embedded in the membrane to help molecules move across

Active transport

• low to high

• requires atp

• moves against the gradient

Action Potential (words)

a brief electrical impulse that travels across the axon of the neuron

Neuromuscular Junction

a synapse where a motor nerve connects to a muscle fiber and transmits electrical impulses to cause muscle contraction

Experimental Research

• comes first

• basic medical research & includes animal experiments, cell studies, biochem, genetic, and physiological investigations

Clinical research

• comes second

• determines the safety and other effects on medications, their devices, diagnostic products and treatment regimens

protein channels

allow potassium ions to pass in or out of the cells

Sodium Channels

allow sodium or Na+ ions to pass it around

Protein pump (Na / K pumps)

pumps 3 “Na” ions out and pumps 2 “K” ions in

Multipolar Neurons

• CNS and effernt PNS

• Most common form of neurons, make up 99% of all types

• 3 or more processes extend out of the cell body

Bipolar Neurons

• found in the CNS. specialized sensory neurons for the transmission of senses (smell, sight, and hearing)

• Relatively Rare

• Two extensions, one axon and one neuron

Pseudounipolar

• CNS and afferent division of the PNS

• Only occurs as a sensory neuron, Fairly common

Unipolar

• afferent division of the PNS

• common in invertebrates, but rare in vertebrates

• large cell body with axon pointing in only one direction.

• Axon appears shorter in this type of neuron

Neuron (nerve cell)

Cell body

Axon

Axon Hillock

Nodes of ranvier

Myelin Sheath

Synapse

Synaptic Cleft

Presynaptic Neuron

Postsynaptic Neuron

Neurotransmitters

Vesicles

Action Potentials (picture)

Axon Terminals

Dendrites

What is an action potential?

A signal that is sent through your body. It has 4 stages.

An action potential acts like a

wave, where one section is triggered and then another, till it reaches the synapse

Na+ and K+ are both

Ions, or elements with a positive (or negative) charge

If there is a concentration gradient, what does that mean

There is more ions on one side of the neuron cell then the other

What is the concentration gradient at resting potential

Na+ are outside the cell and K+ are inside the cell

What is resting potential also known as

on switch

what is an excitatory signal

A signal that stimulates a neuron while an inhibitory signal prevents a neuron from sending a message

what happens to cause the neuron to be more positive, and the line on the graph to go up

Na+ (sodium) enters the nueron

What caused the graph to increase in charge so much

Na+ concentration gradient was eliminated, now most + charged ions are all inside the cell.

What happens to repolarize the neuron?

Na+ channels close and K+ channels open

Which way is K+ going to flow, now that the channels for it are open?

Out of the cell, because there are more K+ inside the cell.

What is happening to the charge of the cell during repolarization?

The cell is getting more negative because it is losing positive charges.

What would happen if the Na+ channels opened right now with the cell looking as it does? (nothing is moving)

Na+ wouldn't move into or out of the cell, as there isn't a concentration gradient.

How does the cell restore the concentration gradients for K+ and Na+?

sodium potassium pump

Which structure of a neuron receive information from other neurons to be processed by your brain?

dendrites

Which structure of a neuron transmits signals from the cell body to other neurons?

axon

What is the signal called that the neuron sends down the axon?

action potential

What is the main purpose of the myelin sheath in the neurons?

speed up the action potential

What is the gap between the end of the axons and the dendrites of the other neuron called?

synaptic cleft

Which structure brings information into the neuron?

dendrites

Where is information processed in the neuron?

cell body

Which structure insulates the neuron and speeds up the action potentials?

myelin sheath

Which structure conducts the action potential signal to other neurons?

axon

What are the spaces between each myelin sheath that allow signals to jump from one node to another?

nodes of ranvier