Neuroscience Final

Functions of the Nervous System

Sensory (senses changes through sensory receptors)
Integration (analyzes sensory information, stores some aspects, and makes a decision to produce an output)
Motor (responds to stimuli to maintain homeostasis)

Integration

Gathering information and generating an appropriate response to maintain homeostasis

Homeostasis

the ways in which body systems regulate and maintain themselves to function correctly and maintain stability; regulated by reflexes

Reflexes

Programmed automated response to stimulation

Which system is responsible for maintaining homeostasis long-term?

The Endocrine System

How long do hormones take to work?

Minutes to hours

What kind of needs are the Nervous System responsible for?

Immediate needs

What happens if the body cannot maintain homeostasis?

Body moves into illness and death, called shock.

What is the first responder in maintaining homeostasis and why?

The Nervous System

Nothing is faster than a neurochemical impulse.

Which cells are excitable?

Muscle fibers and neurons

Hyper-reflex

Too strong of a reflex

No reflex

Bad; cause for concern

Types of Neurons

Motor, Sensory, Interneurons/Association

T/F: Interneurons are only located in the Central Nervous System

True

Which type of neurons are the largest neurons?

Motor Neurons

Frequency Coded

The way neurons transmit information to the brain; the intensity of a stimulus is encoded by the frequency of Action Potentials; signals are the same size, rate of signals is the determinant

Which flavor is taste most sensitive to?

Bitter

Which neurons have more dendrites and why?

Motor neurons

To increase surface area to receive more information

Where are dendrites present?

Cerebellum

What is the Cell Body of a neuron’s job?

Integration

Where is a message sent out through in a neuron? Where does the signal go simultaneously?

Axon; Synaptic Ends

What are the synaptic ends full of?

One neurotransmitter

Where do neuromodulating drugs work?

The Synaptic Ends

What does Parkinson’s disease do?

Stops the inhibitory message from going to muscles that tells them to stop contracting.

T/F: Neurons only make one neurotransmitter and are named according to it.

True

What are neurons that make acetylcholine called?

Cholinergic

Multiple sclerosis means… and affects…

multiple scabs; myelin

A Multipolar Neuron has…

Multiple dendrites (at least 2)

A Bipolar Neuron has…

One axon and one big dendrite

What do bipolar neurons have a role in?

Allows us to see color, edges, shapes

Where are Bipolar Neurons found and how many?

Retinas; hundred of thousands

Spinal cord to separate information

Unipolar Neuron

Only one process; axon is the dendrite

Where are unipolar neurons located?

In the spinal cord to make information more specific.

Does the brain have pain receptors?

No.

T/F: Dendrites can receive information from other dendrites that they overlap with.

True

What are the targets/effectors of neurons?

Other neurons

Muscle fibers (smooth, cardiac, skeletal)

Exocrine Glands (oil, sweat, saliva; secrete from ducts into a body cavity)

Endocrine Glands (hormones; secretes without ducts into the blood stream)

What examples did we talk about in dendritic branching?

Purkinje cell and Pyramidal cell

For touch receptors, what is deformed when you touch something?

The Corpuscle of Touch

T/F: Squeezing/pressuring (or not) the corpuscle of touch causes a message to be sent.

True

T/F: We have light touch and deep touch receptors

True

What are irritant receptors called?

Nociceptors

What are irritant receptors (nociceptors) activated by?

Too much touch, heat, irritation, stimulation

Gate Theory

information comes in through the spinal cord but only so much can go to the brain at a time

What medications block the brain from thinking about pain?

Morphine, codeine, anesthesia

T/F: The brain has pain receptors.

False

T/F: Some medications block pain messages at the source

True

What makes up half the volume of the Nervous System are is not electrically excitable?

Neuroglia

Can neuroglia multiply and divide?

Yes

Which germ layer does neuroglia develop from?

Ectoderm

Where do most CNS tumors originate from and give an example?

Neuroglia; glioblastoma

Microglia (Neuroglia)

Located in the CNS; smallest type; protects cells; is an extension of the immune system, takes out invaders; prevents N.S. cancer

Ependymal Cells (Neuroglia)

Located in the CNS; line the 4 ventricles of the brain; aid in formation and circulation of cerebrospinal fluid

Astrocytes (Neuroglia)

Located in the CNS; connect to blood vessels on one end and the neuron on the other to provide nourishment to the neuron

Schwann Cells (Neurolemmocytes) (Neuroglia)

Located in the PNS; form myelin; provide stimulation for regeneration of neurons/nerves

Satellite Cells (Neuroglia)

Located in the PNS; stimulate general Nervous System growth

Oligodendrocytes (Neuroglia)

Located in the CNS; make myelin

Sources of Nervous System Tumors

1. Cells may have never matured (“blast”) and keep reproducing as immature cells (Peter Pan cells)

   1. Old/mature cells continue to mature instead of die, crowding out new, healthy cells.

Which neuroglia cells produce the myelin sheath?

Schwann Cells (PNS) and Oligodendrocytes (CNS)

What disease affects myelin formation?

Multiple Sclerosis

T/F: We are born with hundreds of thousands of neurons, but only those with perfect instructions (a small percentage) make it to full development.

True

Gray Matter

Neuronal cell bodies, integration center, located on the outside of the brain and inside of the spinal cord

White Matter

Insulated pathways; located on the inside of the brain and outside of the spinal cord

Central Canal

Hole that runs the length of the spinal cord to circulate cerebrospinal fluid to provide nourishment and collect waste

Which side does information enter the spinal cord? Exit?

Enters - dorsal side (sensory)
Exits - ventral side (motor)

Nucleus/Ganglion

Cluster of neurons in the CNS/PNS

How do excitable cells communicate?

Action potentials or graded potentials

Threshold

exciting a neuron/muscle cell enough that enough sodium channels open to generate an AP, which is excitatory or inhibitory

What is an example of a neuron that has a low threshold and is easily excitable?

The bipolar neurons in the retina that allow for night vision.

Resting Muscle Tone

All muscle fibers are always partially contracted and have a low threshold.

Flaccid

Muscle has zero resting muscle tone; neuron is severed

Atrophy

Deterioration of muscles; caused by them being flaccid

A nerve impulse is a chain of…

Action potentials

Action Potentials allow communication over…

Short and long distances

Graded potentials allow communication over…

Short distances only

Plasticity

The capability to change based on experienceReg

Regeneration

The ability to replicate or repair

What voltage do bone, skin, and blood cells have?

0 mV, meaning no potential and would burn if stimulated; positive and negative charge in the cell is equal.

When is there potential to carry a current?

When one side of the membrane is more negative than the other.

Resting Membrane Potential (RMP)

Of muscle and neuronal cells only; they always have a charge of -70mV; maintained by sodium-potassium pump and high permeability of the membrane; inside is negative compared to the outside

What ions are important in the Nervous System?

Na+, K+, Ca2+, Cl-

Current

Movement of charged particles across a membrane; generates electricity

Do proteins have a positive or negative charge?

Negative

Gradient

Change in concentration

Diffusion

Higher concentration moves to lower concentration; high charge density to low charge density

At an AP, sodium rushes into the cell and the membrane becomes ___.

Positive

Sodium is in abundance ___ the cell.

outside

The abundance of proteins in the cell give it a ____ charge.

negative

Potassium is abundant ___ the cell.

inside

Chloride is in abundance ____ the cell.

Outside

At the peak of the AP, which channels open and which channels close?

Sodium closes and potassium closes

Depolarization

The process where a neuron’s membrane potential decays and becomes less negative, initiating an AP; caused by increase of sodium

Repolarization

Phase of an AP where an excitable cell membrane returns to its resting negative potential following depolarization; caused by potassium exiting the cell; prepares for another AP

Hyperpolarization

The process where a neuron’s membrane potential becomes more negative, moving further from zero; more polar than it is at rest; less likely to fire another AP; prevents overfiring

Sodium Potassium Pump

Electrogenic; pumps in 3 sodium and pumps out 2 potassium (net charge of +1 out); repolarizes the cell; generates beginning of a current

Parkinson’s disease and tremors is caused by…

Leaks of acetylcholine (signals muscles to contract) that the brain cannot inhibit with glycine or dopamine because the neurons can’t make them.

What actor suffers from Parkinson’s disease?

Michael J. Fox

Treatments of Parkinson’s Disease

Giving L-Dopa (neurotransmitter that stimulates the production of dopamine, which inhibits)

Transplanting dopamine producing cells from the adrenal glands into the brain

What causes Mesothelioma?

Asbestos

Does mesothelioma have a cure?

No.

What actor died from Mesothelioma?

Steve McQueen