Summer Neuro - Unit 1

The central nervous system (CNS) includes what?

Brain and spinal cord

What is the function of the CNS?

Interpret sensory information and determine motor response

The peripheral nervous system (PNS) is made up of what?

Cranial nerves, spinal nerves, and ganglia

What is the function of the PNS?

Links body to CNS

Afferent neurons are _______

Sensory

Efferent neurons are ____________

Motor

Somatic means ______

Body (skin, skeletal muscles, joints)

Visceral means ______

Internal (smooth muscle, organs)

General means _______

Widespread

Special means _________

Localized

What are the 4 types of neurons we discussed?

GSA, GSE, GVA, GVE

What are some things a GSA neuron is responsible for?

Sensing touch, pressure, pain, and temperature

What are some things a GVA neuron are responsible for?

Sensing internal pain, nausea, and hunger

What is proprioception?

Sensing ones own body (neurons detecting the degree in which muscles are stretched)

What type of neuron is involved in proprioception?

GSA

What are some things GSE neurons are responsible for?

Movement of upper and lower limbs

What are some things GVE neurons are responsible for?

Sweating, going to the bathroom, heart rate, digestion

What are the 2 nerve cell types?

Neuron and neuroglia (glia)

Is a neuron excitable?

Yes

What is the role of a neuron

To transmit a signal

Is a glia excitable?

No

What is the role of a glia?

To support and surround neurons

What is the basic unit of the nervous system?

Neuron

What type of signals do neurons send?

Electrical and chemical

Do neurons divide?

No

What is the role of dendrites on a neuron?

To receive signals

What do we call the cell body of a neuron?

Soma

What is the role of the axon on a neuron?

To send the signal down the neuron

What is the role of myelin on an axon of a neuron?

Conduction (to send signal faster)

What are the 3 types of neurons?

Multipolar, unipolar, bipolar

Describe a multipolar neuron

One axon, many dendrites

What kind of neurons are usually multipolar?

Motor neurons and interneurons

Describe a unipolar neuron

Single process

What kind of neurons are usually unipolar?

Sensory neurons

Describe a bipolar neuron

one cell body, two processes

What kind of neurons are usually bipolar neurons?

Only found in eye and ear

Neurons have _____ and ______

Cell bodies and fibers

In the CNS, cell bodies of neurons live in __________

Gray matter

In the CNS, fibers of neurons travel in _________

White matter

In the PNS, cell bodies of neurons live in __________

Ganglia

In the PNS, fibers of neurons travel in ______

Nerves

Where do neurons communicate?

Synapse

Ratio of glia to neurons

10 to 1

Can glia divide?

Yes

What are the 4 types of glia in the CNS?

Astrocytes, microglia, ependymal cells, oligodendrocytes

What is the role of astrocytes?

Nourish, form part of blood-brain barrier, maintain ionic concentration, assist neurons in cell-to-cell signaling

What is the role of microglia?

To destroy invading microorganisms, dead and injured neurons

Which glia have a developmentally different origin from all other nervous system cells?

Microglia

What is the role of ependymal cells?

Form the simple epithelium lining of the CNS and help make CSF

What is the hair-like part of an ependymal cell called and what do they do?

Cilia - circulate CSF

What is the role of oligodendrocytes?

To produce myelin covering on CNS axons

What are the 2 types of glia in the PNS?

Schwann cells and satellite cells

What is the role of schwann cells?

To produce myelin covering on PNS axons

What is the role of satellite cells?

To surround neuron cell bodies inside of ganglia

What’s in a nerve?

Axon, fascicle, blood vessels

______ —> ______ —> nerve

Axon —> fascicle —> nerve

An axon is can be covered in _____

Myelin

The covering of an axon is known as _________

Endoneurium

Bundles of axons are called __________

Fascicles

The covering of a fascicle is known as __________

Perineurium

Bundles of fascicles are known as _________

Nerves

The covering of a nerve is known as ________

Epineurium

Why do neurons need to be surrounded by blood vessels?

Becuase they need constant supply of oxygen, etc to function

The exterior of a cell is formed by a _____________

Phospholipid bilayer

Heads of lipids are __________ and tails are __________

Hydrophilic ; hydrophobic

Cell exterior is ______ and cell interior is _______

Polar ; non-polar

What kind of molecules can pass through the cell exterior on their own?

Non-polar molecules (oxygen, carbon dioxide)

What kind of molecules cannot pass through the cell exterior on their own?

Larger polar molecules (water, sodium, chlorine)

Name the 2 types of passive transport

Diffusion and facilitated diffusion

Give an example of diffusion

One substance dissolving in another (like tea)

In diffusion, the solute always moves ______ the concentration gradient

Down

What is facilitated diffusion?

Protein components of the plasma membrane allow ions to cross

What are the 2 types of proteins used in facilitated diffusion?

Non-gated and gated channels (“tunnels and doors”)

Active transport is going ______ the concentration gradient

Up

What are 2 forms of active transport?

Membrane pumps and edo/exocytosis

Most common example of a membrane pump

Sodium/potassium pump

Sodium potassium pump moves …

3 sodium out and 2 potassium in

What is the following describing: edges of membrane pinch off to form vesicle

Endocytosis

What is the following describing: vesicle merges with plasma membrane to release contencts to extracellular fluid

Exocytosis

All cells are slightly ______ just inside the plasma membrane

Negative

We refer to the electrical charge difference between the inside and outside of the membrane as …

Resting potential

If gated channels open, ions can flow into a cell, depolarizing the cell. This creates a …

Local potential

Where does a local potential take place?

On cel bodies / dendrites

A local potential is _________ a message

Receiving

A local potential is initiated by ________-gated channels

Stimulus

What kind of stimuli can cause a local potential?

Mechanical, chemical, or temperature

Are local potentials decremental or propagated?

Decremental

A loca potential, if strong enough, can lead to an …

Action potential

What must be reached in order for a local potential to trigger an action potential?

Threshold stimulus

Where does an action potential take place?

On axons

An action potential is ________ a message

Sending

An action potential ueses ________-gated channels

Voltage

Voltage-gated channels used in an action potential only open in response to an …

Electrical current

Are action potentials decremental or propagated?

Propagated

Why are action potentials all or nothing?

Sodium channels always open for the same amount of time

What do we call the time period where a voltage-gated channel needs to reset before it is reactivated?

Refractory period

During this type of refractory period, the voltage-gated channel can definitely not reopen

Absolute refractory period

During this type of refractory period, the voltage-gated channel may reopen but it needs more energy than the first time

Relative refractory period

What is the purpose of the refractory period?

Allows the signal to flow only in one direction

During the refractory period, what is flowing out of the cell?

Potassium