Bio 1202 Endocrinology, Reproduction, and Neuroscience

What are nervous systems made up of?

circuits of neurons and supporting cells (Glia)

What is another name for supporting cells

Glia

What does the organization and structure of neurons reflect?

function in information transfer

What does communication by neurons largely consist of?

long distance electrical signals and short-distance chemical signals

What do sodium-potassium pumps and ion channels establish?

The resting potential of a neuron

What is the signals conducted by axons?

Action potentials

Where do neurons communicate with other cells?

synapses

Where did specialized nervous systems appear that enabled animals to sense their environments and respond rapidly?

Cambrian explosion

What are the 5 parts of the Animal nervous systems

Synopsis, Transmission of nerve signals, Synapses, Diversity of sensory systems, Diversity of nervous systems

What is Synopsis

types of cells and organization

What are the three main types of neurons in the nervous system?

Sensory neurons, Interneurons, Motor neurons

What do Sensory neurons do?

sensory input

What do Interneurons do?

Integration

What do motor neurons do?

Motor output

Which neuron is the effector?

Motor neuron

What nervous system is Motor neurons apart of?

Peripheral nervous system (PNS)

What nervous system are sensory neurons apart of?

Peripheral nervous system (PNS)

What nervous system are the interneurons apart of?

Central nervous system (CNS)

What are the main things of supporting cells

Do not conduct signals, Insulate axons with myelin, Nourish & protect neurons

What are supporting cells of CNS

Glial cells

What outnumber neurons

Glial cells

What is a force that causes electrically charged particles to move between two points (current)?

Voltage

What is Voltage?

electrical potential difference

What carries voltage in wires?

electrons

What carries voltage across the cell membrane

ions

What is the unit of voltage?

Volts

What is the membrane voltage for a particular ion at equilibrium

The equilibrium potential (E_ion)

What can be used to calculate a particular ion at rest or equilibrium

Nernst equation

Why do changes in membrane potential occur?

Gated ion channels

What do gated ion channels respond to

stimuli

What is change in voltage across the plasma membrane of the neuron?

Voltage gated ion channels

When is a cell polarized?

at rest

What is the decrease in membrane potential from resting stare (Na+ in)?

Depolarization

What is it when the inside of the cell becomes less negative

Depolarization

What is it when there is an increase in membrane potential from resting state (K+ out)

Hyperpolarization

What is it called when the inside of the cell becomes even more negative

Hyperpolarization

What is it called when the membrane potential returns to a resting state (K+)

Repolarization

What is changes in polarization with the strength of the stimulus

Graded potential

What is when depolarization shifts the membrane potential massively

Action potential

What is the first step in generation of an action potential

Resting state

What is resting state in generation of an Action potential

Most voltage gated sodium (NA+) and Potassium (K+) channels are closed

What is the second step in Generation of an Action potential

Depolarization

What happens in depolarization of generation of an action potential

Voltage gated Na+ channels open first, and Na+ flows into the cell

What is the number when hit all sodium channels open and become super depolarized

-50

What is the third step of generation of an action potential

Rising phase of the action potential

What happens during the rising phase of the action potential?

The threshold is crossed, the membrane potential increases

What happens during the 4th phase of generation of an action potential

Falling phase of the action potential

What happens during the falling phase of the generation of an action potential

Voltage gated Na+ channels become inactivated; voltage gated K+ channels open

What is the 5th phase of generation of an action potential

Undershoot

What happens during undershoot in the generation of an action potential

membrane permeability to K+ is at first higher than at rest, then voltage gated K+ channels close

What is happening to an Action potential when it moves in one direction and travels only toward the synaptic terminals

Propagation

What does the speed of an action potential increase with

axons diameter

What are axons insulated with in vertebrates

myelin sheath

What does the myelin sheath do to an action potential

causes its speed it increase

What are myelin sheaths made from

glia

What two glia help make myelin sheaths

Oligodendrocytes (CNS) and Schwann cells (PNS)

What is insulation form cation leakage

Myelination

What allows depolarization to spread further before needing to regenerate

Myelination

When is AP propagation faster in

myelinated neurons

What is a benefit of larger axons

less internal resistance

When does depolarization spread further inside rather than leaking out (volume increases faster than surface area)

Larger axons

What happens to an action potential when it gets to the end of an axon

electrical signal becomes a chemical signal

What is the order for action potential when it reaches the end of the axon

AP arrives, Opens voltage-gated channels, Synaptic vesicles fuse with presynaptic membrane, Neurotransmitter binds to ion channels in postsynaptic membrane

What happens when action potential arrives at the end of the axon

depolarizes presynaptic membrane

What happens when the voltage-gated channels open

influx of [Ca]2+

What happens when synaptic vesicles fuse with presynaptic membrane

Releases neurotransmitter into synaptic cleft

What happens when the neurotransmitter binds to ion channels in postsynaptic membrane

Stimulates gated Na+ channels to open and new action potential

Are neurotransmitters excitatory or inhibitory?

Both

What causes depolarization, triggers action potential or other responses, and Acetylcholine

Excitatory

Is acetylcholine excitatory or inhibitory?

excitatory

What causes hyperpolarization, makes action potential more difficult, and serotonin

Inhibitory

Is serotonin excitatory or inhibitory?

Inhibitory

What quickly degrades neurotransmitters (stop signals)

enzymes

What removes neurotransmitters from synapse

Reuptake

Parasympathetic, nerve gas, inhibits enzyme that breaks down the neurotransmitter

Sarin

What does too much Ach neurotransmitter result in

paralysis and respiratory or heart failure

What do most medicines for depression do

inhibit reuptake of serotonin from synapses

What is a neurotransmitter that inhibits postsynaptic neurons that transmit pain signals

Endorphins

What do endorphins do

decrease sensitivity to massive, chronic pain

Heroin, morphine, codeine, methadone are excellent pain killers, highly addictive and are examples of

Endorphins

What is amino based and inhibits the excitatory signals that result in the feeling of anxiety and fear (calming effect)

GABA

Sedatives, alcohol, GBH (date rape drug), anti-anxiety drugs (valium, librium, halcion) enhance the inhibitory effect of what?

GABA

What when taken together can produce overdoses

Alcohol and valium

The stronger the signal (more pressure) it can trigger ____

more receptors

With low pressure on sensory receptor ->>>>

low frequency of aps

What do all signals reach the brain as

Action potentials

Brain then interprets these into perceptions of sensation based on which neurons fired

perception

Which receptor senses pressure

Mechanoreceptors

Which receptor has ion channels linked to structures to hairs (cilia)

Mechanorecptors

Mammalian sense of touch relies on _______

mechanorecptors

Which receptor responds to specific chemicals

Chemoreceptors

Which receptors ion channels permeability changes with stimulus

Chemoreceptors

Which receptor has protection for pheromones

Chemoreceptors

Which receptor detects electromagnetic energy (light, electricity, magnetism)

Electromagnetic Receptors

What receptor detects heat and cold

thermoreceptors

Which receptor has stimuli that reflect harmful conditions

Nociceptors

What are nociceptors associated with

pain

Which receptor responds to pressure, temperature, chemical from damaged/inflamed tissue

Nociceptors

What is for how you feel, able to perceive surroundings (which way your facing)

Proprioception