Unit 1 AP Psych

Nerve Cell Diagram

Nervous System and its Domains

Central Nervous System

Brain and spinal cord

How do reflexes work?

Sensory neuron travels from area to spinal cord’s interneurons, which pass the message to the motor neurons.

Peripheral Nervous System

Includes somatic and autonomic nervous system, includes sensory/afferent neurons that approach and carry info to CNS and motor/efferent neurons that exit CNS and carry info to rest of the body

Somatic NS

Controls voluntary movements of skeletal muscles, part of PNS

Autonomic NS

Controls involuntary actions like heartbeat, digestion, and breathing (includes Parasymathetic and Sympathetic NS, part of PNS)

Parasympathetic NS

rest and digest (part of Autonomic NS)

Sympathetic NS

Fight or flight, part of Autonomic NS

Dendrites

receive signals from other neuron cells

Cell Body (Soma)

Houses the nucleus & produces energy for the cell

If the net electrical charge reaches ___ mV, an electric impulse is triggered and sent down the axon. If the inhibitory signals match or outnumber the excitatory signals, the neuron remains silent.

-55

Axon & Axon Terminals

Sends signals to other neurons or muscles.

Myelin Sheath

A fatty layer around the axon that speeds up electrical signal transmission.

Synapse

The small gap between neurons where communication occurs by transfering signals using neurotransmitters (chemicals) between neurons.

Glial cells

Protect, nourish, and clean up after neurons.

Interneurons

transmit info b/w sensory and motor neurons in CNS

Sensory or AFFERENT neurons

take sensory info to the CNS

Motor or EFFERENT neurons

EXIT the CNS and carry info to muscles

Action Potential

A brief electrical charge that travels down the axon, it is triggered when the neuron reaches the ABSOLUTE threshold of -55mV.

All-or-Nothing Principle

A neuron either fires or it does not!

Depolarization

When a neuron’s charge becomes less negative, leading to firing.

Refractory period

After firing, the neuron needs time to reset before firing again.

Resting potential

The state of a neuron when it’s ready to fire but hasn’t yet.

Action Potential Graph

threshold represents the absolute threshold of -55 mV

at the first flat line area (to left) (-70 mV) it is at resting potential/polarized state, Na+ is not allowed to enter and K+ is inside the membrane

at the area near the action potential (to left) neuron experiences action potential and is now depolarized, Na+ rushes into the membrane K+ is pumped out

at the area after the action potential peak (to right), the neuron’s axon experiences the refractory period, the axon membrane is repolarizing, Na+ is pushed out and K+ is pushed in

at the downward curve at the bottom, the axon’s membrane is hyperpolarized

Neurotransmitters

Chemical messengers that transmit signals across the synapse.

Excitatory Neurotransmitters

Encourage neurons to fire include dopamine, norepinephrine, glutamate

Dopamine

Involved in reward and motivation.

Norepinephrine

Arouses alertness and energy.

Glutamate

The most common excitatory neurotransmitter, linked to learning and memory.

Substance P

neurotransmitter involved in transmitting pain signals to the brain, released by sensory neurons in response to injury or stress.

Inflammatory Response

Increases blood flow to injured areas, contributing to inflammation.

Inhibitory neurotransmitters

Prevent neurons from firing; includes GABA, serotonin, and endorphins

GABA

Calms the nervous system.

Serotonin

Regulates mood, appetite & sleep.

Endorphins

Natural painkillers.

Communication within a neuron is

electrical (action potentials)

Communication b/w neurons is

chemical (neurotransmitters)

Axon Membrane Model

Neurotransmitter Hierarchy