Unit 1: The Nervouse System & Neurotransmission

Neurons

A nerve cell, the basic building block of the nervous system

Glial Cells

The other nerve aids in the maintenance of homeostasis, and forms myelin

Action Potential

Neurons transmit messages when stimulated by our senses or by neighboring neurons. A neuron sends a message by firing an impulse, called the action potential a brief electrical charge that travels down its axon.

Threshold

-55mv

Resting State

-70mv( negative potassium inside / positive sodium outside

Depolarization

This is the phase of the action potential where the inside of the neuron becomes less negative (more positive) due to the influx of positive ions. The is positive sodium inside.

Repolarization

It is the crucial phase of an action potential where it returns to its negative resting state after firing. This means that potassium is released outside the neuron.

Synapse

The junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron. The tiny gap at this junction is called the synaptic gap or synaptic cleft.

Neurotransmitters

When an action potential reaches the knob like terminals at an axon’s end, it triggers of chemical messenger

Neurogenesis

The process by which new neurons are formed in the brain ( this happens in the hippocampus)

Central Nervous System

Brain and Spinal Cord( Interpret incoming sensory info and issue instructions based on past experiences and current conditions

Peripheral Nervous System

Somatic and Autonomic( serves as communication lines)

Somatic

Voluntary movement of skeletal muscle

Autonomic

Sympathetic and Parasympathetic

Sympathetic

fight or flight

Parasympathetic

rest and digest

Sensory Neurons

Run from sensory receptors(eyes,ears,nose,tongue,skin) TO the spinal cord + brain

Motor Neurons

Run from the brain & spinal cord to the muscles and glands of the body

They affect ( bring about) a motor response

Carries impulses to effector organs, the muscles, and glands

The cell body is always located in the CNS

Interneurons

Go between for afferent and efferent neurons

Connect the sensory and motor in the neural pathways

Cell bodies are always located in CNS

Adrenaline

Is the release in response to stress or danger. Increases heart rate and blood flow, leading to physical boost and heightened awareness.

Noradrenaline

This is released throughout the day to help you stay alert affects attention and responding actions in the brain. Contracts blood vessels, increasing blood flow.

Leptin

A hormone that allows you to feel full

Ghrelin

Hormone that allows you to feel hungry

Melatonin

A hormone in your body that plays a role in sleep

Oxytocin

As oxytocin is associated with trust, sexual arousal and relationship building

Excitatory neurotransmitters

Encourage an action potential to occur

ex: glutamate, epinephrine and norepinephrine, acetylcholine, dopamine

Inhibitory Neurotransmitters

Discourage an action potential from occurring

ex: GABA, serotonin

Dopamine

Is crucial for the reward system, motivation, pleasure, and motor control.

Serotonin

This regulates mood, happiness, sleep, appetite and learning.

GABA

Calming neurotransmitter, this calms firing nerves in the central nervous system. High Levels improve focus, low levels cause anxiety. Also contributes to motor control and vision.

Acetylcholine

Learning neurotramitter involves thought, learning and memory. Activates muscle action in the body. Also deals with attention and awakening

Glutamate

Memory neurotransmitter involved in learning and memory, regulates the development and creation of nerve contacts

Endorphins

Euphoria neurotransmitter acts like a potent painkiller and induce feelings of pleasure, well-being

Acetylcholine Malfunctions

With Alzheimer’s disease, ACh-producing neurons deteriorate.

Dopamine Malfunctions

Oversupply linked to schizophrenia. Undersupply linked to tremors and decreased mobility in Parkinson’s disease.

Serotonin Malfunctions

Undersupply linked to depression. Some antidepressant drugs raise serotonin levels.

Norepinephrine Malfunctions

Undersupply can depress mood.

GABA Malfunction

Undersupply linked to seizures, tremors and insomnia

Glutamate Malfunction

Oversupply can overstimulate the brain, producing migraines or seizures

Substance P

Though to have a role in the regulation of pain, asthma, psoriasis, and inflammatory bowel disease and in the CNS, emesis, migraine, schizophrenia, depression, and anxiety.

Agonist

Bind to a neurotransmitter receptor to produce a response

Antagonist

bind receptor to prevent a response

Psychoactive drugs

SSRIs( selective serotonin reuptake inhibitors). These are drugs that prevent the reuptake of serotonin, pushing more into the system

ex: Zoloft, Lexapro, Prozac

Stimulants

Increased neural activity

ex: caffeine, cocaine

Depressants

decreased neural activity

ex: alcohol, opiates

Hallucinogens

altered state of consciousness perception

ex: LSD, Marijuana