Neural and Hormonal Systems Will Explain Why We FEEL…… Nervous Strong Sick Pain

It all Starts with the Neuron https://www. youtube. com/watch

Neuron Structure Neurons do NOT touch each other- the space in between is call the synapse.

Types of Neurons Sensory Neurons Motor Neurons Inter Neurons

Sensory Neurons (Afferent Neurons) Take information from the senses to the brain.

Inter Neurons Take messages from Sensory Neurons to other parts of the brain or to Motor Neurons.

Motor Neurons (Efferent Neurons) Take information from brain to the rest of the body.

How a Neuron Fires It is an electrochemical process Electrical inside the neuron Chemical outside the neuron (in the synapse in the form of a neurotransmitter). The firing is call Action Potential.

The All-or None Response The idea that either the neuron fires or it does not- no part way firing. Like a gun or toilet

Steps of Action potential- Brief electrical charge passing down the axon Dendrites receive neurotransmitter from another neuron across the synapse. Reached its threshold- then fires based on the all-or-none response. Opens up a portal in axon, and lets in positive ions (Sodium) which mix with negative ions (Potassium) that is already inside the axon (thus Neurons at rest have a slightly negative charge). The mixing of + and – ions causes an electrical charge that opens up the next portal (letting in more K) while closing the original portal. Process continues down axon to the axon terminal. Terminal buttons turns electrical charge into chemical (neurotransmitter) and shoots message to next neuron across the synapse.

Simple yet Complex A vast majority of the nervous system multiple neurons connect with each other Creates a complex network cable of almost endless combinations of neurons communicating with each other

How Neurons Communicate

Neurotransmitters Chemical messengers released by terminal buttons through the synapse. We should know at least 4 types and what they do and others as well.

Acetylcholine Its function is motor movement and memory and learning. Too much and you will…. Not enough and you will…. Lack of ACH has been linked to Alzheimer’s disease.

Dopamine Lack of dopamine is associated with Parkinson’s disease. Its function is motor movement , alertness, learning, emotion. Lack of dopamine is associated with Parkinson’s disease. Overabundance is associated with schizophrenia.

Serotonin Function deals with mood control, hunger, sleep and arousal. Lack of serotonin has been linked to depression.

Endorphins Function deals with pain control. We become addicted to endorphin causing feelings.

Agonists and Antagonists

Agonists/ Antagonists Similar enough to a neurotransmitter that it can bind to its receptors Mimics the effect Some opiates are agonists mimic the effect and produces or magnified a pleasing effect dopamine = cocaine, serotonin = LSD or ecstasy Bind to receptors but they block neurotransmitters Botulin found in poorly canned meat block Ach release- lots of vomiting etc Botox paralyzes muscles

Divisions of the Nervous System

Nervous system Neurons building blocks of the nervous system PNS info travels through axons that are bundled into electrical cables we call nerves Info travels to the brain via sensory, motor and interneurons

Sympathetic Nervous System (think stress) Flight or Fight Response

Parasympathetic Think peaceful Slows down heart rate and breathing

Central Nervous System (CN) Spinal cord is the info highway. Connects the PNS to the brain Sensory info travels toward the brain and motor neurons send back info Reflexes consists of a single sensory neuron and a single motor neuron

A Simple Reflex

A Simplified Neural Network Neurons that learn to work together as a team.

The Endocrine System A system of glands that secrete hormones. Similar to nervous system, except hormones work a lot slower than neurotransmitters. Hormones Neurotransmitters

Endocrine and nervous system are close: both produce molecules that act as receptors elsewhere Nervous system = email Endocrine = postal

The Major Endocrine Glands

Types of glands Pituitary= growth Most influential controlled by hypothalamus Also triggers sex glands to release sex hormones Adrenal release epinephrine's and norepinephrine (called Adrenaline and noradrenaline Increase heart rate etc. Flight or fight

Brain as conductor Nervous system directs the endocrine secretions, which affects the nervous system The brain conducts the whole thing