THE NERVOUS SYSTEM
The nervous system also allows you to react to a stimulus. A stimulus is a change in the environment. Example: A hot stove Or… tripping over a rock
The Nervous System is divided into 2 systems: Central Nervous System and Peripheral Nervous System.
The Central Nervous System is made of the brain and the spinal cord. The Central Nervous System controls everything in the body.
Neural and Hormonal Systems Explains why we feel strong, sad, happy & nervous. Neurons are chemical messages that travel from one neuron to the next, sending information like “lift your leg” “be happy”
Neurons do NOT touch each other- the space in between is call the synapse.
Action Potential It is like a battery. There are positive and negative charges and the message is an electrical message. This change in ions is called the action potential. The firing is an all or nothing response. Like a gun.
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.
Sensory Neurons Motor Neurons Inter Neurons
Sends signals TO the CNS (Central Nervous System) For example, touching a Hot Flame would send the signal to the CNS. (red arrow)
Sends signals AWAY from the CNS. For example, if you were about to hit a soccer ball a message will come away from the CNS to tell your leg to kick.
Contained within the CNS. Does the processing in the brain.
There are 4 that we need to aware of. Acetylcholine, Dopamine, Serotonin, Endorphines
+Too much acetylcholine is associated with depression, and too little in the hippocampus has been associated with dementia -Lack of ACH has been linked to Alzheimer’s disease.
Its function is motor movement and alertness. -Lack of dopamine is associated with Parkinson’s disease. +Overabundance is associated with schizophrenia.
Function deals with mood control. -Lack of serotonin has been linked to depression.
Function deals with pain control. We become addicted to endorphin causing feelings. glassrocklife.com
NO!! Largest one is 15 feet!! About how many neurons are in the spinal cord? 1 Billion About how many neurons are in the human brain? 100 Billion
Drugs and alcohol bind important receptors on neurons
Agonists and Antagonists
Divisions of the Nervous System
A system of glands that secrete hormones. Similar to nervous system, except hormones work a lot slower than neurotransmitters. Neurotransmitters fast slow exerts control by releasing special chemical substances into the blood called hormones
Consists of several glands located in various parts of the body. Pituitary gland: a small gland located on a stalk hanging from the base of the brain - AKA “The Master Gland” Produces many hormones. Secretion is controlled by the hypothalamus in the base of the brain.
The Major Endocrine Glands