Nervous System

Root Words

Neurons Units of nervous system that transmits information in the form of electrochemical changes

Dendrites: Receive electrochemical signals

Axons: Extensions that send information

Dendrites: Receive electrochemical signals Axons: Extensions that send information Synapse: The junction between two communicating neurons

Dendrites: Receive electrochemical signals Axons: Extensions that send information Synapse: The junction between two communicating neurons Myelin Sheaths: Fatty coating around Axon that insulates and increases rate of transition

Central Nervous System (CNS)

Consisting of Brain and Spinal cord

Peripheral Nervous System (PNS)

Consists of peripheral nerves that sends message back to CNS

Peripheral Nervous System (PNS) Consists of peripheral nerves that sends message back to CNS 2 parts: SomaticAutonomic

Somatic Nervous System Part of the PNS that is responsible for nearly all voluntary muscle movement

Somatic Nervous System Part of the PNS that is responsible for nearly all voluntary muscle movement Exception: Reflexes

Autonomic Nervous System Part of the PNS that regulates the functions of internal organs such as the heart, stomach and intestines.

Autonomic Nervous System Part of the PNS that regulates the functions of internal organs such as the heart, stomach and intestines. 2 parts: Sympathetic Nervous System Parasympathetic Nervous System

Sympathetic Nervous System Part of the Autonomic system that is responsible for “Fight or Flight” Works by increasing heart rate and blood pressure, and slows down unnecessary systems Often animals will soil themselves when fighting or scared Often animals will soil themselves when fighting or scared

Parasympathetic Nervous System Part of the Autonomic System that is responsible for “Rest and Digest” Lowers blood pressure, heart rate and works to save energy

Multipolar Neurons Contains many processes (dendrites) and only one axon. Found mostly in the brain and spinal cord

Bipolar Neurons Contains only two processes, one axon, one dendrite Found in eyes, nose, ears

Unipolar Neurons Contains only one process. Located just outside the brain or spinal cord.

Brain Teaser A H I M N O T U V W Which of the letters above does not belong with the rest? N It is not a mirror-image of itself

Resting Potential When a nerve cell is undisturbed, the membrane remains in a polarized state (Always negative inside)

Threshold Potential Approximately -55 millivolts, a level, when reached, will result in an action potential, sending a neural signal.

Action Potential Sodium ions (NA +) and Potassium ions (K+) diffuse in and out of the neuron, creating a rapid sequence of depolarization and repolarization.

Anatomy of the Brain Cerebrum : largest part of human brain - Responsible for: - Responsible for: - Thought - Thought - Language - Language - Senses - Senses - Memory - Memory - Voluntary movement - Voluntary movement

Anatomy of the Brain Cerebellum : at base of brain -Responsible for: - Muscle coordination - Muscle coordination - Balance - Balance - Posture - Posture

Anatomy of the Brain Brain Stem : connects brain to spinal cord -Responsible for: - Breathing - Breathing - Swallowing - Swallowing - Heartbeat - Heartbeat - Blood pressure - Blood pressure

Brain Teaser There is a town where 5% of all the people living there have unlisted phone numbers. If you selected 100 names at random from the town’s phone directory, on average, how many of these people would have unlisted phone numbers? 0 They would not be in the phone book if their number was unlisted

Problems of the Nervous System Concussion A temporary disturbance of the brain’s ability to function due to a hard blow to the head

Paralysis A loss of sensation and movement of part of the body due to an injury of the spinal cord or brain

Parkinson’s Disease The brain does not produce enough of the neurotransmitter that transmits messages from the brain to the muscles Symptoms: tremors, rigid muscles, shuffling walk, and loss of facial expression Red areas show where chemical is stored

Alzheimer’s Disease A gradual shrinking of the neurons in the cerebrum Symptoms: memory loss, emotional disturbances, inability to function on own, death

Epilepsy Abnormal transmission of messages between the neurons in the brain Symptoms: seizures