Central Nervous System

The part of the nervous system that contains the brain and spinal cord. It relays messages received by the PNS to the brain which makes decisions on how to react.

Peripheral Nervous System

Part of the nervous systems that relays messages back and forth to the brain and spinal cord. It consists of all the nerves and ganglia outside the brain and spinal cord.

Somatic Nervous System

A division of the peripheral nervous system which controls voluntary movement of skeletal muscle. This is controlled by afferent nerves and efferent nerves. Afferent nerves send messages to the CNS and efferent nerves receive messages from the CNS and relay them to the body.

Autonomic Nervous System

The autonomic nervous system is the other division of the peripheral nervous system that controls involuntary smooth muscle movement. This system is controlled by the hypothalamus and regulates heart rate, respiratory rate, digestion, urination, and sexual arousal.

Parasympathetic

One of three divisions of the autonomic nervous system that controls aspects of life done after eating. It controls activities done while at rest and is complementary to the sympathetic nervous system

Sympathetic

Two of three divisions of the autonomic nervous system that controls the stimulation of "fight or flight" and regulates homeostasis.

Sensory Neuron

Type of neuron that receives information from outside the body, or inside the body, and relays that message to the CNS. It receives its information from the sensory receptors each nearon has. Different receptors receive different messages.

Interneuron

Type of neuron that helps sensory neurons and motor neurons relay messages to the CNS.

Motor Neuron

This type of neuron is found half in the spinal cord and half out. It relays messages from the spinal cord to muscles in the body. These neurons are responsible for reflexes and movement in response to stimuli.

Neuromuscular Junction

The place in the body where a chemical synapse occurs between a motor neuron and a muscle. This process causes muscle contraction.

Acetylcholine

A chemical released by nerve cells to send signals to other cells. Found in the brain and functions as a neurotransmitter.

Norepinephrine and epinephrine

Epinephrine is a hormone produced by the adrenal medulla. It relaxes smooth muscle in airways and decreases blood flow to nephrons in kidneys. Norepinephrine is a stress hormone produces by the adrenal medulla that increases blood pressure, heart rate, and glucose from energy stores in kidneys. Together these two hormones slow blood flow to nephrons in the kidneys. They are released during the fight / flight response.

Synapse

A junction between nerve cells. Allows the passing of electrical or chemical signals across nerve cells.

White matter

Found in the inner brain, thought to effect learning. High concentrations of myelin cause the matter to appear white. Acts as a coordinator between brain regions.

Gray matter

Found on the crust of the brain. Has more nervous cells than white matter and less myelinated axon tracts.

Cerebral cortex

The outside layer of the brain made up of gray matter. Abundant nervous cells are found in the cortex. Nearly 2/3 of the cerebral cortex is buried in the folds of the brain. Credited with having a key role in memory, attention, perception, awareness, thought, language, and conciousness.

lobes of the brain

Frontal Lobe: controls the voluntary movements of specific body parts. Contains the dopamine systems

Parietal Lobe: the main sensory area for the sense of touch. Controls language processing.

Occipital Lobe: visual processesing center.

Temporal Lobe: processing sensory input for the appropriate retention of visual memories, language comprehension, and emotion association

Insular Cortex: conciousness, emotion, homeostasis, psychopathology.

Limbic system

Section of the brain that controls emotion, long term memeory and is credited with the storing and creation of memories.