Question | Answer |
Axon | Fiber than carries a nervous impulse along a nerve cell away from the cell body. |
Cell body | Part of the nerve cell containing the nucleus. |
Dendrites | Branching structures that receive the nervous impulse. |
Myelin sheath | Fatty tissue around the axon of a nerve cell. Helps to protect and insulate the axon. The sheath is lobed, creating gaps between layers of myelin along the axon. These gaps are called nodes of Ranvier. |
Synapse | Space between neurons in which the nervous impulse passes. |
Terminal end fibers | Distal portion of the neuron where the impulse leaves the cell. |
Acetylcholine | Neurotransmitter that causes muscles to contract and aids in “dream” sleep. |
Dopamine | Neurotransmitter that inhibits the firing of nerve cells which in turn relaxes the animal. |
Endorphins | Neurotransmitters responsible for reducing pain and for pleasure. Endorphins are the body’s natural morphine. |
Epinephrine | Hormone that acts as a neurotransmitter to increase heart rate and blood pressure. |
Norepinephrine | Neurotransmitter that causes vasoconstriction, increased heart rate, and increased blood pressure. Also called noradrenaline. |
Serotonin | Neurotransmitter responsible for relaxation. When levels are decreased, it leads to stress and behavioral disorders. |
Microglial cells | Phagocytic cells which protect the nervous system from infection. |
Oligodendroglial cells | Cells that form the myelin around the axon of the nerve cell. |
Ependymal cells | Cells that line the ventricles of the brain and surround the spinal cord. They produce cerebrospinal fluid that circulates around the brain and spinal cord. |
Schwann cells | Dual-action cells that form myelin around the axon and act as phagocytes against foreign organisms. |
Dura mater | Tough, outermost layer of the meninges. Blood can enter brain tissue through this layer. |
Arachnoid membrane | Middle layer of the meninges. Also known as the arachnoid mater. |
Pia mater | Innermost, delicate layer of the meninges which adheres to the brain and spinal cord. |
Epidural space | Space above the dura mater. |
Subdural space | Space below the dura mater. |
Subarachnoid space | Space below the subarachnoid membrane, where cerebrospinal fluid can be found. |
Autonomic nervous system (ANS) | Nerves that control involuntary functions of muscles, glands, and viscera. |