Day 9

4. a gap between the pre- and postsynaptic cells that is about 20 nm
8. chemical messengers that your body can't function without
9. an insulating layer, or sheath that forms around nerves, including those in the brain and spinal cord
10. a rapid sequence of changes in the voltage across a membrane
11. each of the paired lobes of the brain lying beneath the temples, including areas concerned with the understanding of speech
13. a small colorless disk-shaped cell fragment without a nucleus
16. The places where neurons connect and communicate with each other
18. a blood protein produced in response to and counteracting a specific antigen.

1. the administration of a vaccine to help the immune system develop immunity from a disease
2. the electrical potential of a neuron or other excitable cell relative to its surroundings when not stimulated or involved in passage of an impulse
3. a short branched extension of a nerve cell
5. a toxin or other foreign substance which induces an immune response in the body
6. a signal transmitted along a nerve fiber.
7. a large phagocytic cell found in stationary form in the tissues or as a mobile white blood cell, especially at sites of infection
12. a bacterium, virus, or other microorganism that can cause disease
14. a colorless cell that circulates in the blood and body fluids and is involved in counteracting foreign substances and disease
15. the state or quality of being resistant to a particular infectious disease or pathogen
17. responsible for sending and receiving neurotransmitters