Across
- 2. the ability to resist or recover from an infectious disease
- 5. the organ that is the main control center of the nervous system
- 6. the many tiny, thin-walled, capillary-rich sacs in the lungs where the exchange of oxygen and carbon dioxide takes place
- 7. a group of cells that make chemicals for use everywhere else in the body
- 8. a tough connective tissue that attracts a muscle to a bone or to another body part
- 9. the maintenance of a constant internal state in a changing environment
- 12. a protein made by B cells that binds a specific antigen
- 13. a type of protein that speeds up metabolic reactions in plants and animals without being permanently changed or destroyed
- 14. small, bean shaped masses of the tissue that remove pathogens and dead cells from the lymph
- 19. a nerve cell that is specialized to receive and conduct electrical impulses
- 20. a substance that is made in one cell or tissue and causes a change in another cell or tissue in another part of the body
- 21. an elongated extension of a neuron that carries impulses away from the cell body
Down
- 1. a type of tissue that holds bones together in a joint
- 3. the two main branches of the trachea that lead directly to the lungs
- 4. tiny infectious particles that cause disease
- 10. a column of nervous tissue running from the base of the brain through the vertebral column
- 11. branchlike extensions of a neuron that receives impulses from neighbor neurons
- 15. a microorganism, a virus, or a protein that causes disease
- 16. the unit in the kidney that filters blood
- 17. the clear, watery fluid that leaks from blood vessels and contains white blood cells
- 18. a place where two or more bones meet