Across
- 2. Chemical messenger in the body.
- 3. Neural pathway for a reflex.
- 6. Loop of _____. Structure in the nephron that concentrates urine.
- 9. A cell that forms new bone tissue.
- 12. The process of returning useful substances to the blood.
- 13. A pigment that gives color to skin and hair.
- 14. The layer of skin beneath the epidermis.
- 17. A flexible connective tissue that cushions joints.
- 18. How energy in food is measured.
- 19. Colored part of the eye.
Down
- 1. A band of tissue that connects muscle to bone.
- 2. The maintenance of a stable internal environment.
- 4. A mixture of partially digested food and stomach secretions.
- 5. The hormone that triggers childbirth.
- 7. Macronutrients that regulate body processes.
- 8. A device that regulates the heartbeat.
- 10. Part of a neuron that receives signals.
- 11. The most important nutrient.
- 15. The muscular tissue of the heart.
- 16. A macronutrient that provides energy and insulation.