1. Human Body

2. 2 1 4 3 5

3. Levels of Organization The levels of organization in a multicellular organism include cells, tissues, organs, and organ systems.

4. Cells Cells tend to be specialized. Specialized cells are uniquely suited to perform a particular function.

5. Tissues A group of cells that perform a single function is called a tissue. 4 types of tissues in humans: Epithelial, connective, nervous and muscle tissue.

6. Organs A group of different tissues that work together to perform a single function is an organ.

7. Organ System An organ system is a group of organs that perform closely related functions. For example, the brain is one of the organs of the nervous system.

8. Homeostasis Is the process by which organisms keep internal conditions relatively constant despite changes in external environments.

9. Feedback Inhibition Or negative feedback, is the process in which a stimulus produces a response that opposes the original stimulus.

10. The Nervous System The nervous system controls and coordinates functions throughout the body and responds to internal and external stimuli.

11. Neurons Neurons carry electrical signals called impulses throughout the nervous system.

13. Cell Body The largest part of the neuron where most of the metabolic activity of the cell takes place.

15. Dendrites Dendrites carry impulses from the environment or from other neurons toward the cell body.

18. Axon The axon is the long fiber that carries impulses away from the cell body.

20. Myelin Sheath The insulating structure that surrounds the axon. As an impulse moves, it is carried from node to node.

22. Which structure carries impulses away from the neuron? A.Dendrite B. Axon C.Myelin Sheath D.Cell Body

23. True or False: The largest structure of a neuron is the cell body

24. Which structure of the neuron carries impulses toward the neuron? A. Cell Body B. Axon C. Dendrite D. Myelin Sheath

25. The Central Nervous System The central nervous system consists of the brain and spinal cord.

27. The Brain The brain contains approximately 100 billion neurons.

28. Meninges Both the brain and spinal cord are wrapped in three layers of connective tissue known as the meninges

29. Cerebrospinal Fluid Bathes the brain and spinal cord and acts as a shock absorber that protects the nervous system.

30. The Cerebrum Largest part of the brain. Responsible for conscious activities of the brain.

31. Cerebellum The cerebellum coordinates and balances actions of the muscles so that the body can move gracefully and efficiently.

33. Brain Stem The brain stem connects the brain and the spinal cord. Blood pressure, heart rate, breathing and swallowing are controlled in the brain stem. It includes the pons and medullas oblangata.

35. Thalamus The thalamus receives messages from all of the sensory receptors throughout the body and then relays the information to the proper region of the cerebrum for further processing.

37. Hypothalamus Is the control center for recognition, and analysis of hunger, thirst, fatigue, anger and body temperature.

39. Medulla Lower part of the brain stem Controls involuntary responses such as breathing heart rate and blood pressure.

41. Pituitary Connected to the hypothalamus Secretes 9 hormones that maintain homeostasis.

42. Spinal Cord The main communication link between the brain and the rest of the body. 31 pairs branch out from the spinal cord to connect the brain to the rest of the body.

45. Corpus Callosum Splits the brain into left and right hemispheres.

46. Limbic System Controls emotion, behavior, long term memory and olfaction.