| A | B |
|---|
| Neuron | a cell that carries information through the nervous system |
| nerve impulse | The message carried by a neuron |
| dendrite | a threadlike extension of a neuron that carries nerve impulses toward the cell body. |
| Axon | A threadlike extension of a neuron that carries nerve impulses away from the cell body. |
| sensory neuron | A neuron that picks up stimuli from the internal or external environment and convert each stimulus into a nerve impulse |
| inter-neuron | A neuron that carries nerve impulses from one neuron to another |
| motor neuron | A neuron that sends an impulse to a muscle or gland, causing the muscle or gland to react |
| synapse | The junction where one neuron can transfer an impulse to the next structure. |
| Central nervous system | The division of the nervous system consisting of the brain and spinal cord |
| Peripheral nervous system | the division of the nervous system consisting of all of the nerves located outside the central nervous system. |
| Brain | The part of the central nervous system that is located in the skull and controls most function sin the body. |
| Spinal cord | The thick column of nerve tissue that links the brain to most of the nerves in the peripheral nervous system. |
| Cerebrum | The part of the brain that interprets input from the senses, controls movement, and carries out complex mental processes. |
| Cerebellum | The part of the brain that coordinates muscle action and helps maintain balance |
| Brain stem | The part of the brain that controls the involuntary actions |
| Somatic nervous system | The group of nerves in the peripheral nervous system that controls voluntary actions |
| Autonomic nervous system | The group of nerves in the peripheral nervous system that controls involuntary actions. |
| Concussion | a bruise-like injury of the brain that occurs when the soft tissue of the brain collides against the skull |
| Heart | a hollow muscular organ that pumps blood throughout the body |
| Atrium | Each of the two upper chambers of the heart that receives blood that comes into the heart |
| Ventricle | a lower chamber of the heart that pumps blood out to the lungs and body. |
| Valve | a flap of tissue in the heart or a vein that prevents blood from flowing backward. |
| Artery | A blood vessel that carries blood away from the heart |
| Capillary | A tiny blood vessel where substances are exchanged between the blood and the body cells |
| Vein | a blood vessel that carries blood back to the heart |
| Aorta | The largest artery in the body |
| coronary artery | an artery that supplies blood to the heart itself |
| pulse | the alternating expansion and relaxation of an artery wall as blood travels through an artery |
| diffusion | the process by which molecules move from an area of higher concentration to an area of lower concentration |
| blood pressure | the pressure that is exerted by the blood against the walls of blood vessels |
| plasma | the liquid part of blood |
| red blood cell | A cell in the blood that takes up oxygen in the lungs and delivers it to cells elsewhere in the body. |
| hemoglobin | an iron-containing protein that binds chemically to oxygen molecules |
| white blood cell | a blood cell that fights disease |
| platelet | a cell fragment that plays an important part in forming blood clots |
| lymphatic system | a network of vein-like vessels that returns the fluid that leaks out of blood vessels to the blood stream |
| lymph | the fluid that the lymphatic system collects and returns to the bloodstream |
| Atherosclerosis | A condition in which an artery wall thickens from a buildup of fatty materials |
| Heart attack | a condition in which blood flow to the part of the heart muscle is blocked, causing heart cell to die. |
| Hypertension | a disorder in which a person’s blood pressure is consistently higher than normal. |
| Respiration | the process by which cells break down simple food molecules to release the energy they contain. |
| Cilia | hair-like projections |
| Pharynx | the throat |
| Trachea | windpipe; a passage through which air moves in the respiratory systems |
| Bronchi | The passages that direct air into the lungs. |
| Lungs | an organ found in air-breathing vertebrates that exchanges oxygen for carbon dioxide with blood. |
| Alveoli | sacs of lung tissue specialized for the movement o f gases between air and blood. |
| Diaphragm | a large muscle located at the bottom of a mammal’s rib cage that function in breathing. |
| Larynx | The voice box |
| Vocal cords | folds of connective tissue that stretch across the opening of the larynx and produce a person’s voice |
| Tar | a dark sticky substance that forms when tobacco burns |
| Carbon monoxide | a colorless, orderless gas produced when substances including tobacco are burned |
| Nicotine | A stimulant drug in tobacco that increases a activities of the nervous system, heart, and other organs. |
| Addiction | a physical dependence on a substance |
| Bronchitis | An irritation of the breathing passages in which the small passages become narrower than normal and may be clogged with mucus. |
| Emphysema | A serious disease that destroys lung tissue and causes breathing difficulty |
| lymph node | a small knob of tissue in the lymphatic system that filters lymph, trapping bacteria and other microorganisms that cause disease. |
