1.
axon: long fiber that carries electrical impulses away from the nerve cell body
2.
biosphere: part of Earth that living organisms inhabit
3.
cell: basic unit of life
4.
chemical reaction: process that changes one set of chemicals into another set of chemicals
5.
circulatory system: body system consisting of the heart and blood vessels that circulate blood through the body
6.
community: populations of different organisms living in a defined area
7.
dendrites: part of a neuron that carries the electrical impulse to the cell body
8.
DNA: double stranded nucleic acid that stores and transmits genetic information
9.
ecosystem: all the organisms in a particular location, including their non-living environment
10.
endocrine system: collection of glands that secrete hormones into the blood which regulate growth, development, and homeostasis
11.
evolution: change over time; process by which modern organisms descended from ancient organisms
12.
excretion: elimination of wastes from the body (urine, carbon dioxide, sweat)
13.
gland: an organ that secretes hormones into the bloodstream
14.
glucose: simple sugar that is used to make ATP through cellular respiration
15.
homeostasis: the process by which organisms keep their internal environment relatively stable
16.
hormone: chemical messengers secreted by glands into the blood
17.
hypothesis: a proposed answer to a scientific problem; an educated guess
18.
insulin: protein hormone that helps to decrease blood sugar
19.
kidneys: organs that filter nitrogen wastes from blood to make urine
20.
liver: organ that makes bile to break down fats; also filters poisons and drugs out of the blood
21.
metabolism: all of the chemical reactions that build or break down materials within an organism
22.
motor neurons: neurons that carry outgoing information from the central nervous system to the muscles and glands
23.
negative feedback loop: an opposite action to what is occurring in the body to regain homeostasis, ex. if body temperature rises too high, body tries to lower it
24.
nerve: bundle of neurons surrounded by connective tissue
25.
nervous system: consists of brain, spinal cord, and nerves and regulates the body's responses to internal and external stimuli
26.
neuron: nerve cell; conducts electrical signals
27.
neurotransmitter: chemical messenger sent across a synapse which allows two neurons to communicate
28.
nutrient: chemical that an organism needs to live
29.
population: members of a species in a defined area
30.
sensory neurons: neurons that carry sensory information from receptors to the central nervous system
31.
species: two organisms that are so similar they can interbreed in nature and produce fertile offspring
32.
spinal cord: cord of nerve tissue that conducts messages between the brain and the peripheral nerves
33.
synapse: where two adjacent neurons meet
34.
theory: well-tested, well-supported explanation that unifies a broad range of observations
