Term | Definition |
endocrine system | bodys system that controls growth, development, and responses to the environment by releasing chemical signals into the bloodstream |
central nervous system (CNS) | the brain and spinal cord; its main function is to control the flow of information in the body |
peripheral nervous system (PNS) | all of the parts of the nervous system except for the brain and spinal cord; includes the crainal nerves and nerves of the neck, chest, lower back and pelvis |
neuron | a nerve cell that is specialized to receive and conduct electrial impulses |
dendrite | a cytoplasmic extension of a neuron that recieves stimuli |
axon | an elongated extention of a neuron that carries impulses away from the cell body |
resting potential | difference in electrical charge between the inside and outside of a neuron; contains the potential energy needed to transmit the impulse |
sodium-potassium pump | a carrier protein that uses ATP to actively transport sodium ions out of a cell and potassium ions into the cell |
action potential | a suden change in the polarity of the membrane of a neuron, gland cell, or muscle fiber that facilitates the transmission of electrical impulses |
synapse | the junction at which the end of an axon of a neuron meets the end of a dendrite or the cell body of another neuron or meets another cell. |
terminal | end of the neuron's axon from which neurotransmitters are relased to sitimulate an adjacent cell |
neurotransmitter | a chemical substance that transmits nerve impulses across a synapse |
hormone | a substance that is made in one cell or tissue and that causes a change in another cell or tissue located in a different part of the body |
gland | organ that produces and releases chemicals that affect the activities of other tissues |
hypothalamus | the region of the brain that coordinates the activities of the nervous and endocrine systems and that controls many body activities related to homeostasis |
pituitary gland | area in the middle of the brain that makes and releases hormones that control cell growht and water levels in the blood. |
pathogen | a microorganism, another organism, a virus, or a protein that causes diesase; an infectious agent |
vector | in biology, any agent, such as a plasmid or a virus, that can incorporate foreign DNA and transfer DNA from one organism to another; an intermedaite host that transfers a pathogen or a parasite to another organism |
phagocyte (white blood cell) | cell that destroys other cells by surrounding and engulfing them |
T cell | white blood cell that matures in the thyus and destroys infected body cells by cuasing them to burst; also called a T-lympocyte |
B cell | a white blood cell that matures in bones and makes antibodies |
antibody | a protein that reacts to a specific antigen or that inactivates or destroys toxins |
interferon | type of protein, produced by body cells, that prevents viruses from replicating in infected cells. |
inflammation | a protective response of tissue affected b disease or injury; characterized by pain, swelling, redness, and heat |
antigen | protein marker that helps the immune system identify foreign particles |
humoral immunity | immune response that relies on B cells to produce antibodies to help fight infection |
cellular immunity | immune response that relies on T cells destroy infected body cells |
vaccine | a substance prepared from killed or weakened pathogens and introduced inot a body to produce immunity |
allergy | a physical response to an antigen, which can be a common substance that produces little or no response in the general population |
allergen | a substance that causes an allergic reaction |