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Term | Definition |
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Specialized cell | Cell that is uniquely suited to performing a particular function |
Epithelial tissue | Includes glands and tissues that cover interior and exterior body surfaces |
Connective tissue | Tissue that provides support for the body and connects its parts |
Nervous tissue | Tissue that transmits nerve impulses throughout the body |
Muscle tissue | Tissue that enables the body to move |
Homeostasis | The process by which organisms keep internal conditions relatively constant despite changes in external environments and is maintained by feedback loops |
Feedback inhibition | The process by which a stimulus produces a response that opposes the original stimulus |
Neuron | Cells that transmit impulses |
Cell body | The largest part of a typical neuron |
Dendrite | Short, branched extensions that carry impulses from the environment or from other neurons toward the cell body |
Axon | The long fiber that carries impulses away from the cell body |
Myelin sheath | Insulating membrane surrounding the axon in some neurons |
Resting potential | The electrical charge across the cell membrane of a neuron in its resting state |
Action potential | The reversal of charges, from negative to positive; nerve impulse |
Threshold | The minimum level of a stimulus that is required to activate a neuron |
Synapse | The location at which a neuron can transfer an impulse to another cell |
Neurotransmitters | Chemicals used by a neuron to transmit an impulse across a synapse to another cell |
Meninges | Three layers of connective tissue in which the brain and spinal cord are wrapped |
Cerebrospinal fluid | Fluid that bathes the brain and spinal cord and acts as a shock absorber that protects the central nervous system |
Cerebrum | The largest and most prominent region of the human brain |
Cerebellum | The second largest region of the brain |
Brain stem | Connects the brain and spinal cord |
Thalamus | Receives messages from all of the sensory receptors throughout the body and then relays the information to the proper region of the cerebrum |
Hypothalamus | The control center for recognition and analysis of hunger, thirst, fatigue, anger, and body temperature |
Reflex | A quick, automatic response to a stimulus |
Reflex Arc | The pathway that an impulse travels from your foot back to your leg |
Hormone | Chemicals release in one part of the body that travel through the bloodstream and affect the activities of cells in other parts of the body |
Target cell | Cells that have receptors for a particular hormone |
Exocrine gland | Glands that release their secretions, through tubelike structures called ducts, directly to the organs that use them |
Endocrine gland | Glands that release their secretions (hormones) directly into the bloodstream |
Prostaglandin | Hormonelike fatty acid produced by a wide range of cells; generally affects only nearby cells and tissues |
Disease | Any change that disrupts the normal functions of the body |
Pathogen | Disease-causing agent |
Germ theory of disease | Idea that infectious diseases are caused by microorganisms, or germs |
Koch's postulates | Rules that are used to identify the microorganism that causes a specific disease |
Vector | Animals that carry pathogens from person to person |
Antibiotic | Compounds that kill bacteria without harming the cells of the human or animal hosts |
Immunity | Ability of the body to resist a specific pathogen |
Inflammatory response | A nonspecific defense reaction to tissue damage caused by injury or infection |
Fever | Elevated body temperature |
Interferon | Proteins that help other cells resist viral infections |
Immune response | The body's specific defenses that attack a disease-causing agent |
Antigen | Substance that triggers an immune response |
Humoral immunity | Immunity against antigens and pathogens in the body fluids |
Cell-mediated immunity | Immunity against abnormal cells and pathogens inside living cells |
Antibodies | Proteins that recognize and bind to antigens |
Active immunity | The type of immunity produced by the body's reaction to a vaccine |
Passive immunity | Short-term immunity caused when antibodies produced by other animals for a pathogen are injected into the body |
Allergy | The most common overreactions of the immune system to antigens |
Histamine | Chemicals that the activated mast cells realease |
Asthma |