Responding and Controlling - 92%

Stimulus Anything that activates a sensory neuron or causes a response

Receptor Produces signals (electrical/chemical)

Effector An organ (a gland or muscle) that becomes active in response to stimuli.

Response Change in activity of a living organism

Neuron A nerve cell that can transmit an electrical impulse.

Sensory neuron A neuron that carries messages from the body to the central nervous system.

Relay/Accosiation/Interneurons Connects sensory and motor neurons within the brain and spinal cord.

Motor neurons A neuron that carries messages from the brain or spinal cord to effector organs (muscles or glands)

Dendrite A thread-like extension to a nerve cell that relays electric impulses to the cell body.

Cell body The part of the nerve cell containing the nucleus.

Axon Long fiber that carries nerve impulses away from the cell body to another cell body.

Schwann cell A cell that wraps around a nerve fibre

forming the myelin sheath.

Myelin sheath A white

fatty sheath made up of Schwann cells that surrounds some nerve fibres and speeds up the passage of nerve impulses.

Node of Ranvier a gap in the myelin sheath of a nerve

between adjacent Schwann cells.

Axon terminal The structure at the end of an exon that produces neurotransmitters.

Nerve impulse The electrochemical message that travels along the membranes of a nerve cell.

Reflex a rapid

automatic response to a stimulus

Neurotransmitters Chemicals that transmit information from one neuron to another.

Synapse A junction where information is transmitted from one neuron to the next.

Synaptic cleft The gap between two neurons that provides space for chemical transmission of messages from the nervous system.

effect of drugs on neurotransmitters

Frontal lobe Controls memory storage

language

Parietal lobe Receives and interprets information from sensory organs (especially the skin.)

Occipital lobe The sight centre where visual information is received and processed.

Temporal lobe Processes auditory information and plays a key role in speech and language.

Cerebellum Controls posture

balance and coordination.

Brain stem Manages basic functions for survival that require no conscious thought such as breathing.

Pathogen An organism that causes disease

First Line of defence The body has barriers that prevent pathogens from entering the body in the first place. These barriers act to trap and kill most pathogens and include the surfaces of the skin

breathing passages (cilia and mucus linings)

Second line of defence In the inflammatory response

fluid and white blood cells leak from blood vessels into nearby infected tissues. The phagocytes then destroy the pathogens by breaking them down. During this response

Phagocytes White blood cells involved in the inflammatory response and engulfs then destroys pathogens.

Third line of defense Known as the immune response. The immune system cells (lymphocytes) react to each kind of pathogen with a defence targeted specifically at that pathogen. (Specific)

T-cell Identify pathogens by their antigens (molecules on the surface of a pathogen).

B-cell Produce chemicals called antibodies. Antibodies bind to antigens

inactivate the pathogens

Macrophages A type of white blood cell that surrounds and kills microorganisms. In 2nd

it seaches for pathogens