Chapter 14: Response to Stimuli Flashcards
Events of an immune response
Stimulus -> Receptor -> Coordinator -> Effector -> Response
Define taxes
Response direction is determined by the direction of the stimulus
Types of taxes
Chemotaxis- chemically generated taxis
Phototaxis- light sensitive taxis
Geotaxis- taxis in response to gravity
(Rheotaxis- taxis in response to movement: OFF SPEC!)
What type of taxis will single-celled algae show if they move towards the light?
Positive phototaxis. They are photosynthetic so need light to manufacture their food.
What type of taxis will earthworms who move away from the light show?
Negative phototaxis. They can go into the soil where they can conserve water and find food.
What type of taxis will bacteria who move towards a region of higher glucose concentration show?
Positive chemotaxis. They use the glucose as a food source.
Define kinesis
Animal responds to stimulus but it is not directional (almost random).
What happens if the stimulus is unpleasant in a kinetic response?
The animal moves faster and changes direction more frequently.
Why is kinesis beneficial for organisms?
It aids survival as they are more likely to find favourable conditions.
What happens if a woodlouse does not return to a favourable environment for a long time?
It will reduce its number of turns to travel in a long, straight line to increase their chances of moving through the dry area into a new damp one.
What is the nervous system divided into?
Peripheral Nervous System and Central Nervous System
What is the peripheral nervous system made up of?
Pairs of nerves that originate either from the brain or the spinal cord
What is the central nervous system made up of?
Brain and spinal cord
What is the peripheral nervous system divided into?
Sensory neurones and motor neurones
What is the role of sensory neurones?
To carry nerve impulses from receptors towards the CNS
