Sensitivity and Coordination Flashcards
What are responses in plants called?
Tropisms
What is a stimuli?
Changes in the external or internal environment e.g. Light waves, pressure or internal stimuli.
What is a kinesis?
A type of simple behavioural response, a random movement not in any particular direction.
What are the types of kinesis?
Orthokinesis - a change in speed e.g. Getting faster in response to a stimulus.
Klinokinesis - change in rate of turning in response to a stimulus.
What is a taxis?
A movement in response to the direction of a stimulus.
How does a reflex arc work?
Sensory neurones carry info from sensory receptors to CNS.
Interneurones (or relay neurones) in the CNS carry info between sensory neurones and motor neurones.
Motor neurones carry info to effector organs.
What are fixed action patterns (FAP’s) ?
They are brought about by specific stimuli called sign stimuli e.g. nest building, courtship dances etc…
What are the two main divisions of the autonomic nervous system, what do they do?
The sympathetic nervous system – Speeds up activities and thus allows us to cope with stressful situations (fight or flight response).
The parasympathetic nervous system – Inhibits effects and slows down activities. This allows energy to be conserved. Controls under normal resting conditions
What light intensity do rod cells work at best, why?
Low light intensity as many rods are connected to one neurone so they can combine to reach a threshold.
What is the visual acuity of rod cells like, why?
Bad because many rods connect to one neurone so the brain cannot tell the difference between two points close together.
What pigment do rod cells break down?
What pigment do cone cells break down?
Rod cells - rhodopsin
Cone cells - iodopsin
What is IAA, what does it do?
Indoleacetic acid, causes plant cells to elongate.
What does the somatic nervous system do?
Controls conscious activities.
What makes up the CNS?
The brain and spinal cord.
What makes up the peripheral nervous system?
The neurones that connect the CNS to the rest of the body.
What is a chemical mediator?
A chemical messenger that acts locally (i.e on nearby cells).
What is the role of auxins in the control of phototropism?
Auxin is redistributed to the shaded side of the plant. In shoots auxin stimulates cell elongation. So the shoots bend and grow towards the light. In roots high concentrations of auxin inhibit cell elongation. So roots bend to grow away from the light.
What is an effector?
Cells that effect a response. In humans they are muscles and glands.
What do receptor cells do?
Detect stimuli. Receptor cells are often part of sense organs.
What type of receptor is a pacinian corpuscle?
A mechanoreceptor (responds to pressure/ movement).
What is the black pigmented layer that lies behind the retina of the human eye? What does it do?
The choroid layer. Provides retinal cells with nutrients and oxygen.
Where is the SAN located in the heart?
In the wall of the right atrium.
What are plant growth factors?
Are chemicals that regulate various aspects of plant growth and development. The equivalent of hormones in animals.
What is the process by which IAA moves from the growing regions of a plat shoot to other tissues.
Diffusion.
