2j - Coordination and response Flashcards
What is the function of a receptor?
Detecting stimuli
What is the function of ‘homeostasis’?
Maintaining a constant internal environment
What is the function of the coordination centre?
Receives and processes the information from receptors
What is the function of the effector cells?
Brings the required response
What is a stimuli?
A change in the internal or external environement
What is a positive tropism?
The movement or growth towards a stimulus
What is a negative tropism?
The movement or growth towards away from a stimulus
What is the name of the tropism involving light as the stimuli?
phototropism
What is the name of the tropism involving gravity as the stimuli?
geotropic
The roots of a plant are : (tropisms)
positively geotropic negative phototropic (grow away from light)
The shoots of a plant are : (tropisms)
positively phototropic negatively geotropic (grow towards light)
Where is auxin made?
In the tips of growing stems and roots
If light shines on the shoot, where does the auxin move to?
It concentrates and moves to the shaded side
What causes the plant to grow towards light?
The uneven growth on either side of the shoot
What happens if the tip of a seedling is removed?
No auxin is produced, and therefore the plant wont grow anymore
What happens if no light reaches the tip of the shoot?
The shoot will grow evenly (upwards) as the concentration of auxin is the same on either side of the shoot
What is the name given to gaps along neurones?
Synapses
What is the chemical messenger called which releases from the nerve-ending of the neuron?
Neurotransmitter
What do synapses ensure?
That impulses only travel in one direction
What cells convert a stimulus into an electrical impulse?
Receptor cells
What does a sensory neurone do?
It sends an impulse along to the CNS
What happens after an impulse has been sent to the CNS?
An electrical impulse is sent along motor neurons to effectors which carry out the response
What is the function of an effector neurone?
Carry out the response (eg. contract muscle)
What happens to the eye when focusing on a close object?
1) Ciliary muscles contract 2) Suspensory ligaments loosen 3) Lens becomes fatter and more refraction occurs
What happens to the eye when focusing on a distant object?
1) Ciliary muscles contract 2) Suspensory ligaments tighten 3) Lens becomes thinner and less refraction occurs
What happens to the eye in dim light?
1) Radial muscles contract
2) Circular muscles relax
3) Pupil dilutes and lets in more light
What happens to the eye in bright light?
1) Radial muscles contract
2) Circular muscles contract
3) Pupil constricts and lets in less light
Name the structure circled in the diagram:
Ciliary muscle
- Involved in changing the shape of the lens
Name the structure circled in the diagram:
Cornea
- Refracts light rays
Name the structure circled in the diagram:
Fovea
- Area of retina that provides clearest vision
Name the structure circled in the diagram:
Iris
- Regulates amount of light entering pupil
Name the structure circled in the diagram:
Lens
- Focuses light on the retina
Name the structure circled in the diagram:
Optic nerve
- Carries impulses from eye to brain
Name the structure circled in the diagram:
Pupil
- Hole allowing light to enter
Name the structure circled in the diagram:
Retina
- Contains the light receptors
Name the structure circled in the diagram:
Suspensory ligaments
- Hold lens in place and involved in changing shape of lens
