Under stimulus the excitatory D-change will now be relatively feeble compared to the A-change, by which the potential energy of the system becomes increased.
I have shown elsewhere[O] that the sudden initiation or cessation of the current induces an excitatory reaction in the plant-tissue similar to that in the animal tissue.
These various forms of stimuli cause, as we have seen, a similar excitatory contraction of the motile pulvinus of Mimosa pudica.
There is a responsive reaction which is opposite to the excitatory change described above.
As regards stimulation of vegetable tissues, there are various agencies besides electric shock, which induce excitatory contraction; these agencies I shall designate as stimuli.
When the current is sent from right to the left, the excitatory impulse initiated at EE′ travels against the direction of the current in an ‘up-hill’ direction.
The excitatory down movement is followed by recovery on the cessation of light.
All these different forms of stimulus induce an excitatory contraction, a diminution of turgor, and a negative mechanical response or fall of a motile leaf.
The excitatory reaction of the upper half is by contraction, and the response is, therefore, the lifting of the petiole.
The conduction of excitation consists, on the other hand, of propagation of excitatory protoplasmic change.
Change of conductivity may be expected to give rise to a variation in the rate of propagation or to a variation in the magnitude of the excitatory impulse that is transmitted.
In a sub-tonic condition, on the other hand, strong and long continued stimulation will be necessary to induce the excitatory reaction.
It will at first encounter increasing excitatory change during its approach to the perceptive layer where the irritation will be at its maximum.
In the last chapter we studied the electric response of the shoot to the stimulus of gravity, and found that the excitatory effect of that stimulus is similar to that of other forms of stimulation.
The Method of Torsional Balance enables us to compare the excitatory efficiencies of two different stimuli which act simultaneously on the two flanks of the organ.
Hence excitatory geotropic effect is not likely to vary strictly as in sine of angle of inclination.
The observed geotropic concavity of the upper side of a horizontally laid shoot may be due to excitatory contraction of that side, or it may result from passive yielding to the active responsive expansion of the lower side.
A is above and B below; this induces a differential geotropic effect, the upper side exhibiting excitatory electric change of galvanometric negativity.
A stimulus which is just sufficient to evokeexcitatory contraction is termed the minimal, stimulus below the threshold being tacitly regarded as ineffective.
Though rise of temperature enhances excitability up to an optimum, there is an antagonistic reaction induced by it which opposes the excitatory contraction.
The stimulus of gravity is shown to induce an excitatory reaction which is similar to that induced by other forms of stimulation.
The upper side of a horizontally laid shoot is found to undergo an excitatory change of galvanometric negativity.
When theexcitatory impulses are also lost, as in a total transverse lesion of the cord, the paralysed muscles are flaccid and the deep reflexes disappear.
The pyramidal tract conveys impulses that inhibit muscle tonus, while the rubro-spinal tract is the path by which excitatory impulses travel.
That it is thrown into an excitatory state, and that it conducts the excitatory disturbance, is shown however by the contraction produced in an attached piece of muscle, which serves as an indicator.
A by tapping or vibration is prevented from reaching B, we shall then have A thrown into a relatively greater excitatory condition than B.
As the excitatory state disappears with the return of the excitable tissue to its original condition, the current of action will gradually disappear.
A living substance may thus be put into anexcitatory state by either mechanical, chemical, thermal, electrical, or light stimulus.
It has already been said that if two points A and B are in the same physico-chemical condition, then a given stimulus will give rise to similar excitatory electric effects at the two points.
When a plant is stimulated at any point, a molecular disturbance--the excitatory wave--is propagated outwards from the point of its initiation.
The excitatory state evoked by stimulus manifests itself in nerve fibres by E.
But the excitatoryeffect produced in the nerve by stimulus can also be detected by an electrical method.
The excitatory state then disappears, and the muscle is seen to relax into its normal form.
We have thus experimentally verified the assumption that in the same tissue an uninjured portion will be thrown into a greater excitatory state than an injured, by the action of the same stimulus.
Bose detected the various excitatory effects of plants by means of mechanical response.
Bose found, in the plant as well as in the animal, "a similar series of excitatory effects, whether these be exhibited mechanically or electrically.
He found that all sorts of stimulus produce an excitatory change in them.
They dogmatically asserted as physiologists that the excitatory response of ordinary plants to mechanical stimulus was an impossibility.
The impress made by the action of stimulus, though it remains latent and invisible, can be revived by the impact of a fresh excitatory impulse.
Bose demonstrated the very startling fact that not only every plant, but every organ of every plant gave true excitatory electric response--and that response was not confined alone to 'sensitive' plants like Mimosa.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "excitatory" in a variety of sentences. We hope that you will now be able to make sentences using this word.
