Definitions (Stimulation and Reaction)
STIMULATION AND REACTION
Stimulus: A change
in the environment that can induce a plant or animal to react or respond is
known as stimulus.
Response: The reaction of a plant or animals to the
stimulus is called reaction.
Taxis: The movement of an organism or their parts by changing
location under the influence of the stimulus such as light, chemical etc. is
called taxis.
Phototaxis: The movement of an organism in response to the
stimulus of light is called phototaxis.
Chemotaxis: The movement of an organism in response to the
stimulus of chemical is called chemotaxis.
Positive taxis: The movement of an organism towards the
stimulus is called positive taxis.
Negative Taxis: The movement of an organism away from the
stimulus of is called negative taxis.
Positive phototaxis: The movement of an
organism towards the stimulus of light is called phototaxis.
Negaive phototaxis: The movement of an organism away from the
stimulus of light is called phototaxis.
Positive chemotaxis: The movement of an organism towards the
stimulus of chemical is called chemotaxis.
Negative chemotaxis: The movement of an organism away from the stimulus
of chemical is called chemotaxis.
Negative chemotaxis: The movement of an organism away from the
stimulus of chemical is called chemotaxis.
Tropism: The movement of parts of a plant without
changing their location in response to the stimulus.
Positive tropism: The movement of parts of plant towards the
stimulus.
Negative tropism: The movement of parts of plant away from the
stimulus.
Phototropism: The movement of parts of plant in response to
the stimulus of light.
Positive Phototropism: The movement of parts of plant towards
the stimulus of light.
Negative Phototropism: The movement of parts of plant away
from the stimulus of light.
Chemotropism: The
movement of parts of plant in response to the stimulus of chemical.
Positive chemotropism: The movement of parts of plant towards
the stimulus of chemical.
Negative Chemotropism: The movement of parts of plant away from the stimulus of chemotropism.
Geotropism: The movement of parts of plant in response to
the stimulus of gravity.
Positive geotropism: The movement of parts of plant towards
the stimulus of gravity.
Negative Geotropism: The movement of parts of plant away from
the stimulus of gravity.
Hydrotropism: The movement of parts of plant in response to
the stimulus of water.
Positive Hydrotropism: The movement of parts of plant towards
the stimulus of water.
Negative hydrotropism: The movement of parts of plant away
from the stimulus of water.
Thermo tropism: The movement of parts of plant in response to
the stimulus of heat.
Positive Thermo tropism: The movement of parts of plant towards
the stimulus of heat.
Negative Thermotropism: The movement of parts of plant away
from the stimulus of heat.
Thigmotropism: The movement of parts of plants in response to
the stimulus of touch.
Nervous system: The system that receives the stimulus
transmits it to the other parts of the body which show the corresponding
effects.
Neuron: The cell that transmit the messages from one
part of the body to the other.
Axon: A long and tube like structure which arises from the cell
body.
Dendrite: They are highly branched a thin which receives
impulses mostly from the axon of another neuron.
Ganglion: The mass of nerve tissue that transmits and
sends out
Brain: A highly specialized delicate and hollow organ located
inside the skull.
Cerebrospinal fluid: Between the arachnoids and piameter, there is
a cavity called sub-arachnoids cavity which is filled with a fluid which is
called cerebrospinal fluid.
Cerebrum: it is the largest part of the human brain
consisting of two cerebral hemisphere.
Cerebellum: it is a well developed part of the brain and
lies below the cerebrum and above the medulla oblongata.
Spinal cord: The spinal cord is a long, soft and white
jellylike substance present in the neural canal of vertebral column.
Medulla oblongata: It is the lowermost part of the brain which is
located between pons-varoli and upper end of vertebral column.
Nerves: A nerve is a group of a bundle of nerve fibres (axon)
enclosed in a tubular sheath.
Sensory /Afferent nerve: The nerves that carry impulses from
sense organ to the brain or spinal cord are called sensory nerves.
Efferent nerves/ Motor nerves: The nerves that carry
impulses from brain or spinal cord to the various parts of the body are called
motor nerves.
Mixed nerves: Sometimes, axon of both sensory and motor
nerve forms the nerves which are called mixed nerve.
Cranial nerves: The nerves which originate from the brain and
carry the nerve impulses to and from the brain.
Spinal nerves: The nerves which originate from the spinal
cord and carry the nerve impulses to and from the spinal cord.
Nerve impulses: The information that passes though the neurons
in the form of chemicals and electrical signal.
Reflex action: An involuntary action performed by muscles
under the direction of the spinal cord in response to the stimulus.
Synapse: The junction points between the two neurons.
Reflex arc: The route taken by the nerve impulses from the
receptors to the effectors during the reflex action.
Glands: A group of cells that help in secretion.
Endocrine gland: The glands which do not have any duct and pour
their secretion directly into the blood.
Exocrine gland: The glands which have duct and whose secretions
are carried by the ducts to the organs.
Hormones: Hormones are the chemical substance which
controls, co-ordinate and integrate the function of various organs of the body.
Pituitary gland: It is a small oval shaped gland and size is like pea.
Impulses: A wave of electrical disturbance that swept
over the nerve cells.
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